q:
I am slicing with Cura and Slic3r and one important thing that I recently took my attention is that cura positions head in start point of the new layer and then lifts the nozzle. That caused my few printouts to fall as they collided with the nozzle.

Slic3r behavior is different: it raises the nozzle in last printed point and then moves to a new layer starting point (which for me is more obvious)

Is there a way to instruct Cura to lift nozzle before it goes to the starting point of a new layer? excluding Z-hops.

[A]
To lift the head to prevent the nozzle to tip over your print you could use an option called
```
Z hop
```
in Cura. Just enter `hop' in the search box on the right side to make those options magically appear (in a recent version of Cura, e.g. version 3.x.x).
Other than
```
Z hop
```
there is no default action, or series of commands, per layer to be specified before the start of the layer. There are 2 other ways to circumvent this:
The first is saving you G-code to file and open the file in an advanced text editor (e.g. Notepad++). With a (recorded) macro you can find the words
```
;LAYER:
```
, which are inserted by Cura before each layer starts, and insert a pre-copied list of commands that set the movement in relative mode, move Z up 2 mm, set into absolute mode again. When the next layer starts the extruder goes to the layer start from a 2 mm rise.
Write a plugin for Cura to post-process (
```
C:\Program Files\Ultimaker Cura x.x\plugins\PostProcessingPlugin\scripts
```
) the G-code file to inject the code to Z hop before the start of every layer, or a plugin that adds a new option and/or category to the slicer settings sidebar of the GUI.


q:
I am getting a 24 V based Ender 3. From the factory, it has an aluminium bed. So I also put this LJ12 A3-4-Z/BX Inductive NPN NO 4 mm with 6-36 V operation current into the box together with a few other spare parts. Now, as I read up on these things something dawns on me: The normal input and output voltage of a simple switch is 5 V, as sensors are ran on 5 V on most boards (and in digital logics). The sensors run on 6 V plus though.

I do not want to fry my machine by putting in 24 V into the sensor input: What do I have to do (besides making a mount)?

[A]
The inductive sensors work better when you apply a higher voltage than 5 V. Usually they are rated for 6-36 V, but please do check.
To prevent frying your board when connecting the sensor to (12 or) 24 Volts you could optically isolate the 5 V and the (12 or) 24 V circuit with an OptoCoupler module:
Image of an optocoupler module
This module uses an optical switch based on the output of the sensor and should be correctly connected:
Image of connecting an optocoupler module to the sensor and to the board
Please note that the image uses a capacitive sensor rather than a inductive sensor, both are connected similarly
Note that there are many sorts of sensors, a few are listed
here
. Generally speaking, the larger the diameter of the sensor, the larger the detection distance to the bed. Note that these work well with metal beds (Iron/steel better than Aluminium), but will not work for glass (capacitive sensors work on glass but are prone to drift by moisture in the air, a touch sensor may then be a better alternative).

s: huggingface

c: devops

d: intermediate


q:
When I print large prints close to (but not exceeding) the maximum dimensions of the heated build platform on my Anet A8, the brim or skirt or the print itself is printed outside the heated bed, while there is some space left at the opposite sites. It appears as if the print is not in the center.

Why is the print not centered on the bed?
It was centered in the slicer before generating the G-code.

How can I center the print to make it fit on the heated build platform?

[A]
When centered in the slicer correctly, without offsets defined in the slicer, the printer is most probably incorrectly configured! Luckily you can do something about that! Basically, you will have to calibrate the printer for a new center.
Printer origin?
First of all, the firmware determines where your origin of the printer is. This implies that you need to properly set bed dimensions and offset values from the end stop switches in the firmware (usually not necessary out-of-the-box, but important when a newer or different firmware version is uploaded). These offsets determine where the origin of the bed plate is located. For Marlin firmware it is very common (for most printers) to have the origin specified at the front left corner (when facing the printer). From the
configuration of Marlin
we find the origin is e.g. in the front-left corner. Note that this can be rotated 180 degrees in certain printers, so the aft-right. Also be aware that there are a few printers that have the origin in the center, e.g. Delta's and a few Cartesian printers. Marlin definition (edited snippet) of a common bed layout:
```
*      +-- BACK ---+
 *      |           |
 *    L |    (+)    | R
 *    E |           | I
 *    F | (-) N (+) | G
 *    T |           | H
 *      |    (-)    | T
 *      |           |
 *      O-- FRONT --+
 *    (0,0)
 * .(-Xh, -Yh)
```
How do I find the physical origin of the printer?
This can be tested by instructing the head/nozzle to go to e.g. (0, 0, 15) using a
terminal/console
or a simple G-code file with a move to that coordinate that you print from SD card (e.g.
```
G1 X0 Y0 Z15 F500
```
);
note a Z of 15 is chosen for safety!
. When this is performed, the nozzle should be at the (elevated, so X, Y) origin as defined by your firmware. Usually this is at the left front corner of your build plate (there may be clips there, so therefore the elevated value), but this may be different depending on the firmware settings or firmware brand.
Next step is to configure the slicer as such that this coincides with the actual origin. Incorrect slicer settings can cause the slicer to assume the origin is at a different position than your actual position. In Ultimaker Cura, the "Origin at center" is notoriously known for this when the physical origin is not in the center, but in a corner. When the slicer is properly instructed, but the origin is still not at the corner of the build plate (
beware!
in some printers the origin is in the middle of the plate) you might have incorrect endstop to origin offsets.
Determine the offset first!
To quantify the offset of the center as it is known by the printer software (firmware) it is advised to print a large square that is a few percentage smaller than the maximum size of the bed. E.g. you can create a square hull at e.g. 90 % of the dimensions of the bed (parametric designs are very useful for this purpose, see e.g.
this design
). There are many things (
```
.stl
```
models) to be found on the internet. If it includes a cross, even better as some platforms have a mark in the center of the bed.
Example of a bed center calibration model
Once printed, measure the distance from every edge from the build platform to the printed square. If you fail to print the square, please check the level of the platform;
this is also an excellent test for the level of your bed!
The measurements should give you a notion of the offset of the bed. E.g. for the X-axis you measure a distance of 12 mm on the left and 8 mm on the right (when facing the printer) you can easily deduce that the center is (12 - 8)/2 = 2 mm to the right (positive X direction). This implies that the printer manufacturer has done a lousy job by delivering you a printer with an offset bed; better said incorrectly configured in their firmware. Note this is not uncommon!
How to fix this!
Once you quantified the offset, you want to be sure that your next print prints in the middle of the bed. How to proceed? Basically there are a couple of solutions you can use, each with its own advantages and disadvantages.
A simple solution (i.e. if the printer support this) is to adjust the position of the endstops. Alternatively you can print alternate endstop holders to match the position change as measured from the calibration print.
Another simple and popular solution is applying an
offset in the slicer
. You could do that in the printer options some of the available slicers. If such options are not available, you could add
G-code commands in the start code
to create the offset (e.g.
```
G1
```
X-2 moves to the left and
```
G92 X0
```
resets the X origin). Note that this is a quick fix and should be applied wisely. The printer does not know where the actual center is! You merely changed if after the homing sequence. Exchanging
```
.gcode
```
with fellow enthusiasts with the same printer may have adverse effects.
A far better solution is to fix the center in the firmware so that the printer knows the
actual
center. This requires some extra effort by uploading firmware (files including configuration settings) to the printer or send G-code commands. The latter option will be discussed first.
A prerequisite of this method is that it requires the
G-code command
```
[M206](https://reprap.org/wiki/G-code#M206:_Offset_axes)
```
to be supported by your firmware; note that not all 3D printer firmware solutions are able to use this G-code command for axes offset definition. E.g. the stock Anet A8 runs a modified Repetier version that does not support
```
M206
```
, it would be time to upload a new firmware like e.g.
Marlin Firmware
making this particular printer safer as the stock firmware does not include thermal runaway protection! See question: "
What is Thermal Runaway Protection?
". To send G-code commands to a printer you have the option to hook up your computer to the printer over USB and use a 3D printer program that support sending commands to the printer (this is called a terminal; i.e. an interface to the printer). Programs like
PronterFace
,
Repetier-Host
,
OctoPrint
, and probably many more have such an interface. A simple alternative that works also is creating a text file (with
```
.gcode
```
extension) with the commands on separate lines and executing the "print". The following codes need to be sent:
```
M206
```
e.g.
```
M206 X-2 Y2
```
(move center left and to the back, note to use integer values, float values are not allowed!) and store this new center with
```
M500
```
.
The final, best solution is to set it fixed in the firmware. This requires an upload of a more recent configured version of an applicable firmware. See e.g. question: "
How to upload firmware to reprap printer?
". Note that there are different methods to upload a firmware to the board, it is best to search the internet for the applicable method for your board.
To do that you will have to be comfortable with computer software and tools to build source files and upload binary code to the printer. This depends on the type of firmware you choose and therefore cannot be described for each firmware in detail. Various sources on the internet describe this process. Generally speaking, it requires you to set the bed and offset values/positions correctly. For Marlin Firmware this comes down to changing the settings in the
configuration file
, this is similar in other firmware software solutions:
```
// The size of the print bed
#define X_BED_SIZE 220
#define Y_BED_SIZE 220

// Travel limits (mm) after homing, corresponding to endstop positions.
#define X_MIN_POS -35 ; used to be -33, so 2 mm shift to left now
#define Y_MIN_POS -8 ; used to be -10, so 2 mm shift to the back
#define Z_MIN_POS 0
#define X_MAX_POS X_BED_SIZE
#define Y_MAX_POS Y_BED_SIZE
#define Z_MAX_POS 240
```


q:
I read something the other day about a guy who found a way to knock over completed prints with the printer head itself, then slide them to the edge of the build plate, where they fall into a box/basket. This allows printing several Eiffel Towers while you sleep for example. It doesn't work with skirts (duh), and the adhesion has to be just right not to wake up with a pile of spaghetti, but it still sounds useful.

Well, now I cannot re-find the description I read; does anyone know what this process is called? Is there an easy way I can perform such an end-of-print action on my CR-10 with a cura plugin? If such a thing takes a touch of end-time custom gcode, is there a proof of concept rough draft or demo I can start tinkering with? Any more info is helpful.

[A]
You could cool down the heated bed (with e.g.
```
[M109][1] R28
```
) and cool down the hotend (with e.g.
```
[M190][1] R40
```
). This will usually release the print from the plate, perform the actions to move the head (e.g. go to the largest X, Y position
```
G1 X{max} Y{max}
```
, move down
```
G1 Z10
```
to then move to minimum X, Y
```
G1 X0 Y0
```
position such that it sweeps the print to the origin) that it knocks it into the basket and start printing again by copy pasting the whole G-code beforehand a couple of times. Note that this all depends on the product you are printing. You should at least use the end code scripts for the specific tasks to cool down, and start scripts to heat up again.
You can write a Cura plugin to implement a new GUI item to copy the G-code multiple times or create a post processing plugin.


q:
I got myself the Ender 3. The Home position is about 1 mm left and 2 mm in front of the front left corner. Now, the hotend center axis is 11 mm from the carrier plate with the "Mk 10" cooler mounted right onto a pair of 5 mm pegs that are part of the plate. As I want to change to an e3D v6, which has a diameter of 22 mm, I will have to move out some distance (ca. 13 mm) to the current Z axis. This means, that any Y command will be off by this distance.

How do I reconfigure the Home position to have an offset to the 0-positions gained from the limit switches?

According to Repetier Host it runs on Marlin 1.0. Creality offers the firmware on their website as a .hex file - which is hard to edit.

[A]
When homing the printer, the hot end carriage will be instructed to hit the (mechanical or optical) end stops. From this point a well configured firmware knows where to find the origin of the heat bed.
For the printer to know the origin of the bed, offsets are defined in the firmware from the end stop locations to the actual origin of the heat bed.
E.g. in Marlin Firmware this is defined by
```
```
#define X_MIN_POS -35 ; move the head 35 mm to the right to place the
                       ; nozzle at X = 0
 #define Y_MIN_POS -8  ; move the head 8 mm to the back (or the plate
                       ; forward) to place the nozzle at Y = 0
```
```
When you change the hardware (e.g. carriage), you need to re-calibrate the movement from the end stop location to the origin of the bed. Note that any arbitrary point on the heat bed can be used to re-calibrate this. E.g. the center of the bed can also be used, and is frequently much more easy to re-calibrate as the heated beds usually have rounded corners or are slightly larger than the actual print area (e.g. I have a 300 x 300 mm heat bed that actually measures 315 x 315 mm). Printing a large square on the heat bed will therefore give you a good impression of the offset of the nozzle due to your new carriage design.
Note that, if you cannot or will not flash new firmware, an alternative solution exists to set new incremental offset values using the
```
M206
```
command
IF
your current firmware supports
this.
A detailed description to re-calibrate is found in answer
How to center my prints on the build platform?
or in external link
Bed center calibration
.


q:
I am wondering if this piece of G-code is valid:

G0 (Some comment (Its G0 command)) Y10 Z-5

I have tested this on my Chinese CNC machine and it strips out the comment and works flawlessly.

The machine processes this as G0Y10Z-5 which seems like the correct approach to me.

I have however never seen such comment in real CNC practise.
It would be nice if anyone is able to test it out on their CNC/3D Printer.

Many G-code simulators on the internet fail to process such a line in their parser so it makes me confused. I haven't found anything about it on RepRap Wiki or even Google.

[A]
This is not universally valid G-code, and how it is handled depends on the implementation. You can use this style of comment on
some
machines, but not all.
The way parsing used to be implemented in Marlin (a very common 3D printer firmware), it would work fine unless the comment string included a X, Y, Z, E or F character. The parser simply looks for the first occurrence of X/Y/Z/E/F and then tries to parse the bit of text appearing after that character into a number. If the string cannot be parsed as a number, it defaults to 0 instead. For example,
```
```
G0 (Some comment containing the character Y) Y10 Z-5
```
```
would be interpreted as
```
G0 Y0 Z-5
```
and not as
```
G0 Y10 Z-5
```
, because ") " (the string appearing after the first occurrence of "Y") does not parse to any valid number. Your example happens to work fine because the comment string doesn't contain any special characters.
Marlin does support end-of-line comments, which should start with a semicolon and continue until the end of the line.
This is how it used to work in older Marlin versions. Newer Marlin versions have a more advanced parser, but it still would not play well with these parentheses-style comments. It is best to avoid them, as compatibility is not guaranteed.


q:
I made a few successful prints since I got my CR-10 two weeks ago and I didn't run into any major trouble. The printer is new.

Today I set it to "preheat" mode while I was preparing the SD card with the settings being 210°C for the nozzle and 60°C for the bed. When I wanted to start the print I noticed that the temperature showed as "actual temperature" on the printer's screen showed 233°C and it was going up steadily while the "requested" temperature was still 210°C.

Thiking it might be a mis-manipulation on my part I powered it down for a few minutes (I got scared by the high-temp) and then powered it back on. I then immediately requested the print to start. The CR-10 heated up to the proper value, started printing and kept heating the nozzle. I stopped it at 217°C.

I looked for an answer on the internet but all I could find is people having trouble with the nozzle not heating at all ...

[A]
This is not an easy one to solve, the firmware of the printer should be keeping the printer at a certain temperature depending on the temperature setting and the current value. If the firmware is not able to keep the temperature at the requested level, but goes beyond that level, that could be considered "strange". As it measures the temperature (and reports it on your display) it must know that it is over the limit and thus should not power the hotend.
In this process there are a few possible candidates for you to look at:
Check for a faulty
MOSFET
(sort of an electronic switch) on your controller board (is it leaking current to the hotend?).
Check and or update the current settings for the
PID
values (settings for the control loop of the hotend). The PID values control the overshoot of the temperature. E.g. is this is very large overshoot? When incorrectly configured the temperature can get higher, but normally should never increase to infinity, are you sure it keeps rising? The determination of the new values is called
PID tuning
. Important commands (that need to be send over a USB connected printer with a 3D printer terminal application like Repetier Host, OctoPrint or Pronterface):
The
M503
G-code
command shows the current settings (somewhere in the heap of all settings).
The
M303
G-code
command can determine the values.
Reflash the firmware
Replace the printer controller board
You could replace the thermistor and the heater cartridge (just to be sure, most definitely not the problem, but they are really cheap to replace). The thermistor works as it reports the temperature, and the heater element doesn't get powered by itself.
As suggested below
the most likely candidate for your problem is the MOSFET
. These are pretty easy to replace (depending on your board) or replaceable by an external MOSFET module (if you happen to have one lying around).


q:
I am searching for 3D printing filaments, that are suitable for outdoor purposes, but printable on unheated beds.

I will mostly use it for sensor node enclosures (should withstand temperature up to 50°C/120°F) and car accessories (70°C/160°F).

If it requires annealing, it should have low shrinkage, since I will be printing parts that will fit into each other.


q:
Is hot glue suitable for FDM printing, or some process similar to it?

I think it has all of the required properties, and could produce a flexible transluscent print.  It's cheap, hotends are cheap, and the technology has been around for a while.

I couldn't find any examples or anyone talking about such a material for use, on here or the general Internet.  I wonder if there are tradeoffs or challenges that make it not worth pursuing.

[A]
You could mount a hot glue gun to a 3D positioning frame, but you would immediately notice the following:
Hot glue sticks are fat, so you lose a lot of precision for each feed/retract increment. I.e., it's a lot harder to get precise feeds with a fat stick because the stick size is so much larger than the nozzle.
Hot glue sticks are short, so you would to create a filament to spool the stuff or come up with a glue stick feeder.
Hot glue melts at 120 °C and common plastics such as nylon melt at much higher temperatures. So hot glue would make an AWFUL structural part like a stepper mount. Even PLA barely deals with stepper temperatures. Note that temperature tolerance is irrelevant for costume parts.
Hot glue is soft, which makes it a great glue, but not very stiff for, say, making parts for a 3D printer. However, the parts might be fine for  use only in costumes, etc.
But, if you then used your 3D glue printer to dispense glue for gluing stuff together, well...that might be valuable. :D


q:
I own a DIY Hypercube Evolution equipped with Tevo Titan extruder, Clone Chimera hotend and Capricorn's High-temp PTFE tube. I use RAMPS with Mega and A4988's.

During prints, my extruder motor randomly clicks. I touched the filament and during the clicks I'ven't felt any problems with extrusion. I looked at the motor shaft to control if it clicks at special angles or randomly, but it clicks randomly. My prints do look very good: clear and shiny.

Do you have any suggestions? (the sound really gives me headache)

[A]
Even though you may have acceptable extrusion, any clicking from that area of your printer is likely to be a missed step on the extruder motor. This may be insignificant with respect to print quality, but as you suggest, it is an irritation.
If you are confident that your nozzle is clean of debris (which is likely), you could consider to raise the nozzle temperature a few degrees. If the nozzle is not applying enough heat to the filament, it may resist being forced through and a click representing a delay, allows that much more heat to be applied.
You should not have to increase by much, certainly no more than five degrees.  It's also possible that you can slow the feed rate a bit to accomplish a similar result.


q:
I specifically want to test

calibration

tolerances

precision

accuracy

I'm having trouble with Print in Place models and I'm trying to find out if there's something I can do to improve my print quality.

The printer I am using is a Kossel clone, specifically a FLSUN QQ and assume FDM printing.

[A]
The best place to start looking is to go to
Thingiverse
and search on '
benchmark
'. There are a great many models there intended to test various aspects of printing. In fact you could search for example '
calibration benchmark
' or '
calibration test
' and get more specific examples.
Actually,
here
is a collection I just made today of the benchmarks I thought most promising. Disclaimer: I haven't tried them yet!


q:
I need to replace the lid of my water kettle and am searching for a filament, that is suitable for this purpose. The requirements are:

Stable at 100°C (212°F)

Resistant to steam/moisture

Food-safe

Has anyone experimented with this or similar purposes?

[A]
There are few materials that go up to that temperature and beyond.
A very nice generic overview is given by
Simplify3d
:
This figure shows an overview of many of the used materials in 3D printing
When looking closely, and without pointing to specific brands (to avoid a commercial posting), your best chances for appropriate filaments for your application is to look at Nylon, Polycarbonate (do not consider Polypropylene; that is very difficult to print) or (not mentioned in the overview as they are more recent filaments) Co-Polyester polymers.


q:
High performance polymers are becoming available for specific applications.

One of such materials is PEEK (PolyEther Ether Ketone), a thermoplastic polymer in the polyaryletherketone (PAEK) family. PEEK competes with certain Aluminium alloys but is half the weight of Aluminium. For aerospace application this sounds very promising!

NASA has shown that printing these types of polymers is feasible using low-cost, open source hardware.

Does anybody know why the prices of PEEK are so high?

Depending on the supplier/manufacturer you're looking at about 700 - 900 Euro per kg.

[A]
My assumptions about PEEK filament price are:
Raw material is more expensive. Compare price of
ABS
with
PEEK
pellets.
Demand is much lower. There are not many printers able to print peek. If you manufacture PEEK filament you have to store a filament batch for longer time. Manufacturer has to calculate into price storage space, material degradation, ...
Filament machine tuning. You have to tune filament extrude machine for PEEK, which takes time because it's a totally different plastic. Maybe there is a cleanup needed after finishing a batch and switching to another material.
Working conditions. PEEK is quite smelly and I am not sure if you have to improve work conditions like better ventilation.
Research costs. You have to distribute research costs to a filament production where demand is low.


q:
I´ve have read an article to change different pattern depending on amount of layers, but my question is if is possible to have different infill in the same part? For example:

Base: has the infill of 25 % but the same base has some tabs for screws and mount the part for this area the infill need to be 40 % or greater.

The walls and forms: this has the same of the whole part and can be filled at 25 % but some areas need to be filled at 15 % or less.

Probably someone has seen or reviewed another software to achieve this, or I'm fooling myself.

[A]
This answer explains that you can have different infill within the same part. Firstly the implementation in
Ultimaker Cura
is described, secondly how you can do this in
Slic3r
.
Ultimaker Cura
I've used a feature in
Ultimaker Cura
that can be used to alter the infill density locally. What you need to do is load your model into Cura, then load other objects (models) at the size of the area/volume you want your infill differently and position those at the position you want a different infill. Alternatively, you can add support blocker cubes that can be used as well.  So basically, you use other models to intersect with your primary model to create intersections that can take a different infill percentage (please note that you can alter even more options, as long as you add these to the intersecting volume). This is extremely useful for lugs and brackets where you need some extra infill (e.g. extra stiffness for compression stresses) at the fastener holes. Note that this is an advanced feature which is not easy to use, but quite handy if you master it.
I could not find the video (
on second thoughts, I think it was animated GIF
) posted by Team Ultimaker, so I quote a section of one of their forum topics.
A short how-to:
(italic font is not in the reference, but added to reflect recent version of Cura)
Unselect "keep models apart"
(now called: "Ensure models are kept apart")
and "drop models to build plate"
(now called: "Automatically drop models to the build plate")
in Cura preferences
Import a second object (for example a simple cube)
Put Cura in "custom mode"
Select the cube, and use the button "per object settings" on the left side
Select "Infill Mesh"
(now called: "Modify settings for infill of other models")
and enable that setting
The cube now turns transparent gray.
Position the cube to overlap part of your model. It should overlap with the section that you want to change the infill for.
Also with "per object settings"
(now called: "Per model settings")
select the option "infill density"
Set it to the desired value. All is more or less illustrated in the screenshot below
The picture shows a cube on the buildplate with infill 20 %. Locally, with a rotated 2nd cube, the infill % is raised to 100 %.
What happens is that the volume where the cube intersects with your object is locally sliced with different infill.
Please find below another example of a simple bracket that has extra cylindrical objects loaded to create the intersections with the bracket at the fastener holes. In the
example
, the infill at the fastener holes is set to 99 %.
After slicing, you will see that the infill at the intersections is adjusted accordingly.
Note:
I've tested this in Ultimaker Cura 3.4.1, and confirm it works. I sliced a part with the inserts for fasteners and it actually is not very difficult, it just requires a little more work. You will have to make some STL's of cylinders and position them correctly. If you make your own 3D models it will be a very easy task to add extra components while you design, positioning will be a lot more easy then (as they align with your model). An example is the following linear
Z rod bracket of a Hypercube Evolution CoreXY printer
, this bracket requires local reinforcements for the bolts clamping the bracket onto the aluminum extrusion profile:
Inserts are modeled together with the development of the bracket:
When combined, it looks like this:
Now the infill can be modified locally to 100 % to increase compression strength.
Note that this will also work if you want a different infill percentage at the first X layers, just use a large cube (larger than the model) and position it correctly. Note that Cura already has an option called "Gradual Infill Steps" to adjust the density at the top layers.
Slic3r
This reference
describes how to do this for
Slic3r
in detail.
The blog describes the use of a simple volume (the green volume loaded from an STL file). After loading:
Right-clicking on the main part brought up the object settings menu.
From there, clicking "Load Modifier" and selecting the previously
saved model adds it to the part as a modifier.
The green "+" was selected and "Fill Density" was added to modifier
list and set to 100 %.
This shows that the functionality in Slic3r is very similar to the functionality in Ultimaker Cura.


q: I have been wondering about 3D metal printing (steel, aluminium), but after a short research on google I found only too expensive printers (markforged, desktop metal and a few other industrial ones). Is there any less expensive printer that is able to print metal parts on the market ?

[A]
Anzalone and friends published
A Low-Cost Open-Source Metal 3-D Printer
in
IEEE Access
:
This paper reports on the development of a open-source metal 3-D printer. The metal 3-D printer is controlled with an open-source micro-controller and is a combination of a low-cost commercial gas-metal arc welder and a derivative of the Rostock, a deltabot RepRap. The bill of materials, electrical and mechanical design schematics, and basic construction and operating procedures are provided.


q:
I know very little about the history of 3D printing, except that SLA came first (in the 1980's?), and FDM development was probably held back by patents.

By 2016, very low price kit machines were available to hobbyists, in the <€300 price range, as price-reduced clones of designs which had already seen several iterations.

Was this the start of the break-out of cheap FDM machines (as opposed to the >€2000 semi-professional lab budget prototyping class), or were the earlier iterations of these kit machines also suitable/adopted by hobbyists?

I realise that early popularity would grow exponentially, but I'm thinking particularly at what point people could build a printer without needing to compile their own firmware, solder any boards, etc.

[A]
By 2016, very low price kit machines were available to hobbyists [..]
Was this the start of the break-out of cheap FDM machines
No, not by any means. The
RepRap project
started in 2005, and by 2008-2010 there were several open-source printer designs out there that were somewhat workable for hobbyists. These designs were still quite expensive, you needed to source all the components yourself and do a very significant amount of troubleshooting.
However, as early as mid-2009 you could buy a
Makerbot Cupcake CNC
for \$750 as a kit (which might have involved some soldering) or \$2500 fully assembled (presumably without soldering, but it's conceivable it was plug-and-play). Makerbot went on to become quite a successful company, piggybacking off the RepRap project and could be viewed as the "break-out" you ask about.
I purchased my first printer kit (no soldering or firmware involved) for \$500 (plus around \$150 in shipping and taxes) in February 2014; cheap hobbyist machines were commonplace well before that.


q:
It would be helpful to me if I knew in advance how much the empty filament spool weighs.

Not having emptied any spool yet, I can't contribute data points, but has anyone compiled a list of empty weights from various manufacturers and sizes?

[A]
Yes, there is a table on
Reddit - Empty spool weights for estimating remaining filament
which suggests that the norm (in 2015) was between 170 and 330 grams for a 1 kg spool, superficially in a bimodal distribution clustered around the high and low points. Presumably these were for 3 mm filament, this post dating to before the popularity of 1.75 mm...
Manufacturer's have an incentive to reduce the mass of their spools, or even ship without spools, since the shipping cost will eat into their profit margin.


q: I see plans for various spool holders, either for PLA in the open, or for whatever filament in a dry box, that use 608 bearings. Elsewhere, I see warnings not to oil your filament to make it go through the extruder better, because problems going through mean something else is wrong, and it's better to fix the other thing. So, if I use the 608's, will oil leak on the filament, and is this bad?

[A]
Typically, oiling a filament would mean to use a vegetable based or non-petroleum type of lubricant, possibly even PTFE (teflon) or silicone. Those materials will not damage PLA filament.
Oiling filament is not the haphazard application of lubricant, however. One drop on the filament sponge guide will last a rather long time and should be given sufficient time to distribute itself in the sponge, helping it along by alternately squeezing and releasing the sponge.
Ball bearings of the type you've described will not have oil, unless otherwise modified by the user/owner. The bearings are packed with grease which will not leak out under normal circumstances. Running the bearings at high speed will cause the grease to thin a bit and perhaps drip or if hot enough will "sludge up." If your bearing grease turns to sludge, the bearing has already gotten hot enough to melt out of your plastic fitting.
For spool holder applications, you can clean the grease from the bearing with a suitable solvent (denatured alcohol, acetone, soap and hot water in a pinch) and expect little impact on the drag. The spools rotate at such slow speeds and under such small load that the bearings alone will work nearly forever. This recommendation is void in dusty environments.
With respect to oiling the filament, it's not a bad idea to have a sponge dust catcher that has no oil just as the filament enters the last open location. My bowden extruder system is nearly enclosed and the sponge sits at the very edge of the spool, while a direct extrusion system would have the sponge at the entry to the extruder gears.


q:
Let's say I'm modeling a simple box with a lid. Just as an example, we'll say the outer edge along the top of the box is 50 mm x 50 mm. With 3D modeling software, it's easy to build a lid for this box to surround the top with an inner edge size of also exactly 50 mm x 50 mm ...but this seems like a bad idea. Surely I'll want some kind of of gap, to ensure an easy on/off. An exact fit seems like it's asking for trouble.

How much gap do we leave for this kind of thing?

Is it related to nozzle size?

I suppose it also matters how tightly you want to fit, though I expect in cases where a tight fit matters some kind of snap or clip would be used.

Are draft prints with larger layer sizes useful for figuring this, or do the rough layers make things seem tighter than they'll be in a final print?

[A]
Short version:
basically, this depends on your printer, make, model, type, state of maintenance, extruder, slicer settings, belt tension, play, friction, etc.
Long version:
Basically your printer determines how accurate it prints; you can influence the accuracy a little by calibrating and fine tuning the printer. What regularly is done is to print
calibration cubes
of fixed size. Before you do that, you should read "
How do I calibrate the extruder of my printer?
"; this explains to calibrate the extruder. With a fine tuned extruder you could print those XYZ calibration cubes, or in your case create a box of e.g. 50 x 50 x 15 mm. When you measure the length and the width with a caliper, you will know how much the tolerances are for this print size. Eventually, you could change this by re-adjusting the steps per mm in the firmware of the printer, but this is not always a recommendation (as your steps per mm should be related to the mechanical layout of the used mechanism, e.g. the belt size and pitch in combination with the pulley and the stepper resolution).
Please also look into the answer of "
How to make moving parts not stick together?
"; this answer hints to printing a tolerance calibration model that uses diabolic shapes set apart from the outer object by several values for the offset between the pieces. When you print this you can find out what sort of tolerance works for you. Please do note that the tolerances on smaller parts may be different than the tolerances on larger parts.
The answer on your question thus depends on your 3D printing machine, but usually the tolerance values range in the few tenths of a millimeter. To enable a lid on top of a box like in your example, you need to keep the tolerance in mind when designing the lid. Usually an extra few tenths of a millimeter will do the trick, but if you make some test prints first you will know exactly.
To answer the question what the influence is of layer height on tolerance, I
quote
:
Load a 25 mm cube into your slicer and set the infill to 0%,
perimeters to 1, and top solid layers to 0. You’ll also want to print
it at a fine resolution – I chose 0.15 mm and it actualy did make a
small (0.02 mm) difference in the wall thickness as opposed to 0.3 mm.
So yes the layer height has an effect, it is very little though.
An interesting read is "
A Guide to Understanding the Tolerances of Your 3D Printer
" from "
matterhackers
".
Furthermore, when you have calibrated the printer but still run into small deviations, is that most slicers will allow you to compensate for X and Y dimensions.


q:
Recently, I have heard people talking about masterspool, when talking about 3D printing filament.

What exactly is master spool?

Where did the idea come from and when?

Is it being widely adopted? Or to be specific, how many distributors/manufacturers have adopted this already, and is it gaining traction?

Is this something that I should get excited by?

If so, why is it such a good idea?

[A]
A masterspool is the practice of printing your own spool out of filament, which will then be used to support your filament you purchase without a spool attached. The main idea is to create a reusable spool and create less waste.
(
NOTE: I'm in no way affiliated with MatterHackers.com, nor am I an endorser of their products.
There is also a version which
Village Plastics
has created.)
On
MatterHackers.com
website, they state:
Filament without a spool? Why are we making this? The short answer: because the community wants it. We had enough questions, comments and plenty of tweets asking if we had plans to pick up the Master Spool concept. Seeing the response and interest within the community made it clear to us: we needed to bring this idea to the States. With a joint effort between MatterHackers and Village Plastics, you can now purchase Master Spool refills from within the US.
They are tying to apply the
Reduce, Reuse, Recycle
mantra to create a cleaner environment for the rest of the world. While they are not the first to create or use a printable spool, they are pretty happy to be pressing forward with the idea of having a reusable spool and selling filament without a spool attached.
MatterHackers go on to state:
What are the benefits of the Master Spool? Not only is there the  benefit of reducing plastic waste, using a Master Spool will also reduces shipping costs for new spools, and limits the clutter from amassing of a huge collection of used or empty spools. Rather than throwing away, trying to recycle dozens of spools, or trying to come up with a way to reuse them in some (like the Spool Tool), using the Master Spool means you can use all those filament scraps you have laying around on something useful and have one spool for all of your filament.
As far as where it started, it appears to have originated with
this print on Thiniverse
created by
Dingoboy71
. A well known 3D printer named
RichRap
created the reusable spool which MatterHacker promotes, though they say there are several which will work with their product (Village Plastic says pretty much the same).
If you get excited about saving the planet, then you should be excited about this. If you are a robust printer, going through tons (hopefully not literally) of filament per year, this method will save a lot of waste in the long run.
Realize there are (as of this writ) only limited suppliers of spool-less filament, though I think the trend for this type of product will increase in the future as the idea catches on. I guess time will tell.


q:
Let's say you're printing a container or some other object with no infill. What's a good rule of thumb for how thick to make the outside? I'm looking for something along the lines of millimeters thick per square inch of area.

I'm thinking about PLA right now, but answers for ABS and other materials are welcome, too.

[A]
I make small objects (25mm^2) with 1 to 1.5 mm walls and larger objects (think coffee cups)  with about 2.5 - 3 mm walls.  I set the line width and number of perimeters to completely fill the thickness.
I use this for ABS and PLA.
The PLA objects have been electronics enclosures,  with internal structures to support the parts.   They aren't subjected to strong forces.   I've made small containers for stain gauges with the amplifiers,  and larger ones for greater sequences and Arduino boxes.
I've used ABS also for coffee mugs and beverage glasses,  to withstand the mass and temperature of drinks.
It can take some fussing to worry the Slic3r slicing parameters into place.  Especially with mugs the design is for function and appearance,  not for effect.


q:
I have a printer with a 0.1 mm typical layer thickness. Of course I can choose some different sizes in Cura or other slicing software, but most prints on this machine will be .1mm. In my (admittedly limited) experience thus far, the 0.1 mm seems typical for other printers, too.

I want to get a sense of just how thick this is. I know about the paper trick for leveling the print bed, but my understanding is the first layer pushes into the bed a little, meaning it's less than 0.1 mm and so paper isn't a good example for the typical layer.

Is there a similar item with close to 0.1 mm thickness I can use to visualize this?

[A]
Sure. Get a 0.1mm thick feeler gauge.
http://duckduckgo.com/?q=feeler+gauge+.1mm


q:
I've just bought Anycubic i3 Mega printer and trying to level it.
So far I've printed test object and 2 others but looks like there are problems with leveling.

I want to make image of 5 small one layer squares(one in each corner and one in center). Looking for recommendations of simple software/tutorials/approaches to do it. I tried zbrush but found that it kind of complicated.

[A]
You are probably looking for something like
this
:
Note this is for large beds (300 x 300 mm), so you would have to X, Y scale this in your slicer.
This is a simple part that is very easily generated with
OpenSCAD
3D design software (very good modeller if you are familiar with software coding), but could easily been designed in any
other tool
.
Another leveling and centering print that is created with OpenSCAD is
this
, and could be a start for you to create your own design:
Note that the file with the design is located in the "files" section.
Edit
:
Some code for OpenSCAD made within 5 minutes (I don't type fast so it could have been faster if I did not use the constants, but if you go OpenSCAD, making parametric designs is almost a must ;) ):
```
```
// Set constants as you like
width = 30;
depth = 30;
layer_height = 0.2;
first_layer_height = 0.2;
nr_of_layers = 2;
box_size = 180;

// Calculated parameters
height = first_layer_height + (nr_of_layers - 1) * layer_height;

// Draw the test object
translate([-width/2, -depth/2,0]){
  // Draw the center square
  cube(size = [width, depth, height], center = false);
  // Draw the corner squares
  for (x=[-1:2:1]){
    for (y=[-1:2:1]){
      translate([x * (box_size-width)/2, y * (box_size-depth)/2, 0])
        cube(size = [width, depth, height], center = false);
    }
  }
}
```
```
Rendered figure:


q:
I came across this suggestion on the klipper github, https://www.facebook.com/groups/Hypercube.Evo/permalink/192106034761003/. In order to reduce the stretching in the bowden tube you can add fiberglass packaging tape lengthwise along the tube. This would decrease the elasticity while still allowing the plastic filament to run through it. Allowing you to reduce the retraction length and have better control over the amount of plastic being extruded.

Is there any reasons that this would not work or actually decrease the performance of the bowden tube?

[A]
The question seems to be built on a false premise, namely that the major extrude/retract errors in a Bowden design come from tube stretch. The PTFE tube is
not
significantly elastic, actually it is reasonably stiff so there is minimal scope for improvement here.
A longer tube
will
contribute to degraded precision, but slack in the filament/tube gap is roughly as significant as stretch (and filament compression). Constraining the tube path may help marginally (but there is no need to 'bond' the tube). There is not much you can to to reduce the gap between filament and tube, but this will dominate the error for a long tube.
The most obvious weak point is the clip used to secure the tube at each end. I saw a review of a recent Prusa design where high quality clips were called out as making a big improvement to securing each end of the tube.


q:
I just received my new Creality Ender 3. I was going through and checking/adjusting everything for alignment, and I noticed that when you "auto home" the print head, the nozzle stops off the front of the print bed by 5-10 mm.

Is that normal?

Is it perhaps by design to allow purging the nozzle without dumping on the bed?

It doesn't appear that there is any way to adjust the Y stop switch without making modifications to it. It also didn't look like there was any easy way to move the bed either.

[A]
Yes, this is the "intended" behavior, as the home in relation to the physical limit position is not placed correctly about 7.5 mm into the bed in both X and Y.
to correct this, please look at the
Recalibrating Home-position
for the Ender3


q: Cura has a layer view feature that lets you watch a simulation of the extruder head as it lays down material at each layer. Is it possible to get Cura to show a time stamp as it does this? That would let me set reminders to check a print just at certain critical times.

[A]
These estimates tend to be very approximate, even if Cura has the accurate acceleration values for your firmware. An error of 100% is not unusual.
What you probably want is an alarm at a specific layer (a few before the critical ones). You might be able to add this to Octoprint fairly easily - it does support plugins which can provide (for example) pushbullet notifications.
I'm not sure that 'critical' points are much more likely to fail than other less predictable things (like bed adheesion failure, extruder jams, filament breaks) - unless you're testing features (and then hopefully you can print only a slice of the part).


q:
Creality does offer its firmware on creality3d.cn as .hex files. These are pretty good as backups as one can't alter and destroy them by accident.

But... How do you install them?!

This is about installing firmware directly and without another microcontroller. To use another mictrocontroller is How to install new firmware via a Microcontroller?

[A]
Creality also does provide an installation PDF. The process they propose is twofold and might need different settings on other machines
1
. Spots where I assume you might need to adjust are noted with
A
. Note that
this solution depends on CURA
.
1. Install the printer as a periphery machine.
This part is specific for Windows. If you use Linux or a MAC, you will need to use a different setup, but you might get the same results.
Turn on the power on the printer and connect it from the MircoUSB to a USB of the computer. This should automatically install the driver. If not, the Driver is on the SD card provided with the Printer
2
.
To manually install
```
windows Key
```
+ "
```
MANAGER
```
" and choose
Device manager
. Find the serial port that shows yellow, Right-click, choose
```
Update driver software > Browse my computer for driver software
```
. Now
```
Browse
```
, find the location of USB driver on the SD card and click
```
Next
```
.
Generally,the serial port(COM) you need update has the biggest number, but can change.
A good idea is to confirm the correct port with a software like
Repetier Host
, with which you can control the printer directly -  if it works, you got the drivers and the port correct. Also, you know the correct Baudrate.
After the driver installation, launch
CURA
to do some settings. In
```
File > Preferences
```
:
Print Window is "Pronterface UI"
A
Switch to
```
Machine > Machine Settings
```
:
Serial Port: choose the one that just was updated
Baudrate: 115200
A
2. Upload the .hex file via cura
```
Machine > Install custom Firmware
```
Make sure the printer is connected, then
```
OK
```
find the .hex file on your PC, then confirm.
Wait for the process to finish.
1 - most likely, you will have to change the baudrate
2 - This might not be true for all manufacturers, but is for creality. Other manufacturers might have different sources for these.
A - Adjust as needed!


q:
Up till now, I've tended to scale my first layer according to the print quality, so a 0.12 mm first layer for a 0.08 mm print, and 0.28 mm for a 0.2 mm print.

After changing to a PLA which isn't sticking well, I'm wondering if the first layer is best determined by the printer/tolerance/material, rather than the overall print quality settings. Am I going to get more predictable results if I stick to a 0.12 mm first layer regardless? This is with a 0.4 mm nozzle on an Anet-A8.

[A]
Default settings for first layer height in Slic3r Prusa Edition print profiles regardless layer height is 0.2 mm.
If you need to improve bed adhesion then try tips from this video
3D Prints not sticking anymore? Watch this! 3DP101
by Maker's Muse. It's about using glue stick and spreading it using paper towel and isopropyl alcohol.
There are other possibilities how to improve bed adhesion, e.g.
Ultem sheet
or other printing surface like
BuildTak
.


q: Has anyone tried the steel-reinforced polyurethane timing belts? If so, how do they compare to the rubber ones?

[A]
I do not believe the standard rubber/plastic belts have any significant stretching over time, nor do they stretch under drive motor force during acceleration (and in any case, extrusion takes place mostly under steady-velocity conditions).
While I suppose it's possible a steel-reinforced belt might have a longer lifetime, replacing a belt is quick and cheap, so why bother?
[incorporating comments]
My suspicion is that standard belts, e.g., as supplied with Prusa-clone kits will outlive us mere mortals. They can move an entire print bed+heater, so a larger print head is not an issue.
The usual problem with any belt material is ensuring there's no significant slack (which leads to backlash/hysteresis), and changing the material won't help or hurt tensioning control systems.


q:
I have an Ender 3 which I primarily use for printing with PLA. I haven't branched out to other materials yet. :)

I've done some research into PLA fumes and airborne particulates which seemed to mention that PLA is mostly safe, but ABS is rather dangerous to print without proper ventilation. However, I understand that there isn't much research on the topic and that there haven't been many studies.

I have been keeping my printer in my bedroom, far isolated from flammable materials, which I sometimes leave on to print while I'm asleep. Should I be concerned with my health safety with respect to airborne particulates emitted by printing with PLA?

Other questions ask about ABS, but here, I'm asking specifically about PLA.

[A]
Fire is the most obvious risk - firmware can now detect some of the more obvious failure modes such as a detached thermistor, but loose or failing connections can still overheat. A smoke alarm is a fairly obvious (but not necessarily effective) protective measure.
The risk from particulates in particular is
probably
low, but marginal health risks like this are extremely hard to analyse, and will likely take many years to manifest. The closest analogue would be to look at commercial plastics workers since they are exposed to both heated plastic, and any potential dust generated.
You could also compare the risk to other 'hobby' activities such as soldering, painting, woodworking.


q:
I've seen many references to a FDM print being weakest in the Z axis, due to poor bonding between layers compared to the extruded walls.

Thinking about optimising this for a specific material (excluding temperature and geometry), is there an optimum layer height? It seems obvious that too thick a layer will give less compression and maybe less heat transfer into the layer below (so 0.3 with a 0.4mm nozzle might be expected to be a bit weak). Is there a single break point (i.e. less than half the nozzle is good), or are super fine layers either good or bad?

I'm specifically using PLA at the moment, in case different materials have different behaviour in this respect.

I am not asking how to model the strength of layer bonds or how to take that into account when designing a part.

[A]
My3dmatter.com performed a
series of tests
with PLA, using "a universal testing machine". They conclude:
Layer height influences the strength of a printed part when it becomes
  thin. A printed part at 0.1mm shows a max stress of only 29MPa, as
  opposed to 35MPa for 0.2mm (21% increase).
Past 0.2mm, the max stress remains fairly constant around 36 MPa (we
  confirmed this conclusion with an extra test at 0.4mm, not shown here
  because it was not part of the same batch).
Note: It is recommended to read the full article to comprehend the complexity of the subject matter.


q:
What are the 'headline' basic design rules for FDM?

Which topics for design principles do you recommend to someone who has purchased an FDM machine and wants to understand what is practical?  In other words, where is the place to start when you don't yet know what questions to ask?

This question and its answer discuss design tools and the workflow but doesn't cover design rules.

Design rules here meaning the principles of what is special about planning a design to be manufactured with an FDM process as opposed to traditional machining or a printing process like SLA, not the detailed/automated checks that would be applied to something like a PCB layout prior to sign-off.

[A]
Designing a part for 3D printing often doesn't seem to have many special considerations, but I have learned the hard way, that there are some things to do differently. This is just a list of things to that one should keep in mind
in addition to basic principles of design
1
when designing parts, keeping the subsequently slicing the parts in mind too:
Print orientation
There are many ways how you could orient your print, but usually, there is one orientation, that has the least need for support. Look at your part critically and keep this orientation in mind when designing. Especially look at overhangs and bridging, and if you can get away without.
Overhangs
There are 3 sorts of overhangs:
Small overhangs ones that are neglectable.
Long overhangs which can get support.
Overhangs that can't be supported.
When designing parts, you want to make sure you only have type 1 and 2 Overhangs, as type 3 overhangs will sag and fail. Think carefully if you can rotate the piece to get a print orientation that does not need an overhang that can't be supported by an automatically generated support structure. If that is impossible, try to implement a sacrificial piece that can turn the overhang into a bridge.
Smaller overhangs can be made neglectable by adding a phase to the underside. This phase's angle is depending on the printer. In my experience, 70° is something many printers can manage, but I prefer 45° due to the ease of making them. A fuller
can
work to give a small overhang the needed support, but often has problems for larger overhangs!
Bridges
Overhangs turn into bridges if they are connected on both sides. These either have a limited length, depending on the printer you use or need a support in the center. Check if you really
need
a bridge or if you can rotate the piece to get away without.
Avoid vertical holes in bridges
It might be something that might surprise but a vertical hole or slot in a bridging part is something that often fails as the bridging strings just sag as they are terminated mid-air without a support structure and finally fall, ruining the bridge. Yet such a support structure sometimes could not be removed in all cases, so something needs to be done differently.
One such a solution is to add a 1-layer sacrificial layer on the bottom of the hole: printing a solid layer by bridging is possible, and the subsequent hole/slot can still be free. It has to be cut free after printing in post-processing though.
round holes in Walls
Round holes in standing walls can become problematic to print once the diameter gets too large. A trick to keep the upper parts of the hole to sag into the cavity, making it undersized or needing to drill it to size later. To prevent this, the upper side of the hole can be adjusted: instead of a round upper rim, turn the hole into a teardrop. This reduces the overhanging area. Keeping a 60° top angle on the hole should be fine.
If the hole is used to key an item to an axle, put the keyway to the top of the print orientation, so it takes the place of the teardrop-tip.
Some more about holes one can learn from
Makers Muse (Angus Daveson)
Reduce internal structure
I have seen prints fail for strange reasons. One of them was a piece taken from a straight up industrial design plan, then scaled down. This one resulted in
too much
tiny internal geometry, resulting in a lot of material and time wasted on printing these internal pieces that nobody could reach, that were fused together for the original gaps were already 0.2mm and less and besides that, there was the occasional print failure.
Removing any non-essential internal geometry lessens not only the printer's load, but speeds up the print, lessens the material waste and can prevent failures due to clogs or other unexpected behavior. If you can't fix it in design,
there are workarounds
, but try to need to avoid them!
Avoid Intersecting Shells
As we are at it, often game and graphic designers are lazy and use intersecting shells. These can become quite messy in the slicing step. If possible, try to avoid intersecting shells, even as modern slicers have learned to fix this by themselves by now. The results of that are not always pretty if you forget to flag the "Union intersecting shells" option in your slicer.
Sizing
We might not always be aware of it, but prints do
shrink
in the XY axis and to a different degree in the Z axis as they cool, during and after the print is done. This is what causes warping in the first place and lead to many lost prints (especially on non-heated beds). This behavior has to be taken into consideration especially when designing bores. My suggestion for this is twofold:
Intentionally design the hole to be too small and add extra wall material in slicing, then drill it up to the right diameter. Drill slowly to not melt the plastic.
Learn your shrinking parameter for the material and design with that shrinkage in mind, possibly iterating the print a few times. Note that different spools/colors of the same material might have different shrinking!
Minimum Wall Thickness
Without Arachne, a 3D-printer can not reliably print walls that are thinner than the extrusion width of a printer. The choice of the correct nozzle for an extrusion width is
a question upon itself.
. Even with Arachne slicing and variable line width, printing a wall thinner than a nozzle diameter is nigh impossible.
Tapping/Screwing/Inserts
For tapping prints directly, you need wall thickness - according to the norms - you'll need usually about 0.2mm diameter that can be tapped into for smaller standard-size threads. Using 3 perimeters with a 0.45 mm extrusion width will give walls of 1.2 mm, which I consider a rather strong wall, and provides quite some tolerance to drill up to size and then tapping screws into. You will get away with 2 perimeters for smaller thread sizes (M3 and lower), but for large ones (M10+), you will want a fourth or even fifth perimeter.
Remember though, that the
printed PLA is not good for very strong threading
:
Tapping print
s directly is pretty much only for
low- and non-load-bearing connections
. If you combine several pieces with screws, try to design the parts to make some sort of compression fit using a bolt and nut, or use several, small diameter screws with a fine thread. Avoid coarse thread if you can, stay on the small side.
If you need a
load bearing connection
with screws, the best strength comes from using a
metal insert
or provide a
space for a nut to fit into
. Metal inserts are usually placed by heat-setting them: put the heat-set insert onto a soldering iron tip and push it into the slightly under-sized hole, melting and molding the print to fit the insert, providing strong threads that are held really good in the shell of remolded plastic.
As a compromise, modern slicers allow to use modifier meshes, that could be used to increase the strength of modeled threads or holes that need to be tapped.
Do you want to know more?
CNC Kitchen (Stefan)
had made some tests on the strength of these connection type.
Print strength
Keep these general rules in mind when designing load-bearing parts:
Generally speaking, FDM prints are strongest in carrying along their
Z-axis
when withstanding
compressive forces
, as then the print layers of the shell are forced against each other. It also excels at fighting
bending
forces this way. But this orientation is also giving us the
lowest tensile strength
, as each layer boundary is a possible breaking point.
The
XY-plane
usually
excels in tensile strength
but sacrifices some of its ability to withstand compression (it is
not
proportional though).
Printing a part at a
45° angle
will give often a
great compromise of strengths
, but might need an additional surface to get a good first layer - this surface can be sacrificial with the use of support.
For deeper information on the strength of parts and materials in comparison and how to manipulate it, there are large playlists of tests made by
CNC Kitchen (Stefan)
and
Thomas Sanladerer (Tom)
Post processing
Post processing can be your best friend when printing, just as it can be your worst nightmare. I won't detail all methods of postprocessing, but some that are quite applicable.
Assembly/Gluing
Remember to design your parts with gaps for the glue when designing parts for assembly, and you might want to include guidance notches/cones or other
alignment features
to make sure the assembly aligns. This is especially needed as the parts shrink a little and have a rough surface.
If you need to assemble your part due to the available print volume, be especially sure to include ways to key the parts together. Pegs or outcroppings/indents (often called
keys
) that match up to one another make alignment on assembly much easier too, and are a different type of alignment feature. It can be a good idea to design yourself a "cookie cutter" file that is applied after designing the part that automatically includes the glue gaps and keys.
There are a lot of glues and other methods to merge the parts. A more in-depth look at some of them is
What glues for bonding printed PLA to injection-molded plastic?
but you will have to keep in mind how you want to combine your pieces in the design step - and account for it.
Print in Place/PIP
In this vein, learn the
tolerances your printer
can manage to allow print-in-place(PIP), allowing functional parts that require no assembly. PIP is something that isn't possible with subtractive manufacturing usually, but remember that in 3D printing you might need to
break
the parts free after printing from bridges or sagging. Usually, a single strong turn suffices. To be able to do this, you might want to include a position for an Allen-key to manually turn the parts.
To learn how fine your tolerances are, there are many
tolerance gauges/tests
around. A
rule of thumb
for many printers is, that 1 nozzle width is often easily achievable with a good setup, 0.5 nozzles are achievable with some effort and 0.25 is somewhere close to the 'holy grail' - you might want to change the nozzle to a smaller one in case you want to have very thin gaps.
Composite construction
There are ways to turn your (mostly) hollow prints into much stiffer versions of themselves by turning them into composites, for example by using a resin or a different hardening fluid (like foam or plaster) as a filler or coating material.
When planning to do so, remember to include inlets/outlets for it and the air. It can be a good idea to design the part in such a way that it just contains the walls and a pre-planned support structure. In doing so, remember to disable infill in the slicer to enforce the flow you want in your structure. Look at how the ribs inside of an airframe are designed for general rules on hollow parts: include holes. This allows the flow of your fluid into each and every corner instead of blocking the flow. This can also reduce the needed number of inlets and outlets from one per
chamber
to one per
part
.
Plastic Properties
Remember we work with thermoplastics. Learn what kind of postprocessing your thermoplastic allows and its mechanical properties. Some examples:
APS can be vapor smoothed with acetone.
Many plastics can be annealed by baking at or little above their glass transition temperature, increasing strength and layer-to-layer bonding.
When using power tools on plastic, use ample cooling and time, as otherwise, one quickly melts the prints!
Surface Finish
The surface of FDM prints is somewhat rough. To smooth it out there are 2 general ways: fill it up or smooth it down. If you want to fill it up, design the part
undersized
, if you smooth it down, add
sacrificial thickness
. It is common to combine both, adding body filler first, then sanding down till the print material shows through again. If doing this, make sure to check your sizing.
If there comes a lacquer layer atop, remember to account for that thickness: undersize surfaces, oversize holes!
1 - this means, that thoughts about postprocessing that are not unique to 3D printing are not elaborated on here. Examples are painting, coating or smoothing the surface mechanically.
Further reading/viewing
Further information can be gotten from these playlists, though they aim at times for newbies:
CNC Kitchen (Stefan):
3D Printing for Engineers Playlist
CNC Kitchen (Stefan):
3D Printing Tips
Maker's Muse (Angus):
3D Printint 101
Maker's Muse (Angus):
Advanced 3D Printing Tips
Maker's Muse (Angus):
CAD for Newbies
Maker's Muse (Angus):
CAD for 3D Printing


q:
I get the concept of automatic bed leveling...the printer moves around the bed and uses a sensor to identify high and low spots, then "software compensates for differences".

But what exactly does "compensates" mean?

It is extruding more material in the low spots to build them up and thinning out the high spots? Is it adding or removing layers? Is it shifting layers as it goes up to compensate tilt? Or...?

In what ways will this affect the final outcome? Would it be valid to say that if you wanted an automatically leveled bed and dimensional accuracy you should always print to a raft?

[A]
Last first:  use of a raft has nothing to do with bed levelling. It depends only on the features/shape/etc of the object being printed.
Now, as to what the auto-levelling does: the answer is, sadly "it depends."  A simple algorithm will just find the Z-height of the four corners and apply a bilinear correction to Z as a function of {x,y} coordinates.  A really good algorithm would map the entire build plate to some designated precision (perhaps 5 mm) and create a 2-dimensional lookup table to adjust Z over a curved build plate.     What your printer's levelling software does is more likely the former.
Why? because if you try to correct over curves & bumps, then you will end up distorting your entire printed object (basically forcing every layer to follow those distorted axes).  Far better to have some flattened or "fat" spots in the first layer printed, and then print proper planar layers after that.
Example: I know my bed (AnetA8 aluminum) is slightly bowed, peak in the center; so after levelling the overall bed I try to set the Z-zero so the outer extremes of my object have good adhesion, even if the center region of the first couple layers ends up non-extruding because the nozzle touches the bed.


q:
Hey!

Pretty new to all this. Wondering how you would approach this problem to have an extruded element on top of a flat surface. I want to avoid lots of support material (actually no support at all for a cleaner print and no work with sanding etc.) I intend to print this inverted in Z (i.e. text down) for the main structure.

My only idea would be to print it separately and then glue it on. But maybe there is another solution that comes to your mind?

Cheers!

[A]
Supporting the text while printing should simply not be a problem, if printed in the orientation shown. The text, as per your description and shown in the illustration is extruded vertically and there is no overhang. No support should be needed at all.
A few notes:
The bottom (dark grey) portion of your object does have a significant overhang, and may need some support depending on the specific shape. But support for that should not be near the text or affect it.
Text can be tricky to print with high quality if the width is not much bigger than your nozzle size. This is not specific to text, but rather feature size, slicer settings, and printer/filament capabilities. Experimentation is your friend - print it, and then address any quality problems that you find.
If you want the text to be a different color (as in your illustration), you might be in luck. There is a technique to pause the printer at desired layer height, swap out the filament, and resume printing. Your shape would lend itself to this technique. It's not too hard, but the specifics do depend on the software and printer you are using. There are quite a few good writeups on various 3D printing sites. If you want to ask about this, please ask another question, with this information.


q: Are there any specific type of FDM 3D printers that I should look for?

[A]
Not all printers are suitable to print flexible filament. E.g. 1.75 mm filament printers with a Bowden extruder/hotend combination will not work (you may have more luck using 2.85 mm filament, which is stiffer because of the increased diameter). For 1.75 mm filament you require a direct drive extruder, e.g. with the stepper mounted onto the hotend, even then some additional guide parts need to be printed to make it work. This also depends on the amount of flexibility of the filament, some are more flexible than others.
E.g. Ultimaker 3D printers use 2.85 mm filament with a Bowden setup. They also sell a flexible filament that can be printed with these printers. Even for direct drive extruder printers like the Anet A8 (a cheap Chinese Prusa i3 clone) inserts exist (e.g.
this
or
this one
) to even better guide the filament to prevent it to buckle.


q: A couple weeks before, I bought a custom 3D printer that has an Ultimaker 2 motherboard in it. However, the dimensions of the printer is not same with Ultimaker 2 (X and Y same, a bit smaller on Z). The printer had tinkerfirmware installed in it. Today, I tried to print a premade .gcode file (Which was for another 3D printer I guess) and after pressing print, The machine told me the file will overwrite machine settings, and I pressed yes for it. After that, the dimensions of my 3D printer has changed in it's firmware. The bed is raising more than it should while starting calibrating, and not setting it's position precisely. (To make the 1mm gap, I had to move the bed down 4-5mm away from where it should be.) Now the question is, what can I do to fix this problem ? I also tried reinstalling original firmware which didn't really worked. (All the parts are orginal except the frame, which is a bit more smaller on height) How should I measure the height of printing area?

[A]
Your printer is an Ultimaker clone or something else?  All of the original firmwares located on TinkerGnome's Github are configured for Ultimaker printers so if you are using them on something different you will need to configure it before using it.  The easiest option would be editing this print file that changed your settings to your desired settings and then reloading it.
How to find your actual Z? Well that's a bit difficult without more information.  I'm guessing from your description that your printer homes at Z max?  If it's homing at Z max you need to home the machine, jog the Z axis to where you want 0 to be (usually using a piece of paper between the nozzle and bed), then record the Z axis position and enter that as your travel limit in the firmware.  If your printer homes at Z min this could be as simple as changing the homing offset.


q:
I've heard I should store filament in sealed container, preferably with a desiccant.

But let's say I let a spool get a little old on the printer, or I purchased a filament spool that was old or improperly packaged. How would I know? How would this impact prints (what kind of symptoms would I see)? What things could I do (perhaps in the slicer) to correct for this and prolong the life of marginal filament?

And the corollary... in a typical environment, how long can filament be left out without suffering from the exposure?

I'm thinking mainly about PLA, but responses for ABS and other materials are useful, too.

[A]
The primary issue with long-term exposure of filament to the environment is that it will absorb water moisture from the air. When a filament that has absorbed water is passing though the hot end of a printer, the water will turn to steam and cause problems with extrusion:
Small bubbles of steam can form, causing extrusion to sputter - you might hear a sizzling noise and have poor consistency.
Large steam bubbles can cause significant oozing followed by no extrusion.
Extreme cases can cause mysterious jams that seem to clear themselves (the extruder cannot overcome the steam pressure).
In short, this will cause terrible print quality and failed prints. As the effects are not consistent, there is nothing that can be done by slicer settings to "recalibrate" for filament that has absorbed water.
This can be avoided by storing filament in an air-tight container with desiccant to ensure low humidity. Some people use "dry boxes" that allow the spool to be mounted inside while filament can be passed to the printer, so there is minimal exposure even while the spool is in use.
If you do suspect that your filament has absorbed moisture, you can dry it out, by placing the spool in a warm oven or in a food dehydrator for a few hours. If you weight it before and after, you should find that it weighs several grams less afterwards.
WARNING:
It is important that the temperature does not soften the plastic at all, or it can become distorted or bind on the spool. Most ovens will peak well above the set temperature as the thermostat cycles. Of course, fully melting a roll of filament could destroy your oven or cause a fire.
It's hard to say how much environmental exposure is too much, as every filament and environment is different. When I started out, I had several spools of PLA that I stored in the open for months. I didn't think I was having any problems, but I was also learning much and improving my printer settings at the same time. After getting PETG, it became unusable with oozing and jams after about two weeks but a few hours in my oven was a miracle cure! I then dried some PLA as well, and I found that print quality did improve, but not amazingly so. I have not used ABS, but in theory it is less hygroscopic than PLA, so it is probably not very sensitive to exposure.
I set up a dry storage box, and I am careful to always store PETG or my "good" PLA when I'm not actively using it. I have a couple rolls of PLA that I don't like as much anyway and generally just use for draft prints, and I don't really worry about it that much.
Note: An object that has been printed will also absorb moisture, but in general this isn't a problem.


q:
I had recently purchased an ender 3 and after setting it up and plugging it in, I received an electrical shock from the power supply. I live in the UK and so I was provided an EU to UK adapter which I used and I set the voltage to 230 V.

Does anyone know why I was shocked and if there is any solution? Was it because EU to UK isn’t grounded (or am I wrong)?

Would an older 10 amp monitor power cable work better as it’s grounded?

[A] The "shock" is likely from noise filtering circuitry at the power supply's input. For filtering, every power supply has a small capacitor that connects the live input wire to ground (a so-called "class Y capacitor"). A small amount of current can flow through this capacitor, which can give an annoying, but otherwise harmless shock/tingle. Grounding the power supply would solve the problem (which you should do anyways, because it is dangerous to run electronics that are supposed to be grounded without ground).


q: I have an Adventurer 3 printer from Flashforge and every time I unclog it, it gets clogged up again. I’ve done about 6 or 7 prints with it. So after I unclog it, I load the filament and it comes out of the nozzle like it should but once I start a 3D print, it’s clogged again. The process of what I do to unclog it is by heating the nozzle up and then shove a small metal rod down the nozzle to push out the clogged filament. I do this several times until its all gone. I’ve read up on what I can do to prevent it but it doesn’t seem to work. What should I do?

[A]
The Flashforge documentation is not much help, so unless there's a way for you to connect with their user community (because, maybe what you're dealing with is a known issue related to firmware or the machine itself) or Flashforge's customer service folks, you've got some fun detective work ahead of you. Seriously--you will enjoy solving this!
So: It will help to teach yourself the ABC's of clog symptoms, so you can see what the cause(s)
could
and
couldn't
be, in your situation. This is
not a bad starter guide
, and there are lots of others. You say you've "read up" on preventive measures--that's great! When your original post says, "but it doesn’t seem to work," please understand, though, that we who read don't yet know what "it"
means
, in this case. Clarity & details are you friends here.


q:
I need help with finding what properties or designs I need to look for. I know that I will need these characteristics to work with the material of my choice:

Can reach 300 °C or up

Can handle nozzle size larger than 1 mm

Can be used with polycarbonate filament

I plan to use it in a custom RAMPS 1.4 3D printer running the Marlin firmware, in case this changes something.

[A]
By  interpreting your question as
"Can most hotends print polycarbonate at 300°C+?"
, and taking into consideration the answers to
Can cheap hotend parts sourced from China actually produce good prints?
1
, then it would seem to be safe to assume
2
that most hotends can, given a few adjustments or considerations:
Use of a PT100
3
or thermocouple, en lieu of a thermistor
Use of PTFE tubing
Taken directly from
E3D's V6 product info
:
The V6 can comfortably reach 285°C with the supplied thermistor. By swapping a thermistor for a thermocouple (may require additional electronics) or PT100 you can reach over 400°C. This not only allows you to print extremely high temperature materials like Polycarbonate and Nylons but also eliminates HotEnd meltdown failures associated with PEEK/PTFE designs. The PTFE filament guide inside the V6 HotEnd is never subjected to high temperatures, so there is no risk of damage through overheating.
Footnotes
1
The materials used by cheaper clones of the higher quality, more expensive, branded hotends are
probably
the same as those used in the branded hotends, and indeed are probably produced using the same pirated patterns/molds/casts, but with less care and quality involved. They can even be produced in
the same factory
, but are items that have failed the QA tests, and as such are not deemed to be
brandable
.
2
Although, to paraphrase a quote from a movie: Assumptions can be considered to be the mother of all
disasters
.
3
A Pt100 or Pt1000 is a Platinum RTD (
Resistance Temperature Detector
) with a resistance of 100 ohms at 0°C which changes with temperature. From this manufacturer's
website
:
A Pt100 or Pt1000 is a Platinum RTD (Resistance Temperature Detector) with a resistance of 100 ohms at 0°C which changes with temperature. They are suitable for applications in the temperature range of -200°C to 600°C but are more commonly used in the range -50°C to +250°C. These temperature sensors are reliable and can offer a higher degree of accuracy.


q: The company I work for is protective of IP and has security procedures for disposing of anything that could be stolen for industrial espionage.  Paper gets shredded and sent to trusted recycling center, all old data storage media gets obliterated, but what do we do with 3D prints?  For any functional prototype, I have 10 or more early versions and failed prints.  Is there a good way to dispose of these so that they are unrecognizable?  Given the volume of prints I need to dispose of, it should be safe, cheap, and able to handle large batches.

[A]
If your company has a shredder which would handle large amounts of paper at one time, it should be able to handle the plastics from 3D printing. Most larger shredders can handle paper clips and staples. 3D plastics would be even less of a burden than them. You may need to break the pieces down into smaller chunks, but I doubt it would be an issue. Even destroying most prints by hand shouldn't be too arduous.
Secondarily, you could also melt them using something hot ... a heat gun would probably do the job without issue.
They get in excess of 1100°F
. Since we
usually
melt filament at around 200°C (~392°F), a heat gun should be more than hot enough to make it an unrecognizable blob of plastic.


q:
I've got a bracelet concept that I've sketched up as a flat design. I'm trying to found a route by which I can extrude this into a 3d object (depth map?), curve it into a bracelet, then ultimately create a STL file out of it. I'm having trouble finding a way to do this that allows me to "warp" the flat object into a bracelet before I try to print.

Is there a recommend technique for this? I'm not worried about representation of the picture; it's effectively meant to be an 'etched' pattern.

[A]
This may not be your cuppa tea, but if you're willing to learn to use
OpenSCAD
or already know how, there's a
Thingiverse
post that appears to directly address your objective.
Correction, this particular post on Thingiverse consists of a series of Python files, of which I have zero experience/qualifications. It may still be of value, if you are Python capable.
Another resource that is strictly OpenSCAD is from Eric Buijs, a rather talented 3D design person. His YouTube channel has a number of useful tutorials for both OpenSCAD and Solvespace.
This video
in particular describes applying a flat object to a curved one using OpenSCAD, resulting in a lithophane.
As I created this answer, I did not re-watch the 12+ minute video, but I recall how he explains clearly how the program dissects the surface into a number of flat panels and then superimposes the image on each segment. From this presentation, I suspect one could expand to a full cylinder.


q:
When exchanging the mainboard of my Ultimaker Original, I found the new (unoriginal) mainboard to have a condensator that is quite a little higher than on the original, which means the fan duct doesn't fit any more.

I read somewhere that those A4988 stepper motor drivers don't have to be actively cooled, but a heatsink will be sufficient:

After testing the theory I found the heatsinks to be really hot, but not too hot to touch. Sadly I do not have any means of temperature measurement other than my fingers...

How hot do they normally get, when should I abort printing and look for a different solution?

Are there any good solutions other than the original cooler & cooling duct?


q:
problem solved by resetting cura.

I have problems like this: How can I fix this? I can't find the right setting.

Also, what are these yellow lines? Do you know how to remove them? They disappear when I disable to show the brim/raft/skirt.

[A]
I'm pretty sure the yellow lines are showing the full path of the extruder head, including where it's retracted.  Somewhere in Cura's maze of menus, there's an option to turn on/off various displays related to the slicing.
As to why the top layer isn't there -- most likely it's too thin in your source  model.  You might try enabling "Print thin walls" options in the Preferences advanced list.  BTW, if you post the original STL or CAD file, we might be able to provide more accurate diagnosis.


q:
Can the glTF format be used for 3D printing?

If not, is there any tool can convert it to another format such as STL, OBJ, STEP, and IGES?

[A]
As far as can be found it should be possible to convert glTF into STL (or OBJ).
You could try to use an online converter to do this, e.g.
this one (greentoken)
; and
this (assimp)
may be useful too.
According to
this
greentoken supports glTF as input and STL as output, but it is reported by @Trish that that does not work. Assimp could output STL files which then could be used by slicer programs to generate the specific G-code file to print the model on your printer.


q:
I'm looking for clamps to fix the glass on my heatbed. After some search I found that some people use clamps printed of PLA. Can I use PLA clamps for a heated heatbed (~60 °C)?

I also tried foldback clips but they block my nozzle. The Anet A8 starts in the front left corner. When I start to print, the nozzle moves a little bit up on z, then up on y and right on x. At this first move it moves into the fold back clip. I'm looking for a way to fix the corners and not to fix the edge in the middle.

What other clamps or clips can I use to fix the glass (~3 mm) on the heatbed (~2.5 mm)? I don't want to use glue.

My printer is an Anet A8.

[A]
Let's analyze the problem:
We have a 5.5 mm total thickness.
We want to (semi)permanently affix the two layers together mechanically.
The clips shall not be higher than about 0.2 mm to allow the nozzle to pass over them.
(non)Solution attempt zero:
Let's look at the problem objectively... we can print something, can we? Well... 0.2 mm or below of PLA means 0.2mm of PLA that need to withstand the stress of trying to push the glass to the bed. PLA, just like any plastic, isn't super strong in thin layers, especially when heated to 60°C to get a good bed adhesion. And then you might want to print something like ABS, which demands an 80°C or higher bed temperature. The result will not be pretty: either the clip breaks after a very short time or it starts to bend. The result: no clip, bed slipping free.
Solution attempt one:
Let's look at old picture frames that consist of just a glass sheet and a paper/wood backing. A "Frameless Picture Frame" like
this one
1
. These clips do need some kind of mounting on the underside.
Using this design as a base, you might either get these clips or make similar ones yourself. But how to mount them?
Well, here comes the nice part: we got some options.
Glue or solder the clips to the underside of the bed. Removing the sheet gets a PITA, but is still possible
Cutting mounting slots for the clips. The sheet can be removed by removing the clips now. But the bed heating might not like us cutting slots into the aluminium.
Adding a mounting point. Again, we can use glue or solder to add some kind of framework that we mount the clips to. Like a piece of aluminium U-profile with the opening to the centre of the bed, giving us mounting points for the clips.
1 - This was just the first one that I found that had the right setup. I am not affiliated with them and don't get money for this.
Solution attempt two:
Take this idea up a notch and look for this same principle applied.
There is the
"Swiss Made Glass Retaining Clip"
Perplexed Dipole
mentioned. Good idea, and instead of having to cut a notch into the aluminium bed, a simple, small hole would be sufficient. About the same price than a frameless picture frame but less construction work!
And then there is, of course, the option to look at the Ultimaker and its
Build Plate Clamps
like
0scar
mentioned. If you can get them (also in the same price range as the other options) you even might have an easy installation: they are supposed to be mounted in the corners of the build plate by being held by the springs. For the A8, you'll have to possibly adjust the mounting point some, maybe even give them a little nub to pivot around to secure them in place, but this clearly is a solution too.


q:
The pictures explain my problem. I have already tried to reduce the retraction but that showed no effect. Thank you for your help.

The effect is a total stop of the print (no material is extruded).

Creality CR 10

Cura 3.4.1

I recently added this new feeder aluminium block because the 3D printed stock version was bad quality.

[A]
This is typically caused by resistance in the tube or hotend but in your case it appears to be mostly caused by a very poorly designed extruder.  The filament needs to be constrained closer to the drive gear.  You may be able to drill out the PTC connector to allow the PTFE tube to reach closer to the gears or print a spacer to fit in between but you need to support the filament in that gap.
You can try raising the hotend temperature as a band-aid until you can fix the problem, do not exceed 240 C if you have a PTFE lined hotend. Long retractions can also pull molten filament into the cold zone where it solidifies and make extrusion harder.
As an example, here is a picture of a Bondtech BMG extruder.  Note how the extruder constrains the filament path all the way from the drive gear to the hotend entrance.  While this example is extreme for normal PLA/PETG/ABS, it is required for flexible filament.  A 4mm gap (or closer) should be fine for PLA/PETG/ABS or other hard filaments.


q:
There's PLA filament clogged in my Bowden tube, is there a best practice for cleaning it out or do I need to replace the whole tube?

Also, the couplings are totally stuck, so I guess those would need replacement too or are there ways to get stuck couplings off?

Click here for a video.

[A]
If you are able to force the filament from the interior of the bowden tube without causing damage to the tube, you will be able to determine the cause of the clog. My bowden tube clogged recently, but it was because I left the system idle with old filament inside. The filament broke from brittleness and the edge of the broken pieces managed to wedge against the tube.
I was able to use a "healthy" piece of filament along with great force (pliers pushing close to the tubing end) and remove the damaged filament.
Once removed, the new filament slid easily within.
Your PTC fittings may not have to be replaced if the tubing is not damaged inside and if the existing spacing meets your requirements. A PTC fitting has a ring of teeth which gouge and/or grasp the outside of the tubing preventing removal. It is frequently necessary to push the tubing into the fitting, then compressing the release ring followed by pulling the tubing.
The PTC fitting at the end where only the filament exits is probably a stock fitting. The fitting which has the bowden tube extending through it has been drilled and may be challenging to find. Your best source for such a fitting is the original manufacturer.
It's clear in the video that the threaded portion of the two fittings are different.


q:
I've been looking into the viability of manufacturing a replacement part for a kitchen blender that has a broken part. I found this page that talks about what makes a print food safe. One of the items mentioned was:

... a brass extruder may contain lead, and lead contamination can cause some nasty health problems. ...

I own an Ender 3, and I haven't replaced the nozzle yet. How can I tell if my printer is capable of creating food safe prints in its current state?

[A]
Yes you have to change brass nozzle it contains lead.
If you are planning to print in PLA don't do that because  PLA filament we are using in 3D printer are not food safe it contains some nasty colour dyes which are not food safe. Consider some special food safe filaments available in market. I think extruder gears are also made up of brass. Consider also changing them.
Steel extuder gears are available in market like below


q: I am a newbie to 3D printing and ran into a weird infill line on my second 3D printing object on a new Qidi X-Pro machine (which works great). I've included a screenshot of the infill line, which is deliberately printed the full height of the object. I'm thinking this line has been deliberately inserted by the Qidi slicer for some reason, but I have no idea why. Do all slicers generate these kinds of lines? If so, why?

[A]
I do not know the Qidi slicer, but if you look closely, you will see this line is thinner than the normal support infill lines. You could try to visualize the G-code in a viewer, usually this can be done in the slicer itself, but
online viewers
are available. The viewer will not only show the printed lines, but also show moves by the print head (usually in a different color). You can check whether this extra line is actually printed or a move. If it is a move, this extra line is caused by your hotend which is leaking when it moves. You need to properly tune the hotend with respect to the retraction settings and temperature. There are numerous retraction test print objects to find on the internet.
Depending on your slicer settings, some slicers are able to define where each layer starts printing (e.g. random, or start at sharp corner). The fact you see a support structure "printed the full height of the object" tells you that each layer starts at the same position. It is not uncommon in uniform simple parts where each layer starts at the same position (X/Y) as this is instructed by the slicer setting. In Ultimaker Cura such an option is called
```
Z Seam Alignment
```
.
Bottom line, all slicers will do this when your printer is improperly tuned (incorrect settings for e.g. print temperature, retraction, coasting, travel speed). It is up to you to find the correct settings, test print objects help you with that.


q:
I'm building a 3d printer of size 500 x 500 x 500 build area. For the Z axis, I'm planning to use this Linear actuator.

The maximum weight Z axis might encounter is 15 Kg due to it being a clay printer. A single linear actuator can, according to the specs, lift 10 Kg. So I'm planning to use two of this.

My question is a ball screw of pitch 4mm or 5mm, will it be able to Maintain it's position when the motor is de-energized under a load of 15 kg shared by two systems.

What effect the diameter of rod has on it??

Is there any way to find that??

[A]
My question is a ball screw of pitch 4mm or 5mm, will it be able to Maintain it's position when motor is deenergized under a load of 15 kg shared by two systems.
The detent torque of a
typical NEMA 23 stepper
varies between around 3 and 7 N·cm. This is the torque produced when the windings are not energized.
Using this
leadscrew torque calculator
, you can find that the torque required for a 12 mm diameter, 4 mm pitch leadscrew to hold up a 75 N load, is around 5 N·cm - assuming there is no friction. If there is friction, then the required torque will be lower.
So, the torque required is almost equal to or possibly even higher than the detent torque. Therefore, you should not count on a de-energized motor holding up the build platform. In practice, you might see that friction is enough to hold up the build platform, but that any disturbance (such as somebody bumping into the printer) is enough to get the leadscrews to start spinning and have the platform drop like a rock.
What effect the diameter of rod has on it?
Increasing the pitch also increases the torque required (so, go with a lower pitch leadscrew). The diameter does not affect the torque directly, but having a larger diameter increases the friction and so is beneficial.