q:
From my understanding, the power of heater must higher than heat dissipate to ambient air so the bed can heat up. The reason why a bed heats up too slowly is due to its heat capacity compared to heater power.

As the heater is a resistive load, I think we can put higher voltage to get more heating power.

The PCB heater has two parts: copper and laminate. The reason of failure is that the copper can come off the board due to high temperatures. In this case we can control temperature with firmware. The questions are:

Will this method work?

What can go wrong or what is the risk of this method?

[A]
Not necessarily
Potential differential U
, aka
Voltage
of a part, is not to be ignored: a 24 V part needs only 24 V, not 36 V. A 12 V heartbeat is only safe for 12 V. There is a little tolerance for those measurements, but rule of thumb is about 10-15% of the rated voltage, so a 12 V bed should not be operated at more than 13.8 V for an extended period.
What actually facilitates heating is the
Current I
aka
Amperage
going through an item, as the formula for the Work P
h
(dissipated in the shape of heat) of the electric resistance R is
$P_h=R I^2$
.
As long as you stay below or at the maximum
rated Power P
r
or
Wattage
of the heating pad
$P_r=U I$
, you can increase the Current up to the limit of
$\frac {P_r} U=I$
. On the bench, with a regulated power supply, we can use that to get a perfect, maximum output as we want it. But the printer isn't a bench with an expensive PSU, we get only something akin to 12 V out of it, so... what to do?
DON'T route in extra Power!
Yea, in DC circuits we can just add batteries behind one another to get twice the Voltage and push a circuit. Or we can put them in parallel, to sum up the current. But that doesn't work just as straightforward in AC circuits (phase shift between parts has to be taken into account). And routing in an extra pair of wires providing 12 V into an already 12 V part would get us something in the order of 24 V and fry the part. You'd accomplish nothing more than turn your heated bed into a fire hazard or a hunk of scrap!
So straight routing in another 12 V on top of what is rated?
NOPE!
Unhooking from the same PSU?
Some printers unhook the bed from the board's PSU, running a (differently) regulated power source. In the best case, it's set up to a Voltage/Current pair that maximizes the bed's heating. In such a setup, the whole heating power runs through a MOSFET that acts as a switch: A signal comes from the board to the MOSFET to allow current to flow. No signal on the Gate of the MOSFET leads to no current reaching the bed and no heating.
However, that is a complicated setup - yet one of the only ways how a "mains voltage bed heater" can be done with a board that runs on 5 V. You
also
will have to route the high power through a properly rated set of wires and connectors. These thicker wires will need proper strain relief as they need larger bending radii than what is installed before. In other words:
you need to know what you do!
Finetuning the power supply to the bed!
In many printers, there's also a less invasive method to finetune the power curve of a bed. usually, there is a Potentiometer that is used to tune the output of the heating wires. Altering the potentiometer's setting with a screwdriver results in the output voltage shifting.
$U=R I$
does not change when flipping to AC but U and I became wave functions instead of constants. However, R of a long wire (such as a bed) does depend only on the frequency of the signal and not on either the current nor the driving potential, we can assume R to be constant. So, we know we want to maximize I². So what can we do easily?
A 24 V heatbed has something in the order of 2 Ω and accompanied mainboard in my Ender3 is - according to the labeling - good for about 13 A on the bed output, while a typical 12 V bed runs in the order of 1.2 Ω while such boards typically are limited to 10-11 A.
$U= RI$
to the resuce and... Voila: For the 11 A/1.2 Ω case we can tune the potentiometer to get just a smidge below 13.2 V - just at the 10 % point, for the 13 A/2 Ω case is
technically
safe at 26 V - and still well within the 10% rule of thumb. However, if you have a 1.2 Ω bed and your borard only allows to draw 10 A, then you are limited to 12 V.


q:
I'm struggling with bed adhesion for nylon on a glass bed (122 °C measured) in an enclosed chamber (45 °C near the front, likely more on top of the print bed). I used a glue stick to enhance adhesion, but after around 20 minutes the print comes off the bed.

I tried a no-brand glue stick and a Pritt glue stick.

Now I wonder whether they are suitable for the purpose, because nylon should really be printable in these conditions. Maybe the glue cannot hold those 100+ °C temperatures.

How to find out whether a glue stick is PVA-based and suitable for nylon (or polycarbonate, ABS) printing?

[A]
Not all glue sticks work! The working ingredient of a glue stick is
Polyvinylpyrrolidone
; a more elaborate answer is found
here
on question:
"Why does hairspray work as an adhesive for ABS?"
.
There are very good alternatives to glue sticks and hair spray nowadays. Specific adhesion sprays exist for several years now (e.g. Dimafix, 3DLAC, Magigoo for PA, Plasticz, PrintaFix, Dr.Mat, etc.; my personal experience is with the first 2 mentioned, both work for nylon: Dimafix has more tack at higher temperatures > 80 °C, up to 80 °C 3DLAC works perfect).
E.g. Dimafix has a higher temperature application range than e.g. 3DLAC. From the
manufacturer
can be seen that:
Source:
http://www.dima3d.com/en/home/dimafix/
This image shows that the spray has its maximum tack/adhesion at about 120 °C and holds this adhesion level at least up to about 145 °C according to the image.
However, not all glues get stronger with temperature! PVA (also called PVAc) glues soften very quickly, making them good only at low temperature. See "
Influence of temperature on the strength of bonded joints
" which discloses this graph for PVAc Rhenocoll 3W, 4B Plus:

s: huggingface

c: devops

d: intermediate


q:
From what I've seen, you can take a typical extruder heater, apply the designated supply voltage without temperature control, and as long as the heater isn't contacting something with a flashpoint below the temperature the heater reaches, the heater will not catch on fire.  Thus, unless one catches the filament on fire, it seems that thermal runaway of the extruder heater wouldn't normally start a fire.

I'm not sure what would happen if someone installed wrong components, such as a 12V heater to a 24V supply. What are situations that could cause a 3D print to catch fire?

[A]
A normal hotend will not melt or cause fires, usually, see first video. However, if the power regulating unit fails as well and higher voltage is supplied (19 V on 12 V cartridge are enough) it can happen, see second video.
Fires are more likely caused by overheating wires, especially where joints are presents.
Hotend runaway does not cause fires from the hotend itself, but it could cause fire related to its wiring. Also, the uncontrolled temperature may make the hot end fan fail, worsening the situation.
Issues canbe caused also by a runaway on the bed and overheating MOSFETs.


q: I am looking for a way to generate 2D horizontal templates for manually carving an object. My thought was to produce an STL of the model, generate the G-code, and then transform that into slices. Appreciate any suggestions for where to start. I'm not afraid of getting my hands dirty with python, R, matlab, whatever.

[A]
I would approach following way. I saw interesting example of using
Autodesk Fusion 360
to generate moves (G-Code) for carving in vertical slices. Fusion generated moves like for CNC tool in "parallel mode". You can see details in the video
3D printer cutting styrofoam like CNC router
(software setup is presented at 11:00-14:30). Steps/settings important for manual work would be:
selecting parallel strategy
steup length and width of tool - reflecting "depth/width of slice"
check the simulation
create NC program - creating the G-Code file
I think that even if really working manually, the benefit of such approach would be that you focus on one layer/slice at time, and carve in one depth from the top of "material block" to the line defined be two points (the move in G-Code). The trouble could be actual number of such "G-Code lines": there will be probably too many of them, e.g. to measure each by hand and draw on the sufrface. But maybe this could be reduced with resolution (and quality). You could try to use any G-Code visualizer to project lines (of given single layer/slice) with beamer on the material sufrace.
The depth (real width of slice) could be controlled only manually, to avoid carving too deep.
The video uses parallel carving strategy to work in vertical slices. "Adaptive cleanring" strategy could be used to work horizontally.


q:
My CR-10 S5 has a feature, that stops the print, when the filament runs out.

However, when the printer pauses, the bed cools down and the print plops if the bed. Is there a way to tell the printer to keep the bed heated, when paused (by the runout detector)?

[A]
This is varying underextrusion due to loss of material to oozing in the interior of the model.
When printing the infill pattern, the nozzle doesn't follow a single continuous extrusion path, but moves from the end of one path to the beginning of the next, and under Cura defaults,
does this without retracting the filament
. This causes unpredictable amounts to ooze out during travel from one to the next, thereby desynchronizing the planned/intended amount of material extruded so far and the actual amount. This means, when the next outer-wall extrusion starts, there's an unpredictable deficiency between the amount of material at the nozzle to extrude, and the amount the slicer intended to extrude. The result is what you're seeing.
To fix it, you need to eliminate oozing, not just outside the model where it appears as visible stringing, but inside too. Either disable "Combing" entirely in Cura, or set "Max Comb Distance With No Retract" to something very low (0.8 mm or less). Also set "Minimum Extrusion Distance Window" to 0 to ensure Cura doesn't skip retractions for other reasons.
You may also want to play with extrusion length and speed. Too short or too long can be bad; 5-7 mm is the reasonable range for PLA with a bowden. Higher speed generally helps too; the printer should be able to handle 50 mm/s or faster.


q:
After a long battle with SKR Mini v2, TFT35 and BLTouch and creating the right firmware. I thought I was through it all and ready to start printing again after finally being able to set the Z offset and auto level the bed. My printer has other thoughts. Now my bed temperature will only heat up to 10 °C below the set point temperature and after a few minutes it starts beeping and says this on the screen "Heating Failed: Bed Printer Halted, Please Reset". As an example, set it to 60 °C, it will get up to 50 °C normally and stop at 50 °C.

Anyone gone through this? I'm sure there is some setting in the firmware that I have missed up. I'm hoping someone can educate me on my mistake.

[A]
Searching the error message "Heating Failed: Bed Printer Halted, Please Reset" seems to indicate that the bed heater is timing out from not reaching temperature.
If you measure the voltage applied to the bed heater before the error message, does the voltage stay at Max.; i.e. 12 V for a 12 V bed heater?  Or, does the voltage stay constant?
If you raise the target bed temperature, does is still error out at stop at 50 °C?
Since you only indicate changing firmware, we would assume the bed heater is the same as when previously working.  Is this true?
Is the resistance of the bed heater a few ohms and not megaohms?


q:
I am looking to 3D print some small molds that will allow wood glue to dry but not stick.

Is there a recommended filament that is known to resist binding to simple wood glue?

Alternately, is there an inexpensive adhesive (like wood glue) I could use instead that will not stick to the 3D printed mold?

[A]
You are looking for a filament that does not bond to wood glue, or as weak as possible. You misunderstand how wood glue "bonds" to plastics:
Wood glue is typically PVA. It
bonds
to wood and paper by seeping into them before curing and hardening. The mesh of the glue entangles fibers of the wood/paper and itself, bonding with not only the exposed surface but also with material up to the depth it penetrates.
When such a glue is applied to a typical print surface, it seeps into the cracks and through print imperfections but does not penetrate the print to the same degree as it does in the open wood fiber setup. It clings to the surface and only bonds - if it does - only to the surface layers. The
same
effect happens when you cast resin into for example a silicone mold: there is much less chemical bonding, at best at the interface, and quite some interlock.
To prevent such, two things should be made: first, you need to smooth the mold as much as possible and have all the angles right.  It might be easier and faster to coat the hard molds in a smooth lacquer, which not only removes the creep areas but also acts as an interlayer, making release easier.
Then, you should use a mold release agent. Mold release agents come in many shapes: I have seen Talcum Powder being used effectively for both metal as well as cold casts, if the shape of the mold was well made (no undercuts, no unpowdered areas). Easier to apply are usually mold release sprays for many applications - careful, some are PVA based and would be the same as the glue you want to cast. For a concrete casting, I had used plant fat as a decent mold release agent.
What might be an alternative to wood glue depends on what you want to do with the finished product.
As far as materials that actively don't bond go, you could look into POM (Which is a pain to print and expensive - it's a bearing material) or nylon (also a pain to print).


q:
I am looking at printing a fair amount of text, ideally using some custom fonts. I quite like Stay Classy but will likely have to consider change if it causes issues.

I am a little stuck on where to start with using these in some tools. I have tried creating an SVG using the font and importing to Tinkercad however that always fails. I only want to print the text, nothing else.

How do I properly convert my font into .svg and import that so I can make my bodies? While I have tried Tinkercad I am open to alternative tools if this can be achieved more easily.

[A]
Fonts are not saved in a format that is .svg compatible. However, text that is written in a font and saved as a black-and-white picture can be turned into a .svg by software. This .svg can be imported by Tinkercad then.
Step 1: Text Picture
Use any software to create a .png or .jpg or something similar. Among the multitude of programs that can do this are GIMP and Adobe Photoshop. Even Paint can do this, or any word processor and then screen capture. If you know your Inkscape, you can skip this.
Step 2: making the .svg
Either you use software like
Inkscape
to import your picture and trace the outlines, or you use a web service. For example
Convertino
or the
Fontquirrel Webfont generator
. You only need the outlines, no filling!
In Inkscape the rundown to tracing is:
File/Import
Path/Trace Bitmap
Update
OK
Step 3: Import
You got your outline .svg, so import that into any software and you can start making your embossed letters. Personally, I would use Fusion360, but most CAD software support importing an SVG and treat that the same as if you had sketched in that software.


q:
I need to print a rotor for a DC motor I'm designing. In the process of testing the behaviors of the motor performances, I would need a material that will not deform at a temperature range between 100 °C to 150 °C.

Since I don't have a 3D printer yet, I would like to know what would be the best choice for my need.
I was planning to buy an Ender 3, but I'm not sure this entry-level 3D printer will allow me to obtain the results I'm looking for. I'm excluding PLA material because I think it's the most "fragile" material from this point of view and for my needs.

My questions are:

Which material should I use in order to have a 3D printed object (rotor) that will not deform at a temperature that varies from 100 °C to 150 °C?

Can an Ender 3 (planning to use full metal hotend and also hotbed) be used to print the filament that is heat resistant? Should I buy a resin 3D printer?

[A]
PEEK (poly ether ether ketone) has a glass transition temperature of 145 °C (293 °F).
Melting temperature
345 °C (653 °F)
Nozzle temperature
370 - 410 °C
Heated bed
120 - 150 °C
Polycarbonate has a glass transition temperature of about 147 °C (297 °F)
Polypropylene has a glass transition temperature is 215 °C
Polymaker PolyMide CoPA (specialized Nylon) Filament has a softening temperature of ~180 °C, but they don't specify the glass transition temperature.  Other materials have the glass transition temperature about 5 °C below the temperature the material softens.
However, the glass transition temperature is only an indication of a physical change: while uncommon, a material may be rigid enough well above it's glass transition temperature.
How to interpret various thermal-related filament properties?
A side issue to consider as far as layout is FDM prints are weakest between layers (layer separation), so you want a layout where this affects your print the least.


q: After seeing a question about FDM printing of temperature-resistant parts, high-temperature 2-part epoxy came to mind. Are there any (experimental or production) FDM extruders for laying viscous, fast-curing epoxy, mixing it at the last moment before extrusion? Or likewise other cured/resin materials, either 2-part or UV-cured (with whole print volume flooded with UV)?

[A]
Is this what you're looking for?
(
https://the3dprinterbee.com/how-does-a-resin-3d-printer-work-sla-dlp-lcd-explained/
)
Material Beam
Material blasting is a unique 3D resin printing technology that can be compared to an office inkjet printer. It is also considered one of the fastest and most accurate 3D printing technologies available for resin printing today.
Material Beam 3D printers are similar to inkjet 3D printers in that they also have a print head from which thousands of tiny resin droplets are applied to the building platform and then cured with UV light. Once a layer has been completed, the building platform automatically lowers to the height of a layer and the process is repeated until the object is completed.
The technology of material blasting enables high dimensional accuracy, but speed is also a convincing point. The process in which the resin droplets are ejected from several print heads, which in turn move back and forth over the building platform, is known as line-by-line cutting. This ensures that multiple parts can be produced without affecting the build speed. As a user, you also have the choice between matte and shiny surfaces on your 3D printed object. However, the individual components for material beam technology are very cost-intensive. Other disadvantages are the waste of material when you choose to print matt surfaces and the low strength of the 3D printed parts.


q:
I got this message from my Creality Ender 6 printer.

Now every time I want to print, or when it heats up, the printer gives me this message.

Can anyone please help with this?

[A]
Someone with experience using an Ender may give a more specific answer to you question.  This is a general answer, not for a specific model.
"Soon enough" is saying the printer timed out before reaching temperature.
Do you see the temperature increasing on both the hot end and bed?  If one doesn't, that's where the failure occurs.
Are you setting a temperature higher than you have ever used on this printer?  If so, check to see if you are beyond the printers capability.
The hotend will reach temperature first. Does it reach the target temperature? If so, the issue is probably with your bed heater.  If not, the issue is with your hot end.
If you are pushing the extremes of your heaters, especially the bed heater, and your printer isn't in an enclose, you may need and enclosure to run that temperature.
Once you determine where the issue is at, there are things to can do to determine what is failing.


q:
I'm using Cura to slice prints from a biodegradable polyester called PCL (Polycaprolactone).

I need to print @ ~70 °C but extruder does not run until nozzle reaches 175 °C.

Which setting to change so extruder will turn on when nozzle temperature has reached 70 °C?

Here are my settings for the material:

[A]
70 °C is a specialty filament. It is well below the
```
MIN_TEMP
```
defined in any sane firmware. In Marlin, you
can't
turn on the extruder in any way, while this is online.
You do need to define your firmware to allow such a print - either by dropping the value in the firmware or disabling Mintemp-protection and then
flashing that firmware
. That is quite invasive.
To
temporarily
disable the
```
MIN_TEMP
```
, you need to run the G-code
```
M302 P1
```
or
```
M302 S0
```
-
```
M302
```
on its own does nothing. However, some firmware distributions might explicitly prevent these two commands of
turning off
the check.
In that case, you might use
```
M302 S65
```
or similar to drop the
```
MIN_TEMP
```
.


q:
I've just changed the motherboard on my Ender 3 Pro with a MKS GEN_L v1.0 and flashed the latest Marlin version on it.

I've calibrated my bed manually using the default XY and Z auto home commands on OctoPrint and a piece of paper.

I'm happy with the calibration, however whenever I launch a print the Z axis moves up from the calibrated position by about 4 mm and starts extruding.

I've checked my Z endstop status with M119 and it's triggered at the right calibrated position.

How can I correct this?

[A]
If you are already sure that homing is performed correctly and in valid position, then there are few reasons why printer may start printing in unexpected position.
Do the following checks to narrow down the actual one:
steps/mm
: use
```
M503
```
(or
```
M92
```
without parameters) to check if currently configured steps/mm match
your hardware setup
for each axis
offsets:
use
```
M503
```
(or
```
M206
```
without parameters) to check that there are no offsets configured
backoff:
look in
Configuration_adv.h
for following line:
```
```
//#define HOMING_BACKOFF_POST_MM { 2, 2, 2 }  // (mm) Backoff from endstops after homing
```
```
(Having the backoff set is nothing wrong, actually. But be sure to also check final positioning in the generated file.)
slicer's Start G-code:
review slicer configuration, if there is nothing suspicious injected to the print file, which could temporarily overrid printer setup - esepecially
M428
,
M206
,
G92
(set position is normal for E in relative extrusion mode, but suspicious for X,Y,Z)
generated file:
review initial part of generated G-Code file, if there are any similar surprises, and if on initial layer section there is expected move to valid Z position before extrusion is made


q:
Apply / find / create a stainless steel coating to apply to a PETG or PLA part to make it react to a magnet.

My goal is to make a small tubular and conical shapes that can be painted with a stainless steel coating and will react with a magnet.

I know I can buy iron filled PLA but these rust which I want to avoid.  I'm trying to get the magnetic properties of stainless steel (no rusting / reacts to magnets)

I have found videos on how to coat with copper / silver / carbon but I'm looking for stainless steel no rust / magnetic properties.

I'm looking for a "low-cost" solution just for testing.

[A]
The surface won't work
The only true-metallic surface treatments I know to be actual metal in large enough amounts to conduct electricity would be leafmetal, akin to leaf gold, and electroplating. However, you can't use the procedures for stainless steels, and even then, the thickness is in the tenth of a µm area and lower. Not only would that be far too thin to adhere a magnet to, it also would be super easy to damage with rubbing.
Filling?
PLA itself does not block magnetism - I have printed a PLA holder for a magnetic GPS device, into which I inserted a simple 0.5 mm steel plate for a magnetic surface with 0.5 mm of PLA acting as the container and seal against water.
If the prints can be done with one end open and no infill or have a dedicated area that a cheap piece of steel can be inserted into, this method can be used too. The only requirement is that there is a cavity on the inside that at some point is accessible. This also can be during the print.
This cavity could either take a piece of shaped steel sheet or be filled with a different magnetic filler, for example, simple iron powder. The powder could be bound in a non-oxidizing polymer, for example, epoxy resin. This method has been used to
create cast stators for electro motors
. It's
not the most efficient
, but might work in your application - if your walls are thin enough.
With the correct mixture, such a material can be used to coat or fill the inside with enough magnetic material to give the magnets something to stick to and not rust away - the shell and the resin together would shield the iron from any air that could rust it. Indeed, a quite stuffed Resin-Iron-mix and a strong magnet have been
used in 2012 to create furniture by the name of "Gravity Stools"
or other art pieces like in
this video


q:
I have a 3D printer built from generic, scrap parts.
It's controlled by a 2+ years old MKS GEN L board running Marlin version 1.1.x.

I want to do a complete bed assembly replacement, including:

Heated bed

Thermistor

Y-carriage

All the hardware bits, including the z-endstop are sorted and ready to be installed.

My question is:

Once I replace the assembly, what kind of software / firmware modifications do I need to do to Marlin configuration for my printer to work correctly?

I understand that I need to modify dimensions and offsets but I am unsure what else will I need to change within the codebase before flashing Marlin.


q:
Since I have lots of PETG, I ran tuning to 230 °C (average temp for my filaments).
What is it good for, in terms of temperature ranges?

For the same printer configuration, and just different filaments, will I need to run it again and again?
Let's assume that I'll be printing between 200 °C and 240 °C.

[A]
It's not a straight answer, but you don't have to run PID tuning every time you decide to print with different temperature. (Until you change something in a hardware near or related to the hotend.)
You can tune PID for different temperatures and grab necessary values, for example:
```
```
M303 C16 D1 E0 S190
22:14:31.872 > PID Autotune finished! Put the last Kp, Ki and Kd constants from below into Configuration.h
22:14:31.886 > #define DEFAULT_Kp 30.87
22:14:31.886 > #define DEFAULT_Ki 3.06
22:14:31.886 > #define DEFAULT_Kd 77.75
```
```
and then store respective G-code commands (like
```
M301 P30.87 I3.06 D77.75
```
) as few different "PID profiles" as new entries in
custom menu for Marlin
or
menu.cfg for Klipper
for quick switching.


q:
Repetier-host has a setting to specify the "print area". That's roughly the size of the bed.

Note that the printer head can go out of those bounds, in my case my bed is very undersized compared to the printer frame, but this would also be an issue if you had clips or some obstacles in the bed.

Is there a similar setting in Cura where I can specify the "print area"/"bed size"/"margins" to be different from the printer width/depth?

Thanks.

Repetier host settings:

[A]
The print area settings would be in the Preferences > Printers. Select the particular printer on the left side pane, then click the "Machine Settings" button.
You will need to set a printing offset
(
```
M206
```
)
in Marlin: via
Start G-code
in Cura, or any other suitable way (LCD configuration, configuration files, etc.).


q:
I have PLA and PETG filament.

I hear that 3D filament absorbs water and causes problems when printing but after printing they can be used with water and they are water proof.

So my question is why is it different after printing/what has changed to make it now waterproof?

Is PETG waterproof or does it absorb water?

Is there a limit on how much water PETG can absorb or will it keep going until it splits and turns to mush?

[A]
Filament that absorbs water prior to printing is subject to boiling temperatures as it passes through the heater block. In extreme cases, steam will be visible and a spitting sound will be heard. The filament will expand as the water exits, causing multiple structural and printing problems.
Once printed, dry filament may absorb water from the atmosphere, but is unlikely to be subject to boiling temperatures.
Waterproofing as a general consideration usually means the ability to keep water out, which is possible if the model is sealed and some printing conditions will adhere each layer well enough to the previous one to provide floating-type waterproofing.
PETG is hydroscopic, which means it will absorb moisture from the air. When printed properly (layer adhesion), the model can be waterproof.
These terms are independent and should not be used interchangeably.


q:
I'm having a "minor" stringing issue, where I'm only getting stringing in helpers/support and infill area.

Background: Calibrating printer with 1 roll of PLA. Still getting minimal stringing, but mainly, stringing in helpers/support and infill areas. Tried different temps, but didn't seem to affect this.

Suspect some kind of slicer optimization settings? I mean, it's logical to not care about how pretty supports & infill look.

I would like to understand why this is happening.
Please point me to the right direction.
Thanks in advance.

Example photo: Outside in: brim, shell/wall, support, brim.
From Thingiverse.

[A]
It would be great if you could add an image showing the stringing that occurs on the filled and helper/support part of the print. It's quite difficult to visualise what is happening/your problem.
I would assume that the density/fill of the print will be different for infill versus helper/support parts of the print. As a result, there are more gaps in the helper/support parts and stringing can more easily occur between them.
Have you tried enabling z-hop/retraction to prevent further stringing?


q:
I've put together a flashlight mount for a camera coldshoe in OpenSCAD.  I originally modeled it in FreeCAD and it was easy to round the edges of the clamp with a fillet and that makes it a little easier to get the light in and out of the mount.

I'm not sure how to do it in OpenSCAD.  Naively, I'm sure I could calculate where on my semicircle I would need to add some cylinders in order to round the sharp corners, but it seems like there'd be something a little easier than that.

Am I missing something?

Here's the coldshoe light mount SCAD file and this is what it looks like:

[A]
I'm far from a wizard with OpenSCAD, but enjoy using the program, learning something new every time. In your case, it's likely that you can use the
roundanything library
to accomplish your objective.
The library will present various implementations in the samples, making it an exercise for the reader to determine which module calls will present the solution.
The image below shows a part which has had the radii applied in a manner similar to your image:


q:
I recently tried cleaning my CR-10S Pro heat bed with acetone and it made this white stain on it.

Anyone have any solutions to this?

[A]
If you use a build surface such as PEI, acetone frosts your surface, leaving a white film appearance.  If you have no additional surface on a glass or metal bed, it is incomplete cleaning.  If incomplete cleaning, you could try isopropyl alcohol (IPA) immediately after acetone, followed immediately by a water based cleaner or DI/distilled water. (IPA dissolves acetone and water dissolves IPA. Once the film dries the next step may not work.)
You can't clean off a frosted surface.  The black surface of the hot bed in images of the CR-10S Pro appears to indicate that the steel bed has a build surface with a plastic material such as PEI.  Reviews of the build surface being difficult to remove prints also implies a plastic build surface on the steel.  Thus, it appears that the white film after cleaning with acetone is actually a frosted surface.
If you use an Elmer's washable glue stick or one with PWP, it will form a barrier between your print and the build surface, that not only will protect your build surface, but will make it easier to clean your build surface with IPA or water based cleaners.


q:
I'm printing a lot of draft parts so I don't care if they fall apart in my fingers, I just need the shape. I can scroll to the Tune menu on my Ender 3 Pro console and set the speed to 200% and it doubles the speed. But when I set the Print Speed setting to 100 instead of 50 mm/s in Cura, it doesn't save much time, even if I adjust the individual first layer speed, wall speed, top layer speed, etc. What is the difference?

Ideally, I would like the first layer to print normally, and then print at 2x speed.


q:
If someone creates a 3D model of a character for 3D printing can I import that model into Unreal engine or Unity 3D for use in a video game? Also is the inverse true? Can I get 3D model of Mario and send that to a 3D printer?

Specifically, it’s more important to know if I can pull a 3D printer model into an unreal game project

[A]
I haven't seen lifts that aren't on the edge of the print, such as warping, or the entire printed surface lifts.  When I get something like in your photograph, it's because the print surface isn't flat and the first layer matches the surface topology.  If the second image shows the print surface, it looks like blobs on the surface that may be keeping it from being flat.
The first layer thickness greatly depends on how high the nozzle is above the print surface.  If this distance varies, the first layer thickness will vary.  Also make sure your print surface is free of any substances that the hot extruded material might cause to boil.
Any chance you are removing the print from the bed before it cools down.  This can distort the print if the material is still soft.


q:
I have found a video about Invisalign. I saw a 3D printer in the video but I did not understand its type. Can you help me? Do you share a brief piece of information about its type?

Below is the video on YouTube.

[A]
If you look at the video at 37 seconds, it appears to be SLA or DLP.
Further reading:
https://www.solidprint3d.co.uk/wp-content/uploads/2019/04/SLA_vs_DLP.pdf


q: I have been using an Anycubic i3 Mega for about a month now and it worked fine. But when I designed a simple model in Fusion 360 and sliced it with Cura it started to have issues sticking to the bed. I thought the problem was the model so I tried to print a Benchy, but the same problem occurred. I readjusted the bed but it's still not working. I'm not sure how I can trouble shoot this.

[A]
The proper answer could be not related to Fusion, as you already noticed.
I suppose the issue is that the Ultrabase surface (or any other glass surface you have installed) was
not cleaned during the first month
? So it should be cleaned from grease and possibly dust. The general cleaning method is to use isopropyl alcohol (IPA) from time to time (btw. I am curious if it is advised in a printer's manual). If it does not fully help, I suppose using a dish soap with hot water prior to IPA is good step. Though I do not own this bed, so could not be 100 % sure of impact. (Definitely do not use any extra adhesion helpers for Ultrabed, because it has some specific microstructure which will get stuffed.)
You could want review other threads like this
How to get Sunlu PLA to adhere to the printing bed?
to get other hints and supplement your checklist. One thing to check first (and regularly) is proper bed levelling at current moment - and compare to initial layer settings in Cura (thickness, width, flow percentage).


q: Comparing trends show that 3D printing stepped over to another level around 2012~2013. Why?

[A]
A great story on the history of 3D printing is published by
3DSOURCED
. It shows that the patents for FDM and SLA expired a few years earlier and the
RepRap
3D printer self replicating project became very popular. Also, 3D printer manufacturers emerged and electronics, software and parts became available at a larger scale, so that it was more affordable for a hobbyist to dive in.


q:
I am building a 3D printer from scratch, the bed will only move on Z and the head will stay at the top of the printer and move X and Y.

How do I modify the Marlin firmware to have the bed lower as it prints instead of lift like most printers.

[A]
To understand normal commands from a basic printer slicer, all movement commands in g-code are written to be away from the base layer as positive. Note that
technically
a "lower the bed" printer does violate Orthonormal coordinates unless you either swap X and Y while retaining 0 in the front-left corner or put 0 in the front-right corner, going left for +X (e.g. inverting that motor axis too) and back for -Y.
Hardware
To
invert
the movement direction of an axis without rewriting the firmware there are two main ways, from mos invasive to easiest:
Mount the actuator "upside-down" as that flips the rotational normal vector.
use a left-hand-threaded rod and nut. This does not flip rotation but how rotation affects the bed.
alter the stepper cables by "crossing" one of the phases leads. The motor rotates reversed to its commands now.
Firmware
In Marlin, you can also just flip the direction of the motor via
```
configuration.h
```
by altering the line from
```
false
```
to
```
true
```
:
```
```
#define INVERT_Z_DIR true
```
```


q:
Just received my new Ender 3 v2. When using the Auto Home feature, the Y-axis motor drives the bed as far back as possible then the motor grinds for about 10-15 seconds. The Y-axis limit switch is not being depressed and the limit stop is about .5 inches away from the switch. The control unit locks at this point and must be power cycled to regain control. If I manually depress the limit switch then it appears to act normally.

Clearly either the limit switch is way out of adjustment or the bed is not positioned properly. Can this be fixed or should I send it back as defective?

[A]
You could still get heat creep with a Bowden tube.  It has different characteristics.  Instead of jamming up in the direct drive, the filament can melt too far upwards into the heat break where it can refreeze and jam.  The characteristic, if you can pull out the filament, is widened filament extending into the heat break.
See
Air printing/jamming midway through raft creation
and
What are ways to avoid heat creep?
Adding fans to an enclosure improves the temperature control in the enclosure.


q:
So basically I've been having a problem with my Micro+.
It will not level / calibrate itself and I can't fix it. The reason I'm here is that I've been using Cura, and somehow it destroyed my bed. (See image)

I would like to know how to get it off, as I tried freezing, scraping and sandpaper

To clarify some things:

The material is PLA,

bed is made of plastic.

My build plate surface got destroyed after trying to use Cura, which sliced wrong and engraved the print into my bed.

[A]
In general I would use
https://github.com/rcarlyle/StepperSim
which takes into account more parameters.
You can play with voltage and current to see which combination gives you the best results for your motor.
Or you can change to a TMC driver with higher voltage (35-50 V) to keep torque at much higher speeds and push the current motor more.
Since the torque you require is likely not so high, you can increase the speed of your stepper motor with 3D printed herringbone gears, for example 4:1. They don't need to be super accurate, backlash is totally fine considering the ridiculous 40:1 reduction.


q: I want to build a mini CNC machine and need some lead screws. I was wondering I can simply 3D print some. There are a few 3D models out there but I want to know if printing it in PLA+ has enough strength for a small CNC. Is it possible?

[A]
Is it possible? Yes. Is it advisable?
No
Lead screws need to be smooth and have little to no stretch and there can be a lot of tension on them. However, 3D prints are quite rough by the way they are made and super weak on tension forces - and not have a good compression withstanding either.
a 3D printed leadscrew is therefore
not adviseable
, especially since ready-made leadscrews and fitting nuts are cheap in the shape of nuts and threaded rods for the crudest setup.


q:
Being new to 3D printing, I started using Cura (which came with my Ender 3v2) to slice models I found on Thingiverse. I know that there are other slicers and have heard positive things about PrusaSlicer.

I know that settings will have different names, but I am asking more about the setup. What things, settings, etc. should I be aware of when using PrusaSlicer? Will I need to re-calibrate anything in PrusaSlicer?

[A]
Basically all slicers work very similarly, it is a matter of preference, being accustomed, or wanting to use a certain (set of) features. Their job is to prepare the object to be sliced in layers to be executed by the printer you use. For every slicer to work properly, you need to configure the printer settings correctly.
Basically, all slicers have the following basic settings:
Printer settings,
these contain information on the printer like build volume, origin, heated bed, nr. of extruders (and what filament diameter is used), scripts, etc.
filament settings,
these contain e.g. information on the print and bed temperature
print settings
these contain all parameters you use in your normally used slicer, these can be hundreds of options like speeds, accelerations, layer height, nr. of walls, etc.
some of the movement profile settings (like acceleration, jerk, max-speed) might be handled as a
printer
setting by some slicers and as a
print
one by different slicers. In the end, some of these are dependant on the printer's construction.
Printer dimensions and layout, filament diameter, and start and end G-code scripts are the things to look for. The rest is straightforward, you need to specify material and object slice settings as you would normally do.


q: I have read that if I disconnect OctoPrint when printing, the print will stop.  Since I thought the advantage of OctoPrint over, say, printing from Cura, was that it didn't tie up the computer while the print was taking place, what are the advantages of OctoPrint?

[A]
The benefit of using OctoPrint as a printserver lies in the fact that it can be used on a stable computer platform. E.g. when you install OctoPrint on a Raspberry Pi, you are ensured that the "computer" stays online. Other platforms, such as Windows are much prone to interrupt the printing process (user actions during printing, sleep mode, Windows updates, etc.). Furthermore, the power consumption of the Raspberry Pi is also much lower than a full computer or laptop running OctoPrint.
An advantage of running OctoPrint on a dedicated Raspberry Pi is that you can access it from anywhere within your network through a browser interface (or even from the outside) as it is always online. Other advantages of OctoPrint over e.g. Cura is that there are numerous plugins available to tailor the printing process to your needs.


q:
I'm new to the 3D printing world and got my first Ender 3 (with the 32-bit controller board).

I have a problem with every single print. I've upgraded to the newest Marlin firmware, did the mesh leveling then started printing and fix the Z bed option in "Tune - Z bed" during the print (so the first layer is perfect). Please note that I save all the data of the mesh before end of the print. Then, when I start the same print again, the nozzle height is wrong. This happens every single print. The strange thing is that I need to adjust the height differently after every print. Like, the first print was -0.055 mm, second print was 0.30 mm, then it was +0.25 mm somehow.

I really like to print without these constant adjustments.

[A]
It sounds like your bed is unstable. This is what I had to do with my Tronxy X1, and I fixed it by installing a decent bed stabiliser. Now that I have a stable bed, I only have to re-level it occasionally. However, the Tronxy X1 is a cantilever printer with a single rail for the bed, not an Ender 3.
I would suggest that you tighten the bed-levelling springs as far as they will go whilst still leaving sufficient movement for bed levelling, and re-position the end-stop switch. Then re-level the bed. If that doesn't work, try fitting stiffer springs. Upgrades are available for the Ender 3. If that still doesn't work, look for bed stabilisation solutions for your printer.
Note also that the bed-levelling knobs have a reputation for coming loose on the Ender 3. Tightening the springs (or fitting stiffer springs) may cure this, but some users fit locking nuts to stop the knobs moving.


q:
I was thinking about this question and thought of maybe printing a pattern-drawing roller painter.

The question is: is it possible to print with an ink absorbing material that could make a paint roller possible?

P.S: I don't own a 3D printer, nor have I any deep knowledge in this matter. I simply want to know if this is feasible, so I can start looking for someone to 3D print this for me. If it's not, knowing beforehand could spare me a lot of time.

[A]
Not really.
It's possible to 3D print in materials like TPE that are rubbery. In theory, one could print a sheet of the pattern and then wrap that sheet around a roller. That would be expensive, though, and I doubt TPE would absorb enough paint/ink to lay down an good and even coat.
As pointed out in the comments,there is one of foaming TPU filament (
Varioshore TPU
that might be able to achieve the kind of soft, spongy feel that a paint roller would need but it's expensive and, I suspect, soft but not particularly absorbent in the way you would need.
I have no direct experience with it, though, so I can't say for sure. For the price and amount of time that would be required to get a print roller produced the way you need, I think you'd be better off buying a
custom pattern roller/brayer
or making one yourself.
I imagine you could achieve this by getting a sheet of stamp pad foam and plotting it with a CNC cutter (or cutting it by hand) and then taping/gluing it around a tube.


q: I recently got an Ender 3 Pro for my birthday, and I am having some problems with elephant's foot (as the title suggests). I have tried several fixes; lowering the print speed, changing the print micron size (quality) in my slicer, and I have also tried the masking tape trick (it definitely does not work). I want to know if there are any other ways to prevent elephant's foot on my prints. I first noticed it on a game-cartridge holder. It was four and a half millimeters thick on the bottom. I think that it could be an issue with the design, but I'm not entirely sure. I can send the specs for the design if you want to look at them.

[A]
Elephant foot on an FDM machine is typically caused by more material (filament) being present in that layer than it has space for.
The most common cause of this is your z-zero is too low, so for the first layer the nozzle starts too close to the bed and the filament gets "squeezed" laterally. You can try adjusting your z-zero or z-stop to allow slightly more space, fractions of a millimeter, between the nozzle and bed for your first layer.
If you don't want to try that, or you'd like to try a different solution first, consider printing the part on a raft so that it starts raised up off the bed and away from that elephant-footing.
There are a handful of other potential causes and factors which can make this better or worse, things like having a large footprint on the bed, but I hope the above is a quick and easy place to start.


q:
Suddenly my prints start having small strings and I'm not sure what to do to eliminate them.

I have already tried to clean the filament tube, cleaned up the nozzle, and played with various retraction settings. Nothing seems to work and I still see these small strings.

Any idea how I can eliminate it?

[A]
What you're seeing does not look like
stringing
, which I would characterize as material that exited the nozzle after extrusion was supposed to have stopped, usually due to missing or insufficient retraction, but like the extrusions along the concave contours
failed to bond
to the previous layer and got drawn across to a point on the other side of the contour where some degree of adhesion resumed. This happens when the lateral acceleration force of going around the curve overcomes the bonding of the new material to the existing material it's being laid down against, and in my experience it's always the result of
moisture-contaminated filament
. This matches your description of the problem has something that "suddenly" started happening.
To fix it, dry your filament. If your bed is big enough, the easiest way to do this is to lay the whole spool on the heated bed covered by a cardboard filament box with one side cut out to make a heat chamber, and running the bed heater at around 60-70°C (for PLA) for several hours, flipping the spool a few times during it. You can also use an oven but I would not trust the temperature control not to shoot up high enough to ruin the filament. If you want a less hackish solution, all sorts of specialized filament drying systems are available but I don't have experience with any to recommend. I just use my bed for PLA and oven for materials that can withstand higher temperatures.


q:
In slicer G-code is it possible to set the probe Z offset for the first layer only?

For my stock E3 plate I find -4.125 mm best however for glass I need to go to -4.175 mm for the first layer to get better adhesion. So it's a manual process every time. Any way to tell the slicer do the first layer at -4.175 mm and next ones at -4.125 mm?

[A]
I don't understand the reasoning behind a first layer having a different offset from the following layers, but, You can manually add a re-definition of the current height after the first layer, suppose your first layer is 0.2 mm, you just need to tell the printer to move to a slightly higher next layer to redefine this as a different Z-offset.
From a G-code file find the start of the second layer:
```
G0 F600 X141.541 Y109.467 Z0.37
```
Modify this to:
```
G0 F600 X141.541 Y109.467 Z0.42
```
Now insert the following command:
```
G92 X0.37
```
Now it is like you have changed the Z-offset.
The reason for not using
```
M206
```
is that is applied onto current offsets, if you accidentally save setting to memory after printing, it stores this offset. You can use
```
M206
```
, but use it carefully. A re-definition of the Z level is never stored, the next
```
G28
```
erases the effect, so does repowering the motors.


q:
Ive been experimenting will multiple color filament but the colors a more or less blended. Is there are filament that goes from one color directly to another without having transition color ex. red to green immediately.

I've been tinkering with Filament Hub Filament and it is very good (some of the best I've ever used)  however I've had to essentially melt strands of one filament to the next and this is unsustainable.

Anyone know any filaments or methods to have an immediate color change

[A]
It takes at least a few cm of extrusion to purge the old color before switching to a new one due to mixing in the melt zone, and possibly much more depending on the particular pigments. If the old color is something bright like red and the new one is white or something close, it can even take many tens of cm before you get a clean new color.
Multi-color extrusion setups either use separate hotends per color or fancy retraction setups where each color can be retracted separately, along with purge towers. You cannot get a clean color switch in the print just by having one in the input filament, and this is probably why all the mixed color filament that's sold is blended - so customers don't get disappointed when it doesn't work like you expect.


q:
I recently bought a Titan Aero hot end which came with a 24 V 30 W heater cartridge from E3D.  I'd like to use this but the cable length is only 1 meter long and I need it to be 2 meters.  The ends terminate with prong connections and there is no polarity to the prongs.  How can I safely extend the leads one meter and then connect to my Duet 3 Mainboard 6HC?

Should the cable terminate with a JST connector instead of the prongs to connect to the Duet board?

[A]
Heater polarity doesn't matter
The heater cartridges are just large resistors and so polarity is irrelevant. Either can be positive or negative.
You can extend the leads by cutting and splicing in ~20 gauge wires* to a two pin JST connector line you suggest.
*
At 24 volts and 30 watts, you need
wire that is rated to carry at least 1.25 amps
. The US National Electric Code dictates that this should be 20 gauge wire, but their standard is very conservative. Since you don't need to adhere to NEC codes, you could get away with something thinner (ie higher gauge number).


q:
Let's say I've made a 3D scan of my face and managed to get that into FreeCAD. How might I then create an object (it's a mask, okay?) that conforms to the shape of my face, with a given thickness, such that I can export and 3D-print that part only?

So if I printed it, it would fit over my face, but still look like my face from the outside, too. It would be, say, 3mm thickness througout.

To be clear, I'm not looking to make a 3D model of my head (the world does not need such a thing), or 3D model of a mold that I can use to replicate my head. I just want to make parts that conform to the shape of other, complex, parts.

[A]
It depends on the software you're using, but here is an example with TinkerCad.
Step 1: Import your 3D model (imagine that the ball is a head):
Step 2: Change its type from "Solid" to "Hole"
Step 3: Create a "Solid" box around your imported model.
Here is the inverted Solid/Hole version:
Here is the Solid version with the Hole model inside your Solid box:
Step 4: Select both models and group them:
Step 5: Add a box covering half of your mold (ideally splitting it in half):
Step 6: Duplicate the mold and the box
Step 7: Group the left mold with its surrounding box:
Step 8: Invert the box of the left mold by taking its left corner and dragging it over to the right side of the mold:
Step 9: Group the right box and the mold.
Step 10: You now have two molds for each half of your model:
Based on your comment, I'm adding a couple more steps:
Step 11: Take your cast, duplicate it, enlarge the duplicate, make it a hole and fit it over your cast (like so):
Step 12: Group the left cast with the larger "Hole" copy:
And if you're going to 3D print it and fit it over the old model, then you might want to enlarge the cast by a few mm.
It's now up to you to figure out how to clamp the molds, inject them, and then separate them.
A few things to keep in mind:
You might want to play with the placement of the model inside the mold a little better so it's not at the bottom of the mold but more towards the middle.
You could also get a bit more creative with the joining of the two molds by adding channels or some kind of way that they can fit into each other with greater precision. Here is an example:
.
If the parts are more complex, then the cast will be more challenging and might require to be split into more parts.
Good luck! :)


q:
I have a problem in regards to filament jam, however I don't think that my case is any related to the extruder nozzle.
After 30 to 40 minutes printing my filament bends and get stuck on the tube entrance.
To print a nut wheel which comes as a demo file, I had to repeat the operation 4 times, and I had to stop printing when it got stuck, and continue with the printing, which led to a small imperfection.
What's the problem? The filament? The printer? Myself?
I have a Voxelab Aquila (completely new) and the filament u just a generic PLA from Amazon.

[A]
Something is stopping the filament from going down the tube 30 to 40 min. after you start printing.  You are correct that this doesn't sound like a clogged nozzle.  It could be deformed filament, but the closeness of the timing after the start sounds like heat creep.  Other possibilities are also listed at the linked stackexchange article.
Note: with heat creep the filament will not jam in the tube.  It will jam just above the nozzle on a Bowden tube extruder; thus the filament stops going down the tube.  The tube entrance is probably the largest location the tube can kink, although not very large.
What are ways to avoid heat creep?


q:
I am currently trying to print a company logo on another part I have printed in a different colour. To try and maximise the strength of the part, I need to print the part on a different orientation to what I intend on printing the logo on. As a result I need to in a sense re-adhere the part to the bed so I can print the logo. I am using PLA filament on a spring steel sheet (the default sheet with a Prusa Mini).

Any ideas would be appreciated before I accept defeat and just glue the parts together.

[A]
Adherence is the 3D printer's worst enemy.
I use painter's tape, but I heard that you can if you need to remove and re-stick it back, heat the part lightly with a lighter and re-stick it back to the bed. Never tried but I'm guessing you would need to cool the bed, heat the part, and stick it back then reheat the bed and continue to print.
Glue sticks can maybe help or even hot glue. But I would be afraid in that case that the part wouldn't be level hence the glue would be to tick.


q:
I've recently switched to PETG , and I'm using Cura as slicer and Ender 3 as printer.

I'm printing a model which Cura declares to be 35 g, but if I weigh the printed model it weighs 23 g.

I'm printing with just 1 line of skirt, so its weight is negligible on total weight.
I've replaced the stock plastic extruder with a double gears metal extruder (3Dman 11 Dual Gear Extruder ).

I've also replaced the stock springs with metals ones.

I'm not having a quality problem, just I want to understand if this difference is caused by a bad configuration that could be improved.

Which are the corrections/checks that I need to do in my setup (both printer and Cura) for fixing this difference?

[A]
The density of the filament can be specified in the material model of the filament in Cura (Preferences -> Configure Cura... -> Materials and click on the material/filament you are using to slice your model for PETG), look at the value behind
Density
, the PETG filament I use is using 1.28 g/cm³ (
PETG Economy Black -> Specification >
).
This field is user editable, so you can change it to your needs. Cura calculates the weight based on the deposited volume.


q:
Does anybody if the Anycube Mega X comes with a nozzle for 1.75 mm filaments or is it 2.85 mm?
I saw online that it works with 1.75 mm filaments but the Cura settings given by the manufacturer had 2.85 mm.

I should mention that using a 1.75 mm filament works BUT my designs have clear under-extrusion, which is very likely caused by having 2.85 mm in the settings. So at this moment, I am trying to gauge whether to change the settings to 1.75 mm or buying 2.85 mm filaments (this only works if the Mega X comes with the appropriate nozzle).

[A]
Reading all 49 pages of the manual was fruitless. I'm astonished that there is no reference to the filament diameter used in this printer.
From
3dJake's web site
comes a confirmation that the printer uses 1.75 mm filament.
It's not a matter of changing a nozzle to use 2.85 mm filament, as the entire filament path is based, in this printer, on the 1.75 mm specification.
To find 3Djake's site, I used "anycubic mega x filament diameter" as the search terms. Many other links appeared, confirming the 1.75 mm filament size.


q:
Every now and then I'll have a problem with layer shift. Solving this is a separate issue, but it occurred to me: most of the time when this happens I notice right away because of the noise. What if there were an easy to to pause the print, re-home the X/Y axis (not Z), and then resume. I'd only have one layer that was a bit off. Sometimes that's enough to ruin the print but sometimes I could clean up with a razor knife later and just live with the small scarring and weakness.

Is there a way to do this during a print? I suspect it might require support within the printer (or print tool like OctoPrint), and might also depend on how the print is sliced in terms of knowing absolute vs relative coordinates at any given moment.

[A]
Have you tried this? It should just work, at least if you're using software like Octoprint to control the printer over serial interface rather than print-from-SD-card on the printer itself. In such a setup you're free to submit whatever commands (in particular,
```
G28 X Y
```
) you like while the print is paused. You'll need it setup to save and restore position across pause/resume, or the next command executed might start from the wrong starting position; this would be no problem if it's a travel command, but if it's an extrusion move it would make a mess.
If you're using the printer's builtin pause/resume functionality, I'm not sure whether it will work. It mainly depends on whether it
lets you
access the homing function while paused. If not this is more of a logic limitation than any fundamental incapability, and could be fixed in the firmware.


q:
Any hints or suggestions (filament type? suggested settings? model sources?) for 3D printing minis to use in Dungeons & Dragons?

I've done a couple where the support structures were difficult to break off without breaking off a hand or something.

I have a Lulzbot Mini (1), single-extruder if that makes any difference.

[A]
Buckle up, this is going to be rough:
FDM printers are not the best choice for printing figurines in the 25 to 40 mm scale that is typical for wargaming and D&D games. Resolution-wise, that's the area of
resin
printers.
But there are ways to get some partially decent prints made:
you might want a small nozzle. 0.2 is about the smallest you can do without specialty extruders, so there is our lower limit.
You need to make sure to have a minimum layer time set, especially as the crosssections of figures are often rather slim.
Overhangs can be a pain
You might be better-served printing "meeples" than actual figurines.


q: All of my completed prints come out with rough edges. What are some methods for removing rough edges from 3D prints? Also, are there any ways to reduce rough edges on prints? For reference, I use a FlashForge Adventurer 3 and PLA filament.

[A]
To remove unwanted residual material:
You can scrape with a knife
Use sand paper
use files
Very fine sandpaper or files can smooth out the rough surfaces left from filing or sanding.
Dremel tools tend to be aggressive.  They tend to melt the surface if too fast.  Buffing wheels are probably the most useful on a Dremel.  Dremel tools are good for cutting.
A deburring tool can remove sharp edges such as parts of the brim that don't want to come loose.  However, it's not unusually to need to scrape off flat surfaces as well.
If you want to smooth out the surfaces left from layers, you can:
Carefully use a heat gun or heat from other soldering tools; not spending too long in one spot.  The difficulty with using heat is most prints have fill rather than being solid; so, with only two or three outside layers, it's easy to get the surface to deform into the fill. Also the print material will tend to stick to solid surfaces hot enough to melt the material.
Use acetone on ABS.  Don't breath the fumes or dissolve your print.
Paint the surface as the comment from user77232


q:
When I first got my 3D printer (a FlashForge Adventurer 3), it came with a sample pack of filament. With this filament, I was able to use skirts for my first layer. When the sample filament ran out, I switched to Hatchbox PLA filament. For some reason, I cannot use skirts with the Hatchbox filament. Now, whenever I try to print something with a skirt, the print moves around, ruining it. The only first-layer that works now are rafts, which I do not like, as they use up more filament and are more of a pain to remove. Is anyone else having this problem? If so, what are some workarounds to this issue?

Here are the failed prints. I terminated them mid-way, as they started
to shift on the build plate.

[A]
It is unlikely this is a filament material issue since many of us have used Hatchbox PLA without this issue.  This is a first layer adhesion issue.
Your bed may not be clean, or the bed may have had an adhesion layer you cleaned off.
Your nozzle may be too high on the first layer.
Your bed my not be level.
Glue sticks can help adhesion.  Glue sticks usually don't post the composition on the packaging, but Elmer's glue sticks work.  Elmer's washable makes it easy to remove the old layer before adding a new one.  There are also glue sticks specified for 3D-printing.
Here's a discussion on glue sticks:
Are all glue sticks PVA-based? How to find out?


q:
I’ve got this proximity sensor which is a 5 V, it doesn’t say it can be used over 5 V. Can I use a buck converter or is it possible to wire it up direct to a 5 V source on the Ender 3 V2?

What I don’t understand is where to wire it direct to 5 V on the printer or if I use a buck converter then where does the 3rd wire go to on the printer?
If it goes to the signal wire on the Z endstop then which one is the signal wire?


q:
I broke 2 keys (i.e. left ctrl, enter) on my Asus UX31A laptop and it seems that this model is too old to find replacement keys.

Is there any way I can find a 3D model of the needed keys to have them 3D printed?

I do not have a printer nor I have any experience in this field.
What I need is either someone that has models for these or that can point me where I can find such models.

[A]
This is more off-topic as an answer, but serves as a possible solution.
Replacementlaptopkeys.com is a resource that appears to have keycaps for the model you've noted.
https://www.replacementlaptopkeys.com/asus-zenbook-ux31a-db71-laptop-keys-replacement-dark-brown-black/
At seven dollars a key, it's going to be less expensive than 3D printing to accomplish your objective.
If you owned a 3D printer, it would not be less expensive to purchase, but the work involved would increase your cost to have such keys commissioned. As a 3D printed object, the strength is going to be less than a keycap purchased from the linked site.


q:
I have a 3D printer, which wasn't used for a longer time. There is a nozzle, but don't know what diameter is it. I used several widths - from 0.2 to 0.8, switched them depending on my needs, but don't remember which one was used lately.
The nozzle is a little bit worn down, so the diameter on the side is not visible.

How to get the nozzle diameter, without taking it off the printer?

This is more of a theoretical question, because I can simply swap the nozzle, but still - eager to know.

[A]
The best method is to have a scale on your microscope that looks like a ruler drawn in the optical path.  However I usually visually compare an unknown nozzle with known nozzles under a microscope.  If you don't have a microscope, you can get USB otoscope cameras (15mm focal length for looking in ears) for under $20.
You can get a fairly good idea of the size by telling the printer to extrude in air then measure the extrusion diameter with calipers.  Of course, it's better if you can compare with a known nozzle.  If you push the filament through by hand, the extrusion will be too thick.  With the stepper motor extruding, I measure the extrusion diameters between 0.3 and 0.5 mm on a 0.4 mm nozzle.  Low cost calipers are less than $20.  The main different with the low cost calipers is the slides are not smooth, reducing the accuracy in the 0.01 mm place.


q:
I've observed printing PETG that the primary if not the only reason for using a high bed temperature seems to be preventing the bed from acting as a huge heat sink and rapidly cooling the initial layers such that they don't bond well to each other. In particulat, the heat is not needed for adhesion-to-the-bed purposes. This got me thinking whether there's a way we could get rid of the requirement, as a way to save time and all the energy spent heating the bed and cooling the room it's eventually dumped into.

With that in mind, are there viable bed materials that are good thermal insulators? Just putting down a layer of any insulating material between the underlying bed and buildtak or whatever surface you want might work, but I would think these kinds of print surfaces are designed for moderate to high thermal conductivity themselves, and wouldn't be as bad a heat sink as the underlying metal, but might still sap a noticable amount of heat out of the part right away.

[A]
I’m pretty sure it can be brought separately but usually comes with a lot of heat-beds; It is a type of foam that has adhesive on one side and aluminum foil on the other.
Here
is an example of what I mean:


q:
What fan speed should I use with PLA? Do I need to manually set the fan speed in ‘Control’?

Also, on the filament cartridge Bed Temp is listed: "No heat/60-80 °C". Does this mean heating the bed is optional?

[A]
Most commercial blow-molded fuel tanks for model airplane fuel (methanol or ethanol, nitromethane or nitroethane, and some combination of castor, mineral, or synthetic lubricating oil) are made from HDPE.  This material isn't commonly seen as filament, in my limited experience, but it ought to be possible to arrive at settings that will give a liquid tight tank without further sealing if you can find some.  As you note, limonene might be used to smooth/seal HDPE prints, but likely won't be necessary if your settings are right.
You might want to test PETG filament for its resistance to your fuel mix(es) -- this material
is
available as filament, prints with settings little different from generic PLA (in my experience, higher nozzle and bed temperature, and a little more bed clearance for the first layer), with good layer adhesion and, with a good print, is liquid-tight as printed.  It's not particularly flexible (as is the case with HDPE), but since you can customize the shape of your fuel tank, it may work for you -- or it may be more flexible in vase mode, as PLA is.
Sealing PETG may be as simple as baking it (similar to "heat treating" PLA to increase print strength, albeit again at a higher temperature) -- this partial remelting will ensure that layers are adhered throughout the print, which (presuming you have avoided under-extruded areas) should be all that's needed to make a printed tank liquid tight.


q:
I printed a lot of models in last month. I spent 2 kg filament in total. I want to know how many hours have been passed while printing. As far as I read, 1 kg PLA (1.75 mm) is about 110 meters long. My default print speed is 70 mm/s. The nozzle diameter is 0.4 mm. The nozzle multiplier in the simplify3d is 0.9 .

In a very basic math,
220÷(0.7×0.04÷0.0175×0.9)=~ 153 hours.

Is this correct?

[A]
Your math looks correct, and is also a good approximation for what I've seen in the first few weeks with my own Ender 3.
Another way to calculate (to check yourself) is to calculate the volume extruded (nozzle area times extrusion percentage times print speed -- be sure you convert everything to the same units!) in a given second, multiply by the density of your filament (common PLA runs about 1.2 g/cm^3), and get a rough figure for how long it takes to print a kilogram of filament.  Your actual print time will always be higher than this approximation, because there are moves during which the extruder isn't running, infill is often set to lower extrusion level, and of course there's setup and cleanup time to account for.


q:
I want to get my Ender 5 plus to print at 300 °C. As such, I've edited the firmware and increased the HEATER_0_MAXTEMP to 315 °C.

In my slicer, I can slice and print at 300 °C, however, I cannot manually adjust the temperature on the LCD screen past the stock setting of 260 °C.

Any help in getting the manual adjustment fixed would be greatly appreciated.


q:
The problem with my Anet E12 should be on USB connection itself.

If powered down, the board still gets power from USB

If board is resett, USB will still connect

Still works on SD; seem like most part not damage.
What cause the problem? Where to check first? How to fix it?

Note: This printer worked with no problem before.


q: All the blower fans for part cooling I've seen rotate counter-clockwise when viewed from the intake side. I'm looking to replace mine on an Ender 3 with something stronger, and one of the worst parts of the stock design is that it's offset by about 20 mm versus the nozzle position, requiring awkward duct paths that reduce the flow to get uniform coverage around the newly extruded material. A fan that rotates in the opposite direction, with air exiting on the right-hand size when viewed from the intake side, would be exactly right. Are there such models available, and if so, what is the right terminology to search for them by? Or is there a simple way to modify a fan to reverse its direction?

[A]
I see that you have a minimum support angle of 60 degrees -- that may mean Cura Slicer isn't generating supports for that chin.  Try changing this minimum to a lower figure -- 51 degrees or lower.  From what I've read, most filaments and settings will allow 60 degrees with PLA, but this is the easy first thing to try to get that chin supported.
On looking at the photo again, I also wonder if what looks like a bad overhang print is actually supports that didn't separate as they should -- perhaps you only need to adjust your Z skip for supports to get them to come off the actual part better.
Following up, I saw a likely cause for this on one of my own prints yesterday -- coincidentally on the chin of a sculpture part.  What I observed is that supports for this region, which trailed up the body (as would those for your dragon's chin), likely due to their slenderness, repeatedly got knocked over.  The support structure "healed" over several layers after each such incident, but in a very fragile condition that would again get knocked off by a nozzle brush.  The solution to this is either to enable Z-hop on retraction (so travel doesn't brush the nozzle across supports printed in the same layer), or to reorient the part so the problem support is shorter and doesn't run right alongside the actual body wall.  Z-hop has less effect on other areas of the print.


q:
I have an Ender 3, currently in stock Bowden extruder configuration.

I want to be able to print nylon and TPU, both of which require temperature too high for the tolerance of the PTFE Bowden tube (as well as the issues with the flexible filament in the tube).

Therefore, I've considered converting my printer to direct drive.  However, the conversions I've seen, both DIY/print the parts type and commercial, seem to include a short length of the same PTFE tube between the extruder (now mounted on the hot end carriage) and the actual hot end.  This same material ought to have the same temperature limit (about 250 C) as it would have in a Bowden configuration -- and for nylon, at the least, this is a problem, since the PTFE would start to soften from contact with the heat break.

Am I missing something in these conversions, or is the PTFE's glass transition not the limiting factor in printing hotter with a direct drive conversion?

[A] Direct Drive v.s. Bowden has no relation to the maximum print temperature. What determines the maximum print temperature is the design of the hotend itself. There are "all-metal" designs, where the PTFE tube (Bowden or not) stops in the cold zone and the heatbreak and all other components that get hot are fully made of metal. Other hotend designs have the PTFE tube run all the way down into the hot zone and this limits the maximum printing temperature. It has nothing to do with whether the hotend is Bowden or not.


q:
I just assembled Ender 3 and noticed that the X-axis movement doesn't correspond to the commands. When I make it move 1 mm with the encoder it moves 16 mm. Everything is in the "out of the box" configuration.

The current steps/mm for the X-axis read (from the display) 80 steps/mm.

Am I supposed to manually fix this with steps per mm setting or could it be another problem. Other axes seem to work fine. I also double checked and everything should be built correctly.


q:
My Tevo Flash works well. Right now, I'm trying to print a thin, disc-like part on supports. The 3 perimeters at the edge of the disc are OK. The dense fill zigzag pattern makes many U-turns near the perimeter. It all looks OK in Simplify3D. But in the printed part, in several spots, the zigzag pattern doesn't reach the perimeters, leaving a ~1 mm gap.

My guess: in those spots, the filament has nothing to grab onto underneath, so the U-turn region is dragged back by the nozzle a bit (away from the perimeters) and/or it droops. I'm using the smallest support res in Simplify 3D: 1 mm. Any options I can try?

[A]
The zig-zag pattern are known for this kind of fluke...
I will use Cura to demonstrate, but it's gonna happen on the majority of slicers.
See this example:
Because nothing is really a circle on a cartesian plane and there's resolution limitations on the real world, the slicer has to account for these and, assuming you are using zig-zag to save time, they are doing what is expected. The Zig-zag pattern is a continuous, fast way to fill the top/bottom layers.
Now, see this lines pattern top layer:
It has much smaller air gaps. Every time the nozzle finishes a line, it has the chance to reposition itself to make a much smaller gap, just because isn't continuous.
So yeah, the air-gaps are a "feature" for zig-zag patterns, but you can mitigate this effect reducing the line width on top/botton layers.
It seems that increasing "Skin Overlap Percentage" on cura mitigates this effect too, but i really haven't seen the effects of this setting on a real life object


q:
Having started with an Ender 3, it just seemed natural to me that the heatbreak should not be load-bearing; Creality's stock hotend has 2 bolts holding the heat block to the heat sink, which of course waste some heating power and increase the cooling needed to avoid heat creep, but serve the important purpose of keeping the nozzle position rigid relative to the carriage and making it so you don't bend or snap the heatbreak when changing nozzles.

Looking at hotends (especially all-metal ones) for a possible future printer build, I'm surprised to see that many (most?) don't have this property, and have the heatbreak playing a load-bearing role. This seems really undesirable. Only the Mosquito makes a point of doing this right, and supposedly has a patent on this or related design decisions. Is that really the case? Are there basic all-metal hotends that are designed to avoid making the heatbreak load-bearing that don't cost $150?

[A]
The drop-in replacement all metal hotends for the Ender 3 that I've looked at seem to have the two screws -- though I've read/heard opinions that these are intended to be removed after assembly, these are common Mk. 8 type hot ends, but with 2 mm bore through the entire heat break instead of 4 mm.  That seems to be the only modification (other than not anodizing the aluminum heat sink).
While the brand name units of this type run approximately 65 USD at retail, they're available from Chinese vendors for under 10 USD plus a few dollars shipping, if you don't mind waiting a few weeks instead of a couple days to receive your part -- and if they aren't from the same production but sold without extensive vendor support, they're very close physical copies, according to review videos I've seen.
It's also possible to replace just the heat break for similar cost, either in stainless or titanium, with a 2 mm bore unit; this would obviously preserve whatever additional mounting hardware exists on/between your original heat block and heat sink.
BTW, if they aren't already, replacing the screws with stainless will significantly reduce heat loss through the screws -- stainless is a much poorer conductor of heat than common steels used with plated screws.


q: I am pretty sure that sanding makes a lot of microplastics, so it would be nice to collect the dust, and melt it to got a blob of plastic again instead of millions of tiny particles. What is the best way for collecting it, do you use any dust extractor, or are there different techniques like sanding wet surfaces and filtering it from water?

[A]
As an environmental thing, micro plastics are an urgent problem for ocean life, it’s getting into the entire food chain. With that in mind dumping it down the drain would be the worst, city filtration systems can’t get the tiny bits of plastic before it drains into the ocean. Sanding outside is kind of bad. I sand stuff over a lined waste basket outside, which maybe catches 75% of the dust. Inside (or outside) with a vacuum running would be good, I think best would be a vacuum with disposable bags. Yes it is still micro plastics, but it ends up at the dump, where the soil is already poisoned, and hopefully nowhere near the ocean/waterways, and likely will stay there while it breaks down. PLA takes ~80 years, but ABS takes 1000 years.
The idea of collecting the dust and fusing it sounds like it would be too much hassle to be feasible long term, it’s good, sustainable habits over years that add up.
As a side note, card scraping is a nice way to smooth 3D prints, that doesn’t make fine dust.


q:
I didn't have any printer-related problem for the past 6 months, but now all of a sudden my Prusa MK3S stopped extruding during printing.

This is very strange as I can easily load\unload filament and control the step motor via Settings\Move axis\Extruder. When I did so, the filament got extruded normally.

However, when I try to print something or do First Layer Calibration, nothing comes out of the nozzle. I tried changing the Live Z (maybe nozzle too low) and it didn't help. I once managed to extrude something by increasing the temperature and the flow (in the printer's menu) to a ridiculous value of 999. Obviously, this isn't the best way to solve the problem.

Is there an easy way to fix this? I only had this problem yesterday and with some midrange-priced PETG

Edit: I tried different filaments, default slicer profiles, reinstalling slicer (prusa slicer) and drivers. None of these methods really helped.

[A]
It doesn't seem to be heat creep. See
What are ways to avoid heat creep?
Have you measured the actually temperature of the heater block?  You may have a failing sensor (thermistor) or sensor circuitry.  Optically is the best way to measure.  The least expensive way is with multimeters that come with a temperature sensor, such as a thermocouple (lowest cost about $20 U.S.).


q:
A Bowden tube extruder (like the stock one on an Ender 3) is known to have issues with printing the most flexible TPU, and with filaments that (either due to composition or condition) don't take well to too much retraction -- though the latter can be ameliorated somewhat with slicer settings.  Direct drive extruders, on the other hand, by reducing the extruder to hot end distance to the practical minimum, greatly reduce the amount of retraction needed as well as the effect of filament compression and stretching.

One potential down side I'm aware of is that putting the extruder stepper and drive on the X carriage adds mass that the X drive motor has to both accelerate and decelerate; this could in theory have an effect on print quality, increasing ringing and overrun on the X axis (though this isn't generally a problem with the steppers used on the Ender 3 and similar printers).

What other reasons might there be to prefer a Bowden tube over direct drive?

[A] Other than higher carriage mass as you already noted, the only other reason to not go with Direct Drive over Bowden is the higher level of maintenance required. In most cases Direct Drive will provide advantages such as increasing the maximum flow speed, enabling the use of Linear/Pressure Advance, shortening Retraction moves, and better resistance to obstructions in the filament path, and more reliable printing of flexibles as you have already noted. As well, A direct drive system would allow a less-powerful stepper motor to be used, which cuts down on the carriage mass problem.


q:
I've got some sliced models that represent the right-side arms and legs of a robot. I'm really happy with how they printed, so now I'd like to print the left-side arms and legs.

I was thinking it would be pretty trivial to parse the G-code file using Python and change the value of all the Xn commands from n to 2*h - n, where h is in the middle of the bed, say 110 or 120 mm for an Ender 3.

Before I fire up my favorite IDE, are there any major gotchas I might encounter from such a naïve approach to mirroring the G-code like this? I originally sliced in Cura 4.9.1.

[A]
If your slicer does not have a mirror operation or a scale that allows negative values then mirroring in the G-code should be straightforward.
As long as your printer doesn't have certain specific tool change or homing or purge positions that are done in the G-code you can just transform it, otherwise you would want to skip these sections and just do the model data (it should be obvious looking at the code where model data starts).
In order to mirror it you just need to swap out the X coordinates in your G-code, If (0,0) is the center of your bed, as is often (but not always) the case for delta printers you will just want to negate the X, so
```
G1 X30 Y-3 Z2
```
becomes
```
G1 X-30 Y-3 Z2
```
.  If your coordinates have (0,0) in a corner  (often the case for orthogonal printers) then you want to subtract X from the maximum X value. for instance if your bed is 250 mm wide then in
```
G1 X30 Y10 Z3  X30
```
becomes
```
X(250-30)
```
or
```
G1 X220 Y10 Z3
```
.
There is only one caveat, some slicers will switch to relative movement using
```
G91
```
for certain operations and then back to absolute with
```
G90
```
, so you will want to look out for these. Between a
```
G91
```
and a
```
G90
```
you will want to negate the X, no matter where the origin of your printer is.
When writing your script, I'd keep track of the minimum and maximum values encountered and the new minimum and maximum values and print them at the end as a sanity check so you can see if anything is wonky.


q:
Some people have figured out how to take raw LiDAR data and after going through multiple steps (using LAS tools, converting to digital elevation model (DEM), converting to an STL) getting an STL file that they can then slice and print.

Could you write a program that cuts out all of those intermediate steps and converts raw LiDAR data directly to an STL that can be printed? Could you even cut out the need for slicers and just go straight to a G-code file?

Is this even possible?

From 3D Printing Models derived from Lidar Data:

Retrieve Lidar Data

Process Lidar Data

Create a DSM

Export the DSM into a .STL

Process for 3D Printing

3D Print!

[A]
TL;DR - The problem would
appear
to be that some of the steps require a bit of manual tinkering in order to complete them successfully - it isn't just a simple question of conversion. So, no (not currently).
Also, whilst writing this answer, it dawned on me that unless someone has actually managed to automate the whole process already, then your question may merely invite opinions (rather than factual solutions).
From the link that you provided the conversion stages seem to be:
Obtain the
```
LAZ
```
file from LiDAR
```
LAZ
```
to
```
LAS
```
```
LAS
```
to
```
DSM
```
```
DSM
```
to
```
STL
```
```
STL
```
to G-code
These stages would need to be put into an automated pipeline.
Step 1
This step could be automated.
Step 2
The LAZ to LAS seems to be a straightforward conversion using  command line tools
```
las2las
```
,
```
lasview
```
and
```
las2dem
```
. This step
probably
could be automated (assuming that no manual intervention of the settings is required), as command line interfaces are easy to script (when compared with a GUI).
Step 3
This step uses one of three GUI applications and looks like some manual labour (like adjusting settings)
may
be required, it is not clear. If the applications suggested by the article have APIs then a CLI option of automating the process could be possible - again it is not clear just by reading the article.
Step 4
This step again uses a GUI (possibly to employ the export plugin and certainly to visualise the results) and so would appear to need some settings modifications and reiteration, to quote:
the conversion settings are something that will have to be explored via trial and error in order to figure out what is right for your dataset. In order to visualize the differences between the different settings you will have to open the .STL file into a software designed for 3D Printing.
Step 5
While the use of a slicer
can
be automated (assuming that you have predefined (known parameters) thresholds), it usually requires some manual intervention (at least to begin with). If you google "automate slicing" then some interesting links appear, but usually they are for batch processing of similar objects/models.
Summary
The language used in the steps above contains a lot of conditionals (may, can, could) because there are a lot of variables involved. A substantial amount of research would be required to get these elements of the pipeline to work together seamlessly. So, it is unlikely that a "point and click" solution exists where an STL file would just pop out at the end, with no manual intervention.
That said, if your LiDAR datasets were consistent (i.e. similar environments, similar objects being scanned) then you
may
be able to find a range of settings, for each stage, that work consistently well for a particular scenario. Then with these settings - in combination with some command line or Python scripting and/or an appropriate GUI scripting tool - you might be able to automate some, if not all, of the process.
Looking even further ahead, by using
Machine Learning
you may be able to train a model to learn to examine the visual feedback stages and then auto-tinker with the settings in order to get better results - however, whilst not in the realms of impossibility, it certainly is rather cutting edge (at this point in time). In a few years time though, it almost certainly will be possible.


q:
I have a Prusa i3 MK3 or maybe it was upgraded to a i3 MK3S.

How can I figure out?

The description of the upgrade kit talks about

the SuperPINDA (how is it different from the old one?)

a number of small changes (which?)

improved plastic parts (which parts, how are they different?)

metal clips (where to look for them?)

a number of minor changes to the extruder plastic parts (which ones, before and after?)

I'd like to figure that out without taking the printer apart.

[A]
The MK3 has 4 pins on the filament sensor, the MK3S has only 3 pins. While you need to take the extruder apart to see that, you can also have a look at the cable instead:
Matching the sensor, the MK3 has a 4 strand wire including blue and the MK3S has a 3 strand cable without blue.
Looking under the heatbed, you'll find the MK3 bearings are fixed with U-bolts while the MK3S has broader bearing clips.


q:
I recall seeing that it's possible to "bake" or "anneal" or even "remelt" PLA prints to strengthen them.  As I understand it, the main effect is improving layer adhesion, which is the main source of weakness in tension in the original Z-axis direction.

Yes, I can print with a hotter nozzle (up to a point) to increase layer adhesion, print with a larger nozzle orifice, print with increased layer height, print slower -- but at a minimum those require reslicing, and affect print appearance (hotter nozzle causes stringing, thicker layers are more visible, etc.).

Baking a print does none of that, as long as it's supported (often done by bedding it in salt).

Question is, how hot?  I presume I don't want to go all the way to printing temperature of 180-220 °C, but the plastic transition level of roundly 50 °C isn't hot enough for this.

[A]
I've only annealed PEEK personally, but a quick search returns varying recommendations:
All3DP
recommends 1 hour at 70 °C.
X3D
recommends 1 hour at 110 °C.
Matterhackers
recommends 10 minutes at 105 °C for Tough PLA or HTPLA.
A post on
Reddit
recommends "a few hours" at 110 °C.
I'd do a test suite with pieces at 70 °, 90 °, and 110 °C for an hour each and test/compare.
Be mindful of any chemicals that might be released.


q:
I know that it's said the PLA becomes brittle when kept in a humid environment, but my case is slightly weirder:

I have rolls of 1.75 mm PLA that I bought years ago and they are fine. But if I leave my spool fed inside the PTFE (Teflon) tube of my 3D printer, that part that is inside the PTFE tube, and only that part, gets brittle. The filament spool is always (even when stored) in open air.

Is it still the humidity that somehow is better kept inside the tube, or is there a weird reaction of PLA with PTFE?

[A]
I have this exact problem as well. I am feeding filament from the dry box through the tube into the top of the hot end. After approximately 2 days I would notice that the filament is broken somewhere close to the hot end. I don't believe that it's just humidity.
I suspect that the filament being brittle and being made to conform to the PTFE tube's shape, having been recently on a spool, is causing the breaks.
As a result, I'm going to write a small script that will heat the hot end and eject 200 mm of filament every so often.
EDIT: Whilst the script works, the filament would just break somewhere else lower down in the tube. Therefore the amount of filament that would need to be extruded periodically would be just wasteful. A better solution would be to unload the filament, either manually or automatically (somehow).


q:
I'm currently printing 11 copies of the same model.  I noticed as it's printing that it seems to work on one model at a time but doesn't travel to the nearest model next.  I suspect it's traveling around the bed in the order that I put the models in the slicer.  This is resulting in extra unnecessary travel and therefore, increasing print time.  I slice in Cura 4.9.

Is there a slicer that handles this better? Or is there a way to optimize movements in Cura?

[A]
Long story short:
I only know the setting "Combing Mode OFF" that improves the travel paths. In my case it did not help. In your case I suggest you should give PrusaSlicer a try. I assume that the overall print duration will be improved because of a better calculation of the travel paths. But this is only my personal opinion between these two Slicers.
Further explanation:
I downloaded the Cura 4.9 and made an install from scratch. I tried to reproduce your issue by placing lots of copies of the same part. As printer I selected the Ultimaker S5 and used the standard configuration for slicing. I let Cura arrange the parts on the print plate.
I checked the travel paths between the parts and in most cases Cura has chosen the nearest distance to move the printhead to the next part. In my opinion, there could be a more efficient choice for the next part to print.
After this first test I experimented with the settings (e.g. "Combing Mode" OFF) but without an improvement in travel movements.
In the past I used Cura in combination with an Ultimaker S5 at work to print parts for production usecases. Over the past two years I recognized lots of parts where the travel movements have been chosen very unefficiently at the cost of high print duration.
For comparison I used my standard slicer "PrusaSlicer" and did the test under the same conditions: standard settings, auto-arrangement of the parts.
Overall the travel paths are calculated more efficiently, but there is also some room for improvement.


q:
I have designed a cupholder for my center console in my truck with PETG. I was hoping it wouldn't deform and it didn't for a while but we got some high temperatures the past few days (around 32-38 °C or 90-100 °F).

Kind of figured it wouldn't hold up mid-summer but I was wondering if ABS would be my next best choice or if there is something better for this. It does see some sunlight but not a lot.

I do want to start producing some to sell and don't want it deforming in high-temperature areas. Also, I have an Ender 3 Pro so I can't do super crazy filaments.

[A]
ABS, or preferably ASA which is "a better ABS", is probably your main option. ASA holds up better under UV/sunlight and is easier to print (less warping). Like ABS it should be printed with ventilation, and benefits some from an enclosure but can be done without it or with a primitive one (cardboard box).
Another great option would be TPU. It's not subject to a glass transition temperature above room temperature (my understanding is that technically its
$T_g$
is very very cold, but that may be a misunderstanding) and does not really warp/deform permanently until you reach temperatures near what you could print it at. I've used it as a mold for melting crayons in an oven at 175 ˚F (80 ˚C) with no problem. Depending on your perspective it could be easier or harder than ABS to print. If your extruder is bad at handling flex materials you might have to go really slow, or you might have trouble with jamming on retraction, but unlike ABS it has no heat/warping issues while printing and can be done even on a cold bed, and does not particularly need ventilation (although as always, be careful if you have pet birds around).
Note that while TPU is considered a "flex" material, it can be fairly rigid at high infill with rigid infill patterns like triangles or cubic, or printed 100% solid, especially if you go with harder variants. 95A is typically the highest you see but sometimes you can find 98A.


q:
I want to plug in my drivers from the printer into my Raspberry Pi. I want to control the printer's axes by sending G-code directly from the Raspberry Pi command line (if possible) to the drivers.

Is that possible and if yes does anyone know how? As I stated above without using any 3rd party program/software.

[A]
You can send the data to the serial port using
```
echo
```
, but you'll have to use
```
cat
```
to get the response.