q:
I have printed a MPCNC machine.  It has a print area of about 30" x 30" and up to 11" tall.  (yes, those numbers are correct).

I found a perfect piece of glass at a garage sale for $5.00 to use as my print bed.

My problem now is how to heat the glass?  I was wondering if there is some sort of tape that would perhaps mimic what is on the rear window of a car, but I couldn't find it anywhere.

Any ideas or links to something that can get me some progress on my search would be greatly appreciated.

[A]
Your best option may be to seek out a silicone rubber heating mat, using those terms for your web search. A quick search on my part shows many resources, some of which are known to the 3d printing manufacturing world, while others are equally suited for that purpose.
Don't bond the heater to the glass. You'll need to replace it when it breaks. Consider to use borosilicate glass for better heat tolerance and smaller chance of breakage. A quick search for such a large size pane comes up empty, invalidating that suggestion.
I've read of some people using water bed heaters for large area coverage, but they may heat the area unevenly.
It could be to your advantage to use multiple heater panels with temperature controls for each one. This would provide more uniform heating although more complex temperature management.
I would post links, but there are so many from which to choose.


q:
I have a Mini Kossel and I am going through calibration.

I can home carriages and find the bed with paper-test getting some Z value with M114. Then I run the effector almost full height up and then down - and now Z value for the bed is greater!

If I repeat the process I get greater and greater values in paper-test. It seems that travel per step is different moving in different directions.

How can I fix that? I am using RAMPS 1.4 with Marlin firmware.

UPDATE:

Z values near bed after subsequent runs of five passes of G1 X100 G1 X10

100% speed: 0.1 0.3 0.5 0.7 1.0

 20% speed: 0.1 0.4 0.9 1.4 4.6 6.6

300% speed: 0.0 0.7 1.0 1.3

[A]
According to discussions in comments, I'm pretty sure the problem lies in too low current.
Please review
this answer
to
How do you make sure you have the right voltage on the trimpots on a A4988 stepper driver?
.
Why it happens?
If there is not enough current then motors can omit some steps as the stress is not equal while going up and down. Sometimes inertia can have higher influence than friction.
Additionally because the resistance/stress/friction on towers is different for sure then there are some issues in centering hotend.
So friction/inertia/assembly inaccuracy and current settings inaccuracy can cause such effects. If you are "on the edge" your printer may work well one day but the other day it can fail positioning.
Please refer to post mentioned above. Perform calibration and temperature test (finger test could be ok). I hope you'll manage the issue.

s: huggingface

c: devops

d: intermediate


q:
I have a LARGE piece of glass (36"x26") that I will soon be printing on using my newly build MPCNC machine.  It is capable of printing about 34"x34"x10".

Anyway, I have had GREAT success printing on heated glass that is sprayed lightly with hairspray using PLA and being able to EASILY remove my prints after the glass has cooled.  I attribute this to the slight expansion and contraction that occurs when glass is heated and cooled.  This would weaken the cohesion of the PLA print to the glass.

I have another posting where I asked how to heat this LARGE glass bed.  However, there weren't any feasable (inexpensive and easy) solutions to heat the glass.  So, now with cold glass, what are some good strategies for removing large 3d printed objects without breaking them or the glass?

[A]
Because you will be printing on unheated glass, you will be using some form of adhesive material. If you use an off-the-shelf glue stick, you will likely find it is water soluble. If the bed is removable, immersing it in warm water for a relaxing soak will provide easier model removal.
I don't have experience with various tapes, so will avoid recommendations regarding masking tapes or similar material.
Thermal cycling will also provide release. Not a heat gun, as that will break the glass, but a hair dryer applied to the underside near the model, then cooling. Repeat until it releases.
I have used the Fleks3D print plate on my Flux Delta printer in the past, and it releases "like magic" but I don't think they make monster sheets of your printer size. I had also purchased a pair of 20" square Fleks3D plates for a similarly sized printer that never materialized. I'd be happy to sell you the pair, but I think they are too small for your full plate.
It has been said that one can use sand-blasted acrylic, which I believe is the construction of the aforementioned Fleks3D plates. If you have access to 1/8" or 3mm acrylic and can apply a uniform blast of abrasive, you may be able to construct your own easy-release build plate.
It is practical to consider to use a raft for your large builds. Rafts are useful for small items, to provide a greater bonding surface and avoid release, but it also provides a "wedging" location for your release tool. You can more easily slice away the middle of the raft and deal with a thinner layer after the model is completely freed.
EDIT ADD: If the bed is not removable, one can build a dam around the model with clay to hold the water for dissolving the glue.


q:
I was wondering if anyone could give me tips for designing a 3d printable structure that can "pinch" down onto a hockey puck shaped piece and hold it tightly.

I'd like for the structure to normally want to "pinch" two edges together, but I can pry/force them open when I shove the hockey puck into it. Once I let go, the two ends are now holding the puck fairly tightly.

My first thought was something like a potato chip bag clip, but that would require a couple pieces and a spring.

Is there a way to do something like this with one solid piece?

[A]
Here are first 3 the most simplified and generalized options you have:
All you need now is to give use more details about your needs. If you reveal more details we could help you to apply (and modify) one of these  options.
Each of above has its own pros and cons of course. You said you don't want to have spring... so maybe a rubber ;)
But in fact whole-red is one-piece-clip in which the force comes from material elesticity or stiffness.
Please tell me what is the application of such clip.


q:
Good morning everyone,

I am developing a consulting job in a clinic of dental CT scans.

This work involves the development of administrative software, and preparing a routine for conversion of tomographic files in DICOM format to STL format. The files in STL format will be used for both visualization and analysis of 3D models, such as printing in 3D printers.

Our problem is just the conversion DICOM to STL.

Has anyone come across this kind of situation? We did not find any documentation or tool for this purpose in our searches and we are really with a gande urgency in the solution.

Advance grateful for any assistance.

[A]
there is a nice software to do it, a brazilian one, called Invesalius (
http://svn.softwarepublico.gov.br/trac/invesalius
). Itksnap is probably a better initial choise, since it is more intuitive (
http://www.itksnap.org/pmwiki/pmwiki.php
).
But anymways, it is not a easy job to do, and probably you will need other softwares to help you clean the mesh, like meshlab or Geomagic.
Good luck


q:
I have used cyanoacrylate glue aka superglue to bond PLA. I have created several electronics enclosures. (Definitely the most time-consuming part of the project.)

Now my question is which debonder/solvent can I use to separate the pieces again without destroying the PLA parts?

Wikipedia proposes the following:

nitromethane

dimethyl sulfoxide,

methylene chloride,

gamma-Butyrolactone.

[A]
Acetone
Acetone will dissolve cynoacrylate (superglue) and should weaken it enough to be able to separate the parts.
A readily available cheap source of acetone is nail varnish remover (just make sure you don't buy the acetone free version!).
Give the pieces a soak in nail varnish remover for 10-20 minutes and they should come apart with some prying.
Acetone does not dissolve PLA, so the PLA parts should be undamaged. If you were to try this on ABS parts however, they would begin to dissolve.


q: I'm looking for a strong filament that can handle a large tension load and no bending deformation when a perpendicular force is applied to it. Any suggestions?

[A]
As far as I know, Nylon filaments are among the strongest. I'd look at the technical specs of
Taulman3D's Filament
. They're the only nylon I've ever tried, and I know they have in-depth specs of how their filament holds up. I'm sure you can find other providers, though.


q: My 12V DC 30A Power Supply 360W Power Supply is really cheap, and it's worked well for setting up the motors; but now that I'm on to the heated bed, which uses considerably more Ampage than that of just the motors, I'll confess, I'm getting frightened to continue using it;  if the summer was a bit longer, maybe it wouldn't bother me, but we're getting into the cold months, and now I'm afraid of ending up using too much ampage just trying to heat the bed in the winter months...(and I don't mean my bed).  Is there anything I should look out for in terms of using the either the cheap power supply I already have, or are there certain specs on a new not-so-cheap power supply that I ought to be using instead?

[A]
A MK2 heatbed will draw around 12A. The motors and hotend draw only very little power (around 2A, 5A peak), so the 30A supply you have has significant headroom (it is often recommended to derate a power supply by 20%, so a 30A supply would be good for 24A - you're still well under that). It should work fine, even given its dubious provenance.
Winter versus summer should not make a big difference. The largest power draw is during the heat up phase. In winter, the bed will use slightly more power to stay warm, but regardless of whether it is summer or winter the peak power draw during heat up will be the same.
The cheapness of these supplies tends to be reflected in more output ripple (but for heating the bed and running the motors you don't need a very stable voltage) and improper filtering. This may inject noise back into the mains, possibly affecting other equipment nearby. Should this occur, you can just stop using the power supply. However, in my experience, they can deliver the rated power just fine. They're not completely horrible.
Your biggest concern should be whether the wires that lead to your heated bed can handle the current and whether the screw terminals are properly tightened. During the first use, you should check that the power supply does not get extremely hot. If it's so hot it's impossible to touch for more than 1-2 seconds you should not use it.


q:
I have an M3D Micro 3D printer that printed fine for a couple of weeks and then was plagued with issues afterward. I've done the fixes from the forum to get proper heating and cooling of the nozzle (I've added aluminum foil around the nozzle to make sure the hotend is fit snug against the nozzle and I've added an external fan, powered externally, to compensate for heat creep).

This works very well for short prints and it usually finishes successfully. When I do a longer print it always stops midway and usually at the same exact point.

I tried printing at 200 °C with black PLA and then again at 215 °C with the same filament and it stops at the same exact point. I also tried M3D brand white filament. I am using CURA slicer with Octoprint GCODE sender and M3D Fio.

I know it is not clogged because if I stop the print and press extrude without letting it cool down, it extrudes fine.

What is causing my printer to stop printing?

[A]
Placing this suggestion as an answer, because all information appears to point to the slicer software and/or the operating system. Consider to use alternative methods of slicing and sending the model, such as the previously mentioned
Craftware
or other free slicers, such as
Slic3r
- both of which have Linux versions. If, as you suggest, your firmware is so tied down that it won't run alternate versions without re-flashing, that would be your next step. Unfetter yourself from the limitations of the current suspect software.
If you are able to use other slicers and discover that the problem remains, the re-flashing of the firmware is likely the only solution.


q:
I've built the mechanics of my 3D printer myself, because I need to print parts that are really huge, (and for budget reasons). So, I already have the 3D movement functionality.

But what I need now, is the printing mechanism itself. I've been reading a lot, but it became clear to me that things are more complicated than I thought.

Let's skip mechanics and software, I'm just interested in how the print head works. Can somebody explain me that?

To be honest, I was so naive that I thought that I just had to buy one part with one data wire (print/noprint) and the 5 V/GND wires. But it came to my intension that things are way more complicated.

For example, these RepRap printers have some kind of air tube attached to the print head. I'm not sure what that's all about, is it cooling?

Perhaps I'm always reading the wrong manuals (i.e. the more advanced ones). Can somebody enlighten me or point me to a good starting point?

[A]
The first point to start would be the RepRap wiki entry for
extruders
:
cold end
The "Cold End" is usually the bulk of the extruder. It is
often the actual carriage on one axis and supports the rest of the
parts. In some designs, the "Cold End" is split into two parts; one
part does the driving of the filament that is stationary and connected
to the carriage portion, of a lighter weight design for easier
movement, with a flexible tube. The drive is a motor that rotates a
knurled, hobbed, or toothed pinch wheel against a pressure plate or
bearing with the filament forced between them. Usually, the motor is
geared to the pinch wheel to increase available torque and extrusion
control (smoothness). The gearing can be a 3D printed pinion and gear,
stock worm wheel and gear, or a more expensive integral motor gearbox.
Stepper motors are used almost universally after initial trials with
DC motors did not achieve the required repeatability. Servo motors are
an option, though they are not seen in the literature yet. The final
function, some form of cooling, keeps the "Cold End" cold. With the
close proximity to the "Hot End" and possible heated build platforms
and enclosures, it is sometimes necessary to have additional passive
or active cooling of the cold end parts. Heat sinks and fans are often
used; water and Peltier effect cooling is also discussed. Much of this
bulk is usually made from 3D printed parts and the temperature is
maintained within safe limits.
hot end attachment
The "Cold End" is
connected to the "Hot End" across a thermal break or insulator (the
Bowden tube if used is on the cold side of this thermal break). This
has to be rigid and accurate enough to reliably pass the filament from
one side to the other, but still prevent much of the heat transfer.
The materials of choice are usually PEEK plastic with PTFE liners or
PTFE with stainless steel mechanical supports or a combination of all
three. A Hot End is frequently joined to the Cold End using a Groove
Mount where the thermal break or insulator is part of the Hot End
assembly and the Cold End body is provisioned with a cylindrical
recess. Many cold ends push the filament out a large hole centered
between 2 small holes about 50 mm apart. (Is there a name for this
de-facto standard?) Some people rigidly attach a groove mount hot end
to such a cold end with the mounting plate adapter and two short
bolts. A few people put 2 long bolts through those holes and then put
a spring around those bolts to make a spring extruder.
hot end
The
"Hot End" is the active part of the 3D printer that melts the
filament. It allows the molten plastic to exit from the small nozzle
to form a thin and tacky bead of plastic that will adhere to the
material it is laid on. The first RepRap hot end was made of brass.
Researchers have also made hot ends from glass or aluminium. The hot
end consists of a melting zone or chamber with two holes. The cold end
forces the filament into the hot end -- into the heating chamber of
the hot end -- through one hole. The molten plastic exits the heating
chamber through the other hole at the tip. The hole in the tip
(nozzle) has a diameter of between 0.3mm and 1.0mm with typical size
of 0.5mm with present generation extruders. Outside the tip of the
barrel is a heating means, either a wire element or a standard wire
wound resistor. The heat required is of the order of 20W with typical
temperatures around 150 to 250 degrees Centigrade. For feedback
control of the nozzle temperature, a thermistor is usually attached
close to the nozzle, though a thermocouple may serve with suitable
control hardware. High temperature materials are needed here. These
include metals, cements and glues, glass and mineral fibre materials,
PEEK, PTFE and Kapton tape.
mount to rest of machine
The ways
extruders are mounted on the rest of the machine have evolved over
time into informal mounting standards. These informal standards
include the Vertical X Axis Standard, the Quick-fit extruder mount,
the OpenX mount, etc. Such de-facto standards allows new extruder
designs to be tested on existing printer frames, and new printer frame
designs to use existing extruders. (Does the "greg-adapter.scad"
adapter in the Prusa i3 Build Manual let me mount an OpenX extruder on
a Vertical X Axis machine?)
You can also google for extruder and/or hotend in combination with 3d printing for a first starting point.


q: I recently finished building my first printer. The only problem that I'm having is that the hotend is not getting hot enough to start printing with PLA (180 to 230 degrees celsius), the hotend getting hotter stops at 170 degrees. Please help I've been stuck on this problem for days. Thanks in advance.

[A]
Usually, this kind of problem is due to an issue with the control loop of the temperature. You can try to do
PID Tuning
by running the command
```
M303 E0 S200 C8
```
. This will heat up the hot end and cycle it around 200C a few times, and afterwards tell you Kp, Ki and Kd values which you need to enter into the PID settings of your firmware configuration, or store them in EEPROM using
```
M301
```
.
If this does not solve the problem, then disconnect the heater cartridge and check its resistance with a multimeter. For a 12V system, it should not be higher than 6Ω (24Ω for a 24V system).
If the heater cartridge is okay, then perhaps it is a problem with the power supply. While the hotend is heating up, measure the voltage across the heater cartridge. It should not be much less than the nominal 12V/24V your printer runs at. If it is, you may have a bad MOSFET or power supply.
Finally, if you have a very powerful fan blowing on the hotend this can cause issues with heating up as well. Adding a fan shroud (or pointing the fan away from the nozzle and only at the print) can help with this.


q: So, I'm having this problem where almost anything I print with a section(s) that is not directly connected to something below it breaks when I try to pull the small filaments meant to hold it up during printing off. For example, I 3D-printed a Rayquaza(this one) from Pokemon for my little brother, and as I was carefully pulling the filament from under the mouth, the whole head just snapped off. Does someone have a recommendation as to a way to get the small filament off without breaking the object? Would a solution just be to print it bigger and see if it holds up better, or is there something else I can do? Thanks.

[A]
The small filaments you remove that hold the parts up are called supports. The one model I located on Thingiverse clearly requires a number of supports, as the model is not easily designed for 3d printing with FDM printers. It would be better printed with SLS, but that's not the focus of your question.
You don't specify how large you printed the model, but certainly a scaled-up version will be stronger at the weak points. You will want to use sharp non-shearing cutters to clear away as much of the supports as possible, without torquing on the model.
Another option which also reduces the forces on the model body is to use a soldering iron to smooth and clear/cut the supports. If you are able to use cutters and not damage the model, the soldering iron can remove and flatten the remnants of those supports.
Please note that if your careful work has resulted in a model that snaps to pieces, your little brother will soon destroy the successfully cleaned up model just as easily.
If you have skill with 3d modeling software (Meshmixer and Blender come to mind for such organic models), you can add insignificant items to the model to provide functional support. Would the Rayquaza look fiercer if you 3d printed a cage as an integrated part of the model, using the bars of the cage to provide support?
I successfully printed a model that was created by an artist unfamiliar with 3d printing restrictions. The support material was wash-away PVA. I provided the model to the "owner" who washed away the support material and snapped the legs in two. It's sometimes impossible to solve poor designs. You have a good chance if you build a cage for this one.


q:
On their website they say the following

0.25 mm nozzle: 150 to 60 micron
0.40 mm nozzle: 200 to 20 micron
0.60 mm nozzle: 400 to 20 micron
0.80 mm nozzle: 600 to 20 micron

That confuses me. Why can I go down to 20 micron with the 0.40, 0.60 and 0.80 nozzle but only down to 60 micron with the much smaller 0.25 nozzle? Is that a typo and should say 6 micron?

[A]
You need a certain minimum flow rate to achieve consistent extrusion. Flow rate is the product of print speed, extrusion width (proportional to nozzle size) and print speed. If you use a very small nozzle and very low layer height, you'd need a very high printing speed to achieve a reasonable flow rate. Therefore, it's quite possible this is not a mistake and intentional.
Keep in mind that Ultimaker uses 2.85mm filament. With a 0.3mm extrusion width, 0.02mm layer height and 60mm/s print speed, you would need a feedrate of 0.06mm/s into your extruder. The extruder might not be able to develop enough force on the filament at such a low speed (which, owing to the small nozzle size, requires a relatively large amount of force).
The ultimaker can not print 6 micron layers since the smallest increment the Z-axis can move in is 5 microns. 6 microns is not a multiple of that.


q:
My wife wants me to use an FFM 3d printer to make custom stamps for her to use on paper (scrap books, letters, etc.). She is convinced, however, that they will be too rigid to make good stamps.  A quick google search showed ones made from PLA and ABS. Logically, though, a TPU or similar would address her concerns.  A good quality stamp needs to hold ink and make good, even contact with the paper. It would probably need to be able to be sanded or smoothed in some way.

I am supposed to receive my printer next week or so and am trying to get some filaments, STL files, and accessories I will need ready in advance so I can rapidly learn how to use it.

[A]
Recently I've experimented with printing some
Nylon 618 filament
after
reading stuff online
about it.  I'm using a Craftbot original with the stock hotend, keeping the Nylon dry in a ziploc bag.  It prints really well, just tricky to get it to stick to the bed (I'm still working on that), but otherwise it's great.
Once printed, the main difference from PLA prints is the nylon remains more flexible.  If you bend a thin nylon print, it tends to just spring back to the shape that came off the printer.  That's very different from my PLA prints, which will either stay bent or break apart.
I believe that nylon would be a good material for you to try for stamps, because of this flexibility and shape-preserving quality.  The comments show some other materials to try, but I'm limiting my answer here to my own personal experience.


q:
I have a weird problem with my old 3D printer, it is a Prusa/Mendel type.
When I print a 20 mm cube, X and Y are correct, Z is resulting 16 to 17 mm.
I have checked the correctness of the movement on Z using the manual controls and there are no issues.

I played a bit with the layer thickness, I have a 0.4 mm nozzle, setting the layer height to 0.12 mm (normally is on 0.16 mm) but no changes in the result.
I am printing PLA on a cold bed at 180 °C without any other particular defect.

I would appreciate some direction on how to solve such problem.

[A]
You should check that the steps per mm for your Z-axis are set correctly. This depends on the pitch of the leadscrews/threaded rods driving the axis and parameters of your steppers (microstepping and raw steps/revolution).
This Calculator
.
Make sure that your layer height is a multiple of a full step of the Z-stepper. The Z-stepper may be disabled intermittently, and when re-enabled it may "snap" to the nearest full step position. If your layer height requires microstepping, you may notice it getting rounded down or up due to this.
For instance, if a full step were 0.08 mm, then 0.16 mm layers would require 2 full steps, printing fine. 0.12 mm layers would require 1 full step and a half microstep. Due to rounding, some layers might be reduced to 0.08 mm instead. This might account for the height discrepancy you're seeing (though 0.08 mm is quite a high, unrealistic amount for a full-step).


q:
I am wondering if making an hermetic box is feasible using 3D printer. The box would be a cube with a front face removable, with screw and sealing joint to close it.

I searched for different materials, however, none talks about hermiticity. (However, I found a product that seems to improve water resistance of 3D printed items here, which might be a starting point)

Does anyone have experienced to make hermetic things ? I am specially interested in carbon fiber reinforced materials.

[A] I believe this can be achieved using o-rings.  That's what they use for scuba diving lights.  The component doesn't need to be circular, but the o-ring needs to be slightly smaller than the component so that it is held in place via tension.  Additionally, you'll want to create a groove for the o-ring to set it in and make sure that the o-ring protrudes slightly so that it applies pressure and creates a tiny amount of friction when it's coupled with its counterpart.  Apply some type of lubricant to prevent the o-ring from sliding out of place and to keep it from drying out and cracking.


q:
I'm trying to print with Laybrick and for the most part it is going.  The problem lies with the top layer and gaps appearing.  I've tried increasing the number of top layers but the gaps still appear.  Any ideas what else I can try?

I'm using Simplify3d.

[A]
When using Simplify3D, you may try referring to their awesome troubleshooting guide:
https://www.simplify3d.com/support/print-quality-troubleshooting/#holes-and-gaps-in-the-top-layers
3 reasons (from the guide) for gaps in the top layers:
under-extrusion: you may try to increase extrusion multiplier to see if this helps
low infill percentage: not likely in your case if increasing number of top layers did not help
not enough top layers: you already tried increasing number of top layers.
In addition to that, you may change certain parameters (such as extrusion multiplier) for a given number of layers by using Simplify3D features. It can be helpful to avoid problems to for the rest of the model.


q:
I've a friend who is expecting.  There are several adorable weapon themed rattles on thingiverse.  I am, however, concerned about safety associated with such a product in the hands of a baby who will gnaw on it.  To me the safety concerns here are much larger than for most food handling applications.

What steps should be taken to ensure such a print is safe for use?

This includes: filament selection, pea material selection, wall thickness, smoothing, construction, etc.

My current thoughts are as follows: "food grade PLA", dried peas, sanding, and single piece construction

[A]
You're on the right track.  Since you asked for "steps" here you go:
Step 1. Choose a safe material:
Consider chemical safety and physical safety. Food grade PLA should be chemically safe, but could be too brittle depending on the design you choose.  PETG, T-Glase, or similar filaments (depending on dye) are normally also chemically safe and are less brittle than PLA so may be a better alternative.  ABS is NOT typically considered safe for food contact.
Step 2. Choose a safe design:
If using PLA, be sure the design is robust enough to ensure it won't break.  Broken rattles with sharp edges make baby...sad.  Even less brittle filaments can still break with jagged edges if the design is fragile.
Step 2a. Choose a single piece design:
Choose a design that requires you to add the peas (or other safe filler) during the print such that the finished rattle is fully enclosed.  This will minimize parts becoming loose or peas spilling and minimize choke hazards.
Step 3. Consider post processing to improve safety:
Sanding could reduce ridges and minimize crevices that could harbor bacteria, but sealing it with a food-safe sealant may be more effective.  There are many sealants that the FDA considers safe, but polyurethane or food-safe epoxy finishes will work well with PLA. (If you use a different material, test to verify good adhesion.)
Step 4. Test:
Make a test rattle and run it through the paces.  I guess you could chew on it, but since babies don't have teeth, this might invalidate your data...
Step 5. Consider alternatives such as professional printing services:
If your tests don't inspire confidence, professional services can offer additional materials (metals, ceramics, etc.) that could be safer than a typical fused filament printer.


q:
What materials, available as filaments for use in FDM printing, are known to be the most physically and chemically inert? In particular, stability (not necessarily simultaneously) in the presence of the following should be assumed:

pH 0-14

oxidizing agents (ozone, permanganates, dichromates, acidic hydrogen
peroxide)

organic solvents (particularly acetone, methanol, toluene, formamide)

temperature up to 160 degrees Celsius

pressures between ~10^-7 torr and ~2 bar

oxygen or argon plasma

[A]
PEEK, a plastic known for its superior chemical and physical resilience (
http://www.zeusinc.com/materials/peek/chemical-resistance-chart-peek
), has been successfully used for filament-based printing (
https://3dprint.com/52713/indmatec-peek-fdm-printing-filament/
). However, it is unlikely to be an option on most existing printers given its high melting temperature (around 343 degrees Celsius,
https://en.wikipedia.org/wiki/PEEK
). Though it does not meet all the criteria proposed (for instance, its glass transition temperature is around 143 degrees Celsius), overall it is a fairly good choice.
Teflon, an obvious choice, unfortunately has a decomposition temperature very close to its melting temperature, and appears to be unsuitable for extrusion.


q:
I have a QIDI Tech 1. It has a heated bed, and a cooling fan attachment. Whenever I print without a raft, the first inch or two of material laid down does not adhere to the bed, but the rest of the first layer is flawless.

I have tried speeding up and slowing down the first layer walls, but the problem remains. It also seemed to get a little worse when slower. I also tried not turning on the cooling fan for a bit to see if maybe the material was cooling too quickly, but that had zero effect on it.

I'd like to avoid using tape and other methods since the rest of the print is perfect, and the bed already has a material on it to aid adhesion.

What else can I try to prevent the dragging for the start of the print?

[A]
I've had this problem in the past with a Flux Delta printer. The first attempt to resolve it was to always use a brim along with a raft. The brim will often have settings to allow number of passes as well as number of layers. If you are not using the brim to provide adhesion, you still can use it to prime the nozzle.
Later versions of the software allowed for start g-code which moved the nozzle to the edge of the print area and extruded 10-40 mm of filament, also providing for priming the nozzle.
You've not noted what slicer you are using. You may find there are suitable locations to position the head to an unused area, run a few mm of filament, then begin your print.
Amazon Q&A says your printer accepts g-code, which implies the slicer generates same.
In combination with a brim, you may have your solution. I've also found that you have a heated bed. If you have a cold spot on the bed, adhesion may be a problem, although I think that is not the case, based on your description.


q:
In 4D printing technology or by means usage of Shape-memory alloy (non-metal, iron based, copper based or NiTi material) for 3D printing.

Is there any software simulation tool which I can use to simulate this material change behavior with respect to time?  For example, when introducing a change in humidity or temperature.

Note: It would be best if the simulation tools targeted automotive parts (power train, cooling system, interior & exterior etc.).

[A]
I am going to say that this probably is a whole dimension out of scope for this group ;-)
That said this new type of 3d printing is still at the University level. Also 4d is not necessarily 3d printing related at all. All it has to be is self assembling. Like
http://www.selfassemblylab.net/4DPrinting.php
Unless you have a connect with MIT. Then you aren't going to be simulating any 4d models.
But if you HAD to do this, then you should write a paper about it and become a researcher. You could get published. You might need a PHD in material science. There might be some simulation in solid works.. but I would say you are mostly on your own and have to develop the models as they simply do not exist, especially outside of academia and stratasys.
That said if you take the "4d" part and use models based on the current understanding of the raw material you would have more success.


q:
I have my nozzle close to the substrate that I am printing on, so that a piece of paper can just about slide underneath it freely, without catching.

Is this the right way to do it?

[A]
Using a piece of paper won't guarantee you get exactly the "correct" height (because different papers have different thicknesses, and it's hard to determine exactly when it no longer catches on the nozzle) but it gets the bed level and the distance will be close to correct.
You can then further adjust the height by observing the first layer and making adjustments based on whether you see the first layer being squished down enough or too much. The babystepping feature (if enabled) is very useful for this.


q:
What are the methods to auto eject parts (into a collection area/box/basket) in order for the 3D printer to continue printing?

For some reason this feature isn't common (yet?). Is there a hidden reason why?

Will using the print head to ram the part off the build plate into a basket nearby cause the print head to misalign (if using belts).

I am planning to use a Cartesian XY-Head type (like CoreXY) printer, where the build plate moves along the Z axis and XY axes are on the ceiling of the printer using belts to move the print head.

[A]
From the standpoint of a hobbyist user with a mid-range machine, my answer is based on the model release from the build plate. With a heated clean glass plate, my model will
almost
always release once the plate has cooled. The "almost" aspect means that if you want to use the print head to push the model clear, you will be confronted with a stuck model occasionally.
The amount of force applied by the head may be enough to release a stuck model, but "may be" is not going to be sufficient. Especially with a core-xy system (used by my Emblaser laser engraver), you can either toss a belt or cause a stepper motor skipping. More powerful motors will reduce the skipping possibility, but not the belt jump problem.
You could consider to add one additional motor with a sweep arm, geared in such a manner as to provide the necessary torque, along with a force sensor to register a model stuck so badly as to be impossible to dislodge.
Your g-code would be written to lower the bed to the appropriate location to allow the sweep arm to operate, while the force sensor would be tied into the pause/stop circuit of your controller.
Some controllers already have the ability to manage an additional motor, as some are manufactured to provide for dual extrusion.
If such unattended operation is going to be a requirement, you'd also want some form of aborting a failing or failed print.


q:
I had a problem with my Z limit switch bracket falling just short of the bottom edge of the z stage.

I'm trying to make the bracket thicker so it's pushed more towards the left.

1) how do I measure the thickness of the bracket in the stl
2) HOw would I make it thicker if it is indeed too thin

It's might to be mounted standing up right.

I want to make it thicker x axis (if it's stood up)

[A]
Looks to me like you have your slicer set to 3mm filament when you're using 1.75mm filament. Confirm that your slicer has its filament setting set to 1.75mm and not 3mm (this obviously assumes you are using 1.75mm filament..)
Failing this:
Test extruder steps/mm
Ensure nozzle diameter is set correctly (usually doesnt make too much difference anyway...)
Ensure extrusion multiplier is set correctly.


q:
I am new to FDM RP.  I've done a lot of work on ZCorp and Connex.

The question is can vectors curve drive an extrusion nozzle?  Within a 3D volume I can generate curves that I want the print nozzle to follow. Is this possible or has it been done? If so, what software or is there a hack?

Another question is, can you print a part with no sidewall or containment boundary?

[A]
Vectors do not drive the extrusion nozzles in current software. There are methods to take vectors and create a solid model with them which can be used. The standard workflow is to take a solid model, save it in the STL format, and then import the STL file into the slicing software and outputs Gcode with contain coordinates for the extrusion nozzle to move to.
I have not seen any software that will create just the infill geometry without any bounding surfaces. This would be such a specific use case that it is unlikely to appear in current software. That is not to say that it couldn't be done, but you would likely have to implement such a feature yourself.


q:
I have been using PLA filament for two years now and have had good prints. ABS on the other hand has not been so good, so my choice of filament is PLA.

I am getting ready to do a sign for the American Legion and the colors are black, blue, and red and are 0.8 mm thin. The black letters are 4" x 2.5", blue are 3" x 2" and the red are 7.75" x 5.5". I plan to treat them with UV protection spray and attach them with clear epoxy to white back lit Plexiglass.

As the letters are quite thin, my question is how well will this hold up in the weather? The sign hangs on a pole that points east & west so the letters will be facing north and south. The original was painted with spray paint and the red paint south side faded to the point you could hardly see it at all. The sign had been there for some time and was done at a professional sign company.

[A]
I printed a handle for a rather big rolling door in natural PLA (From Fabberparts) - no UV protection. It's on the weather side of the house and is exposed to direct sun half the day.
And after three years cycling to all the German seasons it's still absolutely fine. Also, Wikipedia told me that PLA has good UV resistance - so you should be fine IMHO.
Here is a good blog post about your question:
Using PLA for Long-Term Outdoor Applications
.
Update: After ~ 8 Years the door handle ist still fine.


q: A lot of consumer desktop F.D.M. printers comes with a 0.4mm nozzle. I'm looking to print fine details objects and I was considering trying to use a smaller size nozzle. But before I do so I would like to establish a list of downsides and unwanted consequences.

[A]
Here are some things to look out for when switching to a smaller nozzle size:
Curling
(out of the nozzle): Make sure the nozzle is clear of any debris to avoid the extruded filament from catching and therefore curling around the nozzle.
Warping
: You might experience more warping on the build plate and delamination between layers as a result of the smaller surface area of the layers.
Reduce speeds
: You should reduce your print speeds anyways when printing fine-detail objects. However, the smaller nozzle size will need a bit more time to adhere to other objects (see above).
Standoff distance
: The distance between the nozzle and build plate, a.k.a standoff, should be a bit smaller with the nozzle size. Typically people use the paper reference (using a piece of paper to "calibrate" the standoff), which is about 0.004".
Make sure your slicing engine knows the change!
Most slicing software will allow you to adjust the nozzle size. This can also be used to fine-tune your machine.
Beware of clogging
: Clogging is usually a result of poor cooling between your heater block and your drive gear, poor filament quality, and/or incorrect extrusion rates. You might want to perform a benchmark print with the new nozzle to "rediscover" which temperatures work best with the new "basin" volume in the nozzle.
I'm sure there are many others, but this should help get you started.


q:
Are there any 3D printing services or something similar to 3D print or injection mold light reflectors?

I'm trying to find something that is similar to PCB printing that allows you to upload a 3D design of a reflector and they will produce this reflector and coat it with mirror surface.

[A]
I would not recommend extrusion printers for this, because they are unlikely to produce a smooth enough surface.  To get a clean surface, the irregularities have to be a fraction of visible wavelengths, which is to say on the order of 0.01 micron.
Without knowing what sort of reflector you're thinking of (flat? spherical? parabolic?), it's hard to recommend a specific optimal, cheap approach.  All in all, you're probably best off looking in standard catalogs such as Edmund Optics.


q:
I'm a novice in 3D printing. I have a Lulzbot Kittaz 3D printer with a hexagonal hot end of 0.35 mm. I have printed a test subject, and while I was printing I encountered this extrusion problem. I'm using ABS with 230 °C hot end temperature and 85 °C bed temperature. What kind of problem is this and how should I rectify it?

I took this photo when the printer printed the first layer:

[A]
It looks like you are not extruding at the correct rate. I would check your slicer settings for nozzle and filament size. Also check and calibrate for your filament diameter.
It looks like you could be getting better adhesion too. Lulzbot recommends a 110C bed temperature. That might help. (lulzbot.com/store/filament/abs under specifications)
These are some good resources to troubleshoot prints,
RepRap
All3DP
Simplify3D


q:
I had my printer printing fine when using the stock trigger switch as I used it to print the green bracket you see in the picture.

My problem now is when I do a print with the sensor, it moves to 0,0 position. However in this position the sensor is hanging off the bed hence there is nothing for it detect so it crashes into the bed.

As far as I can tell the nozzle is homing in the right place.

How do I tell Marlin the new minimum position it needs to be in so it doesn't crash into the bed?

[A]
There are at least 2 options to address the problem that you have:
Adjust end-stops so that in 0,0 position Z-sensor would still hang above the printing table. This would reduce printing surface but allow perfect calibration
Mount extra metal plate at the table mount where it would not bump into printer parts and remain reachable for the sensor (perhaps with sensor relocation) when positioned at 0,0. This option requires extra space within table movement boundaries but saves printing surface.


q:
We all know (or should!) that the repeatability of common spring-arm limit switches is crappy at best.  I'm looking to build & install one of the precision height adjusters for the Z-axis limit switch, and noticed a post on some forum suggesting removing the arm and triggering the switch button directly (e.g. with a screw end).

Has anyone tried this, and if so has the repeatability of Z-homing improved any?

Edit

Sorry -- this is a stock Prusa i3, which depends on physical contact between the vertically-moving subassembly and a microswitch mounted on the frame.

[A]
No. Buy a better switch if it's an issue (see below).
You would need to have some very tight tolerances to hit that micro button with whatever your arm is. If you had a machine with good tolerances you would not be considering this modification. That alone is why I would say this is not the greatest idea.
Following it might work if your Z is connected to the hot end and smashing into the bed. But I suspect you will still have a myriad of issues, such as the switch getting out of position enough to cause the head to crash into the machine. The real question now is how many rotations of the Z axis could happen if the printer is moving at maximum speed and the button is pressed? That metal arm is your grace period. Now your printer is potentially smashing into the switch.
Lastly, just get a switch with a more solid and less springy metal tab.
The real question is whether there is actually a variance caused by the metal arm? I would suspect that it hits the switch very precisely, consistently and within an acceptable tolerance. Removing the arm will buy you little. Replacing it with a stiffer-arm switch might serve you better.


q:
I finally manage to setup the ABL on my Prusa.
I run G28 to home all axes (for z I use the same probe used for ABL). Then
I run G29 E ( I use E because otherwise for some reason I have not understood yet, Z does not lift during probings) probing 4 points on the corners of the bed.

finally I get the map of the bed:

Bed Level Correction Matrix:
+0.999999 +0.000000 +0.001233
-0.000005 +0.999992 +0.003905
-0.001233 -0.003905 +0.999992

and after that, the print starts.
The first layer looks perfect however I have not seen Z moving a single step along the printing.

Any hint about what to check? Is the obtained map indicating that the bed is already too leveled to act on any compensation?

UPDATE
I printed a 180 mm diamater cylinder and the Z axis is not compensating the 1mm difference from edge to edge of the bed.

[A]
I believe that the matrix is shown transposed from how it should be, but that doesn't affect the answer. The compensated Z position is derived from the original
```
(X,Y,Z)
```
position by multiplying the corresponding vector with that matrix. This means that the new Z position would be
```
```
Z' = 0.999992Z - 0.001233X - 0.003905Y
```
```
If you have a 200 x 200 printbed, a diagonal move from one corner to the other would correspond to a 1mm change in Z-height. This should be noticeable, but if perhaps you're printing something quite small you might not notice it.
Though, if your first layer is perfect, I would see no reason to mess with it.


q: When 3D-printing on an 20*20cm, I've heard that the quality of the printings get worse if I fill out the board... Is it true? Should I keep it to small amounts at the time or doesn't it matter?

[A]
No, that's not (entirely) true. There might be some loss of quality if you print multiple objects at once, because when the printhead "hops" from one object to another it might leave a mark or ooze out some material. Also, a large number of retractions in a short period of time might lead to inconsistent extrusion.
However, none of this is particular to "filling out the board" as it happens even if you print only two objects at a time (or even when you're printing only one object with multiple islands).
It all depends on your printer (and in particular how well it handles retractions). If you're willing to do a small amount of cleanup afterwards (to remove the strings and blobs) then printing multiple objects at a time is completely viable.


q: I cleaned up my Flashforge Creator Dual tonight, and loaded some transparent ABS prepping for a print.  The filament extruded fine, then started to wiggle, then became fine again.  Hot end is 0.4 mm and was heated to 230C.  What sort of steps should I take to troubleshoot the issue?  Has anyone seen this before?


q:
I've recently designed a non-self-aligning caged deep-groove ball bearing. Now I'd love to get one 3D printed.

However, assembling those can be tricky and I highly doubt it's even plausible to print them. All the components themselves can be printed without a problem, but I'm not sure whether I'll be able to put them all together in the end.

What are my options?

FDM printers are probably out, although it would be great if I can find a way to use those. Would an SLA or perhaps an SLS printer be able to pull it off?

Of course the thing still has to work (move) in the end.


q:
I've actually solved this, but I think its still a useful question which I don't think is easy to answer with existing questions.

As soon as I'd built my ANET-A8 (Prusa i3 DIY kit), I found I was having problems with the extruder crashing into the bed. Although I thought I'd adjusted the bed leveling OK, the calibration seemed to keep getting messed up.

I tracked this down to two factors. First, I was winding the extruder head up some distance before loading the filament and starting a print. Second, at roughly half-way up the axis, the right-hand thread seemed to be getting stuck (more often when moving up than down).

What wasn't clear (and not mentioned in the building instructions) was what might cause this problem.

[A]
I assume you did everything according to the instructions but here is a checklist of what could be possibly wrong:
Friction - check if you can rotate/move parts without lot of resistance
Screws - check if screws on couplings are tight and they don't slide over a shaft or thread
Stepsticks - check if they are cooled properly and similar (as there are two of them)
Carriage nuts on threads - check if they do not slide out of their nests while [the x-axis] carriage goes up
Filament - check if filament unrolls without resistance which can eventually cause [the x-axis] carriage to hang.
IMO #2 and #3 are the most possible cause


q:
5AxisMaker has a 5 axis CNC/3D printer combo machine.  I understand what the benefits of 5 axis are for CNC machines, but are there any benefits for 3D printing.  In this video they show the printer printing on an angle, but this could have been done with just linear layers.

Would there be any cases where a 5 axis printer would preform better than a 3 axis printer?

[A]
One aspect of having this level of control with 3d printing of a model is the removal of the need for supports and the attendant post-processing. In the case of the model shown in the video, some effects are created by printing the continents in a conformal manner that would otherwise be impossible with conventional 3d printing. Cosmetically, the results of the "5d" printer are superior in this example.
There would also be some structural benefit for models with high organic content, that is curves and bulges, as opposed to orthogonal designs. Even with orthogonal designs, one can achieve stronger parts with cross-layered plastic in all directions, rather than being limited by x and y filament layers.
I see on the web site that one can exchange tool heads as well. One could print a 3d model, layering the filament on all the surfaces, then use a tool head change to a milling bit and smooth the surface under CAD control.  Alternatively, one could use foam or wood and mill a model shape to be covered with a 3d printed material.
Considering the relative novelty of this product, it's likely that many aspects of the creative utility have yet to be discovered!


q: I want to skeletize the surface mesh. For that I need to export .STL from Solidworks and then convert that into .OFF file to be able to use it in CGAL library for skeletonzation. How can I do this?


q:
I've recently bought a 3D printer and waiting for it to be delivered I've given quite a lot of time to looking things up on Thingiverse. I see people create incredible models with gears, screws, lids and a lot of very cool and functional connectors (there are some project for boxes with an iris tipe lid that can be printed already assembled as a single model). I'd like to learn to do some of that as well. At the moment I have some proficiency with Blender where I can navigate the interface and sketch up some simple shaped model without any of the functional parts described above. My question therefore is:

Are there any tutorials that could help me create better models? If I need to I'm ready to learn to use a software other than Blender. I've tried searching for a similar question but found nothing.

[A]
The answer to your question is yes, there are tutorials to help you create better models. Unfortunately, the back-story to the answer is beyond the scope of StackExchange.
Don't limit yourself to Blender, especially if you are attempting to create non-organic (engineering-type) models. Blender is great for curves and bulges and bumps (and animation, and so much else) but not so great for parametric modeling. Meshmixer is a useful program, but more organic than engineering.
Consider to search for OpenSCAD, Fusion 360, TinkerCAD, but also use terms such as "parametric 3d modeling software" to find a wider range of solutions to your quest.  The above programs are free, there are too many paid programs to list even a small number.
Oh, yeah, stay away from SketchUp for any 3d print modeling. So many failure modes result from models created with that program.


q: I am completely new to 3D printing. I need to build a calibration plate, which I was told can be built using  vero back plastic and a 3d printer. But I am afraid I need to know more if I give this to someone for fabrication. In particular, I am wondering how to get the white dots on the surfaces. My question is probably ill-posed, but I am trying to get as much info as I can before I consult any 3d printing vendors. Thanks

[A]
The photo is too small to be clear about the entire objective and there are no dimensions provided. A quick google search returns nothing 3d printer related to "black vera plastics" other than a reference to vera bradley, vera wang and an obscure reference to a woven black carpet with white spots of increasing size.
Even within those limitations, one can certainly print a strip of black with white dots. One method involves a dual extruder printer, enabling two colors to be printed, one layer at a time. The black layer would be extruded with suitable holes and the white layer would be place within those holes.
Another method involves printing the black layer with holes, swapping out the filament with white and creating white plugs of appropriate sizes for the necessary fit.
You've used the term calibration plate, which implies some level of precision. Is the precision related to spacing, dot size, dot color, or a combination of the above?
Such requirements may make the cost slightly higher, but not excessively. I can print up to to 290 mm long strip, possibly longer by going diagonal on my 290 mm print bed, with or without the two colors done simultaneously.
If you require crisp edges to the white/black transition, the holes-and-plugs method will give best results and require a bit of post processing. It may be necessary to ream the holes to correct diameter and sand the plugs to fit. Dual extrusion rarely provides sharp delineation from one color to the next.


q:
Should it be possible to directly send G-code to the printer serial connection using pipes under Linux?

Example:

echo M106 > /dev/ttyUSB0

My controller runs at 250000 baud, I have tried setting the TTY baud rate to 250 kBd with:

stty -F /dev/ttyUSB0 250000

But, unfortunately, this particular baud rate appears to be unsupported under Ubuntu, giving the error:

stty: invalid argument ‘250000’

[A]
This forum page
strongly suggests you should be using
```
setserial
```
for a port, not
```
stty
```
, which is for terminals.  I'd give the code snippets there a try.
Alternatively,
stackoverflow
has a similar discussion, with somewhat more complicated modifications.
Are you sure you can't talk with your printer at a lower baud rate than the maximum capability of the printer-end?


q:
Is it possible to 3D print an axial turbine 2 - 4 inches (50 - 100 mm) in radius, capable withstanding temperatures about 800 - 1000°C and rotation speeds of 100 - 120 x 103 rpm?

How expensive is that? Is it cheaper to mill such a turbine from a whole piece of alloy?

What technologies and materials should be used?

Are Inconel alloys suitable for 3D printing?

Are there any titanium alloys suitable for this task? I've read titanium is rarely used in rapidly rotating parts due to its ability to ignite if mechanical failure occurs and rotating blades touch the casing. Do titanium alloys still have this drawback?

Is it possible to make disk of titanium and blades of Inconel, and have them welded (considering heat expansion)?

How blades or blisks can be ceramically coated?

Thank you!

[A]
This depends primarily on economics and on desired lifetime.  Rather obviously you need a material whose strengths and melting points exceed the operational specs.  Determining the various break strengths (shear, bending, etc) is an engineering problem, not a manufacturing problem per se.
Next, consider the production time and cost of 3D-printing vs. some typical assembly line process.  Nearly always the 3D approach loses for large quantity builds.
Designing and operating devices like this can be extremely dangerous. Very tight tolerances are required.
This site
describes the difficulties, starting with material choice, moving on to tolerances, and so on.  I don't think you want to go at this in your basement.


q:
I bought a self-made Reprap Prusa Mendel 3 printer, modified to be built from cheaper materials, and immediately after the deal I got various problems. I fixed the majority of them, but don't know what the reason of the strange extruder behavior is: The stepper motor is not rotating while extruding filament, it's moving back and forth with small steps instead. I made some footage, Reprap Prusa Mendel 3d printer extruder problem, hoping that someone has met a similar problem before.

If so, please tell me what to do to make it work as it should.

The obvious option while encountering this problem was to slacken the bolt which holds this parts together (in the left bottom corner of the video), but that did not help.

Any ideas are very welcomed. Thanks for your time. I hope this is an appropriate kind of question here.

[A]
Your controller board probably requires calibration.
It sounds like, maybe, the extruder's stepper motor is
not receiving sufficient
current, to make it turn.
Or
, somewhat confusingly, maybe the stepper is
receiving too much current
, and overheating.
You don't say which controller board you are using, but regardless, there should be an adjustable potentiometer on the board, next to each of the stepper drivers, or on the stepper driver daughter boards.  Like so,
This potentiomenter adjusts the
reference voltage
used to control the stepper motor. From this
reference voltage
, and the resistance of the stepper coils, one can determine the current, which is used to drive the stepper motor.
For the stepper driver of the extruder, you could try turning this adjustable potentiometer slightly, in order to provide more current to the stepper, in turn to provide
sufficient torque
such that the motor is able to turn.
Or
, less current to stop the stepper from overheating.
The adjustments
can
be made whilst the power is on, but a
non-ferrous
(i..e. plastic) screw driver should be used, so as to avoid short circuits. Also care needs to be taken, when turning the potentiometer, as they have been known to just fall apart whilst being turned. If you are paranoid, then make micro adjustments with the power turned off, and then turn back on to check the behaviour.
Note
: it should go without saying that one should
never disconnect a stepper whilst the power is on
, as both the driver and the stepper motor may be irrevocably damaged.
The photo above is taken from
POTs Calibration – RAMPS 1.4
.
If a POT is set too high then the associated stepper driver will tend to overheat and go into over-temperature thermal shutdown (to prevent damage to its components). The first sign of overheating is erratic stepper motor behavior. Typically, this can be recognized by the sounds of the stepper motor suddenly losing power (thermal shutdown). If no load or movement is required of the motor, it is hard to detect whether it is over-powered as the driver is barely producing any heat.
and
Conversely, if the POT is set too low, the stepper motor can enter an underpowered state. This can be recognized by a lack of holding torque and a stepper motor that is skipping steps because the necessary movement  requires a higher power demand than the POT setting allows for.
Driver cooling
In addition to the possibility of the stepper motor over heating, it could be possible that the stepper driver is overheating, although the symptoms may be different, to those that you are experiencing. Regardless, you may still find it advantageous to cooler the controller/driver board with a fan that is always on (not temperature controlled).
Additional reading
RigidWiki -
Stepper Driver Adjustment
, which goes into further detail about the adjustment of the potentiometers, that I outlined above, as well as the
reference voltage
and the adjustment thereof.
RepRap Wiki -
RepRapPro Setting Motor Currents
describes a different controller to yours, but goes into the process of adjustment, and description of the
reference voltage
(which is applicable to all boards):
The wiper on each potentiometer generates a DC voltage that is sent to the chip. This is the reference voltage; it defines how much current the stepping motor driver chip supplies to the motor. The bigger the reference voltage (VREF), the higher the current (A) that the chip will send to the motor. For most NEMA14 motors, the current maximum is 1A, but this will generally cause it to get warm, so a setting of 750mA is recommended. For NEMA17 motors, depending on size, the limit on current is generally between 1.3A and 1.7A. If you drive stepper motors with more current than they were designed for, the motor will get hot, and may be damaged.
Pololu -
A4988 Stepper Motor Driver Carrier with Voltage Regulators
- this is a very common stepper driver.
MyHomeFab -
DRV8825 Adjust Stepper Current
goes into the adjustment of the reference voltage, for the commonly used DRV8825, which is an alternative to the popular A4988.
This thread, about non-actuating steppers, may also be useful,
Motors
, which mentions
setting the trimpots
and points the OP to RepRap Wiki -
Pololu stepper driver board
, which, in turn, refers to this thread,
Strange stepper behavior
and this video,
video-2012-02-02-16-37-26.mp4
, which describes a jitter in the stepper behaviour.


q:
I am using an M3D printer and loaded an STL design with holes in the middle:

However, the output is an object without holes (so I stopped the printing):

What can be done to be able to print with holes?

[A]
Case 1:
There may be an issue with the precision of the print nozzle, not being able to fully articulate the hole. That is to say, the printer is trying to print it with holes, but the material is filling in that area.
Try increasing the size of the hole. Granted, it is not an exact process but there may be an inner hole diameter that winds up mimicking the diameter you're looking for after the material extrudes.
This case could be rejected by nature of the printer depositing straight lines through the center diameter of the cylinder's base.
Case 2:
There may be some discrepancy between the file's appearance and the file's information.
If you downloaded the file from somewhere like ThingiVerse, try designing the part yourself if possible. If you designed it yourself, overwrite the file with a second version.
Case 3:
If downloaded, verify that the center hole is extruded though the entire thickness of the part. It may be that it's extruded most of the way through and there is a sealed bottom layer.


q: Does anyone know where I can get a free 3D design (STEP or STL) of an M4 Screw and nut? I have found only an M3 on Thingiverse: M3 Bolt by Kaleta.

[A]
The thing you linked to describes itself as being generated from a parametric model:
http://www.thingiverse.com/apps/customizer/run?thing_id=193647
To generate any different bolt or nut, you will need to identify the correct dimensions for not only the thread (where hints exist in the customiser), but also for the hex head. These are obviously less critical to define than the thread.
Once you have generated a custom model, you can share it and answer your own question.


q:
I just want to ask if anyone has successfully printed a screw (M3 or M4). Is the printed output usable as a screw? What printer is capable of printing screws? I am using an M3D printer - is there a configuration to successfully print a screw that is usable?

Can anyone share a picture of the best 3D printed screw?

[A]
well... it's hard to imagine printing M3 or even M4
I haven't try but I haven't because I'm pretty sure it's not possible (on my printer of course)
but some time ago I've tried M8 which is of course way from your needs
it was printed on 0.1mm layer height
it went ok into the nut without any problems but the strength is not very high I suppose
I know the quality is poor but even such bad photo shows issues


q: I have generated a few 3D prints in G-code using KISSlicer and Slic3r, but when I load them into Ultimaker Cura I'm unable to get anything. The number of layers says one but I cannot see anything and print option is not working. I have viewed these G-codes online and they are fine. I'm using a Lulzbot KITTAZ with v2 toolhead (hexagon) and I can print only using Ultimaker Cura. Please tell me what the reason for this is.

[A]
Cura prior to version 2.5 does not take G-code as an input. I'm not sure what you mean by "print only using Cura." Don't you have a SD slot on your control board? For that matter, why can't you drive the USB port from Slic3r?
Remember: G-code is the equivalent of "compiled code," the raw commands which drive the printer, while STL or OBJ, etc., are the "source code," which you edit to get the shape you want.
I've looked at a few apps which will render a 3D image on your computer from G-code, but I don't know off-hand of one which will "decompile" into a STL or mesh file.


q:
What resources or methods would OpenSCAD users suggest to piece together disparate STL files?

I'd like to take an existing STL model-library of STL parts (head, torso, arms, legs) and make it a Thingiverse OpenSTL maker, similar to the castle generator and/or the puzzle generators available.

This way, users can generate a custom model using the designated parameters and download the model for printing.


q:
3D printing can be used to make injection molds of unimaginable complexity but which kind of 3D printing process is suitable when?

Suppose that a part is to be made using injection molding in large quantity for an extended period of time, what Additive Manufacturing (AM) process will be the best, such that the mold does not give way too soon?

Also, suppose that the part to be made is custom and only has to be made in small quantities - that is to say that the injection mold will be used limited number of items and then thrown away - which is the best AM technique then? Best in the sense of economic feasibility, lower cost, lower capital investment etc.?

[A]
Yes, this is very broad. That said...
For high detail you want SLA. i.e. jewelry. If you just want a prototype of a mold, you can do a standard FDM style printer (95% of printers are FDM, and that number is a guess)
Really, you should be asking what material you need for your mold, but you can open a second question for that.
Do more research on injection molding. There is a great deal of information on how molds are made, i.e.
How It's Made Plastic injection molds
.
You will see there is a vast difference between a plastic, or silicon, mold and an injection molding machine. You are thinking that injection molding as a single mold, when it is really it is a system composing of several pieces of heavy duty machinery that can pump out hundreds of items a day automatically. However, it usually starts at 20k USD for the tooling for injection molding. Your costs could be a fraction of that or could be several times that. This is just a generality. So, if you are making 100 units you won't want to go down that route. For 10,000 units, on the other hand, it would be acceptable.


q:
I have Prusa i3 derivative with MK8 extruder and Marlin 1.1RC8 as firmware. I already reduced the default speeds as well as the accelerations. But sometimes when trying to print with BQ PLA filament (220°C), mostly during filling areas, my extruder clicks. The below screenshot of Slic3rs Layers view shows the clicking "lines".

What settings I need to change to avoid the overextrusion in this case?

[A]
The only time that I've observed clicking from the extruder on my Anet-A8 is on the first layers when I have the head height set too low - the nozzle is unable to extrude at a high enough rate to allow the filament to progress as requested.
If you have a somewhat repeatable scenario, you could try reducing the filament feed rate to 90% or so, and see what effect that has. I have already observed with one of my reels of filament that 90% feed rate gives me a less over-filled solid area, so maybe the default feed rates are a little on the high side (or this filament is of excessive diameter).


q:
I'm looking to buy my first 3D Printer, on a tight budget of $250. Unfortunately, this printer that I found on Amazon comes with all the bells and whistles, except for a heated bed.

I want to know if this would affect printing severely, as I have read that the plastic/ filament cools down rather quickly, and that it results in Printer "fails".

I'm actually a bit nervous with this buy, as I don't want to spend $250 on a printer that produces 90% print fails.

An example of the printer I'm referring to is the Cube 3 Printer, Grey
by 3D Systems.


q:
Just started doing some design. First project was a replacement handle for my angle grinder, so basically a hollow cylinder. I want to reduce the amount of material used in the print. I could sit here and punch holes through the handle with a smaller cylinder, or some other shape etc., but is there an easier way to do this?

It must be a pretty common requirement, just like in the movies where the spies look at a photo and tell the tech to 'enhance ... enhance'. Ideally you could select a surface and overlay some sort of pattern to remove material.

[A]
Updated to match the improved question format.
There are a few ways to reduce material usage. First is what you have touched on. Which is to reduce the design by punching out holes, and removing all material that does not add anything to the structure. Even better is what you touched on, reducing it to the point where your print is more like a suspension bridge, where it is a the bare minimum scaffolding in a geometric pattern.
Most tools you will find for reduction are like
this tutorial from Shapeways on Meshlab
where you reduce the surface detail. It might be worth exploring these a bet, however probably not what you really need.
Next the more hard core cad tools such as solid works will allow you to preform
Parametric optimizations and Topology Optimization.
Topology Optimization. seems to be your real winner
Now from the 3d printer standpoint we just simply tweak our slicer settings. There are entries for Infill. I usually print with 7% infill. AKA my print is 93% hollow inside. I then set a few solid shell layers. Think of solid shells as the skin. Usually that is enough to reduce my plastic usage. The only reason I don't make a part 100% hollow and a few solid skin / shell layers is that I need something to print on top of or if I need the part to be strong . Even low percent infill can be very strong if the correct geometric pattern is used (I.E. triangles).
Generally the reduced infill will be enough, unless you are making thousands of this item, though in that case you are probably not going to 3d print it anyways.
3dprintingforbeginners
has a nice article on the relationship between infill, number of shells and part strength. A bit more information about the terminology (infill/shells/etc...) can be found on
3D printing blog
.


q:
I've read different things about PLA and heat-bed. Some say it is not needed, others recommend 60-70°C, but not for the first layers.

For larger objects I often have the problem that the object does not stick to the blue-painters-tape-covered aluminium print plate. Instead the print "curls" up on one or more corners. To reduce this effect, I'm using a brim between 5 and 10mm. Depending on the size of the object the brim works quite well. Will heating the bed also improve the print quality by reducing the amount of heat warping / curling?

[A]
It really depends on your formulation. 70 °C would be on the higher end. I think I do between 70 °C - 75 °C. Not any higher.
Add a glue from a glue stick to help with keeping it on the bed.
Use a raft to reduce the issue as well.
A fan is the number one thing you can do.
The last solution is to build a heat enclosure. They are not on every 3D printer because of patents blocking them. You can easily make your own.
Technically it is not 100 % needed, i.e. the MakerBot does not use it, but the guys at MakerBot have PLA down to a science.
Also I thought Kapton is not for PLA usually... see these
MatterHackers
articles:
How to succeed when printing with ABS
;
How to succeed when printing with PLA
.
From
RepRap Wiki - Glossary
:
Raft
A technique used to prevent warping. Parts are built on top
  of a 'raft' of disposable material instead of directly on the build
  surface. The raft is larger than the part and so has more adhesion.
  Rarely used with heated build surfaces. For the small area models, it
  is very useful to prevent warping via adding a raft for the model
  before slicing it. It can also help with with precision parts by
  removing the slight first few layer distortion caused by the heated
  bed.


q: I'm in the process of building the D-Bot core XY printer, and I was hoping to know if the Z-axis 'zero' is near the hot end or near the bottom of the printer furthest away from the hotend? In this printer the Z-platform moves up and down and the nozzle stays at the same height.

[A]
Yes, Z-Zero is typically at the "top" of the printer, closest to the nozzle(s). X and Y zeros are also typically in the lower-left corner of the buildplate.
However, the XY zeros are re-interpreted in slicing software to produce cleaner G-Code as it's sometimes difficult to read G-Code in negative coordinates. For this functionality, slicing engines utilize the machine build space length and width.
So if you encounter a situation where your machine "over travels" in either -X or -Y direction during startup, verify that the length and width of your build space is correct in your slicing engine.


q:
When printing the first layer, the infill overlaps on just one side of my print. Thereupon there's a rough, and a lot higher, surface on the first few millimeters after the wall.

Printer: Arduino Materia 101

Filament: Rec Pla

Temp: 210 degrees

I have tried to troubleshoot it, but I just found information about a problem when the infill isn't close enough to the wall everywhere.

However, for me, the problem is the contrary and just on one side.

[A]
Yes. That happens. I personally prefer this to the alternative which is it does not go far enough and curls back. That said depending on your slicer you will have a line overlap tolerance. But what's really happening is you are smooching your first layer. Aka your hot end is too high in relation to your first layer multiplier.
Failing that and if you see it later in the print. Again I don't think you really can fix it but you should recalibrate your printers firmware, steps per mm and your slicers filament size.
Looking at it I again it is a bit much. Maybe the plate is not flat. Does it happen on any other sides? After that we have the unlikely case your hotend is too hot. Which the slow down of the printer could cause too much material to ooze out. But I'm going to say plate level as number one suspicion.
3D printing is a lot like trying to spin 3-4 plates at once.. if you still have issues I can expand more on calibration steps you need to do.


q:
When trying to print parts that should contain certain sized holes, e.g. for screws, how to achieve that they are sized correctly?

Is it possible to calibrate the printer perfectly, so it prints holes correctly sizes in all common sizes (e.g. starting at 2mm diameter)? Or is it better to design the holes larger or print prototypes and increase the sizes according to the real prints?

[A]
The reason holes come out undersized is generally the slicer
, so calibrating the printer itself cannot solve the issue (without making other things worse). The output of the printer is exactly what it should be, given the G-code provided to it. It's just that the G-code does not represent the hole diameter correctly.
It would be best to simply account for the deviation in your design, or simply drill out undersized holes to the correct diameter.


q:
I run a high school 3D printer lab and we have several 5th generation MakerBot printers. On one of them I have considerable trouble with "thin" prints and filament slip warnings.

So far I've tried changing extruders and using different filament rolls with no luck. But, if I move the job and the extruder to a different printer it works.

I'd appreciate suggestions for how to sort this out. I would have expected the slipping problems to follow the extruder.

[A]
Oh interesting. By slips, I take it you mean that the raw filament slips, not the print slips.
This will happen for a few reasons. First the tooth gear that grabs the plastic is either:
Worn out
Out of place
Not the correct distance from the guide wheel.
This is all part of the mechanism that the Smart Extruder attaches TO. Not the Smart Extruder itself. You might be able to fix this yourself, worst case you will need a replacement assembly from MakerBot.
I would look into online auction sites for the part
Another option is to try thicker filament. Which you might be able to custom order. So instead of 1.5, maybe get 1.8. I am not sure where you can buy off sizes.
From there this machine might just be getting jammed. It happens to some machines. This again points to the base of the X axis assembly.
Last which I would say is not likely as you have tried multiple extruders, you might have the nozzle becoming clogged. I often pop open my extruders
voids warranty
and clean them out. Also micro hand drills are a good option here.


q: I am planning on buying a cheap 3D printer to get into 3D printing, but the printer I'm planning to buy only takes 1.75 mm filament, I was wondering if it might be possible to change the hotend of that printer or something to take in 3.0 mm filament, the reason I want to use 3.0 mm filament is because it is cheaper than 1.75 mm filament.

[A]
First it really depends on your printer / extruder. That said generally 1.75 mm is cheaper and much more common.
If one were to change the hotend, likely you will need to replace most or all of the hot end. In the case of my personal hot ends, when I did this conversion I had to replace both the tube and the PETF lined mouth. I did not have to replace the tip, core, or the thermsister.
My advice is to pick a different printer. You see 3 mm on older extruders like J Head direct gear from around 2012-2013 and Bowden style (like the Ultimaker) use 3 mm (actually 2.85 mm).
Possible yes, advised, no.


q:
I would really like to be able to print moving parts that fit well enough to move without excessive friction, but also aren't excessively loose.  Using an Ultimaker 2, what should be my expectations be, and how would I go about produce well fitting parts?

Using a tool like Openscad to generate parametric parts is really useful because it facilitates the creation of geometrically precise parts such as cogs and drive shafts, which also have precise dimensions.  The problem arises when the parts are printed and joined together.

I recently printed some cogs that were supposed to be able to rotate freely around a shaft, which was also printed.  I made the shaft about 0.1 mm smaller than the center hole of the cog expecting it to be able to rotate freely, however I found that I had to bore out the center hole slightly and sand down the shaft.  I then found that the boring was imprecise and the center of rotation was off center.

[A]
I think that you've got the right idea in concept, but benchmarking is typically the best way to prove this out.
You should get in the habit of designing with assembly in mind.
This means:
Hole sizes should be larger than intended and/or shafts should be smaller than intended
Scaling does not always solve the issue! Avoid relying on scale tools as it can result in reducing/enlarging features you did not intend to scale
My own experience has shown that a
clearance
of about
0.005" to 0.010"
(~125μm to ~250μm)
should be enough. However it may be different for your situation with a different printer, filament, climate, etc.
Also consider material shrinkage from the printing process!


q:
tried searching but couldn't find anything.
I do not have a 3d printer so can't really experiment on my own, which means that when I am going to order a 3d print I want to get it as good as possible. So, my question:

Do quality of geometry matters when 3d printing? Will 3d printer only print quads, or ngons are fine? Are there shapes to avoid?

Cheers :)
M.


q:
I'm trying to design a camera handle, which will be around 8" long and will have a brass camera thread insert in the end, where the camera will be mounted.  (That way, I don't have to screw the camera thread into plastic which will wear out faster.)

If I print the handle normally, the end of the handle won't be solid so I can't solidly put that brass fitting in.  If I set the fill in Cura to 100%, the print will take a very long time and will be unnecessarily solid.  I only need a centimeter or two at the end to be solid.

Is there a way to get one particular wall in Cura to be very thick (1-2cm) without affecting the other walls?  Is there some other way to get a solid chunk in the end of the part?

[A]
I think you are approaching this wrong. Sounds like you need to design it to have a hollow wall. That said to answer your question no you cannot have your slicer modify prints like that. But it bears mentioning you can set all shells to what ever you want have have a very sparse infill. To you can set vertical shells to 3 or so. Top to 3 bottom to 2 and infill to 7-15% so it will be 93% hollow not counting the 3 layers of solid skin.
Post pics of your design. Or let me know what else I can add. Check out my answer to this
other stack overflow question


q:
I have never much cared about self intersecting meshes when slicing with Cura. Geometry like the one below are often practical. I for instance add lots of rivets that self intersect with the base geometry:

Now I have switched printer, and am using Simplify3D instead. All of a sudden, I get lots of problems with these models. The intersection of the objects become hollow. Simplify3D has a setting to join the outer solid shell but it also fills holes (such as the center hole of a gear).

I make models to sell so this is a big deal for me.

EDIT: Also, they printed perfectly fine in formlabs "slicer".

[A]
Self intersecting meshes are considered dirty, yes. The reason you haven't had trouble before is probably that the software you were using was cleaning your mesh for you, behind the scenes.
Generally speaking, these meshes can be cleaned without too much trouble by software like netfabb (
https://www.netfabb.com/
) which has a nice free version that I use for basic cleaning of some of my meshes. A quick google on "netfabb free fix mesh" should turn up a tutorial or two.
If you're interested in learning more about an operation you can use to make this a
single unified mesh
, it's called a Boolean Union, and the blender project has a nice (open source, I think?) implementation of such: (
https://www.blender.org/manual/modeling/modifiers/generate/booleans.html
)


q:
I'm new with my 3D printer, I just print two different pawn pieces from thingverse. I just used Cura to convert the files to be readable for the printer. Is my problem with the pieces has to do with the configuration from the Cura software? or with my printer itself?

Update:

I just printed a baymax that came with the SD printer. And it looks awesome. I think the problem is with the configuration from Cura.

[A]
That looks like horrible underextrusion. Either the extruder steps/mm are way off, but more likely is that your nozzle is clogged (because I wouldn't expect the steps/mm to be this far off). It's also possible that the temperature you're printing at is inappropriate for the filament you're using. Also, make sure that the fan that is cooling the heatsink of the extruder is always on. If not, filament may soften in places it's not supposed to and jam.
Try heating the extruder up and pushing the filament through by hand. You'll probably feel a lot of resistance and the filament won't come out smoothly. You could try doing a couple of
cold pulls
, that is, put a piece of filament in while the hotend is hot, then let it cool down and attempt to extract the filament at the lowest possible temperature. This may pull debris or particles blocking the nozzle out.
If this doesn't help, there are various other ways of clearing a clog from the nozzle. One popular technique is disassembling the entire hotend and burning out all the debris from the nozzle with a blowtorch. Another is using a special drill bit to clear out the nozzle but this has a high risk of damaging it.


q: Hello is there a way to prevent bend on print with M3D printer?

[A]
You can to print a brim, a thin layer on the bottom connected to the model. This will help hold it in place. Since it is thin (one or two layers) it will not warp itself.
The brim is not the same thing as a raft. A raft is under the model. The brim is on the same layer as the models bottom layer but outside the model. It looks something like this:
I assume that you use a heated bed if you have one?
Also, it is imperative that you get a good first layer. Calibrate your machine carefully.


q: I recently had a problem with the z-axis of my printer. To resolve the issue with the Z axis not moving I remove the left polished rod. Am I able to use the printer with just one smooth rod?

[A]
First a resounding no. Not a good idea. Are you saying it works now that you have removed the smooth rod?
That tells me for sure your issue was Binding. Which is a tricky problem to solve. Binding usually happens when your carriage is not level. Take a bubble leveler and verify.
Another time it happens is when your Acceleration / Jerk settings are too high. Try reducing the Acceleration for Z in the firmware.
Another possibility is your rod is Bent. Take the rod on a flat surface. Inspect it as you roll it around. Do the same with the other rod. If it bows and is not completely flat, then you will need to replace it.
Last is make sure your printers frame is put together. If it is causing the rod to bend as it is not aligned right then you should try to see if you can fix it and contact the seller.
Technically you can run without the second rod. Maybe. I do not advise. It is sort of like cutting off a leg because you have a cramp. It will hurt your overall quality and it is better to just resolve the issue.


q:
I want to create parts for a 3D printer using OpenSCAD. Having some STL files from the vendor, but nothing else (no technical drawing, no CAD files).

Does anybody knows a free tool, that allows me to

measure distances between 2 selected vertices,

measure distances between a selected vertex and a plane defined by 3 vertices,

measure the radio of a circle defined by 3 selected vertices?

I very much like the way Blender allows to work with meshes, especially select vertices or planes, but unfortunately haven't found a way to measure with Blender.

[A]
I suggest Blender. It's not the simplest of tools but it is free and learning it will improve your 3D printing skills. :-) (I write this answer also for future viewers of this question so I start basic).
Another answer can be found here,
How do I measure a distance between two points?
Import your STL file.
Press the Home key to view everything.
Select the model by clicking on it with your left mouse button. (Blender changed to left-click-select as of version 2.80)
Hit tab to enter edit-mode.
Press N (or use View | Properties) until the Properties panel shows up.
Select the "Length" checkbox in the "Edge Info" section of the Properties panel (see image below).
Select "Edge Select" mode (see image below)
Select the edge to measure by clicking on it with your right mouse button.
If you need to measure the distance between to vertices with no edge. Create the edge by selecting them and pressing
F
.
If you need to measure the distance between a vertex and any other point, select it and press
E
to extrude.


q:
Nozzle diameter = .4
Extrusion multiplier = 1
Extrusion Width = .45    <-- I feel like this could be reduced to fix it?

Layer Height = .3

I'm using Simplify3D.

[A]
Oh thats simple. First you will see the "elephants foot" on first layers if you have the extruder over-extruding or do not have enough distance between the bed and nozzle.
It's very common that the first couple of layers of a print is wider than you expected them to be. This is because you will generally want to make sure the first layer is nicely squished into the build platform so that it sticks properly. By doing this the plastic gets squished out into a thicker line than normal and thus the bottom of the print will bulge out a bit like an elephant's foot. You can decrease this effect by leveling your bed so that the nozzle is slightly further away from the bed and lowering the bed temperature a bit. It's hard to get rid of this effect entirely without sacrificing bottom layer quality and bed adhesion. It will be easier on small prints as they are less likely to warp and detach from the platform and you can therefore get away with not squishing the first layer as hard.
See this visual guide on more information
If you are seeing this on all layers. That means you have oozing. When your printer hits the end of the line. It has to slow down, stop and start the next vector. During this time if your printing very hot, you will ooze material at this intersection. Also the extra time over that spot mayhaps also warm the corner, causing more disruption. Best thing in this situation is to verify you cannot lower temps more. Add a fan. Also double check that you are extruding the exact amount you think you are. (distance of material and the material size average)
Here is another visual trouble shooting guide
I will note, I don't think thats too bad. If it needs to fit into something, just clip it.


q:
I've build a 3D printer from sourced parts and mounted the hotend cooler to blow air over the heatsink.

Talking to a friend, he said it's better to reverse the airflow over the heatsink, but couldn't give me an argument other than everywhere he saw it was like this: all coolers are mount to suck the hot air away from the heatsink.

Is it one way better than the other way ? And if so, why ?

[A]
In the case of 3D Printing, it's going to be faster to cool the radiator by blowing out the heat from the source.
The idea is that you're trying to get rid of as much heat as possible in the quickest means possible. By blowing away from the radiator, you're allowing the ambient temperature to cool the hot air being blown out.
If you were to blow the ambient air towards the radiator, the blown air will warm slightly as it is overwhelmed by the heat of the radiator. Even though the ambient air may be cooler, it will take more time to cool off the radiator.
Example of bad airflow, which will take much longer to cool the radiator:
Example of good airflow, allowing the hot air to be quickly cooled by the ambient temperature of the build space:


q:
In this question I was told that I should use silver solder to connect the heating element to the power supply.

(I was also told that a ceramic extruder head was the way to go, but I'm working with what I have)

I bought two types of silver solider from Radio Shack:

96/4 Silver-Bearing Solder, Lead-Free 0.62" diameter.

62/36/2 Silver-Bearing Solder, 0.15" diameter.

Is there any reason I should use one of these over the other to power the heading element of the J-Head extruder?

[A]
The first is not suitable. ASTM96TS Sn96Ag4 has a melting point of 221–229 °C according to
Wikipedia
. Pb96Ag4 would be OK, but that is not lead free so doesn't seem to match your description.
Update from comment to explain the letters and numbers: the data comes from wikipedia, the numbers are Tin(Sn) 62%, Pb(Lead) 36%, Ag(Silver) 2%, for example, see below for an electronics solder compound
.
Sn62Pb36Ag2 is an ordinary expensive electronics solder (but not lead free), with an even lower melting point.
You need to find a high temperature silver solder, with a melting point of about 305 °C (which confusingly might be a soft silver solder), for example one of
these
. Hard silver solders melt at 600 °C, that would be excessive in this application.
The nomenclature 'silver solder' came about before lead-free electronics solder was introduced, since when more alloys containing silver have become popular as general purpose solders.


q:
I'm using a Flashforge Pro and attempting to print a wheel about 6mm thick to serve as a platform.  In other words, the wheel doesn't have to be solid, but spokes won't do the job.  I've experimented with different temperatures, but, because of ABS' thermal expansion, I don't think that will solve the problem.  Also tried putting lots of 2mm holes in the wheel.  I've considered other designs for the interior, but doubt that would be a solution.  Has anyone tried using different print paths, i.e. actually altering the path that the slicer suggests?  (grasping at straws)
Thanks for your suggestions.

[A]
If you can, set your slicer to do honeycomb fill.  Depending on the weight requirement choose maybe 10% - 20% fill.   That ought to do the trick.  It won't be solid, but it should be strong enough.
What are you going to put on the platform?


q:
I'm trying to use one of the RAMPS GPIOs to control an external device that requires a 5V low-current logic level signal from Marlin. In order to do this programmatically, my host software (Octoprint) is sending an M42 command. I am using the following syntax:

M42 P4 S255

according to the pinout in the following image:

However, the pin appears to not be driven to a logic HIGH level. Is there firmware-level configuration I need to do as well, or is my syntax/pin number incorrect?

[A]
I looked at the current Marlin code and the P24 command should work as you expect it unless the pin you are trying to use in listed as the "SENSITIVE_PINS" list:
```
```
#define SENSITIVE_PINS { 0, 1, \
X_STEP_PIN, X_DIR_PIN, X_ENABLE_PIN, X_MIN_PIN, X_MAX_PIN, \
Y_STEP_PIN, Y_DIR_PIN, Y_ENABLE_PIN, Y_MIN_PIN, Y_MAX_PIN, \
Z_STEP_PIN, Z_DIR_PIN, Z_ENABLE_PIN, Z_MIN_PIN, Z_MAX_PIN, Z_MIN_PROBE_PIN, \
PS_ON_PIN, HEATER_BED_PIN, FAN_PIN, FAN1_PIN, FAN2_PIN, CONTROLLER_FAN_PIN, \
_E0_PINS _E1_PINS _E2_PINS _E3_PINS _E4_PINS BED_PINS \
_H0_PINS _H1_PINS _H2_PINS _H3_PINS _H4_PINS \
_X2_PINS _Y2_PINS _Z2_PINS \
X_MS1_PIN, X_MS2_PIN, Y_MS1_PIN, Y_MS2_PIN, Z_MS1_PIN, Z_MS2_PIN \
}
```
```
These pins are printer specific; so, without access to your Marlin build, I can't see if pin 4 corresponds to one of these.  If this is the problem, the command should be returning an error.  If there is no error, I would look closely at the hardware.


q: I'm trying to gear down a servo even further. I notice that the majority of the gears are made of nylon, and I want to create new gears that come close to the resolution and strength of the existing gears. I have a Replicator 2, but the resolution does not seem to come close to what I need. Any suggestions on how I can create nylon or other hard material parts that might work?


q:
PTFE tubes are typically delivered coiled up. And because they are quite stiff, they always want to spring back to their original curvy shape, making them harder to route properly.

Is there a way to straighten them out?

[A] I just plugged the ends of tube and soaked it in real warm water for 5 minutes then stretched it out on a table. That helped then the hard part I spooling it up against the arch and soaked it again. This seem to work the best.