q:
During printing, my printer occasionally makes some mystery moves: it will very slowly move either the X or Y axis all the way to the left/front, before very slowly moving back to its original position and resuming the print as normal. I've checked my G-code files, and the moves are definitely not part of the G-code. What could be causing this?

I'm printing from an SD card on a Cartesian printer.

[A]
The issue was due to a corrupt SD-card, which was occasionally having some garbage read from it. It turns out that Marlin will try interpret a corrupt move command like
```
G0 X1q3.54
```
and still read as many numbers as it can. In this example, it would be interpreted as
```
G0 X1
```
rather than (as might have been intended)
```
G0 X103.54
```
.
This explains my symptoms perfectly:
X and Y always moved to (approximately) their home positions, but it was always only one of them (it's quite unlikely that both moves are corrupted).
Z was not affected because Z moves are much rarer in the G-code (only on layer change) and thus it was very unlikely that a Z move would be affected.
E was not affected since a request to move E to near 0 would be prevented by Marlin's long extrusion prevention.


q:
I have a 3D printer that is going crazy with x-axis shift, and I need a tension gauge belt to measure the tension.

I've never used one before, and looking online, I can't tell which one would be the right fit.

Any ideas? What things should I look for?

[A]
It's extremely unlikely that belt tension is actually your problem. I've never heard of anyone using a gauge to measure their belt tension. Typically you just pull your belt tight by hand so that it produces a low note when plucked. It's far more likely that you're experiencing shifts due to too high or too low stepper current.
Unless your belt is so loose that it easily skips over the pulley (which should be obvious without using a gauge) or so tight that it completely binds up (it would be impossible to get it that tight without some kind of superhuman force) it's definitely not the problem.

s: huggingface

c: devops

d: intermediate


q:
I have a really bent heatbed PCB, the middle is elevated about 3 mm with respect to all edges.

I have found this thread Warped PCBs, where a heating method is applied by baking a PCB in the oven, as described here: 3.2 Bow and Twist Repair.

Can this help straightening out a Prusa heatbed PCB? If so, can I apply the heat by the heatbed itself, or do I need to utilize an oven? Will the pressure from the strongly clamped glass plate be enough or will the glass break at these temperatures (given that the heatbed can reach them).

[A]
Baking PCB in an oven is not a good idea, I would say. I know PCBs are resistive to the heat (especially heatbeds) but, still, it sounds odd. But the real question is how baking would help. Let's leave it.
If your heatbed is such bent you can do few things depending on your situation/environment.
You can:
Add two glass plates (at the bottom and at the top) and clip them all together;
Support your HB with flat aluminium or even wood;
Add an aluminium frame, or;
If you use glass plate, clip the HB to the glass using stronger (wider) clips.
Ad#1 the thermistor can even stay sandwiched between the PCB and the bottom glass plate.
Ad#2 If your HB is bent up in the middle, you can use the middle thermistor hole. Drill it a bit with fi8mm drill (but not too much, I would say halfway through) and use a cone head screw to screw it flat on to the aluminium/wood support. Of course you will have to install a thermistor into the new place.
The simplest, and less destructive, solution is #1 and I would recommend that.


q:
Before you put duplicate from this Which are the food-safe materials and how do I recognize them? please read

I need to know if this 3D Ink™ (PLA Filament) is food safe

[A]
In general, PLA is known as a "food safe" filament, especially
Natural PLA
. However, filament suppliers have different processes that may detriment the food safe quality.
Doing a little digging, I found
an article on the M3D site
which mentions the following about their filament
All of our products, including our filaments are made from 100% non-toxic components and considered generally safe under normal use. They are not considered a chemical, or a hazardous material by OSHA standards. Therefore, OSHA defines it as an "article" and does not require MSDS sheets. You can see more information about that here:
http://www.ilpi.com/msds/faq/partb.html#article
So, without contacting M3D directly to acquire an MSDS (or asking if its food safe), you will not find one online.
Here
is an article on a few tips for printing food safe objects as well. In a nut shell, don't 3D print food handling objects with crevasses, using uranium, or intend to put in the oven (a.k.a common sense).


q:
I have a prusa i3 with Mendel firmware and a RAMPS board.  Recently it has been randomly stopping during prints.  The LCD screen will lock up, the print will stop, and the heating elements will turn off.  Pressing the reset button on the RAMPS restarts the system and it works fine.

In addition to stopping during prints, it has also frozen up while just sitting while on.

My first thought is the power supply (12V 30A) is going bad, but is there anything else I should check before I buy a new one and replace it?

Update:

I replaced the power supply with a new one, and the printer did not stop and completed a print.  I am voting to close the question.

[A]
It could be several things.
Your ramps board is overheating or has to much load on it. If you're not cooling the ramps board adding a fan may help the issue.
I know Robo3D had this issue and started shipping with a fan to cool the ramps board.
The ramps/arduino board could be faulty, the firmware may have gotten corrupted or the current version has a bug in the code.
If you are not printing from the sdcard on the lcd controller and using software through a usb connection, that computer may be causing the issue as well.


q:
I made a torus that was 1 on the x and y axes, and 3 on the z axis in Blender. It is supposed to be a bead for a beaded necklace. It was exported to Cura as an .stl, then printed on a Lulzbot Mini. It worked fine in plastic, but when we tried it with bronze filament the nozzle clogged and it didn't start printing.

Is there something I need to add to the model that will provide instructions for the printer? The person who operates the printer says that most, but not all, of the models he prints in bronze have a border around them when they print, and this one didn't. I don't know if that makes a difference.

[A]
We print a lot of stuff in a variety of materials, and I think it is likely what you are experiencing is a problem caused by some combination of the following: Object size overall, object detail size, wall thickness, or span width/thickness.
Blender gives pretty clean stls, but the last-mile needed to get output is primarily a materials engineering problem.... (and saying thias, I am assuming you got a valid stl that the printer was able to read and rip...)
A first thought: Try loading your stl into one of the services that price online. Shapeways does, and Cubify does or did... and you can download the driver software for the Form2 even if you don't own the printer.
Bring your stl into these apps and look for error messages. The Shapeways ordering app does a nice job of showing issues, particularly ones like wall thickness and manifold faces/vertices (another possibility I did not mention above) very quickly.
I'd offer to look at your stl if it is something you can share... and/or you can ask your output guy for a sample stl he has printed with some success before. Bring that stl file into Blender beside your model and compare.
I do not recognize a "border" around stls, but all of the printers have preferences for the support sprues that support the model as it is built.... possible that he means these?
In any case, shout if I can help. We have used a lot of materials, but some of them take tweaking -- most often with detail size (how small of a detail you can recreate on the rpinted surface) and step size (how small the steps are inbetween printed layers in additive rinting systems.
Or... just chuck it onto a CNC with a big ole' block of bronze and machine it down!  That's pretty old school, but it works, too... just by removing material rather than adding.
Here's a torus at Shapeways I uploaded....


q:
I just recently purchased a new MightyBoard (Rev G) for my Replicator that requires a new power supply.

The power supply for the Rev E was a 24 V/9.2 A which was necessary for the dual extruders and heated bed. I know I need a 24 V power supply, but should I be concerned about the amperage? What will a higher (or lower) rating affect on my machine?

[A]
I suggest looking at the maximum amperage draw for all components that could be on at one time, and then find a power supply that can supply at least 20% more current.  You would never want to get a supply rated for lower current than your max draw, because then it will affect the torque or your motors, or the temperature to which your heaters can get.
Think of it like this: An outlet at home may be rated at 115V/20A.  Your blender is not going to draw the full 20A; having a little extra never hurts.  But if you try to run a large appliance (dryer, hot tub, etc.) on a smaller amp circuit, the breaker would blow because you are trying to draw more than it can supply.
The point is, get something rated for higher than you need, within reason.  It will draw only what it needs.
Pro tip:  Make sure to set the current limits on your stepper motor drivers for maximum performance!


q: Some 3 mm filaments seem to actually be 3 mm - is there any way to shave off the excess and use it as 2.85 mm?

[A]
I would not recommend you to try and somehow re-size the filament, since even the smallest of irregularities and error in diameter occurring from such a process would ruin your prints with sporadic over and under extrusion. Rather, if you have the tools available, you could grind the filament into pellets, and use a filament extruder to make it anew with your desired diameter.
Alternatively, depending on your printer setup, you might very well extrude true 3.00 filament with your 2.85 mm filament printer. If you try to do that, make sure to:
Adjust filament diameter in your slicer
Check that your filament isn't getting squashed by the extruder wheel
Check that all mechanical parts actually can pass through your filament freely
I do not own a 2.85 mm printer myself, and therefore have not tried this procedure. There are, however,
several people
who seem to have done this successfully.


q:
I was working on my printer when something metallic came into contact with the pcb. I smelled smoke and quickly unplugged the printer. Anyway, this is the result and, of course, the heat bed won't heat.

Can this be salvaged or should I toss it and buy a new one?

update the heat bed was not hot at the time. I had the heat bed unscrewed from the chassis but had forgotten to unplug the printer. I am not exactly sure how it shorted but I think it shorted between the power lead connection and the thermistor.

[A]
What happend was short circuit of course. There is no doubt you overheated HB so copper detached from HB base plate. Because you wrote it doesn't work it means copper tracks are broken.
There is very low chance to fix it. I mean it - near to zero.
What you could do is:
Detach HB from arduino
Find a place where track is broken (which needs to uncover it from protective layer)
Connect it with a wire
Unfortunately even if you do it and your HB will work (electrically) your fixed HB which won't be flat anymore.
So definitely it's to be thrown away.
[edit]
I just realised you have double power HB, which means your HB has 2 heaters... which gives a bit hope.
take a look here
here is schematics
which could give you an idea
You could check if your second heater works ok
If yes then you are salvaged! :)
[edit2]
I really suppose the schematics of HB is more or less like this
So if H1 is broken there is a chance to use H2 connecting pins respectively


q: Since I'm running a 3D printing facility of an engineering school, students are always wondering how much infill percentage affects the stiffness of the part. I know that it is impossible to get a numerical solution for this question, but maybe there is an option to simulate in software an already sliced model. I haven't seen in any slicer an option to export as .stl or .step or any other format which can be accepted by simulation software. Has anyone seen or thought about something similar?

[A]
I don't believe that slicing engines create any sort of solid model that would be useful for CAD simulation. When a slicing engine slices a 3D model, it's goal is to spit out the preferred machine paths in G-Code (of some kind). However, I've read a few articles, done some tests, and heard through the grape vine that anywhere between 10%-35% is good enough for most applications. I once watched a webinar for understanding the new MakerWare interface that explained how they chose such settings. Although I can't find the clip directly,
here
is the page for all of MakerBot's webinars. I think
this
webinar was the one I watched explaining a little bit about preferred infill percentages.
From experience, anything over 35% doesn't yield much more strength from infill side of things. Beyond 35% and you're going to want to reconsider how you're orienting the print when you print it and what you're printing to utilize the grain structure for proper strength.
However, infill percentage/patterns are not the only variable for creating strong parts. Infill is really just a way to save time and material. Here are some other ways to potentially increase strength:
Increase your shell. Shell is the number of profile patterns per layer. Typically (in FDM/FFF), each shell is
about
the diameter of your extruder nozzle.
Increase your floor/roof. Similar to shell, floor/roof refers to the number of layers that make up the "bottom" and "top" of the part with regard to the build plate.
Print orientation. Pay attention to which areas of the part are susceptible to strain along the "grain" of the layers. Try to rotate your part on the build plate in a way that minimizes potential failure both in print and post-print use.
Post process. Don't be afraid to do some post-processing to increase the strength. There are
some 3D printers on the market
that go as far as including Kevlar strands in the printing process to beef up their prints. However, it may be as simple as just coating the part in an epoxy with some basic finishing techniques. It's a bit more work, but it turns weak 3D printed parts into full production quality prints.
Update:
Based on some of the comments, it sounds like your best bet might be to find a custom application that can either convert the g-code file into a solid model (try CAM software?), or create a plugin for your CAD software (I know Unigraphics NX and Solidworks allow for this) and essentially recreate your own slicing engine that takes your solid model and generates the same infill pattern dynamically inside.
Perhaps look into the works of
Simlab
or similar which has a lot of 3D software plugins. I'm not promoting them and I don't work for them, this is just a reference of what to look for.


q:
Is there any type of software in which you can animate the way the .stl object will be printed?

I'm not talking about what the end result looks like. I'm talking about a tool which acts like it's printing the given object as an animation.

I know it somehow depends on your printer but is there anything I can use?

[A]
You may wish to consider
Craftware
for your purposes. It's a free program in beta form that does provide a tool-path animation for printing the layers. It is not so much specific to a printer as it is configurable for your own requirements.
The video
shows what I believe you are seeking at about the two minute point.
Simplify3D also provides such information, but is not a free program.


q: My MakerBot 2 jams after a couple hours of prints. It is a couple months old, and the tip stops extruding after a couple straight hours of prints. I am guessing that there is a design flaw and that the media is melting inside the extruder before the feeding teeth. Does anyone have experience with this?


q: I've been interested in 3D printing for the past month however, I have noticed that it's sort of a "reserved" topic. Meaning that everyone who talks about it, has already some basic knowledge about the topic. What are some good resources for someone who wants to start learning from zero? My main goal is to acquire enough knowledge in order to build my own 3D printer.

[A]
The resources you have at your fingertips are going to be more up-to-date than anything you'll find in a paper/published book. Use this amazing thing called the internet and read everything you can find. Use Google or your favorite search engine using appropriate terms. I'd suggest, based on your overly broad question, that you use "build your own 3d printer" as a starting point.
You'll find that
Instructables
is one useful resource as well as
MakerShed
for additional material. You will find a very large source of helpful information at
3dprintboard.com
simply by reading others' posts there and at other forums as well.
There is quite a bit to absorb and understand but with the internet at your fingertips, you won't be lacking for information.


q:
I'm trying to squeeze a little better quality out of my time lapses generated by OctoPrint.

I'm using the Raspberry Pi Camera Module V2 with a Pi 3. I've already edited the Octopi config to get 720p resolution, but the encoding during time lapse rendering is horrific. Blocky as hell.

Right now the encoding is set up at 5000k.
What am I doing wrong here?


q:
I've printed mostly ABS in the past and encountered delamination between layers many times. I've ensured the following conditions regularly:

Build plate is level

Base of print isn't warped (using ABS slurry)

Prevent air draft. I've added acrylic panels to the sides of the machine and the machine is in a custom cupboard.

Nozzle temperature at about 225C

HBP temperature at about 112C (I live in NW USA, so the ambient temperature is typically fairly cool).

Using MakerBot filament

What are some other variables to consider to help prevent delamination between layers?

[A]
I know some could not fit your question but maybe someone will look for all possibilities.
Delamination can be caused by:
filament
humidity
diameter
extruder
pressure (holdfast) - soft filament can be crumpled caused by extensive retraction)
dirty jagger teeth (knurls)
thermistor/wire failure - when it reports temp under ie 170C then extruder doesn't extrude
caret floatage (extruder motor cannot pull filament so it climbs)
general
printing speed
temperature issue


q:
I have a RepRap Prusa i2. I have done the majority of my printing with clear PLA that I got on the cheap from eBay. It works just fine.

I bought a roll of Hatchbox Silver PLA (1.75 mm) from Amazon. I have never had a print go well with it. I have tried various combinations of hotter and cooler extruder and bed (180 - 220°C extruder, 50 - 78°C bed). Prints always either curl up from the bed after 5-20 layers are deposited or delaminate in the middle of the print. I print directly on the heated glass bed, and have also tried various cooling fan settings.

Does anyone have good settings (Slic3r) to use with this stuff? Or any other advice for getting a successful print?

[A] I've been using Hatchbox 1.75 mm (but white), and settled on 190°C extruder temp, and 60°C bed. I've had trouble getting some prints to adhere to the bed, but most have been ok; I don't see a clear pattern. I don't know whether it's the fiber or my settings. I'm trying slightly higher temperatures, higher extrusion rates, and other filament brands to see if those help. Will post back if anything clear shows up...


q:
I am looking to others who have successfully printed in ABS using a Wanhao Duplicator i3.

I have tried and get a lot of warping and delamination. I tried putting a large box over the printer which did help with the warping some but I am still getting some layer separation. I used 235 °C for the extruder and 100 °C for the bed. I am printing at 40 mm/s and 0.2 mm layer height.

If someone has ABS and PETG settings for this printer, your help would be appreciated.

[A]
I am an official Wanhao Distributor
By experience I can recommend you to print with this settings:
Extruder 230 °C
Heated Bed 65 °C
Have a glass surface
Use hairspray over the glass
Continue to enclose the printer or at least put it where there is almost no wind
Print at 45 mm/s
Note that this settings vary a lot depending on humidity and other factors related to where you are printing, so it would be very useful to know where in the globe are you experimenting.
Also note that humidity is very very bad for 3D Printing Filaments so keep them sealed while not using them.
Please do  comment if you have any more doubts.


q:
I have seen mechanical (micro switch), optical  and magnetic(magnet + hall sensor) end stops.

Are there any differences in how exact they switch at the right location? If so which are the most precise?

[A]
I think there are several factors involved in which sensors are best, but the general ordering for me would be Hall, Optical followed by mechanical. All of the types will be subject to some drift due to vibrations and changes in the printer over usage. Therefore it's the ease of adjustment as well as the accuracy of the stop which counts in the assessment.
In my experience the hall effect sensors are the most accurate and easiest. They don't rely on physical switching (as with the mechanical) meaning there is no "wear and tear" on the component and the point of switching will remain fixed. They have a potentiometer which can be adjusted to make the position of the stop change without any mechanical intervention allowing very fine tuning. They can be very accurate.
Optical are similarly accurate but usually have a fixed component that cuts the beam to switch on/off the sensor. The adjustment of the stop will usually be mechanical because the mount points will need to be adjusted - this reduces their accuracy. There are various adjustable mounts to alleviate this on thingyverse or the like.
Mechanical switches are similar to optical in terms of adjustment with the added inaccuracy of the actual switch mechanism which may degrade over time.


q:
I am very close to buying a 3D printer and have started to do some preliminary design work from the things I'd like to make, but I have a question: Which corner of the print bed corresponds to the origin (0,0,0) in slicer software? Is this the same across slicers and printers?

The reason I ask this is because of the difficulty some have in removing items from the bed. It seems to me like I'd want to print small items closer to the front of the printer to make access easier, but it looks like most slicer hosts only show a box representing the build volume with no real indication of what's "front".

[A]
Depending on what kind of printer you have, the build table origin and slicer origin (0,0) are usually either the front left corner, or the center of the build plate. This can be changed by the end-user in most open-source printers. There is no standard or requirement for a particular origin location. The important thing is merely that the slicer and printer coordinate systems match, so parts actually come out where your slicer thinks they should.
In practice, it's usually quite easy to tell what's "front" in your slicer's build volume. When you open the program, the bed usually appears as it does when you stand in front of your printer. It is rarely an issue.
In terms of difficulty removing prints from the bed, a removable build plate is an excellent solution. Plastic has a higher coefficient of thermal expansion than most build plate materials (like glass), so throwing the print+plate in your freezer will generate large separation forces and help remove the part for you. Non-removable build surfaces are a deal-breaker for most serious 3D printer users I know. Either don't buy such a printer, or add a removable plate yourself.


q:
I recently decided to upgrade to auto bed-leveling using an inductive proximity sensor and an aluminum build plate on my Prusa i3. I also wanted to try to secure the build plate using neodymium magnets at 4 points, with the magnets being secured with bolts to the Y-carriage, and steel washers glued to the bottom of the aluminum build plate (since aluminum is not magnetic).

I would like to know if anybody has attempted this, and what the results were, as well as any issues incurred. My primary concern is a possible interference between the small magnetic field that is created by the magnet, and the sensor when probing the plate. I fear this question may sound a little open-ended, but I would just like to know if this could work. Please feel free to ask any follow up questions to details I may have missed. Thank you.

P.S. I would also like to note, in case there is any relevance, I do not plan on using a heated build plate, since I have a heated build chamber.

[A]
Good question. The magnets from the build plate will almost certainly interfere with your inductive sensor, the movement from the carriage will induce a current in the inductor as it approaches the magnet and may cause it to trigger. If you're looking for a mag build, I'd suggest looking at:
http://www.3dprintermods.com/prestashop/index.php?id_product=9&controller=product
I'm just about to get into auto-leveling myself, with this particular build there are a few ways to get around the issue. If you plot your auto level to occur as far from the magnets as possible (x,y location wise), then you might be ok. Otherwise you might consider investigating optical and touch probes.


q:
I have a Prusa i3 that I am mostly happy with. However, I am seeing these strange artifacts when the extruder moves along one axis in one direction - in particular from the back of the printer towards the front. The extruded lines look uneven and the surface is quite rough, but only in that area and only while the extruder moves in that direction.

Here is a recent print that shows this happen. The pieces were printed side by side, and both of them show this on the left hand side, while the right is okay.

I am thinking maybe the extruder tip is slanted (not perpendicular to the bed), which causes some sort of scraping while extruding? What do you think?

[A]
In case of such difference in printing in different directions you can check if;
for x and partially z axis
filament is blocked and cannot be pulled as it should
spool is blocked
for x and y axis
rods on which caret/HB is sliding are parallel
timing belt idlers are parallel and they are in a line
Shape of the nozzle or its perpendicularity should not be the case as it's hot and it wipes layer itself.
You can also check if it's not an issue of cooling fan. It can vibrate as such.
Eventually it could be an issue of cooling itself. Let's assume you have cooling fan at the back and it pushes air to the front then when caret moves from the front to the back then cooling time is longer than when the fan goes in opposite direction.


q:
I have a Flashforge Creator Dual.

One corner of my print bed is warped down.  I am thinking about having a steel print bed made so it would tend to stay flat.

Has anyone tried this?

[A]
I would consider getting another aluminum build plate for the following reasons:
Lightweight
. Aluminum is a very lightweight metal, making it suitable for most machines that have injection molded platform arms. This reduces potential sagging of the arms and overall load on the -Z- axis stepper motor.
Conductivity
. Referring to
this
simple Google search for heat conductivity, aluminum is significantly more conductive than steel (205 vs 43 respectively) with copper at about double that of aluminum.
Availability
. Aluminum is already a widely used material for 3D printing, so finding one will be relatively easy and probably cheaper than having a steel build plate custom made.
In conclusion, I personally would not recommend using steel for your build plate as aluminum seems to have the most benefits. Yes, steel will be more rigid and durable, but I don't think that these should be variables that are significantly more beneficial over aluminum.


q:
I use Prusa i3 with one extruder for some years and I would like to print from one material in two colors or from different materials for one model. Therefore I'm lookig for new printer with dual extruder.

Is there some way how to measure and/or compare quality of printers with dual extruder on the market?

For example to create 3d model - ask the seller(s) to print it - and then compare? - what details to focus on?

[A]
As you suggest yourself, ordering test prints of some model is one way to do it.
3D Hubs
and
MakeXYZ
allows you to get your model printed by hobbyists and small businesses for a fair price. Both sites also allow you to order prints based on printer type, which I believe is what you may be looking for.
On 3D Hubs, visit on of the
trend reports
, and select the printer you want a sample from. Similarly, on MakeXYZ,
search local makers
for your desired printer.


q: I just received my E3D v6 hotend and I am installing it on the open source design of a Prusa i3. How do I clean my hotend after each print and after using different filaments?

[A]
Usually there is no need to clean the hotend, as filament sticks well to itself rather than to the inside of the hotend. If there are remains - the simplest way to clean it up is to extrude 5-10 cm of new filament, which will gather all remainings clean the hotend.
The above concerns changing filament in the same group of plastic. So if you print PLA you can switch colors/manufacturers and so on without issues. The same goes for ABS.
There is also usually no problem when switching from PLA to ABS.
The worst scenario is to switch from ABS to PLA. This is because the extruding temperature of these two materials is different. Unfortunately ABS can have such a high melting temperature that the PLA will burn. So having a dirty hotend with ABS remainings, there is no way to extrude PLA to clean the hotend because the PLA temperature will not result in melting ABS. It can eventually lead to total plug of HE.
So what can you do when you are in such a situation (ABS -> PLA)?
You can clean the hotend first with ABS. Extrude some, wait until it is cold, ease the springs and pull or tear out the filament from the hotend.
If you are stuck you can use special drills to clean the nozzle.
But to totally omit the issue you can have two hotends :) One for ABS and one for PLA ;) But I think you can manage cleaning if you apply what I've written above.


q:
BuildTak is great because the printed plastic really sticks to it, it pretty much solved all the problems I had with prints detaching from the buildplate during printing.

However, it does sometimes cause the opposite problem of prints sticking too much and just not detaching from the build plate.

I'm specifically not asking how to prevent this from happening - I'm asking what to do after I made a mistake and now have a print that isn't coming loose.

[A]
If you have a heated bed, bring the bed up to a reasonable temperature, then do as best as you can to create rapid cooling. If you can remove the bed, heated or not, consider to place it in a freezer or refrigerator. Obviously, if the bed is heated, you'll want to handle the bed carefully and not place it on anything in the freezer that could be damaged while it cools.
Unrealistically, pour liquid nitrogen over the bed. This may crack the bed and/or the model, as well as be all the more dangerous for unprotected users.


q: What is the least expensive 3D printer available today? I am looking for something suitable for general use in a home office.

[A]
Depends on your definition of "available" and your definition of "suitable for general use."
The cheapest 3D printers are mostly Kickstarter promises that take a year or more to ship, if they ever do. For example, the Peachy 3D printer Kickstarter just imploded and failed. There have been many other failed low-cost 3D printer crowdfunding campaigns. Another low cost Kickstarter printer, the 101Hero, is ongoing now (May 2016), but most competent observers I've talked to don't believe it will succeed at delivering working printers to all backers at that price point. If they do deliver, it will be painfully low-cost components and the printer will not perform well or last long.
Stay away from crowdfunding campaigns for your first printer.
At best, you get a beta product with lots of kinks to work out. At worst, you get nothing and lose your money.
For actual products you can purchase today, there's a wide spectrum of quality/cost tradeoffs.
Under \$200 there's nothing credible. The Tiko (\$179) might deliver, but post-Kickstarter units are widely expected to cost more.
Around \$200-300 you get into low-quality Prusa i3 kits from China. These aren't a great value -- most people end up spending another few hundred dollars on upgrades to get them working reliably and with high quality.
Around \$300-400 you can get an
ok
3D printer, often with "chipped" proprietary filament so the vendor can make high profits on locked-in consumables. ("Razors and blades" model.) For example, the XYZPrinting Da Vinci Jr is \$350 but locks you into high-cost chipped filament. The Wanhao Duplicator i3 is currently a community favorite for value-for-money at \$399. The Printrbot Play is much higher quality/reliability but much smaller at the same price.
If you get up around \$600, a big range of decent printers opens up. But this is no longer the "least expensive" option, so I won't get into it.
If you want to tinker, the Duplicator i3 is a good choice. If you want a machine that just prints, the Play is a good choice. There are other printers and cheaper printers, but most of what you'll find below $400 is going to end up causing pain unless your goal is simply to tinker with printer troubleshooting and upgrades.


q:
I'm running Repetier Host v1.6.1 with Repetier Firmware v0.92.9.  My computer is running Windows 7 Pro SP1, 64-bit.

If I set a print going via USB then switch to another user (note: I do not log out), then the pinter's display shows that the command buffer drops from 16 to 0 until it stops printing altogether.  If I switch back to the user that is running Repetier Host then the buffer fills up again and the print job resumes.

Before I updated Repetier Host this didn't happen, I could leave it running while I switched users and the job would run just fine.  I'm not sure why this behaviour has changed, but is there any way to get it to run properly under a background user?

[A]
I believe what happens here is that Windows suspends the process running the print job, either due to the program not being in focus, because you switch user, or both.
You could try to
increase the priority of the print process in task manager
, and see if that helps.
In Windows 7:
Open Task Manager
In the
Applications
tab, right click the application, and select
Go To Process
, which will take you to its background process in the
Process
tab.
Right click the process, go to
Set Priority
and select some priority higher than the current level.
In Windows 10:
Open Task Manager
In the
Processes
tab, right click the application, and select
Go To Details
, which will take you to its background process in the
Details
tab.
Right click the process, go to
Set Priority
and select some priority higher than the current level.
PS:
Avoid setting the priority to Realtime
, as that effectively will give the process full control of your computer's resources, which could kneel your computer if the program is poorly written.


q:
I've been having a hard time lately getting the raft off of my ABS prints.

Is that a symptom of either a nozzle or bed that are too hot? Or is there some other factor I should be looking in to?

I have an UP mini that I've modified both the nozzle and bed to customize the temperatures on.

Bed gets heated to 100˚C and nozzle is either 266˚C for UP ABS filament or 236˚C for off-brand ABS filament.

[A]
A couple things to consider:
Ensure that your build plate is flat and level. An un-parallel HBP could result in the object "welding" to the raft.
Turn down your nozzle temperature. It is likely that the material is hotter than it needs as it is extruding. This results in a slower "cool-down rate". So, if it takes longer for the filament to cool between the raft and the first layers of the object. Therefore, cooling together in a manner that somewhat binds them.
Personally, 266C seems VERY high to me. I've primarily only used ABS on my MakerBot and have successfully printed with 225C +-5C nozzle temperature and 110C +-2C HBP temperature.
Typically you want to extrude slightly above the melting point. You don't want to liquefy the material, but make it pliable enough to bond it to other layers of material (or a BP).


q: I've been working on my own DIY 3-D printer recently, and I've been trying to experiment a little with different materials for the body. Someone suggested using HDPE (high-density polyethylene), since it works well on a CNC machine, which would make creating a number of prototypes easy. I know HDPE can also be used for filament, but I've never tried it before. Does anybody have any input on HDPE, or other potential materials for the body? I'm trying to avoid using wood, as I've had some poor experiences with it.

[A]
I've used what is commonly described as UHMW-PE, aka, Ultra-high Molecular Weight Polyethylene for various projects. You may know this material is often used in cutting boards, as it cleans easily and doesn't cut easily.
it does machine in a manner similar to aluminum, although the tool should be cooled/lubricated to prevent a build-up of melted plastic on the cutting edges. You can get away without coolant or lubricant if cutting speeds are slow and the swarf is cleared away from the cutter.
I'd not considered such a material for constructing a 3d printer, as it's expensive, but I've also not compared the prices to equivalent sizes of aluminum.
I'd consider that the use in a 3d printer would be a good substitute for lexan, as one can tighten the bolts without fear of cracking. For bolts subject to rotation or vibration, self-locking nuts are a good idea. If you have use of a broach, cutting out a pocket for the nuts would be easily accomplished.
I have downloaded the plans for the open-source 3d printer known as DICE, which calls for aluminum, but the pricing I've found was excessive for the right quantities. I think I'll explore the same bill of materials in HDPE or UHMW-PE (which may be different names for the same substance).
Equally useful to know is that the material is very slippery, effectively self-lubricating under the right conditions. Unfortunately, for a 3d printer application, I don't believe the self-lubricating part would work for carriages but might be fun to try with linear slides.
It is not as stiff as aluminum, so where stiffness is needed and not provided by the architecture, a thicker piece may be indicated. I can just barely bend with my fingers a piece of 3 mm (1/8") a small amount, but cannot do so for aluminum.
Here's the result of a quick search for UHMWPE:
https://www.interstateplastics.com/Uhmw-Natural-Virgin-Sheet-UHMNV~~SH.php?thickness=0.125&dim2=12&dim3=24
which gives a price for 1/8" white sheet 24 x 12" as US\$ 26.06 while the black version is available only as thin as 1/4" for about US$ 28.00
The equivalent size in aluminum 6061T6 at onlinemetals.com is about US\$ 3.00 more expensive. That is lower than I expected, skewing the idea farther away from UHMWPE than one might hope. The equivalent for 1/4" is almost US\$ 60, quite a bit higher.
It would appear that if you need the thicker stuff, the price is better for plastic, not so good for the aluminum.


q:
I have an object that I want to print in 3D. But I have a few questions about it. What are the things that I have to watch out for when 3D printing?

I know how to change the metric size etc. Some  people said that it's best to set the thickness to a low amount and not make the object solid (to leave the inside empty/hollow) in order to save money when printing.

Is this true or does it not matter?

Also what if I want two parts of an object to be separate colours or materials?  Do I have to change this in Blender?

Any advice and information would be helpful, thanks.

[A]
You are correct about the walls. Using a
Solidify
object modifier is probably your best bet. A low
Thickness:
value (
0.1
is probably good) helps keep the walls thin but strong. You can monitor the thickness while you adjust the value from
Wireframe
view.
Additionally, and
this is probably the most important thing to know
, your mesh must be clean. By clean, I mean it must all be one piece. No separate cubes, cylinders, etc. that you added while modeling, just one solid piece. Think about it this way. If you have added a cube and part of that cube is inside the rest, it might look good from the outside. But the 3D Printer isn't printing the outside, it's printing everything. So that wall, albeit hidden, that is present on the inside of your mesh
will be printed
.
Bad:
Good:
Lastly, if you have parts of your mesh that can't be printed from the bottom up, or wouldn't stand by itself, consider adding supports. You can always cut these off later.
Leg added because it wouldn't stand by itself:


q:
First, a little background. A couple of years ago, I was researching making my own candy, and I came across this page: Lego brick shaped gummy candies, describing how to use real Lego bricks as a positive to make silicone molds for Lego brick shaped candy. Now that I have a 3D printer, and inspired by the usual description of ABS filament ("It's the same plastic used to make Lego bricks") it occurs to me that I can now make any positive I want.

The question is, would that be safe? I know the filament I'm using is not food safe, but if I create positives for a food safe silicone mold, would toxins leech into the mold? And if so, is there a barrier I can use to prevent this, such as some kind of coating?

[A]
The plastic is not quite your main concern (though it still can be). You should worry about the cracks and crevices in FDM prints. Bacteria loves to hide there. For most people, this is the first concern when it comes to "Is X 3D printed food-safe?" If the end product is a hard material, you should sand or smooth your print to prevent the layer crevices from appearing in the end use product. Also consider food-safe epoxies for filling in gaps. If the end product is made of a flexible silicone, then this is less of a concern.
ABS is not food safe. PLA as a material is considered food safe by the 3D printing community, but I have not seen a scientific study on this. However, many filament makers do not extrude pure PLA. Therefore, the answer to your question is that it depends on the manufacturer. You will need to contact the company to know what is in the filament first. Beware of untrustworthy manufacturers that claim food safety without backing that up.


q:
I have a home built RepRap with all sides open..

Would there be any advantage to enclosing the print area in acrylic?

[A]
It is hard to tell whether you personally should enclose your printer. However, you asked for the advantages and I will name some of them on which one can base a decision.
A 3D printer enclosure
helps to keep the temperature of the whole print at controlled levels, if you use a heating element, thermocouple and
pid regulator
. This is one of the most direct uses of the enclosure, which can be achieved by almost no other means. One could sloppily say it does for the whole print what the heatbed does for the initial layers. Controlling the temperature can be beneficial for layer adhesion and can help against delamination problems. This can go as far as fixing cracks and complete delamination (Thanks to @J. Roibal for bringing these cracks to my attention in the comments)
keeps
dangerous fumes
controlled. Here you can find a scientific study about it, published in
Atmospheric Environment 79, titled 'ultrafine particle emission from desktop 3D printers
, on exactly that topic. You can embed a
filter with a fan
in your housing to filter the air from all dangerous fumes that are created when melting certain plastic types. It could just circulate the air inside the chamber or get the filtered air out of the housing. This is another use which cannot be achieved otherwise (afaik).
can keep humidity away from your printer. This is helpful for filaments that attract water (and don't print well under that circumstance). This should be realized separately for stored filament, too, adding some silica gel to regulate humidity. (Thanks to @Obmerk Kronen in the comments)
minimizes losses of your heatbed. This happens in at least two ways, - the heated bed will also heat the surroundings, that is the inside of the enclosure. By raising its temperature, the temperature difference and hence heat loss is minimized. Also wind, introducing high fluctuations in the transfered (i.e. lost) heat is minimized. In that sense, it also
shuts out any wind for print temperature stability. Also dust and particles that could be blown on the print will be shut out (thanks to the addition of dust/particles: @Obmerk Kronen). This is a benefit that comes without having a heated chamber or filter.
helps to keep the printer clean in between use. Your axes will thank you being free from dust.
reduces smell and noise. If you use the printer in you living area, that alone can be a great benefit.
makes sure that your printer is safe during storage, nothing will fall on it.
can look pretty nice and add to the style of your printer,
even if selfmade
;-)
There are obviously also downsides, as: connected work/money to make it, increased space used for the printer, and, if not well made for that purpose (which it should be), increased difficulty in repairs and maintenance of the printer itself (i.e. to get the printer out of the enclosure).


q:
I am printing on a non-heated bed right now, but the question also applies to heated building plates.

How often should you replace the glue layers that's supposed to be applied before printing? Some say you can do up to a few prints, such as in this forum, while others say to replace it every print. What is the correct approach?

[A]
As noted in the answer to the other question you asked, the Flux Delta steel plate bed will handle multiple layers of glue. The determining factor regarding this particular printer and specific glue is how many ripples, bumps and/or lines you are willing to tolerate on the first layer of your prints.
You'll notice that a print made with a couple layers of glue, freshly applied, will have a relatively smooth surface. Peel off the model, apply glue over the now-cleared areas, and you've created a slightly-less-than-smooth surface for your next model.
I've found that I can apply six to ten layers before the ripples become objectionable.


q:
I use OctoPrint on an Ubuntu system with a M3D printer.

Midway through a recent print, the filament just stopped extruding although the motor-functions of the printer were proceeding fine. Since then, every print I attempt has trouble extruding proper amounts of filament. It's always not enough. The output is stringy and not cohesive.

I'm thinking there may simply be a clog in the extruder and wondering the safest way to remove it.

The weird thing, though, is that when I use manual control and extrude at, say, 220C, the filament comes out fine.

You can see the raft definitely isn't printing right. Way too little output:


q:
I'm new to 3D Printing. I've created this star from Blender3d. As far as I know, most printers require a flat bottom.

As you can see (blue line is Z-axis, red line is X-axis, green line Y-axis), the star doesn't have any flat sides or points.

There's a hole in the middle of the star.

Is there a printer (brand/model) that can print this object that doesn't have any flat bottom or sides having a hole that goes through in the middle? Any workarounds to print this object?

[A]
Typical FDM desktop 3D printers might struggle with this model as it requires you to either print large overhangs and use support structure (when printed laying down), or lacks a natural flat bottom surface to get good print adhesion (when printed upright). A couple of suggestions:
Some FDM printers are great at printing support, and some even allow you to print dissolvable support structure. If you find one of these, you are home safe.
You could split the model in two, print those parts separately, and then glue them together afterwards. This is quite common for complex models, and allows you to print your model on even basic FDM printers. Tom's answer illustrates this well.
There are naturally other 3D printer technologies too (SLA, resin etc.), but I have no practical experience with these myself, and leave it up to others to give you a good answer regarding these.


q:
I have this GoPro mount for a quadcopter as STL file. It looks as follows.

How do I modify it so that it is wider and longer by a few millimeters but the screw holes stay the exact same size? Additionally the angle of the upper surface must stay the same. Please suggest the easiest solution for someone like me who as no idea about CAD software.

The perfect solution for me would be to just import it in Tinkercad and then modify it however I have no idea what the steps are.

[A]
Many resources are available for modification using 3D CAD (including learning a tool such as sketchup, which is VERY beginner friendly). The easiest and fastest solution to your particular problem may be the
reddit community "3D Print My Thing"
which was created for EXACTLY this type of situation (help with modelling parts which will be 3D printed.) Another potential useful reddit community is
"3D Modelling"
which will have many people who are able to help you with this quadcopter/Go-Pro attachment 3D model.
Third solution: Thingiverse has a customize option for 3D models (including this one). have you explored using this interface to edit the model? This is most likely the easiest DIY solution.


q: Is it possible to connect two pieces of 1.75 mm filament end to end, with no change in width? I am asking the question because I am interested in creating a multi-filament feeder to a single extruder, and I am curious about the process of changing filament while the 3-d printer extruder continues uninterrupted. My current best-guess at the optimal solution is to someone 'cut' one end of the filament and 'melt' it to the end of another filament.

[A]
You'd have to ensure that the joining portion of the two filaments do not "bloom" or increase in diameter, which would happen if unconstrained at the melting and joining time. Alignment is also critical, otherwise you have a varying diameter from one color to the next at the point of join.
There's an item on ebay which is precision drilled and has precision machined mating surfaces to ensure alignment of the filament. The filament is extended through the two components, heated (in the case of the video, with a match) and the two metal parts are pushed together. The joining of the metal parts also cuts away the excess bulge of the melted filament, ensuring correct diameter.
In the case of the above item, the joining devices have to be threaded with the filament prior to the joining process and then have to be threaded off the filament by pushing them the entire length of the filament.
This would be okay if one were joining short lengths only. Consider how much fun it isn't to have to slide these two pieces over an entire full spool of filament.
A split device which would enable one to un-latch or otherwise open a clamshell to release the filament would require much more challenging machining to achieve the necessary precision, which is probably why we don't see such a product.


q: Is it possible to print toothbrush bristles using a common FDM 3D printer? I am particularly interested in the width of bristles, closeness together of each bristle, and the flexibility of each particular bristle.

[A]
Actually last year a group did use a normal FDM printer to 3d print hair, brushed, etc. See the press release from Carnegie Mellon University
https://www.engadget.com/2015/10/29/3d-printing-hair-is-as-easy-as-using-a-hot-glue-gun/
http://technabob.com/blog/wp-content/uploads/2015/11/3d_printed_hair_by_Gierad_Laput_Xiang_Chen_Chris_Harrison_1.jpg
That said as far as I know you will not have access to this process, and is probably under a mountain of patents and other innovation killers.
Now how to do this outside of fancy software.
For a FDM printer the smallest nozzle I ever got was 0.1mm, it jammed instantly. One could print rows at this precision.
Now we have to move to something more advanced, such as DLP. Not the materials you want, but closer to the size you want. a formlabs can print at 25 microns. Which as a hair is 17 microns, you are "close enough" .. but a resin would be brittle and break. They do have other materials such as flexibles, but I am not familiar with them enough.
Also just going to mention. Tiny slivers of plastic is more likely to cut you than comb you.


q:
What are the differences, and pros & cons, between 3D printers with varying layouts for moving head vs. moving build plate?

Example layouts would include:

X Head; YZ Bed;

XY Head; Z Bed;

XYZ Head;

etc.

In particular, what are their respective strengths, weaknesses, specializations, maintenance considerations, etc.?

[A]
Without going into too much detail, since this is a very exhaustive topic, I'll write some pro's of each down from the top of my head:
Cartesian XZ hotend, Y bed (eg. Prusa Mendel):
easy to build (relatively)
easy to maintain
easy to modify
understandable kinematics
with the right frame, no x-y-z orthogonality (90 degree angles) needs to be adjusted
affordable
bad for timelapse recordings
print quality will theoretically always be inferior at the same speeds and accelerations to kinematics that have less mass to move (heavy printbeds will lead to ghosting)
z-wobble is only existent in this approach
big build-plates are no option for this design (last feasible size might be 20x30 cm)
Cartesian XY hotend, Z bed (core-XY, sparkcube, Ultimaker, Makerbot)
less mass to be moved -> faster print speeds possible
almost no size limitaions
construction is easy to enclose in most models due to the cubic frame
looks almost always professional
enclosure can be hard to modify due to constraints in space
XYZ hotend (Delta bots)
master of circles
less mass to be moved -> faster print speeds possible
impressive to watch
more load on the processing unit due to more complicated kinematics (32 bit needed for fast print speeds and responsive control with display)
kinematics not easily understandable
error-cause search can be very complicated
more accurate in the center than on the outer limits due to the kinematic approach
The list is for sure not complete, and as a major disclaimer: print quality will always, with every approach, depend more on the setup and calibration of the printer than on the model. There are people around that produce great prints from an acrylic frame cartesian printer and lots of people that produce mediocre results with expensive printers in fancy designs.
I will add some links to the list items when I find the time, for now you have to believe me. I am highly appreciating corrections and additions!


q: I have a (HIC) version of the Prusa i3. I have recently installed the E3D v6 hotend and titan extruder. After fixing some other issues, I noticed that there is no filament being extruded. In addition, the gear looked like it was going in the wrong direction. How can I fix this?

[A]
You can either flip the connector for the motor around (i.e. plug it in backwards) or (if you are using Marlin firmware) look for the following line in configuration.h:  (using the Arduino editor open the Marlin file For your 3D Printer,  one of the tabs is labelled "configuration.h" click on that tab to bring it to the front for editing.  use the Edit, Find and put E0 in the find box, click find.  When you find the line below
```
```
#define INVERT_E0_DIR false
```
```
change
```
false
```
to
```
true
```
(or vice-versa). Note that if you go for the connector-flipping route, make sure that you only do this when the printer is turned off.


q:
I am using Slic3r to generate the GCode for my Marlin-based printer. For some reason with increasing height my print starts to get messed up. On another part it starts to act like this when there are small parts. Is this related to my Slic3r settings, maybe to much filament being extruded or is this due to something else?

Any help is highly appreciated and I can provide more pictures of messed up parts or slic3r config if necessary.

[A]
To me, this looks like a combination of bad filament, high temperature and/or fast speeds.
Too high extrusion temperature will make difficult to let each layer cool enough before the next layer begins. This is why you see the poor results on the smaller areas of the print in your second photo.
If you're using bad filament (out of round, non-virgin, or poorly stored filament) you might see a series of over/under extrusion areas or smoke from moisture in the filament.
Slowing down your feed rates can be tricky if your extrusion temps are too high. By slowing down, you're allowing layers to cool down a little bit more and solidify. If your previous layers are still relatively molten, you'll notice that the new layer of filament will adhere to it and potentially drag the previous layers as the nozzle continues to move. You'll see the results of this in the top-arc layers with an uneven curvature.


q:
I'm using a CraftBot original to print PLA, but some of the filament has become stuck in the teeth of the extruder gear on its way into the hot end.  I'm having issues with the gear becoming stuck and "clicking" instead of turning, and I suspect it is because of the clogged teeth.  I haven't changed materials in a long time.  I've cleared several print head clogs, but each time the gear gets back around to the one spot, it seems to get stuck again.

Are there any good ways to clean this gear?  I was thinking of putting it in a toaster oven and trying to melt the PLA off it, ideally without setting my house on fire in the process.  Anyone have better ideas?

[A]
If you are able to remove the gear, as I suspect you can, a useful tool is the file card. It resembles a flat hair brush but the bristles are short wire, very stiff. In traditional use, it removes metal shavings from conventional metal files. It will easily remove plastic from between the gear teeth. If you are unable to remove the gear, but can access a portion of the exposed teeth, a suitably named dental pick can remove slowly the clogged material.
Cooking the gear may not cause a fire, but could carbonize the plastic onto the teeth, perhaps creating a greater problem.


q: Is there any simple way of creating tappered thread in OpenSCAD? I need something like 10 mm in diameter at the end, 9 at the top and the height of 10 mm.


q:
So I have a self build Mendel Reprap style 3d printer.

I've not used it in sometime after moving house but I'm looking to use it again. What should I pay attention to before calibrating and running it again?

[A]
PLA absorbs moisture, so keeping the filament dry is a key factor. Aside from that, PLA is naturally more brittle than other plastics like ABS and Nylon Sorry, tried to find a graph to prove it, but couldn't find one.
There's a good
Google Group discussion
and many other resources that go over good storage habits, but as for fixing the existing filament.
Try the following:
Place PLA in an enclosure (plastic bin, Zip-loc bag, etc.)
If you have some, add some moisture absorber(s)
Place the tub in a warm environment (naturally or artificially) and make sure the area is dry as possible (not in the shed in the back, by the woods...). Possibly next to a heater vent or space heater in your house?
Essentially, you're trying to treat the material. When the material goes through a heat treatment (aka the heat block in the extruder), the mechanical properties are beginning to change. The brittleness can be set by how quickly the material cools. I'm speculating that the moisture does any of the following:
Keeps the filament from heating up to the desired extrusion temperature.
Burns the filament.
The moisture is evaporated, leaving gaps in the extruded filament (under microscope).
I looked into this a few years ago and have forgotten most of what I found out, but I'll keep looking and update my answer here.


q:
I search about that topic, but all what I found, was the mechanical part of the 3d printer. But I didn't find, how to program it using arduino.

I want to make a cartesian 3d printer. I don't have a printer yet, but I will buy all the components that I need actually.

I know, how to control stepper motors, but I don't know, how I can program it in order to make the shape that I want.

This is my question: what I need to learn in order to let this 3d printer make this shapes?

[A]
Yes.
Look up Arduino Ramps 1.4
http://reprap.org/wiki/RAMPS_1.4
Following the programing is all done for you in the firmware. That said you can edit it. Just open the firmware files -- it is compiled when you upload them. Generally however one usually sticks to the preferences header alone..
http://reprap.org/wiki/List_of_Firmware
Over all you are trying to reinvent the wheel. When I started 5-6 years ago it was barely a thing. Now you buy a proven kit and get to the printing. That said if you are truly interested in designing check out.
https://www.facebook.com/groups/cncbuilddesign/
If you want help on picking a kit. Or what I really think you are looking for. A good place to start. This is one of the larger 3d printing groups. Full disclosure I run this one, but at 6k members I don't recruit.
https://www.facebook.com/groups/3DPrinterHobbyists/
I got my start in reprap IRC
http://reprap.org/wiki/IRC
Be aware there are trolls that now camp the IRC looking to sell you a printer. I would not engage with them, their printers are usually overpriced and sub par.
Best of luck.
Most of all I think you need to know it's Reprap all the way. Reprap forums, Reprap printers, Reprap kits, Reprap community. All the commercial printers started off the reprap project. Even if you buy a makerbot (don't) it's Reprap in it's roots.
https://vimeo.com/5202148


q:
I created a new project in Materialise Magics, added a few parts (different STLs), moved them around in certain positions and now I want to export this project into another STL, containing my recent work.

The export menu seems to be all grey, like this function is not available. Do I have to do some repairing first or something similar? Or Magics needs other software in order to export a Magics Project to a STL file?


q:
My Craftbot Plus Craftware slicer estimates cost per job based on filament prices I add as parameters.  What costs per meter would you use?  I created spreadsheets to calculate this for 1.75mm diameter filament and arrived at PLA = 6.6 cents per meter, ABS = 6.1 and PET XT = 18.6 cents per meter.

Edit:  thanks for feedback!  I paid \$22 per kilogram for PLA and ABS.  I paid \$57 for .75 kilogram of Colorfab XT Black.

[A]
The simplest method is to divide spool price by its length. That's obvious I think. If PLA 1.75 (1kg net) has about 120m length and it costs 16usd then it looks like 1m costs arount 13c. =price/length
I think everyone can buy different filament at different price from different vendors so there is no good general price to enter into your slicer app. It has to be calculated each time you use new filament.
There are also other parts of the price. Electricity, time, wear, depreciation, know-how even the rent is some part of the ending price of the final product. Of course most of them are incalculable as they are permiles or so. But if you don't plan to sell it you can base on the filament price only.


q:
I've been looking into this, but:

I'm not certain how to configure my multimeter;

I don't know how to keep the voltage going, and;

I don't know how to keep the multimeter connected to the VMOT?

I'm told you're supposed to aim for about 1 A.

[A]
Generally speaking voltage on stepstick output should be around 1V.
To imagine more or less what the current and what the voltage is, you can think about it in the same way as about water.
The wire is more or less the same as the pipe.
The voltage can be imagined as (sort of) the height from which the water flows but the current can be imagined as an amount of water which flows. To simplify things we assume that all our pipes are closed into circuit and we have pump/battery and we have a motor which is a reverted pump ;) and finally we have our stepstick which is a tap in our model.
So no matter what the height (voltage) is we know that tap (stepstick) will pass some amount (current) of water. We can drive it turning tap or turning a potentiometer on the stepstick PCB.
So we got it. Principles (deadly simplified) are now clear.
See here for more details
Getting back to your question.
You have to know what is your stepstick reference voltage. To make sure about that you have to check out resistor(s) next to main black element on stepstick board. There should be R100 or R200 which are very common.
Now you should read data from motor label to know what is proper current for your motor and calculate
voltage = motor_current * 8 * resistance_of_resistor
So now you know what is proper voltage for your motor and stepstick.
You measure voltage between potentiometer and GND (see on the picture)
If you set and connect everything and start printouts you should check motor temperature. Use your finger. If you can touch motor and hold your finger not more than half a second then probably the voltage set on potentiometer is too high (motor can reach 80° Celsius and it's fine but more will shorten its life span) and you should reduce it a bit (reduce by 5/100 V). If you notice that motor growls or barks then your voltage is probably too low and you can increase it by 5/100V.
Too high current will also reduce longevity of stepstick so cool them out with fan.
Please be noticed.
Z-axis motors will usually be not too hot as they work less than X and Y but as they are both connected to one stepstick so they need more current - set higher voltage there.
Here is a
reprap.org site
to get basic knowledge about stepsticks.


q: At the moment, I am thinking about print fans that cool the plastic when printing. I am not asking about the design of the fanducts, which might be a whole book on its own. I would like to know how to find out the best application of print cooling for a given PLA filament, - that is fan speeds and setup in a slicer of your choice (to learn what the different options are).

[A]
I use side-wind to cool down model as simple as possible. It's just a 12cm in diam fan which is driven from arduino (the same contacts as the fan next to the nozzle). No duct, no other stuff. The only thing I consider in terms of making things better is to set up 2 fans which could coll down model from both sides.
The issue is that when model is more complex then cool air is not reaching out oll these crannies and then on some corners I see the difference. Because of this issue I have to orient model facing to the fan in the way which will decrease such effect and I'm usually happy with results. If you are able to imagine how the airflow behaves then you can achieve perfection :)
Of course fan is driven but to be honest I usually use 100% of its blowing power except with first layer which I usually don't blow at all.


q: I am using a BAUDrate of 115200 since I cannot make a connection to my printer with the advised 250000 rate. Are there any downsides or limits I reach earlier given by the lower BAUDrate?

[A]
Baud rate
is the rate at which information is transferred in a communication channel, given as a number of bits per second (bps). So a baud rate of 250000 is capable of transferring a
maximum
of 250000 bits per second (31250 bytes/s). When working with serial ports, both ends of the communication line will have to "talk" with the
same speed
- the same baud rate - to understand each other.
So when using a baud rate of 11520 you will theoretically be limited to transfer data with about half the speed of 25000. If you are transferring large amounts of data, this might be a limiting factor for your application, but if you are not pushing the limits of your serial port, it probably won't matter at all.


q:
Because of the weight of my Z-axis and the relative ease of its motion, when the Z-axis motor is powered down the bed has a tendency to slip and fall down.

Obviously leaving the motor powered solves this problem, but that is not ideal.

I am looking for some kind of solution that passively stops the Z-axis motor from slipping; some kind of brake or clutch. Ideally I'm looking for something that I can add onto my current motors and that I could print myself. Commercial solutions (preferably ones that could be replicated with a 3D printer) would also make valid answers.

[A]
The simple way to do this is to use a self-locking screw pitch. Pretty much any single-start thread using a sliding nut cannot be back-driven so the load will not fall. Normal 8x8 trapezoidal thread screws will easily back-drive because of the steep pitch.
Likewise, a worm drive between the motor and Z stage will hold the load. You would want to switch from screws to belts for the main motion stage in that case though, to avoid having too much total gear reduction.
Both of these solutions will limit your maximum Z speed, of course. But they're simple and reliable. Clutches and brakes add a lot of complexity and must be actuated somehow. Designers who want the load to stay suspended almost always simply use single-start screws.


q:
My first and only 3D printer is a Printrbot Simple Metal, which has a hotend that doesn't expose any of its internal parts. Easy for beginners, I suppose: "The hotend is that tube that heats up the plastic and deposits it on the print bed."

But I've been trying to learn more, and many hotends out there don't look quite as simple. My Printrbot hotend probably isn't as simple as it looks, either.

What are the parts that make up a hotend, and what do they do?

(PS: This is a general question, not specifically about the two example hotends above.)

[A]
picture on the left
This hotend is made out of
PEEK plastics
(beige). It can work in temperature upto 250C. As it is also good heat insulator then it doesn't need to have cooling fan. Red part on this picture is just a cover (insulator) of the heater which heatup nozzle (gold). Black are just wires and connectors.
picture on the right
This hotend is metal so it needs two things - cooling fan and heat barrier. Beginning fron the left - red wires are connected to (silver) block which is heater itself. Between the block and this round silver part (which is a heatsink) there is heat barrier (thin pipe which is poor heat conductor). Heatsink has plastic funnel (blue) which directs an airflow from fan (black) through heatsink.


q:
My question is...
Is there a SIMPLE/easy way to load TPU without tearing my printer apart to insert a hose that probably wont work anyways. It keeps curling up by the cog. I have read a few topics in other places but I didn't like the answers. Hoping you all might have a simple fix.

[A]
Loading TPU/TPE can be particularly challenging because many printer loading scripts run too fast for the soft flexible filament to effectively purge whatever normal filament you were using before. A couple tips:
Load with a slightly higher temp than either the TPU or previous filament require, so as to minimize the melt viscosity and reduce the force required.
Make a custom gcode file that contains a slower loading routine: wait for heat, then advance the extruder at a very slow rate for a long distance. Then you just "print" this gcode file whenever you need to load TPU.
However, simply being able to load is not necessarily enough.
Not all extruders can reliably print flexible filaments, period.
The larger the gap between the pinch wheel and inlet to the hot end, the more likely the filament is to buckle and come out the side. You need to make sure this gap is as short as possible. If there is more than a couple mm of gap, you'll need to make gap-filler or print yourself a new extruder designed for flexibles.
Printing slow and without major velocity changes can help, too. Use relatively low layer heights and low, constant feedrates so the extruder doesn't have to run fast or change pressure often.
Harder flexible filaments will be easier to print if your setup is borderline. Ninjaflex is one of the hardest to print because it is relatively soft. Semi-flex type filaments are much easier to print if your hardware isn't set up optimally.


q:
I am trying to 3D print an iPhone case, however, I want it to print standing up. Is this possible to do?

I have a picture of the case in the link below.

[A]
Yes this is possible. For an FDM/FFF printer, you'll need to print with supports. I might also recommend printing in PLA to minimize the chance of warping during the print (from experience).
It might also help to slow down the feedrate to ensure smooth surface finish and avoiding delamination on such small layers.
You'll probably see a decrease in the surface quality on the inside due to the printing of support scaffolding depending on the slicing engine you use.
However
You'll want to pay attention to the strength of the case. If you print the case upright then it will be more susceptible to breaking without post-processing.
Conclusion
Ultimately, if you can get away with it, it would be better to subtract the star instead of extruding it in the model. Then you can simply print the case back face down on the plate with much better results.


q:
There was a contest to develop 3D printable files for the International Space Station's 3D printer.  The winner got a 3D printer ... runners up got Fluke DVOM's and all entrants got a t-shirt.

ISS 3D Print Contest

They offer 3 materials:  ABS, HDPE, and PEI+PC ... I'm not familiar with the last one. Anyone know?

If found this material on Matweb: PEI+PC Alloy

These links are thought to last a very long time.  I hope many of you decide to upload a project into contest site and compete for the grand prize ... A sweet John Fluke DVOM.  If nothing else a free awesome T-shirt.

[A] PEI - polyethermide is a "common" coating for heated print beds. PC is so many different things, but in this context, it's likely to mean polycarbonate plastic. From what I've read, it's challenging to print with and especially challenging to get a good bond on the build plate. One reference suggests to use a PEI coated bed with a slurry of ABS applied prior to printing. As with so many things 3d printer related, many people have many different methods. The above one appears to be well received as a successful method.


q: I have a prusa i3 and have been trying to calibrate it. I have been trying to upload the new steps per mm and I get to done uploading. However when I go into Repetier host and type M503 to get the printers settings it still shows the steps as 100 for the y axis, it needs to be 96.1810. I am using ramps 1.4 I think, with Adrunio mega 2560. If I am remembering this correctly isn't there something you have to do when uploading a new sketch like hold the rest button or something?

[A]
See here
for why you
shouldn't
calibrate your X/Y-steps. The value of 100 is probably better and will give more accurate prints overall than the value you came up with.
When uploading new firmware you generally do not have to press any button. Pressing reset manually is only necessary when your upload method does not provide a reset pulse, but if you upload with USB this is not necessary.
What is probably causing your problem is that the E-steps are stored in EEPROM, and uploading new firmware does not override the EEPROM settings.
You should run a
```
M502
```
to restore the default settings from the firmware you uploaded, then
```
M500
```
to save them to the EEPROM.


q: I was advised that it would be possible to use an AC SSR to wire up a Mains Based heat bed.  Any idea how one would do this with a RAMPs 1.4 board; Also, what do I hook a heated bed of this sort into?

[A]
A link to the bed you have/are buying would be very helpful. AC heated beds exist but are fairly uncommon.
As
one of the answers
in the question you linked notes, the heat bed is probably not actually intended to use the 110 VAC/220 VAC directly from the wall and instead needs either 12 VDC or 24 VDC.
If the current it needs is less than 11 A, then it can be connected directly to port D8 on the RAMPS 1.4, where it will take power from a suitably powerful 12/24 VDC supply connected to the 11 A input on the board.
A more powerful heater will need an external relay/MOSFET/etc. to control.
If you do, in fact, have an AC bed, you can connect a SSR like
this
to either D8 or D9 on the RAMPS (D10 could be used, but it would need a supply connected to the 11 A input) making sure the polarity is correct, as long as your RAMPS DC supply voltage is within the input range of the SSR.
The linked one is 3–32 VDC, so almost any supply voltage compatible with the RAMPS will work.
The AC outputs of the SSR should be connected in series between one side of the bed and the AC hot wire, with the AC neutral wire connected to the other side of the bed so most of the circuit isn't carrying high voltage when off.
This
video has some useful hints.
However, while an AC bed can get you faster heating, will let you use thinner wires, and avoids the need for having a big DC power supply, I would recommend against using a mains voltage bed if you don't know what you're doing—a great deal more care must be taken and there is a serious possibility of injury.


q: Hello I have a Prusa I3 I am currently able to get press fit parts with my current settings. I am using Ramps 1.4 hardware and repetier software and cura as my slicer. I am printing with a .2 mm layer height right now but would like to get a better number such as .1 or .09. When I try to print with say .1mm layer height in the middle of the print the filament stops coming out of the nozzle. However I can still see the gear moving. I have check some sites that I have been using for troubleshooting but I haven't found anything that fixed the problem yet. How or what setting need to be changed in order to print with better resolution?

[A]
There are no settings that you should need to change. Rather, it seems like you are suffering from another issue that is not directly related to layer height.
It is possible that your hotend's heat sink is not being cooled enough, causing heat to migrate up and soften plastic in the heat sink, ultimately jamming it. Depending on your hotend's make, the heat sink should be cooled by a fan that is always on.
Normally, the plastic being fed into the hotend provides some cooling, but printing at a thinner layer height decreases this effect because less plastic is fed into the hotend per time unit.


q:
I own a delta 3D printer. The problem is that, at the beginning of a print the extruder outputs dirty filament. I want a clean filament flow at the start of my prints!

How can I make the hotend exit the print surface (glass plate) by 10mm, extrude the bad filament and go back to printing again? Can this be done with G-code?

My Z high is 190 mm and the glass plate diameter is 120 mm. I'm using Marlin + Ramps 1.4.

I'm using Repetier-Host and CuraEngine as Slicer, but I really would like a G-code that can work on multiple environments like Cura and Repetier. I just want to add it to the start G-code and print!

[A]
A lot of slicers will have a Wipe option. Here are some examples:
See
Unofficial Simplify3D Documentation
. Go to the section talking about
Wipe Nozzle
, under the heading
Extruder Tab
Two more ooze-fighting options are Coast at end and Wipe nozzle. Coast turns off the extruder the specified distance before it normally would, to drain what would have oozed as the end of a line. This can help with ooze-induced blobs at the end of lines, but if turned up too high will lead to gaps in your print walls. Changes to this setting will be visible as gaps in the g-code preview.
Wipe has the nozzle retrace over the start of a perimeter line at the
  end of a perimeter for the specified distance with the extruder off,
  to leave any ooze behind before proceeding. It is similar to Coast in
  that it moves the extruder without extruding, but wipe occurs after
  the end of the line while coast occurs before.
Slic3r has some sort of coasting. But I think in their docs the option is there:
Slic3r Manual - Fighting Ooze
Wipe before retract - Moves the nozzle whilst retracting so as to reduce the chances of a blob forming.
As you asked for G-Code here you go:
Reprap Forum - Wipe nozzle via GCODE
Example
```
```
;Sliced at: {day} {date} {time}
;Basic settings: Layer height: {layer_height} Walls: {wall_thickness} Fill: {fill_density}
;Print time: {print_time}
;Filament used: {filament_amount}m {filament_weight}g
;Filament cost: {filament_cost}
;M190 S{print_bed_temperature} ;Uncomment to add your own bed temperature line
;M109 S{print_temperature} ;Uncomment to add your own temperature line
G21        ;metric values
G90        ;absolute positioning
M82        ;set extruder to absolute mode
M107       ;start with the fan off
G28 X0 Y0  ;move X/Y to min endstops
G28 Z0     ;move Z to min endstops
M117 Auto-level...
G29        ;auto-level
;G92 Z-.01 ; Lower = Z Pos, Lift = Z Neg
M117 Preparing...
G1 Z10.0 F{travel_speed} ;move the platform down 15mm
G92 E0                  ;zero the extruded length
G1 F100 E30              ;extrude 10mm of feed stock
G92 E0                  ;zero the extruded length again
G1 F{travel_speed}
;Put printing message on LCD screen
M300 S900 P160         ;start beep
M300 S1000 P160
M300 S2000 P160
M0    ;Wait for the user
M117 Printing...
```
```
Lulzbot forum - Start GCODE Script for Wipe
, in particular
this post
:
Example
```
```
G91 ; switch to relative positioning
G1 Z10 ; safe raise of z axis to ensure probe doesn't hit bed clamp
G90 ; switch back to absolute positioning
G28 ; home all axes
G29 ; level print bed
G1 X298 Y137 Z2 F5000 ; move to wait position right hand side of the table
G1 Z0.4 ; position nozzle
G1 E25 F300 ; purge nozzle
M400 ; wait for purge to complete
G1 X285 F1200 ; slow wipe
G1 Z0.5 F1200 ; lift
```
```
That should get you started.


q:
I am looking to print an enclosure, which will have a PCB inside with some LED indicators. I was wondering if it is possible to 3D print the enclosure such that the following look can be achieved? What material and technique?

When LEDs are off, it looks something like this:

WHen the LED turns on, it looks like this (illuminated symbols):

[A]
Achieving this with 3D printing would be quite difficult, and you might be better served by creating this effect some other way (I would personally recommend getting some inkjet transparencies and stacking a few layers together: an entirely black layer, and a few layers with the symbols in negative space).
One way that you
might
be able to achieve this using just a common FDM printer is to print the part face down, and printing just a single layer or two that covers the entire face, and then printing more layers that cover everything but the symbols. However, those symbols look small and detailed and you might not be able to reproduce such detail.


q:
Related to an issue I had in this question, where the PTFE tube feeding my filament to the metal tip of the extruder clogged and became discolored: what are the advantages and disadvantages of changing out my extruder (Mk10 on a FlashForge Creator X) for an all-metal solution like the one advertised here (by Micro-Swiss).

I understand that the conversion would allow me to print higher-temperature materials (like nylon), but I'm also trying to figure out the trade-offs with regard to printing PLA/ABS parts.

[A]
In general, metal extruder without PTFE feeding is useful when printing with materials that require high temperature to melt: 300
o
C and above.
Polycarbonate
with recommended printing temperature at up to 310
o
C is a good example.
PTFE melting point is around 320
o
C, but it may become soft at much lower temperatures, according to RepRap wiki:
http://reprap.org/wiki/PTFE
From the other hand, all-metal extruder lacks advantages that PTFE ones can provide, the most important of them is the ability to have longer retracts without risk of clogging the filament tract.
This is mostly important for users with Bowden-type extruders as well as for printing with soft or stringy filaments.


q:
I'm having a really hard time printing on my aluminum heated bed... Cleaning it just results in it being scratched (trying to scrape dried hairspray/glue/etc off) and I don't think it is particularly flat either.

I was thinking of stopping by the dollar store on my way home and getting several picture frames and using the glass from them as interchangeable glass beds - this would also make it easier to take them off the printer to clean without needing to re-level the bed every time as the aluminum base would stay-put.

Do you guys think the quality of it would be okay to print on? (withstand the heat, be flat enough, etc) I'm planning to coat it in purple-glue-stick as I have heard that works well for adhesion purposes.

For reference: Printing PLA, Prusia i3 printer.

[A]
Picture frame glass (generally float glass) will work well enough, but count on it eventually cracking/getting chipped. It's always very flat (due to the way the production process works).
Taking it up to 100-110C for printing ABS should not be a problem, but you'll want to avoid sharp changes in temperature, and should be careful that your prints don't adhere too well: I've had PLA/PETG prints take out pieces of glass with them due to the force required to remove them from the build plate. You might want to try without any (or very little) adhesive first, and make sure your nozzle isn't too close to the build plate.


q:
When using a heated bed with your printer, I have seen claims of running temperatures of 90c throughout the print.

That seems like a fairly high power use to keep a large slab of, say, aluminium at 90c for long print times (ie multiple hours).

Is there a common 'sweet spot' for operating temperature?

Does it depend on material?

Is a heated bed required?

[A]
Googling "what temperature for different filaments" gives a few good links, but the top link looks golden.
https://filaments.ca/pages/temperature-guide
They have temperature guides for both extrusion temperatures and heated bed, as well as suggestions for better adhesion. I'm not that experienced, but their information is similar to information I've seen elsewhere.
Their suggestion for PLA is 215-235 degrees Celsius and a bed temperature of 60 to 80 degrees. That sounds a bit hot to me but every brand (and type) of filament will perform best at different temperatures. I've had problem getting nice bridges at 210 degrees, but had excellent results at 190.
For ABS they say 230 to 240 degrees with the bed at 80 to 100.
Use these values as a starting point, when they fail you make an educated guess about what went wrong and adjust (one parameter at a time) til it works for you. Find a calibration object you like and trim the temperatures so it prints the best your printer can. At this point in the technology experimentation is a large part of making things work.
One thing that's important to remember is that the temperature that you set your bed to and the temperature that your bed gets to is not the same thing. Depending on the construction, assembly and quality of your heater the actual temperature can differ anything from almost nothing to twenty degrees or more.


q: I have a new German RepRap NEO 3D printer, and when I try heating the Extruder to 215°C with Repetier-Host Mac 1.0.1, it always stops at 130°C - does anybody have an idea what could be the reason?

[A]
A few possiblitites.
You wire is too small. If your wire is HOT that is a fire hazard.
Your thermistor is bad. Check with a high temp heat probe or try replacing thermistor.
Your heating element is bad (rare).
Last it could be a limit in your firmware. But that would surprise me.
Any chance you have the bed and the hotend reversed? If you had the Bed as Hotend, then it would max out around 100. This last one I would say is most likely..


q:
I have a object to print for which I want the base to be printed very rapidly because it's just a cube but as the print reached around 70 % a complex circular structure needs to be printed at a slower speed. Is there any way I could control the speed at the given percentage of job done?

I want the cube to be printed at 50 mm/s and the complex circular structure at 40 mm/s.

Printer Type - FDM

[A]
Simplify3D
has the ability to create more than one process, to be applied to the model at specific layers. It appears that feature fits perfectly with your requirements. As an example, you might create a process within S3D for layers 1 to 500 at the desired 50 mm / sec along with any other modifications you wish. The second process would specify layers 501 to 800 to be printed at 40 mm / sec.
The preview mode of S3D allows you to identify layer numbers in order to provide the necessary precision.


q:
I'm currently attempting to  make a repstrap using paper printed parts, like this guy : http://www.mariolukas.de/2012/05/repstrap-3d-drucker-aus-computerschrott-teil-1/
I replaced the DC motor in a paper printer carriage assembly

with a stepper motor (NEMA17). But there was not enough space to fit the axis of the nema 17 at the exact spot of the older DC motor axis, in short, the axis are not in the same place. The question is : if the axis is not in the exact same spot, will it affect the movement of the carriage or not at all ?

I supposed it would but i'm not sure since the carriage is limited in movement by the rails and that we still move the belt around.

[A]
Axis should definitely be at proper position. Otherwise you will get at least 2 issues.
Carriage will be pulled up which will cause stresses on rollers or slides and it will stress your belt
The way the carriage will go will change but because carriage itself is fixed then it will change the speed
3D printing is a precise process. Both issues will have impact on printouts and all your printouts will have broken dimension in the axis in which carriage moves.
Have a look on the picture (it is big to show details)
fig A
shows a situation where carriage is far from the axis
In such situation the distance between vertical line of black cross and pink circle is almost unnoticable so both - the force and the distance (so speed) change are very small.
fig B
shows a situation where carriage is relatively close to the axis
Then both - the force and the distance change is noticable


q: My goal is to 3D print a 5 liter miniature barrel with a side stand, similar to this wooden one on Amazon. I want it to have a removable top so that a boxed wine bladder may be put inside, and there should be a hole on the top as well so that the spigot may stick out and be used. I have no experience with 3D modeling or printing, but I have access to a public 3D printer at my local library. I know you can print parts individually (ex. curved wood-colored sides with staves and holes to interlock and make up the body of the barrel, the metal-colored hoops to go around the barrel). I don't know what software to use, though. I was thinking of starting to learn Blender? Would that be effective for this project?

[A]
Your question begins in an inappropriate format for StackExchange, but you've ended it with one more appropriate by asking if Blender would work.
If you are willing to take the time to learn Blender, you are certain to discover that it will do as you require, and much much more. Your referenced model could be created using engineering-type design software such as Fusion 360 or SolidWorks or many of the free packages, but the free-form aspect is more suited to the flexibility of Blender.
2020 UPDATE: Fusion 360 now supports a sculpt feature, which combines organic modeling with the engineering-type for which it is previously known.
Even though Blender is not an engineering-type program, it has internal support for precise modeling. Should you learn to use those features, you get the best of both types of software.
If you construct your model in the software in segments/pieces as you suggest, your result will have greater flexibility at the printing stage, specifically with respect to color and filament choices. Instead of wood-colored sides, you can use wood-simulated PLA filament! Depending on the printer at the library, you could also use filamet, a filament containing 88 percent metal for the hoops.
I use Blender for some aspects of modeling, often importing the STL into Meshmixer to address things I've not yet learned in Blender.
I hope your reference to 5 liter is the original size and that your model will be a miniature of it. A 3d printer with 5 liter capacity would be a wonderful asset at the public library!


q:
This came up in one of my groups today. That we could not color bend, or mix 3d printing filaments. I have researched but I am not finding anything talking about Plastic mixing in an extruder.

Why is it that we cannot take say a Diamond hotend, or a hotend with 5+ inputs, and mix any color we want? (assuming all the same type, ABSm, PLA). I think it would be interesting to at the least get a gradient effect on prints.

The best I have seen is natural plastic and a marker system. Or a powder / advanced / out of hobbyist price range process that sprays ink. The only Color Bending I know of is with Recycled plastic that uses multi color. Not quite what I am looking for.

Thanks!

[A]
I just started with google and phrase "3d printing color mixing" and on the first place (in fact first two were valueless adverts) I got this
Instructables - DIY Full Color Mixing 3D Printer
.
How it works?
It uses magenta / cyan / yellow filaments and mixes it while printing with Diamond hotend.
It definitely does what you are asking for and it's exactly the same idea you come up with ;)
Overview
Getting the controller board ready for three extruders... I hacked
  a RAMBo board to drive three extruders, however, you can use any board
  you want... (most people use a RUMBA due to it having all the
  pins/components needed for 3 extruders native on the board)
Rewriting Repetier firmware to get color mixing working on your
  machine.
How to install, configure, and use the diamond hotend - tips /
  tricks / lessons learned / etc...
My original Bowden extruder design and various ways to mount the
  three extruders for your set-up
My universal magnetic effector plate and accompanying hotend mounts
  for quickly swapping various hotends. (delta specific)
How to design multi-color models and making STLs that can be
  exported and used as a individual STLs or combining them into an AMF
  file for slicing...
Configuring color mixing in Repetier and Slic3r to print above
  mentioned multi-color models.
Anything else I can think of later that I can't think of now.
Comprehensive overview of Quantum Mechanical Entanglement as it
  pertains to multi-color printing (just kidding, I don't understand
  that... But I will cover multi-color printing throughly)


q:
The turntable support part in my microwave has broken. It is a three armed part, with small wheels at the end of each arm.

I'm confident I could print a replacement, and reuse the existing wheels (since they can be removed).

The heat of the food would be unlikely to conduct through to the PLA, but I'm concerned that it might get heated up by the microwave radiation. I can't find any clear information online about whether PLA absorbs microwaves, or if it is in any other way unsuitable for this.

Will this be a disaster, or should I give it a go?

[A]
I would say PLA itself should not be heated up by microwave. It's because microwave oven creates oscilations which excites water particles
(see microwave explanation here)
so assuming PLA doesn't contain water, it won't heat up.
(removed to not mislead as the water is not only material which heats up by microwaves. Thanx to Tom van der Zanden for being vigilant)
But as usual, it's more complicated.
First. PLA can contain water as while producing it can be cooled down in water bath. Of course well made PLA will have as less water as possible as water has an influence on printing process.
Second. PLA is absorbing humidity so in fact it gets water inside right from the air. This unfortunately causes problems in microwave oven.
Water can be overheated and oven can overheat water above 100C. But even at 100C, PLA will not be hard anymore so your 3 arm star would "collapse". Wheels could get oval or start sticking to their axis.
Eventually if high power is delivered to very "wet" PLA, I think it can... well maybe not explode but break.
Here goes a test which shows it can be used to
defrost things on PLA plate in microwave
But here Daan Snijders
claims PLA gets soft in microwave during the test
Will it be a disaster?
In my opinion it will work only for short uses of MW. Heating up a glass of milk or so. But for longer sessions when there will be much more heat (out of heating dish) it won't work.
SHORT TEST
20sec and 950W gives no effect on my sample (hotend cooling fan duct)
40sec and 950W caused the sample became a bit warm
Inspite that it's not a good idea to run MW without "proper-absorber" this little test confirmes my suspisious - short sessions are ok.