Pronterface not connecting ERROR: A device attached to the system is not functioning I'm assembling a 3D printer with the RAMPS 1.4 shield (board) and an Arduino Mega. I have assembled the structure and the electronics (set drivers, placed the jumpers, connected stepper motors, etc.) and have uploaded Marlin firmware (configuring: thermistor, etc.) on to the Arduino Mega.

At first I tested my printer without end stops and at that time it worked perfectly.

Today I added three end stops and tested again. First it worked fine but after couple of minutes Pronterface gave this error:

> Connecting...
Traceback (most recent call last):
  File "printrun\pronterface.pyc", line 1053, in connect
  File "printrun\pronsole.pyc", line 720, in connect_to_printer
  File "printrun\printcore.pyc", line 46, in inner
  File "printrun\printcore.pyc", line 197, in connect
  File "serial\serialwin32.pyc", line 31, in __init__
  File "serial\serialutil.pyc", line 261, in __init__
  File "serial\serialwin32.pyc", line 71, in open
  File "serial\serialwin32.pyc", line 186, in _reconfigurePort
**ValueError: Cannot configure port, some setting was wrong. Original message: [Error 31] A device attached to the system is not functioning.**

I tried removing end stops, re-wiring, removing all cables from the RAMPS shield except power cables. Still it gives that error. Although Pronterface connects to the Arduino board when the RAMPS shield isn't powered up. Also the Arduino's regulator is heating up.

Do I need to buy a new RAMPS shield?

Finally, I found the solution after frying up a Mega board.  The problem is with the Mega board. Part of the board is not functioning properly or not connecting with the RAMPS 1.4 shield properly. So I tried with a new Arduino Mega board and it worked.
Also removing the D1 diode is the solution for the voltage regulator overheating on Arduino mega board as mentioned in question "Arduino Mega voltage regulator overheats with RAMPS board".


Parts of my (apparently manifold) model aren't appearing in my Slic3r preview I have an STL file that, when I load it in Slic3r, looks fine, but somewhere in the actual slicing process, something goes wrong and parts of the model disappear.

That's the render on the left, and the slicing preview on the right. That big hole is the most obvious fault, but there are more little notches elsewhere on the model; you can see a couple on the bottom edge there. It looks like the program is ignoring some of the model's faces entirely. What's all that about?

The model passes every manifoldiness test I've thrown at it: Slic3r's, Meshmixer's, Blender's, and a couple of online services I've forgotten.The walls that go missing are pretty thin, but they're at least a millimeter at their narrowest point, so I think it should be thick enough for the printer to handle.

Here's a link to the STL file in question, on FileHosting.org, FlashHovering.stl.

I fixed it!

I had my extruder diameter set to 0.5 mm, and the narrowest point of the model was just a hair under a full millimeter, so I guess the program took it to mean that it should only put down one line of material. I made the walls a little thicker and now it looks fine.


Temperature sets to cooling when print starts CR10s Pro v1 I've got this second hand printer today, but, when I want to start printing, the temperature sets to cooling mode and the print never starts.

This is what I've done so far...

Upgraded firmware for the board and screen to Tiny Machines latest version.
Check temperature manual for bed and nozzle and works fine
Level the bed
I used Cura with several profiles, even with an Ender 3 profile from my other machine to see if the slicer is the one giving issues

On other G-codes that i tried, the message changes to in the pause and completing percentage is set to 218 %...
Any ideas?

File name is too long, I had the same issue, shortened the file name and now printing perfect


I need assistance replacing the PTFE tube in the nozzle on our Flashforge dreamer We disassembled everything in order to unclog the filament from the tube, but now I can't seem to get the nozzle to screw back in to the hotbed with the PTFE tube in place. Is there some kind of trick? I feel like if the tube were slightly smaller in diameter it would work. I'm using the same tube, just without the filament that had clogged it. Am I just not using enough force?

I got the same issue before. When you tried to push out the material from the tube, one end of the tube was being pressed. The tube was so soft that the diameter at that end was slightly increased. Hence it was difficult to put the tube back. When you tried to tighten the screw, more force applied and the tube end was pinched more. I got some spare tubes from the supplier. I simply replaced the tube. The PTFE tube could be pulled off from the nozzle.


Does the resin vary from a printer to another? I am using a clear resin to print parts using a Formlabs printer. At the moment, I am using the resin from Formlab which comes in a cartridge that fits in the printer. However, I would like to move to a cheaper option if available. I would like to able to refill the cartridges that I have rather than buying a new cartridge.
Is it possible to buy some clear resin from an outer source or would that damage the printer?

According to Formlabs (at least their FormLabs Form 2 and 3 models), their resin is 405 nm which is a fairly standard resin.
There's a wide variety of resins our there that are compatible with 405 nm, and many resin makers/resellers advertise what brand, make, and model of printer they are compatible with. I have an AnyCubic Photon v1 and it uses the same 405 nm resins. You might have to do some testing to see what specific brand or style works for you, including changing your settings (if possible in the software you use). FYI, I use a version of CHITUBOX which does allow settings for exposure time, raise height, pause time, and a few others.
Knowing that it uses 405 nm UV also allows you to know what kind of UV lights to get for easy indoor curing, too.
I'd like to say that it's not likely for these resins to damage the printer, but FormLabs seems to use a plastic tray, instead of the aluminum tray I'm used to so I don't know if there would be a chemical reaction, though I'm skeptical if there would be. I'm assuming it's using a similar FEP clear film for the bottom to the AnyCubic, but I can't confirm this, since the FormLabs film seems to be integral to the tray, rather than replaceable.
I can see why you are looking for other resin options. One place I saw online has a 1 L FormLabs cartridge for \$150, when 500 mL on Amazon is usually between \$20-30. I've seen special resin, such as flexible, as high as \$60 for 500 mL and ABS-like resin for $40, though. Water washable resins seem to be in the \$40-50 range. There's also "natural" or plant based resin for about the same price as regular resin, but might have a different reaction to your tank.
I'd assume that every brand of resin (except for the rebranded stuff) has their own chemical makeup besides the various types of resin, so you might have to some testing, although I realize that messing up a tank that's \$150 to replace is not exactly something you want to do every day.
I can tell you that I've used at least 6 different brands of resin and they all react differently to the UV. I mostly have tested clear, and just that produces a variety of results, from how easy/hard it is to cure to what color it turns when it over cures. (I'm still trying to find a clear that fully cures actually clear.) Where I was going with this is that with all these resins I've used, I haven't had any that caused damage to the FEP film. Some have stuck really hard and I had to be really careful pulling it off. However, I've only had 1 film need to be replaced due to clouding, and I have 4 Photons and used all resins I've tested with all my machines.


Is PETG filament food safe? I've been trying to find a 3D printer filament which would not release any chemicals if in contact with heated water for a substantial amount of time. So far, I've easily ruled out both PLA and ABS, as they're not considered food safe from what I can find. I have found PETG filament, which seems to be food safe.

My question is: "Is there's anything special you'd have to do to make sure the print is food safe, or as in my case, to make sure it's safe for usage in a mug?".

I will be using a steel extruder as brass ones may contain lead.

Many manufactures list their filaments as being food safe, but I would not treat this as "gospel truth". Apparently, the FDA considers PETG to be safe for food contact, but they are probably thinking about injection-moulded and vacuum-formed parts. Unfortunately, an initial search of the FDA's website did not yield any definitive information.

Even if a particular filament is genuinely food safe, that does not mean that a 3D-printed part made from it will be food safe, since there will be an abundance of nooks and crannies where bacteria can lodge and reproduce. You would have to sterilise a utensil before and after every use to be absolutely safe.

Anyway, good luck with making a water-tight mug with an FDM printer. You will probably have to seal it to make it water-tight, and then it will be the food-safety of the sealant that you will need to worry about. I would give it a miss, if I were you (at least, for other people's use). Items intended for one-time use would be OK, I suppose.


When should I use a raft, when should I use a brim? Taken from the answer provided by @EricJohnson,

When should I use a raft, and when should I use a brim? What advantages does each have over the other?

Raft

Brim

A raft will allow for better adhesion for the whole print as the raft attaches to the printing surface and the print attaches to the raft. Rafts go all the way under the print and consist of multiple layers, whereas a brim is only 1 layer and on the outside of the print. Rafts are normally harder to remove than brims because of the increased contact with the print.

From my own experiences, the brim does not help a lot with layer adhesion as it is only 1 layer. I normally use a raft when I need a nice looking 1st layer that is not on the bed or when there are not enough contact points.


Dual PSU with one switch fuse My home built printer has been having issues running properly. The x/y/z motors will run freely with standard non build position commands but when they are suppose to start a raft layer and they freeze up and don't respond properly. When I put my hands on my x/y motors they're cold as if no power is getting through, yet they ran just a moment before. I currently have a variable PSU which allows from 0-48v power output. I started turning the supply up and as I reached about 34v I noticed the motors started to run properly but my board did not regulate the power and instead started pushing the power through all of the ouptuts activating the second empty extruder and causing the heat on my extruders to rise to an extreme 300°C vaporizing my PLA. Ever since this incident my board continues to attempt to push power through all outputs regardless of the power output settings (ie if I set the output on my PSU to 11v, the motherboard still activates all motors and heaters) I am curious if I were to use 2 24v PSUs in parallel (or a series) if that would allow my motors to get the power they need without putting strain on my motherboard.

@TomvanderZanden's comment is right.  You have probably damaged your motherboard and/or driver boards by applying 34 volts.  You should never exceed rated voltages.

It might help to study stepper motor driver circuits a bit.  Stepper drivers usually act as current sources, not as voltage sources.  They typically have a high-frequency switch that applies pulses of voltage so that the current through the inductance of the motor matches the current needs for the desired step position.  Motors generate torque from the strength of the magnetic fields, with is linearly related to the current through the coil.  The voltage drives the current, but the current cannot change instantaneously in an inductive circuit.  Unless the motors have an uncommonly high coil resistance, two to five average volts will be enough to provide the maximum current.

The motors are pretty insensitive to the voltage applied, as long as the current meets the specifications.  The motor driver chips are sensitive to the applied voltage.  They are sensitive because the internal switches and logic can only withstand certain voltages, and they are sensitive because the circuits assume that the current won't change too quickly.  If the current gets so high that the magnetic material in motor saturates, the inductance suddenly becomes much lower, and the current can spike to very high levels.  This current spike can destroy drivers.

Heaters also have a voltage spec.  The heaters I've seen are specified for 12 or 24 volts.  To avoid burning out, a heater must have a low enough thermal resistance to the object being heated that the inner heater temperature is not so high that the heating element is damaged.  Powering a 12v heater from 34 volts would cause the current to increase by a factor of 34/12 = 2.83.  The power would be that ratio squared because both the current and the voltage are higher.  The heaters, whenever they were on, would be generating 8.02 times the power.  This might not result in the good behavior of the heater control systems, and could damage the FETs which are driving the heaters.

As for changing the power supply, before doing that I would want to check that the power supply was not supplying the needed voltage and current.

When you've replaced the motherboard and drivers, and configured the drivers for the required operating current, attach a voltmeter to the power supply.  Turn on all the heaters, power up the otors, and watch the supply voltage.  If it remains true (say, within 15%), the power supply isn't the problem.  If the voltage dips, or pulses, or does anything other than staying stable, I would consider a higher current (not higher voltage) supply.  Connecting two supplies in series causes problems with the ground reference of one of the supplies.  Connecting two supplies in parallel, unless they are designed for that use, often isn't any better than a single supply because they will not necessarily share the load well.

Good luck!  I look forward to further questions.


Filament extrusion always stops at some point during print I own a Creality CR-10 (using Ultimaker Cura for slicing) and I am experiencing terrible printing problems.

My problem:  I am not able to print anything that takes several hours to print. For parts printed in 30 minutes or so, my printer usually works.

The prints end up like this (unfinished and with a lot of stringing)

This below is actually the best result I got so far.. (important note: there is no under extrusion during the print, it suddenly stops out of nowhere..)

(Although I have to use terrible retraction settings and need a lot of post processing because of all the stringing - you might have an answer for that too.. I just couldnt get the 3d printer to print parts properly with good retraction settings.)

The problem is that at some point of the print, no more (PLA) material is extruded and the printer moves without actually printing anything. The first couple of layers usually work (you can see that in the images) but after wasting almost 600 grams of PLA, I am not able to find a solution myself.

.

I have some suspicions:

Could the problem be the angle, the PLA is inserted into the feeder? (so that it is almost a 90 degree bend)? The filament comes from a spool in the right hand side. But I dont think that this would cause such a problem..

Is it a software problem? Here are all my cura settings (I even reduced the printing speed to 30mm/s at 205°C - still didnt work..)     :-(

Could the length of the bowden tube and it tangling up be a problem? (as you can see in the image below)

And annother important thing: The feeder always grinds into the filament (even at those low retraction settings) and it is always very hard to pull the filament out of the bowden after a failed print. Sometimes its almost impossible and i have to use heavy tools for it.. that should be the probelem

I already did some atomic pulls, replaced the nozzle and switched the bowden tube.

I have a dream: My printer printing a part without any stringing and actually finishing the print. Please help me to achieve this dream..

Thank you for your help in advance. :)

(and the filament I used, sorry for the bad quality of the pic)

Stringing?

The stringing is explained by your relatively low retraction settings, 1.5 mm is not much for a Bowden setup. As do too high printing temperatures.

Stopping mid printing?

What you are experiencing is called clogging, the extruder cannot push the filament through the hotend and cause the grinding you report. Clogging mid printing is usually caused by insufficient cooling (for the temperature you print at) of the cold end (causing heat creep; slowly increasing temperature of the heat break), especially all-metal hotend assemblies are notoriously known for this problem.

Your Bowden tube does make a lot of kinks, maybe you can improve the path of the Bowden tube. Also if you are concerned about the sharp filament intake angle, you could print a filament guide:


Can commodity 3D printer extrusion hardware and filament be used for injection molding? Assuming you have a suitable oven to maintain temperature at the filament melting point and a suitable mold that can handle the temperature, is a commodity 3D printer hotend and extruder, with large nozzle, suitable for injecting material into the mold? I'm thinking of a setup like having the hotend mounted through a wall of the oven, braced against a hole in the mold inside the oven, and feeding filament via motor or manual cranking outside. Or is much higher pressure needed to make something like this work?
Certainly there are better setups to do this for manufacturing at scale, but the point of this question is whether you can do it with minimal setup effort and cost using commodity parts and filaments rather than needing expensive or custom-built equipment and material sourcing.
For relevance to the site in case it's questionable: certainly if this technique is possible, it could be used along with initial 3D printing of a design and using that to produce a (e.g. high-temperature epoxy) mold.

Injection molding requires two major components: pressure and heat. So your question can be broken down into those two halves: can your average extruder handle injection molding temperatures, and can it handle injection molding pressures?
Let's start with pressure.
Per this page on the University of Minnesota's site, plastic injection molding tends to require pressures of around 2 to 8 tons per square inch. Assuming you're using a 0.4 mm nozzle, which has a cross-section of 0.126 mm², that works out to be 0.000195 (1.95E-4) square inches, which translates to about 3 lb of pressure total at the nozzle assuming you're going for the high end of 8 tons (16,000 lb). However because of the way that you're treating the molten filament in the extruder as a hydraulic fluid, you've got to deal with the fact that the "piston" on one end is actually quite a lot larger area, which means you have to multiply the force by that difference in size. The cross-section of 1.75 mm filament is approx. 9.62 mm², or 0.149 in². That's 76.4 times larger, which means you need to be pushing on the end of that filament with roundabout 230 pounds, or 105 kg, of force.
For reference, the Nema 17 that's on my extruder is spec'd at 76 oz-in of torque, geared down 4:1 through a Wade's extruder, and then acting on a hobbed gear with a 6 mm effective diameter (3 mm radius). Much to my own surprise, as I write this, that means that my little plastic extruder is actually capable of just north of 160 lb of pressure force! All these numbers would need to be recalculated for 3 mm filament, and I have no experience with 3 mm, so we're going to skip that one for now.
Now, that being said, my extruder is also capable of shredding filament if conditions aren't just right. The main two problems you'll have to overcome is 1) gripping the filament hard enough without destroying it, and 2) keeping the filament from buckling. I think if you got clever with some gears keeping multiple hobbed gears synced up, and a polished aluminum or steel feed tube, you could absolutely make your own extruder that's capable of consistently putting 300+ pounds of force on your plastic filament without it buckling or stripping. The downside is that your feed rates are going to be fairly slow, so each injection molding is likely going to take you quite a bit of time. A larger motor such as a beefy NEMA23 might help offset that by giving you much higher torque at higher speeds, so long as you can melt the filament fast enough. However we'll need to revisit these pressure numbers in a few moments, after I explain a few things about temperature.
Next, let's look at temperatures. Obviously we know that we can melt the filament itself as it's moving through the extruder. Using a Volcano nozzle or something, you can even guarantee molten filament at a fairly high extrusion rate. However most printers are designed such that the filament cools to solid (60-80 °C normally) almost immediately. Injection molding designs require that the entire mass of plastic be kept molten. Fortunately, ABS and PLA melting temps are easily reached by literally any toaster oven, so stick your setup in there and you're golden, right?
But wait, there's more!
One of the problems you'll run into immediately is that extruders are carefully designed so that the plastic is molten for as little time as possible, because molten plastic against a metal tube introduces a bunch of friction, hence the need for super high pressures during injection molding. If the plastic melts too soon, then you'll clog up your heatsink (the "cold" side of the extruder), and won't be able to extrude at all. This is a fairly common source of jams in 3D printing, where you're extruding too slowly and there's not enough cooling on the heatsink. Fortunately, E3D sells a water-cooled Titan extruder that would keep the heatsink cool. However the rest of your gearing assembly, and the motor, will also need active cooling, as heat damages the permanent magnets in the rotors, and the printed geared assembly obviously will melt if put inside an oven. Your best bet might be a water-cooled Bowden setup, assuming you can find tube fittings that can withstand several hundred pounds of force. You might look into using solid tubes like brake line rather than your normal PTFE shenanigans.
TL;DR:
Get you a water-cooled extruder, make a super-strong Bowden setup, and gear down a huge motor with a bunch of synchronized hobbed gears, and you might actually pull it off! There's plenty of Thingiverse extruder files you can use as a starting point.
As far as commercially available extruders go, however, I don't think you're going to find anything that's immediately available that can handle what you need it to without some level of modification depending on your selected injection pressures.


Klipper BED_SCREWS_ADJUST and SKEW_PROFILE interaction Klipper lets you define a skew profile that is loaded / unloaded on demand during START_PRINT / END_PRINT macros called during printing of a sliced file. This seems to be the recommended way to apply the skew in Klipper, in fact it is in the documentation this way: https://www.klipper3d.org/skew_correction.html.
My question is, should I also manually load the skew profile prior to executing the BED_SCREWS_ADJUST built-in command in Klipper?
Or does BED_SCREWS_ADJUST ignore the skew entirely so it doesn't matter?

The skew correction works in X/Y axis while bed screws helps you correct the ax axis. Since they don’t work in the same axis, I don’t see why they would interfere with each other.


Ender 5 Plus not going "home" (or zero) correctly I have been successfully using the Ender 5 Plus for a month now. But suddenly the printer wont go back to zero or "home" correctly. Whenever you press home or start a print it should go and hit right side, then top and finally go to zero. However right now it moves up directly from wherever it is place. What can I do to fix it? Any ideas?

Is your BL touch flashing red, or is it solid red? Flashing red means that the bed is raised up too high, there needs to be enough clearance for the measurement probe to fully extend when you start it up.
Even if it is not flashing red, try moving the print head and bed manually:

Remove your SD Card, unplug any computer hooked to the printer's USB cable

Boot UP Printer

Tap Settings

Tap Move

Move Z down at least 50 mm from print head

Move Y so it is resting against the stop switch

Move X so it is resting against the stop switch

Turn it off and wait for a minute or so

Turn it back on

Tap Settings

Tap Leveling - this will make it do the homing function

This should get you to the correct home position, but if you are still having problems, you need to re-level your printer manually and you may need to adjust the Z-offset.
The Z-offset tells tells the printer to Add or Subtract height on the Z-plane to get the nozzle close enough to the print bed that the extrusion sticks.
Let us know if this works for you, or if you found a different solution.


How to configure Cura to run the Z probe before heating I'm using Cura as my slicing/printing software and I just started using the BuildTak printing surface.

The BuildTak is damaged by pushing a hot nozzle into it and my printer's (Robo3D R1+) autoleveling feature works by pushing the nozzle into the build surface.

Is there a way to configure Cura so that it runs the Z probe first, then heat up the nozzle?

My first sheet of BuildTak already has 10 small holes in it (at the homing position and at the 9 leveling touch points)

In Cura (and Slic3r), you can 100% customize what the printer does before printing your actual model through custom start/end g-code.

If you navigate to the Start/End-GCode tab in Cura, then select start.gcode, you can see what operations are run before each print begins. Lines prefixed with ; are comments, and does not affect the printing in any way.

Basically, we want to manually tell the printer to do the auto leveling before heating up the nozzle by editing the g-code in start.gcode.

G-Code generated with the default start.gcode:

If you try to slice some model with the default code found in start.gcode, you will get something like the following (depending on your printer):

; CURA AUTOMATICALLY INSERTS THESE TEMPERATURE CODES

M190 S70.000000 ; Set bed temperature to 70 degrees
M109 S210.000000 ; Set nozzle temperature to 210 degrees

; THESE ARE THE CODES FROM START.GCODE (for a ROBO 3D R1)

G28          ;move printer to endstops (the home position)
G92 E0       ;zero the extruded filament length
M565 Z-1     ;set z-probe offset
G1 Z5 F5000  ;move the printer 5mm above the bed
G29          ;run auto-leveling

; THE ACTUAL MODEL BEGINS HERE

;Layer count: 168
;LAYER:0
.
.

Analyzing the g-code output

At the top of this code snippet, we can see that Cura automatically inserts g-code for heating up the bed and nozzle to their respective temperatures with the M190 and M109 g-codes. This means the printer always will heat up the nozzle before reading the start.gcodes that we set. However, if we manually override M109 code in start.gcode, the M109 at the top will automagically disappear from the generated g-code output! (Thanks, @TomvanderZanden!)

We could therefore use the auto-leveling command G29 before manually setting the nozzle temperature with M109; specifically, we want to add M109 S{print_temperature}, which reads the Basic -> Print Temperature-setting in Cura, and replace {print_temperature} with it automatically.

Manipulating start.gcode:

In order to postpone heating the hotend till after probing, start.gcode could be something like:

G28          ;move printer to endstops (the home position)
G92 E0       ;zero the extruded filament length
M565 Z-1     ;set z-probe offset     <-----   ( YOU HAVE TO ADJUST THIS, READ BELOW)
G1 Z5 F5000  ;move the printer 5mm above the bed
G29          ;run auto-leveling
M109 S{print_temperature}    ;set nozzle temperature, and wait for it heat up

And that's about it! You can then use these codes in your start.gcode. However, you probably will have to recalibrate your z-prove offset.

Adjust z-probe offset:

Normally, auto-leveling is done with the nozzle heated for a reason: when the nozzle is warm, it expands slightly, moving closer to the bed. You might therefore have to adjust your Z-probe offset with the M565 command (as demonstrated in the snippet) to account for the increase in nozzle length when warm.

Remember:

Remember that when editing g-code in this manner, you will take full control of how the printer operates. You could therefore very well do something unintended, so keep the power switch close!


How to I assign an imported STl file to a variable, polygon, or otherwise manipulate it? I have 2 STL files that I want to chop, rotate, and glue together.  If I printed them and literally chopped and glued them together, I would be done.  Very simple operations.

I imported them both into OpenSCAD, but I can't find docs or figure out a way to do anything to the STL files once they are imported.  They imported fine.  I don't know how to assign a variable name to the imported object, which I presume is the next step before I can rotate and move the objects around.  I might be going in the wrong direction though, I don't know.  usually during an import of a module you can assign a variable name, or instantiate it.  Since the import also instantiates it, I'm at a loss for what to do next.  I've programmed in a smattering of languages, but haven't touched OpenSCAD in ~3+ years.

When searching, I find a cornucopia of slightly related information like how to import a file from 2011, but nothing about how to work with it once it's been imported.

One can create a module to import the respective STL files.

  module bring_it_on_1() {

  import("c:/user/models/egg_on_face.stl");

  }

  translate([-10, 20, 0])

  bring_it_on_1();

Other modifiers can be used and will act on the STL file appropriately.


On a LENS printer, does the head move, or is it table that moves when printing? I'm wanting to know how a LENS printer moves to create 3D prints.

Whilst this is not a definitive answer, if you watch the video on their website, LENS 450 Systems, it is the bed that moves in the X and Y axes - the head remains static. The bed also appears to move in the Z axis, after each layer (as there is noticeable bed wobble).

However, the head is on an armature so it could be that which moves - it is not entirely clear.

LENS 450 System for 3D Printed Metals

Note that the MR-7 system appears to be similar to the 450, with its "3 Axis CNC Control System". However, the 850-R differs, inasmuch that it has:

5 Axis CNC Control System
XYZ gantry + tilt-rotate table

which are not mentioned in the specifications of the 450 and MR-7, so the 850-R could well differ from the video.


Why does my Anycubic Predator print backwards? My Anycubic Predator prints really well except for everything being backwards. Text and anything that is right or left handed comes out mirrored. The same files print correctly on other printers.
Is this a software issue or hardware?

The right-hand coordinate system is the most used system on printers. So, when facing the front of the printer, the most common arrangement using a  is:

X+ will move the print head to the right
Y+ will move the print head away from you (towards the back of the printer)

For a Delta printer, when facing the printer, the Z pillar/tower should be at the back, the X tower on the left and the Y tower on the right. Do note that these tower are not corresponding to the axes movement, but are simply named as such so that you can use the designated stepper axes as indicated on your controller board. If you position the printer this way you have access between the X and Y pillars.
If the prints are mirrored in X direction, you need to swap X and Y steppers. X is the left column, Y the right.


Slicing adds holes/cracks to my object I recently got started in 3D printing but here's an issue I can't seem to find a solution for (I don't know what exactly to look for).

Here's what I did:

I used InkScape to convert an emoji in to a svg and imported it in to Blender
Used the Solidify modifier to make the curve a solid and converted it in to a mesh
Extruded the mesh a bit, fixed a few non-manifold vertices and erroneous faces and saved the whole shebang as STL
Imported the STL in to my printers software:

After slicing it looks like this:

Is the software making a mistake during the slicing? Or is my mesh screwed up?

I have a FlashForge Finder and using the software that came with it: FlashPrint.

Edit: I uploaded everything to Thingiverse for those who are interested.

here is just a addenum to Tom van der Zanden's answer

this is (an example of) what you may design - nice object with virtual outline, and virtual fill
so this is what you see (and what you potentially expect)

but here is what you get (and probably not really expect)

red parts are the areas which are not covered by fill because nozzle cannot reach there

solution is

to redesign your object in smart way or
to use smaller nozzle or
to use smarter app (like Slic3r)

and of course you can use all 3 options together to get best results ;)

EDIT
here is simple explanation why smarter app could do the thing

and here goes the difference

green parts are new covered areas

not much but somthing extra


How specific can I get setting layer heights? When choosing a layer height, I know that often you go as fine as your printer will do for better precision, but sometimes you go a little thicker, for speed, for example.

I also see 0.1 mm and 0.2 mm as common thicknesses.

What are my options here? When I'm working on a part where I want to print a draft piece, and the quality matters less, can I set it to 0.15 mm? 0.11 mm? The Ultimaker Cura slicer I normally use will let me put in almost anything, but what can it really do? If I can use values in between simple 0.1 mm increments, are there reasons I might want to do so?

For reference, I have a Monoprice Maker Select Plus with a 0.4 mm nozzle and, again, Ultimaker Cura as the slicer. But more general answers for other printer types and slicers are also encouraged. I want to know about this generally, and not just for one printer.

Layer hight can be theoretically anything as long as it fits into these ranges:

it needs to be at least one step for the Z-Axis motor to be physically possible
it should be at max 3/4th of your nozzle diameter to create an adhesion surface

In praxis, the lowest setting for layer height due to physical limitations of the extrusion systems is around 0.05 mm.

Also, not any number is possible, it is dependant on the Z-axis system: since one or one-half step is the smallest rotation that the stepper can achieve, the raise that belongs to this partial rotation is how much one and the next layer height can be together. The step limitation usually is of no concern though, unless one has a very steep lead screw.

As a rule of thumb: doubling layer thickness results in almost half the print time. 0.1, 0.2 and 0.3 mm are common because they allow easy checking the printed accuracy in Z-axis with calipers.


Subdivision surface for STL files How much should I subdivide a surface in preparation for 3D printing?

For computer graphics, I know that I need to balance the smoothness and the rendering time, but for printing, I'd like it to be completely smooth. Are there any reasons why I shouldn't subdivide a lot (e.g. 7x) in preparation for 3D printing?

Subdividing an existing mesh further won't do anything because you're not adding additional detail, just representing the same thing with more triangles. Subdividing as "preparation" doesn't make much sense. You should make sure the mesh is created with sufficient detail while modelling.

A mesh created for 3d printing should generally have a lot more triangles than one created for use in rendering, but within reason. It doesn't make sense to make the mesh (much) more detailed than the printer can print, and similarly having lots of triangles can make the slicer slow or unreliable. As a very rough guideline, I would say that 10.000-100.000 triangles per model is reasonable (but this obviously depends on the size and level of detail).

Some slicers may output G-code that will have segments corresponding to each and every triangle in the model, even if these segments are very tiny. This may cause the printer to slow down a lot while printing, but most slicers take care of this by merging small segments into larger ones. Depending on your slicer, you might have to watch out for not having the triangles be so tiny that the number of segments created becomes a problem.


Flexible filament frozen I was thinking about what would happen when flexible filament is frozen. Would it become brittle or still be rather tough*. A situation I think of would be a ice tray in the freezer. It is nice to have some flex to get the ice out, but PLA and other filaments wouldn't work, but will flexible filament work?

*when I say 'tough' I mean having similar properties when unfrozen.

The behaviour of "frozen filament" will entirely depend from the specific formulation of it.

The term "flexible filament" encompasses a variety of different polymers as for example: thermoplastic elastomers like TPE and TPU (e.g.: ninjaflex), copolymers (e.g.: bendlay), copolyesters (e.g.: Ngen Flex), polycaprolactones (e.g.: PCL), etc...

Even in those broad classes of chemicals, the amount, type and quality of additives will affect the physical properties of the filament a lot.  In fact rigid.ink even produces a flexible PLA that proves the point of additives radically affecting the properties of the main material.

In general, all materials lose elasticity at lower temperatures (a Space Shuttle came down because engineers failed to account for this).  Polymers that do not contain water are unlikely to crystallise though, so I would expect it to become stiffer but not to fail catastrophically at 0°C.


SeemeCNC Rostock V2 in 2020 Looking to get into 3D printing without spending too much up front for now. Found an assembled seemecnc Rostock V2 for sale at a very good price considering its MSRP is 1k for the kit pre-assembly.
My question is, will this 4 year old printer be significantly lacking in any way compared to a new lower-end printer from 2020? I know the technology moves so fast.
Thanks so much in advance,
Alex

I definitely wouldn't start with a Delta printer.
Cartesian printers have become "the norm" for a good reason - they're very easy to use and tune, so I'd recommend getting an Ender 3 or Biqu B1.
It'll still print just fine, but that MSRP is in no way realistic in 2020. If it's offered under maybe 100$, it might be interesting as a secondary machine, but I wouldn't pay more than that.


Ender 3 v2 Cura Profiles - Anyone willing to help/share? I searched online, and found two YouTubers who shared their Ender 3 v2 printer profiles, and I've been having more or less better success with theirs than mine, possibly because I was basing mine off the Ender 3, and they were basing theirs off the Ender 3 Pro...
Would anyone here have the settings for the Ender 3 v2 for Cura, that's the printer definition, with the measurements, offsets, etc. and also maybe a few print profiles, one of my biggest problems is stringing, lots of my prints have stringing, and the new profiles helped with that, but I'd like to have some more, and also a solid baseline from which to build, and learn, and try to figure out what I'm doing wrong...

Use the profile for any Ender 3 model, or better yet just start from scratch and put in the important properties that actually vary per machine - bed size, temperatures needed, etc.
Cura profiles for specific printers, especially the ones Youtubers are promoting, are almost always misguided if not outright wrong. They're a mix something like 5-10% settings that are actually physical characteristics of the machine, and another 5-10% dubious settings that are tradeoffs that might help avoid common problems for the machine at the expense of making other (often worse) problems, and the remaining 80-90% personal preferences of the person who made the profile. For instance, looking at Cura's base Creality profile:

Machine max accelerations are all wrong, at 500 mm/s². The machine can actually handle at least 3000 mm/s², and unless you've updated firmware to have Linear Advance, increasing acceleration is the only way to avoid inconsistent extrusion.

Z speed limit and acceleration are very low. This makes seam more severe and has no benefit.

Print speeds are random and differ per type (outer wall, inner wall, skin, infill, etc.) which doesn't work right on a bowden machine without Linear Advance firmware.

Z seam type is overridden. This is purely personal preference and has nothing to do with the type of printer.

Gaps filling settings are overridden. Same issue.

Retraction settings are botched, especially increase of window for max retraction count from 4.5 mm (default) to 10 mm, which will cause severe omission of retractions (thus stringing, oozing, and failed adhesion) in any print with thin layers and fine detail.

Enabling skirt. This is purely preference.

Lots of support settings. What's needed here is 90% of a function of the object you're printing and 10% a function of your machine's properties and there's no indication that the settings in the profile have anything to do with properties of Creality machines.

Etc. etc. etc. Most of the above dubious/wrong stuff was added fairly recently in Cura, taken from the "Creawsome" profile popular on Youtube and Reddit. Before that they had a more minimal profile that at least wasn't wrong.
The actual properties you need to set in the profile for your particular machine are:

Bed size/print volume
Heated bed
Filament diameter
Nozzle size
Retraction length (depends on hotend and extruder type, bowden tube length if bowden)
Retraction speeds (depends on extruder capability & friction in path, etc.)
Fan speeds (depends on how powerful your fan is)

Setting max speeds and accelerations is also useful to get more accurate print time predictions, but not necessary.


Affordable 3D printing of reflector Are there any 3D printing services or something similar to 3D print or injection mold light reflectors?

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

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


How to address bed scratching on a Creality Ender 3 So bed scratching seems to be a real thing, and not a single post I've come across (I've looked at more than 30 by now) actually answers the question on exactly how to stop this.
Now, I have an Ender 3 and this is becoming enough of a headache that I want to just give it away. I thought that the old bed was just wrecked so spend £30 on a new glass bed .. Guess what .. Wrecked that too.
Please don't suggest I level the bed - it is levelled, not gravitationally, but mechanically.
I have tightened everything up.
I have tried altering the XYZ axis on the actual printer.
I have tried adding some numbers to the Z axis in Cura, but it just snaps back down to zero.
I have played with base layer thickness, with no difference.
I have run nine different test prints, with every single one coming out perfectly.
I have ABS at 250 °C and bed at 90 °C. Sticking to the bed is not a problem.
Why .. Why, why why, is it scratching the bed when I then go to print something? Nothing has changed!! I even zero'd the test prints in Cura the same way I did my parts prints.
Would seriously appreciate some help before I just toss this thing.

Most likely your print surface is uneven. You can try rebuilding your firmware with mesh bed levelling that allows you to manually probe and store n*n grid bed mesh setting the height offsets at each point manually (however, on stock setup you might need to disable certain features for the compiled firmware to fit). Other option would be to use some kind of ABL as mentioned above. You can also try installing Z offset plugin on Cura and raise it up a bit.
The last thing to check would be comparing the test gcode to your slicer generated ones (via any text editor) looking for differences in G0/G1 Z movement in the beginning of the gcode. If there are ant differences, that would give you a hint where to progress further.


Sudden underextrusion on Ender3 I have printed a couple weeks perfectly fine with my Ender 3. Two weeks ago I changed the firmware but the settings were all fine and resulted in good prints.

Now, suddenly during a print the extruder motor started to under-extrude.

I thought "hey, could be the file" and used a test file that printed well two weeks ago: Under-extrusion, barely a line.

I looked at the extruder, no filament grinding, no clicking from lost steps or moving against pressure. The Bowden tube is firmly seated though.

I measured what is coming out: instead of 50 mm I ordered to push into the hotend got 28.7 mm. So I went and looked at the steps/mm, which is 93, exactly what it is also on the TronXY X1, which uses pretty much the same extruder setup but for a different style, same sized gear.

I cleaned out the nozzle nevertheless, but that didn't change the results.

What might be wrong and how can I fix it?!

Edit:

Touching the filament while I was printing a freshly sliced test, I realized it DID lose steps, just the filament did slip back (almost) quietly. Pressing a finger on the filament made me able to feel the shiver in it.
Inspecting what was printed showed, that the nozzle had migrated against the print platform a little over the weeks.

A close inspection of what happened when printing the first layer resulted in this:

The missing steps on the new print came from the nozzle scraping too close to the print surface, which lead to no first layer
Readjusting the Z-axis end stop, which had moved down, resulted in no more lost steps, but the print not sticking for the first test.
Releveling the bed and making sure the bar was parallel to the bed resulted in a perfect first layer.
Lost steps and under-extrusion could not be replicated after 48 hours of rest for the printer.

I have no idea why the print had failed due to under-extrusion during the print, but apparently, my immediate tests were flawed enough to not detect the first layer height resulting in getting almost no extrusion. This I mistook for massive under-extrusion, making me believe something else was at fault.


How to remove internal part of a hex grid I am modelling a few cut templates to be used on an hexagonal grid (honeycomb) material using OpenSCAD.  Basically, from a reference cell, I need to select all cells that are within a given range and given angle.

I implemented this by creating an in memory grid that covers an area larger than what I need (extra range, 360 degrees), and then testing each cell for both the distance and angle requirements, extruding only those that test positive for both conditions.

Everything works as expected...

...but now I would also like to add the possibility to have the outer contour of the template without having each individual cell within it (so, a single thin line going around the whole "pizza slice" above).

I'm pretty new to OpenSCAD: what would be the best approach here?
(I'm happy even with a solution that requires to re-implement what done until now).

I ended up finding a reasonable solution myself:

Basically, I diffed two identical, non-hollow geometries, in which the first one had the cells larger than they needed to be (so overlapping with others), and the second one had them exactly of the right dimension:

difference() {
  base_geometry(range, angle, infill, extra_padding = 2);
  base_geometry(range, angle, infill, extra_padding = 0);
}

This way the only portion of the solid remaining was the extra_padding on the outer edges of the geometry.


Slow speed of the delta 3D printer I'm running a large delta 3D printer with Repetier firmware.

The problem that is irritating me is that the speed of the carriages are too slow, like an old lady that is walking in a football field. When I command G1 Z10, for example, the carriages move with a super low speed. I checked everything but I couldn't find the problem.

Here are the specifics and the current settting of the printer:

electronics : Arduino Due + RADDS 3 42cmo6 6 kg
2.5 A stepper motors for x,y and z axes
3 TOSHIBA ''TB67S109'' stepper drivers (0.1 resistance, 1/16 mic stepping)
Vref of drivers: 0.7 V (when I    increase this to 1 volt a weird
sound comes from steppers and the carriages won't move)
number of pulley teeth: 20
belt pitch: 2
steps per rev: 200
micro stepping: 1/16
steps per mm: 80
Max. travel speed: 300 for X,Y,Z
Homing speed: 100 for X,Y,Z
Travel acceleration: 3000 for X,Y,Z
Print acceleration: 1000 for X,Y,Z

PS: I'm currently calibrating the printer and haven't printed anything yet.

When you command a move such as G1 Z10, you are omitting the speed at which the tool head travels. Without specifying the speed, the speed from the last command or speed setting is used. Frequently, after levelling the bed, the tool head is raised in Z direction with a low speed (movement in Z direction is always much slower than in X or Y direction), if you command a movement after raising the tool head it uses this speed. For faster movement you must include the feedrate, e.g. G1 Z10 F600, now it will accelerate from the initial feedrate (e.g. 300) to 600 during the move. If you want instant speed you set the feedrate first and then move the tool head:

G1 F600
G1 Z10


What special considerations must be taken when designing parts for 3D printing? What are the 'headline' basic design rules for FDM?

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

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

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

Designing a part for 3D printing often doesn't seem to have many special considerations, but I have learned the hard way, that there are some things to do differently. This is just a list of things to that one should keep in mind in addition to basic principles of design1 when designing parts, keeping the subsequently slicing the parts in mind too:
Print orientation
There are many ways how you could orient your print, but usually, there is one orientation, that has the least need for support. Look at your part critically and keep this orientation in mind when designing. Especially look at overhangs and bridging, and if you can get away without.
Overhangs
There are 3 sorts of overhangs:

Small overhangs ones that are neglectable.
Long overhangs which can get support.
Overhangs that can't be supported.

When designing parts, you want to make sure you only have type 1 and 2 Overhangs, as type 3 overhangs will sag and fail. Think carefully if you can rotate the piece to get a print orientation that does not need an overhang that can't be supported by an automatically generated support structure. If that is impossible, try to implement a sacrificial piece that can turn the overhang into a bridge.
Smaller overhangs can be made neglectable by adding a phase to the underside. This phase's angle is depending on the printer. In my experience, 70° is something many printers can manage, but I prefer 45° due to the ease of making them. A fuller can work to give a small overhang the needed support, but often has problems for larger overhangs!
Bridges
Overhangs turn into bridges if they are connected on both sides. These either have a limited length, depending on the printer you use or need a support in the center. Check if you really need a bridge or if you can rotate the piece to get away without.
Avoid vertical holes in bridges
It might be something that might surprise but a vertical hole or slot in a bridging part is something that often fails as the bridging strings just sag as they are terminated mid-air without a support structure and finally fall, ruining the bridge. Yet such a support structure sometimes could not be removed in all cases, so something needs to be done differently.
One such a solution is to add a 1-layer sacrificial layer on the bottom of the hole: printing a solid layer by bridging is possible, and the subsequent hole/slot can still be free. It has to be cut free after printing in post-processing though.
round holes in Walls
Round holes in standing walls can become problematic to print once the diameter gets too large. A trick to keep the upper parts of the hole to sag into the cavity, making it undersized or needing to drill it to size later. To prevent this, the upper side of the hole can be adjusted: instead of a round upper rim, turn the hole into a teardrop. This reduces the overhanging area. Keeping a 60° top angle on the hole should be fine.
If the hole is used to key an item to an axle, put the keyway to the top of the print orientation, so it takes the place of the teardrop-tip.
Some more about holes one can learn from Makers Muse (Angus Daveson)
Reduce internal structure
I have seen prints fail for strange reasons. One of them was a piece taken from a straight up industrial design plan, then scaled down. This one resulted in too much tiny internal geometry, resulting in a lot of material and time wasted on printing these internal pieces that nobody could reach, that were fused together for the original gaps were already 0.2mm and less and besides that, there was the occasional print failure.
Removing any non-essential internal geometry lessens not only the printer's load, but speeds up the print, lessens the material waste and can prevent failures due to clogs or other unexpected behavior. If you can't fix it in design, there are workarounds, but try to need to avoid them!
Avoid Intersecting Shells
As we are at it, often game and graphic designers are lazy and use intersecting shells. These can become quite messy in the slicing step. If possible, try to avoid intersecting shells, even as modern slicers have learned to fix this by themselves by now. The results of that are not always pretty if you forget to flag the "Union intersecting shells" option in your slicer.
Sizing
We might not always be aware of it, but prints do shrink in the XY axis and to a different degree in the Z axis as they cool, during and after the print is done. This is what causes warping in the first place and lead to many lost prints (especially on non-heated beds). This behavior has to be taken into consideration especially when designing bores. My suggestion for this is twofold:

Intentionally design the hole to be too small and add extra wall material in slicing, then drill it up to the right diameter. Drill slowly to not melt the plastic.
Learn your shrinking parameter for the material and design with that shrinkage in mind, possibly iterating the print a few times. Note that different spools/colors of the same material might have different shrinking!

Minimum Wall Thickness
A 3D-printer can not reliably print walls that are thinner than the extrusion width of a printer. The choice of the correct nozzle for an extrusion width is a question upon itself..
Tapping/Screwing/Inserts
For tapping prints directly, you need wall thickness - according to the norms - you'll need usually about 0.2mm diameter that can be tapped into for the standard sizes. Using 3 perimeters with a 0.45 mm extrusion width will give walls of 1.2 mm, which I consider a rather strong wall, and provides quite some tolerance to drill up to size and then tapping screws into. You will get away with 2 perimeters for smaller thread sizes (M3 and lower), but for large ones (M10+), you will want a fourth or even fifth perimeter.
Remember though, that the printed PLA is not good for very strong threading: Tapping prints directly is pretty much only for low- and non-load-bearing connections. If you combine several pieces with screws, try to design the parts to make some sort of compression fit using a bolt and nut, or use several, small diameter screws with a fine thread. Avoid coarse thread if you can, stay on the small side.
If you need a load bearing connection with screws, the best strength comes from using a metal insert or provide a space for a nut to fit into. Metal inserts are usually placed by heat-setting them: put the heat-set insert onto a soldering iron tip and push it into the slightly under-sized hole, melting and molding the print to fit the insert, providing strong threads that are held really good in the shell of remolded plastic.
As a compromise, modern slicers allow to use modifier meshes, that could be used to increase the strength of modeled threads or holes that need to be tapped.
Do you want to know more? CNC Kitchen (Stefan) had made some tests on the strength of these connection type.
Print strength
Keep these general rules in mind when designing load-bearing parts:
Generally speaking, FDM prints are strongest in carrying along their Z-axis when withstanding compressive forces, as then the print layers of the shell are forced against each other. It also excels at fighting bending forces this way. But this orientation is also giving us the lowest tensile strength, as each layer boundary is a possible breaking point.
The XY-plane usually excels in tensile strength but sacrifices some of its ability to withstand compression (it is not proportional though).
Printing a part at a 45° angle will give often a great compromise of strengths, but might need an additional surface to get a good first layer - this surface can be sacrificial with the use of support.
For deeper information on the strength of parts and materials in comparison and how to manipulate it, there are large playlists of tests made by CNC Kitchen (Stefan) and Thomas Sanladerer (Tom)
Post processing
Post processing can be your best friend when printing, just as it can be your worst nightmare. I won't detail all methods of postprocessing, but some that are quite applicable.
Assembly/Gluing
Remember to design your parts with gaps for the glue when designing parts for assembly, and you might want to include guidance notches/noses to make sure the assembly aligns. This is especially needed as the parts shrink a little and have a rough surface.
If you need to assemble your part due to the available print volume, be sure to include ways to key the parts together. Pegs or outcroppings/indents (often called keys) that match up to one another make alignment on assembly much easier. It can be a good idea to design yourself a "cookie cutter" file that is applied after designing the part that automatically includes the glue gaps and keys.
There are a lot of glues and other methods to merge the parts. A more in-depth look at some of them is What glues for PLA? but you will have to keep in mind how you want to combine your pieces in the design step - and account for it.
Print in Place/PIP
In this vein, learn the tolerances your printer can manage to allow print-in-place(PIP), allowing functional parts that require no assembly. PIP is something that isn't possible with subtractive manufacturing usually, but remember that in 3D printing you might need to break the parts free after printing from bridges or sagging. Usually, a single strong turn suffices. To be able to do this, you might want to include a position for an Allen-key to manually turn the parts.
To learn how fine your tolerances are, there are many tolerance gauges/tests around. A rule of thumb for many printers is, that 1 nozzle width is often easily achievable with a good setup, 0.5 nozzles are achievable with some effort and 0.25 is somewhere close to the 'holy grail' - you might want to change the nozzle to a smaller one in case you want to have very thin gaps.
Composite construction
There are ways to turn your (mostly) hollow prints into much stiffer versions of themselves by turning them into composites, for example by using a resin or a different hardening fluid (like foam or plaster) as a filler or coating material.
When planning to do so, remember to include inlets/outlets for it and the air. It can be a good idea to design the part in such a way that it just contains the walls and a pre-planned support structure. In doing so, remember to disable infill in the slicer to enforce the flow you want in your structure. Look at how the ribs inside of an airframe are designed for general rules on hollow parts: include holes. This allows the flow of your fluid into each and every corner instead of blocking the flow. This can also reduce the needed number of inlets and outlets from one per chamber to one per part.
Plastic Properties
Remember we work with thermoplastics. Learn what kind of postprocessing your thermoplastic allows and its mechanical properties. Some examples:

APS can be vapor smoothed with acetone.
Many plastics can be annealed by baking at or little above their glass transition temperature, increasing strength and layer-to-layer bonding.
When using power tools on plastic, use ample cooling and time, as otherwise, one quickly melts the prints!

Surface Finish
The surface of FDM prints is somewhat rough. To smooth it out there are 2 general ways: fill it up or smooth it down. If you want to fill it up, design the part undersized, if you smooth it down, add sacrificial thickness. It is common to combine both, adding body filler first, then sanding down till the print material shows through again. If doing this, make sure to check your sizing.
If there comes a lacquer layer atop, remember to account for that thickness: undersize surfaces, oversize holes!

1 - this means, that thoughts about postprocessing that are not unique to 3D printing are not elaborated on here. Examples are painting, coating or smoothing the surface mechanically.

Further reading/viewing
Further information can be gotten from these playlists, though they aim at times for newbies:

CNC Kitchen (Stefan): 3D Printing for Engineers Playlist
CNC Kitchen (Stefan): 3D Printing Tips
Maker's Muse (Angus): 3D Printint 101
Maker's Muse (Angus): Advanced 3D Printing Tips
Maker's Muse (Angus): CAD for Newbies
Maker's Muse (Angus): CAD for 3D Printing


Why is CLIP so much faster than SLA? Stereolithography produces parts by projecting ultraviolet light on the top of a vat of liquid photopolymer, causing it to harden.  CLIP produces parts by projecting ultraviolet light through the bottom of a vat of liquid photopolymer, causing it to harden.  This seems like a minor difference, yet CLIP is reportedly much faster (I've seen numbers as high as 100x).  Why is this?

It's important to understand what specifically is being compared. CLIP is much faster than bottom-up technologies that require a peel step between every layer. For example, the Form1 galvo SLA printer tilts the resin vat to separate the transparent bottom from the print. That is, by far, the slowest part of SLA/DLP printing with most modern light sources. Where the speed comes in is that without a peel, a continuous "movie" can be used to cure the resin rather than a series of alternating images and peels.

Top-down printers can print dramatically faster than bottom-up-and-peel printers. CLIP is not necessarily faster than top-down. For example, the Gizmo 3D line of top-down printers are very similar in print speed to CLIP. (http://www.gizmo3dprinters.com.au/)

Most "consumer" SLA printers these days use bottom-up-and-peel techniques, because this has some practical advantages over top-down printers:

Way less resin is required to fill the printer when the part is pulled out as it builds rather than being lowered into the tank (along with the Z stage) as it builds. Resin is expensive. This also means bottom up printers can be smaller and have fewer mechanical parts such as leveling devices submerged in resin.
Standard resins contain an inhibitor chemical that prevents polymerization in the presence of oxygen, which causes the surface layer exposed to air (and low-level stray light) to not cure. So top-down printers must shoot light through a non-curing layer before reaching curable resin. This makes the tuning more sensitive and can somewhat reduce detail compared to a bottom-up printer curing right on the window.
Replacement vats or windows for bottom-up printers may be seen by manufacturers as a profit-generating consumable, since they have to be replaced somewhat frequently.
Top-down printers have to worry somewhat more about resin flow rates as the part is lowered. Air bubbles may be pulled into the resin or the fresh resin layer above the part may vary significantly in thickness if the part is submerged too fast for the resin viscosity. (Admittedly, bottom-up printers will experience excessive suction forces and potentially break off bits of the print at high peel speeds.)

CLIP is a bottom-up technique that doesn't require a peel step, because the vat creates an oxygen layer over the window that keeps the resin from curing directly on the surface and sticking. In that way, it arguably performs more like a top-down printer than a bottom-up printer.

Top-down printers that are designed to overcome the above issues and use high-intensity light sources can achieve exceptionally high print speeds. This includes similar "continuous" build techniques used as in CLIP.


How to activate Power Loss Recovery in Marlin? Standard Marlin has one problem: when the power suddenly is gone, the print is gone. Prusa and many china printers however come with "Power Loss Recovery" or "Power Out Protection" or similar. But especially China printers come without Thermal Runaway Protection, so in order to make the printer safe, one often has to get rid of TRP (in the basic shape it comes).

How can the PLR be turned on?

Marlin firmware has such a feature that can be enabled to resume printing after a power outage.
To enable power-loss recovery you should send
M413 S1

to the printer using a console (e.g. using Pronterface, OctoPrint, Repetier-host, etc.) or put commands in a text file with extension .g that can be printed from SD card. To disable power-loss recovery send/print:
M413 S0

To report the state of the power-loss recovery, send through a console:
M413

This will result in a returning message in the console of e.g. This Power-loss recovery ON.
To retain the setting, you can use M500 to store it in memory.

If you enable M413 in Marlin firmware, the printer will write a resume printing file to SD card e.g. every layer.
From M413 - Power-loss Recovery documentation I quote:

Enable or disable the Power-loss Recovery feature. When this feature is enabled, the state of the current print job (SD card only) will be saved to a file on the SD card. If the machine crashes or a power outage occurs, the firmware will present an option to Resume the interrupted print job. In Marlin 2.0 the POWER_LOSS_RECOVERY option must be enabled.
This feature operates without a power-loss detection circuit by writing to the recovery file periodically (e.g., once per layer), or if a POWER_LOSS_PIN is configured then it will write the recovery info only when a power-loss is detected. The latter option is preferred, since constant writing to the SD card can shorten its life, and the print will be resumed where it was interrupted rather than repeating the last layer. (Future implementations may allow use of the EEPROM or the on-board SD card.)

This means if you cut the power you can resume the print layer, the only problem is that the part must remain attached to the plate, if it comes loose it is hard to resume printing. This feature is now commonly found on printers these days.
The regular pause and resume functionality of the printer will not work when the power is cut over night, i.e. no recovery file is written in such a case.


Thermoelectric cooler for part cooling fan? Is there any research into use of thermoelectric cooler along with part cooling fan to get quicker cooling without strong air currents that apply pressure to the still-soft material? I experimented with custom fan ducts in the past trying to get better cooling and avoid warping for printing thin layers of PLA at high speeds, but found that the concentrated stream of air blowing on the part actually deformed it before it could cool. At the time I wondered if using significantly colder air, at a much lower flow, would work better. But every time I've searched for thermoelectric (peltier) coolers with 3D printing, I've found results that are about cooling motors or the heatbreak (especially inside heated enclosures), nothing about part cooling.
If there is no research on this and I want to experiment myself at some point, are there constraints I should consider for how to mount it (in my case on an Ender 3, but also in general)? Perhaps on a separate intake duct before the cooling fan? Or between the cooling fan and hotend assembly to let the waste heat dump into the assembly that the hotend fan is already cooling?

On the printhead?
TECs or Peltier Elements are incredibly inefficient compared to airstream coolers. Their only benefit is perfect temperature control, from which you will have nothing because there is no firmware that cares for the temperature of cooling air or the cooling body of a Hotend. Also, a TEC creates a lot of heat on its output side - which means you heat the air just millimeters away from where you want to cool the air!
To get the heat produced by the TEC away, you either need a rather large cooling body - which is a lot of weight and space you need. As a result, you reduce the maximum print speed a lot. A water cooler isn't necessarily that much lighter, but it also gets us the trouble of having a highly conductive liquid right on the printhead.
lighter alternative: compressed air
You'd have much better efficiency by having compressed air decompress (as in: get out of a slim nozzle) slowly just a few millimeters in front of the air intake of your part cooling fan - expanding air cools down a lot, and running a compressor for a few moments takes less energy than running a Peltier element with the same temperature drop. In a pinch, a CO2 canister could provide the needed high pressure air, and a nozzle like you have it on an airbrush would work.
Move it off the printhead?
As the weight of the necessary secondary equipment is an issue, it might be better to move the Peltier element off the printhead. For example, by using a flexible hose that supplies the air to the cooling fan, and feeding that with precooled air - and now a Peltier element can shine: by having the weight be no longer a matter, we can use a rather large cooling body on the outside and cooling fins on the inside.


Can I print jewelry without any loss of the precious metal? What is the 3D printing technology that allow to have minimal loss in precious metals when 3D printing jewels?

The jewelry industry typically uses printers that print in wax, and transform the models into precious metal by lost wax casting. Statasys offers wax printing in their Solidscape line, 3D systems offers ProJet. With this process there is basically no waste, since you can remelt the casting sprues.

I am not aware of printers that print directly in precious metal. It might technically be possible with DMLS but you have to fill up the entire machine with metal powder, which is cost prohibitive (and potentially more wasteful).


Layman term explanation of the difference between voxel and point cloud can anyone explain in the simplest terms please what is the difference between a point cloud and a voxel mesh?

A point cloud is often derived by sampling.  Each point represents an observation.  Sometimes, a point cloud is turned into a surface by fitting triangles to the points in the form of an STL file.

A raster is a 2D grid of pixels.  It divides the area of an image into constant-sized little squares.  Each of these squares has a value.

A 3D raster is made of voxels.  It divides 3-space into constant-sized little cubes.  Each of these cubes has a value.

Pixels and voxels are rendering techniques.  A point cloud is a sampling technique.

The Wikipedia article, https://en.wikipedia.org/wiki/Voxel, is helpful.

In a real system the pixels may not be square or the voxels not strictly cubic, but in every system I've worked with, they do form a regular tiling of the plane for pixels, and fill 3d space for voxels.


Marlin 1.0 works: Marlin 2.0 destroys Z-axis motion I have an FLSun 3D Cube, running off an MKS GEN V.1.4 main board. With Marlin 1.0, the Z-axis works great (and has been for three years). When I try to upgrade to Marlin 2.0, moving the Z-axis 10 mm results in extreme motion -50 mm at least, left motor then the right motor, three or four times, very fast. It's loud, it's jarring, and it's at the very least incorrect.
What setting am I missing?

I believe (from reference) the default steps per mm for the FLSUN 3D Cube are:
                                          X,   Y,    Z, E0
#define DEFAULT_AXIS_STEPS_PER_UNIT   { 100, 100,  400, 150 }

Default marlin 2.0.x are:
                                          X,   Y,    Z, E0
#define DEFAULT_AXIS_STEPS_PER_UNIT   {  80,  80, 4000, 500 }

Such a setting would explain the excessive speeds; while the printer only needs 400 steps for advancing a single millimeter, the stepper receives 4000, this implies a tenfold, hence larger displacement and higher speeds.


Options for getting a really flat build surface I've been fighting on and off with issues with my build plate seemingly not being perfectly flat. I've ordered a machined straight-edge and some new feeler gauges to diagnose the problem (and test any potential replacement) better, but I'd like to get an idea of what options are available for obtaining a flatter build surface. I'm not really interested in approaches like BLTouch since I want accurate flat bottoms on my prints, not just consistent adhesion.

My printer is an Ender 3 and I believe my problem is a mix of wear to the Buildtak clone surface and warping in its backing plate. Mine is the newer model with removable buildplate and clips, and the backing is reportedly a "glass fiber" (FR-4) material that's hard to find genuine replacements for.

Glass seems like an obvious option - I might even put a buildtak clone on one side of it and use that most of the time - but I'm somewhat concerned about weight and whether having glass moved by the Y axis is going to limit acceleration. I've had (seemingly unrelated) problems on and off with layer shifts, which seem to be mostly Marlin's fault not mechanical, but I'm scared to introduce another factor that might encourage them.

Are there other non-glass options I should consider that would provide a rigid, flat backing? I'm very happy with the buildtak clones and their adhesion properties, so my leaning it to look for something that makes a good backing for them rather than a material that's intended to be built directly upon.

Measurement results: Using a machined straightedge and feeler gauges, the surface seems to be at least 0.10 mm but less than 0.15 mm lower within a couple inches of the bed center. This is plausibly just wear on the buildtak-clone surface, so I think I'll try to see if I can get by with just replacing that for now. But I'm still interested in the general topic of the question.

It all depends on what you mean by "flat".

Is the problem that the build plate isn't flat (perfectly planar), or is the problem that the distance to the build plate varies based on X and Y coordinates?  They are very different problems.

"Bed Leveling" is the process of allowing the firmware to know the Z position of the build plate for every (X,Y) location.  Some printers support measuring a mesh of points and interpolating the mesh.  This compensates quite well both for warped build plate, and for bad positioning mechanisms which add some position dependent Z-axis offset.

If you really need a flat, planar, build surface, perhaps because you are printing mirrors or precision parts, glass should work well.  It is still, and will not brook any inelastic bending.  It will shatter before it takes on a curve.  If possible, you could consider a Pyrex® bed, since it has a lower coefficient of thermal expansion and won't warp as much with a temperature gradient through the glass.

I tried to find a spec on how flat your glass might be.  I'm assuming it is "float glass", which is made by floating molten glass on a pool of molten tin.  I didn't find a spec, but I found this answer to a similar question:

  I doubt you will find such a spec- float glass isn't manufactured for
  that purpose and it isn't really in the manufacturer's interests to
  maintain such a spec. that said, the stuff is surprisingly flat, just
  as a side effect of how it's made. you don't say what your needs are
  other than near optical tolerances . might just be good enough for
  you. consider though that granite surface plates of certified flatness
  can be had fairly inexpensively these days.

So, it is clearly flat.  I can't tell you how flat.  And the flatness depends on not applying stress to the glass that causes it to bed.  Thicker is stiffer (probably at the third power of the thickness ratio).


First layer of print comes out poorly even when placed on a raft (which prints fine) I'm printing PLA with the Creality Ender 2 and my print comes out totally fine with the exception of the first layer.

Here's the weird part though, if I place a raft or a brim below/around the print - the raft or brim will print perfectly cleanly. Even on a raft though, the very first layer of the actual print comes out ugly, as seen in the photo below, but the raft itself will be perfectly printed.

Following that first ugly layer of the actual print, the rest of the print will be 100% clean. This happens consistently every time I print any object.

The perfectly printed raft can be seen on the right and the ugly first layer that printed on top of that raft can be seen on the left. Be sure to click the image to see the details of what I mean.

Turns out it had to do with the nature of the small holes that I was printing. I had to slow the speed of the initial layer down from 25mm/s to 15mm/s and also set Cura to 'optimize wall printing order' so that it didn't jump back and forth between holes constantly.

I also sped up the travel speed to 50mm/s on the initial layer to minimize oozing (although I'm not sure this actually did anything). Print came out beautifully.

Didn't even need the raft.


Palette 2 with an Ender 3 Printer Has anyone had any luck with printing multi-colored prints with the Palette 2 on an Ender 3? If so, what is your steps/mm for the Ender 3 and your flow rate in whatever slicer you are using? I currently have my flow rate at 100 % and my steps/mm at 104.4, and I believe this is what is causing my Palette 2 to not produce accurate results.

About the Palette 2

Palette 2 is a separate device providing one multi color filament out of multiple single color filaments.

As the Ender 3 does not support multi-colour printing, that's why I'm using the Palette 2. It allows any printer to print in multi color as it adds multi color printing to single extruder printers.

On this thread, Does anyone tried Palette 2.0 on Creality Ender 3 or Ender 3 Pro?, there are a couple of useful links:

There is a video, albeit for the CR-101, but that should be of help: YouTube - Setup Guide: Creality CR-10 with Palette 2;
In addition, this Facebook group, Mosaic Palette, Palette+, Palette 2 (Pro) Users, apparently has some users who have paired their Ender 3 with the Palette 2.

However, with respect to your question about the flow rate and steps/mm, there isn't much info out there about that, and no one seems to have experienced similar issues, but your issue might have something to do with profiles - which, as you haven't mentioned them in your question, it is hard to know if that might be the issue or not.

In the same thread, this post, states:

  I use it with the Ender 3.  There is a profile in Canvas and Chroma for it also.

This link here, Chroma for Palette 2, states that after using Cura, you then need to load the G-code file into Chroma v3.1, after having selected the appropriate profile. However, if you use Canvas, then there is no need for Cura nor Chroma, as Canvas can slice. This link goes through the whole process for Benchy.

At the risk of repetition, the process for preparing the print, post-slicing, is also given here, from Multicolor 3D Printing How To: Using the Mosaic Palette+ with the Creality Ender 3, albeit slightly different from the link above:

  Setting Up Chroma:

  When you load up Chroma, you’ll be presented with a blank canvas ready
  to be filled with your 3D creations.  In the top left corner, make
  sure that you have the Ender 3 selected from the drop down menu.
  After this you can click Load Print.  From there you’ll be presented
  with your gcode files that you have on your computer.

  In this example we will be selecting the butterfly-1.gcode file, and
  clicking Open.  From here Chroma will be compiling and arranging the
  settings for the gcode file to be displayed.  This might take a minute
  or more.

  Selecting Your Colors:

  Once the loading is completed, you will be presented with the 3D
  rendering of our butterfly!  This butterfly will be in 4 randomly
  selected colors by default, but we will be changing this next!  To
  change the colors, navigate to the top of the screen where you will
  see 4 colored circles, and drop down arrows along with each circle.
  These circles represent the colors of each tool head.

  To change the color, click on the Tool Head Colored Circle, and your
  options for color will appear, we’re going to select Black for our
  first color.  After this, you will want to select the Default PLA
  Settings by clicking the Drop Down Arrow to the right of the first
  Tool Head Colored Circle.

  As we make these changes you will notice that the 3D rendering of our
  butterfly will change to our corresponding colors.  Repeat this
  process for the remaining 3 Tool Heads, remember to use the Default
  PLA Settings for each Tool Head.

  Saving Your Project:

  After you have selected all your colors, you will click Save for
  Printer in the top right corner of Chroma.  From there, name your
  file, and click Save.  You will be then presented with a loading bar
  as Chroma prepares our 2 output files.  One of the files will be an
  adjusted gcode file that has added the purge tower we just modified,
  and the other file will be a file that goes straight to the Mosaic
  Palette+.

  Printing Your Project:

  Once the files are ready, you will be presented with a screen that
  says “Ready to Print!”.  On this screen you will be presented with the
  files you have created for your project, which for us are the
  butterfly-1.msf which goes to the Mosaic Palette+ and the
  butterfly-1.msf.gcode file which is your newly created gcode file.
  You will also be presented with “Materials Used” for the project,
  “Number of Splices” for the project, and “Number of Pings” for the
  project.

  After this, you will need to turn your Creality Ender 3 on if it isn’t
  already.  After making sure that you have all your components set up
  and assembled correctly, then it is safe to begin the printing
  process.

  Depending on your specific project will determine how long the
  printing process takes.  But once your printing process is complete
  you will be presented with your beautiful multicolored 3D butterfly
  (or whatever your project was)!  After printing is finished, you
  should let the project cool before you attempt to remove it from the
  tray. Once it has cooled you can now gently pry the project off of the
  tray.

Footnotes

1 The CR-10 is, on a broader level, an Ender-3 with 2 lead screws and a slightly different board.


Could you use ultrasonic vibrations instead of a roller with an SLS/SLM printer? I've been thinking, SLS/SLM printers currently use a roller to spread 3d printing substrate, but wouldn't ultrasonic vibrations spread the substrate more cleanly, accurately, and with greater density than a roller?

No
The problem is twofold. Resonance and Granular convection
Resonance
Let's start with an empty box. We toss in some powder to create the first layer and use an ultrasonic to create a first layer. What happens? The bed starts to resonate depending on the sound you send into it in patterns - and the powder starts to form valleys and ridges along them as one can see in this video.
Granular Convection
What happens if one shakes a box of fine granulate that contains larger items? Granular convection happens! All items raise simultaneously and the small items start to fall first, resulting in them getting under the larger ones, so as a result end up pushing the large items up.
Because of both effects, there won't be an even layer and it would raise the items printed, even if we managed to get good layers.


Optimum ratio of line width to layer thickness for overhang performance? When I have overhangs in my model, Cura colors them red. However, I noticed if I make layer thickness thinner, the red area is reduced or disappears.

This could mean that thinner layer thickness is better for overhang, but it could also mean that a larger ratio of line width to layer thickness is better. It makes sense that if line width is 4X the layer thickness (such as 0.15 layers with 0.6 line width), overhang performance should be better than if line width is only 2X (such as 0.3 layers with the same 0.6 line width.

Is there a model that explains the optimum ratio of line thickness to layer height? Is only the ratio important, or is layer height also important by itself?

Cura high-lights overhangs in red if the printer would end up printing completely into thin air.

If your overhang is angled instead of being a purely vertical-to-horizontal transition, a much thinner layer height can increase the chances that enough of the prior layer exists to support the next layer being printed.

Basically, the thinner the layer (within reason), the greater the allowable angle of overhang that is safe to print.


After 1.5 hours of printing quality degraded Testing my new Wanhao i3+. PLA plastic(Wanhao), basic normal quality settings in Cura (I guess 0.1 mm layer, 40 mm/s speed, 60c bed temp, 200c extruder temp). After 1.5 hours of printing quality degraded, it makes some loose structure.

Edit:
After finish I noticed that problem exists only in layers where it cycles printing/no printing. There is no problem on layers where it print continuously.

What is the reason can be and how can I fix that?

This is very likely under extrusion caused by your feeder pressing down too hard onto the filament. If the feeder presses the filament very hard it then gets squished a bit, this is not causing much issues when you're only feeding in one direction as the drive gear is still pulling on fresh filament and shoving the squished part down at a steady rate. BUT once you got retractions things get awful as the squished filament then gets retracted and fed again at the same pace but due to the elongation at a smaller rate of material causing underextrusion.

You can either trade it in to some overextrusion by adjusting the extra length on restart setting, retract a shorter piece of filament (like only retract half a mm or something) or loosen the feeder so it doesn't squish down on the filament as hard.


Loss of extrusion in Stratasys FDM liquefier I am running a Stratasys Dimension 768 SST, with a "rebuilt" extruder (dual setup includes support + model). This extruder, basically, follows the OEM design with exception to the tubing diameter (few mils smaller for rebuilt, although there is a generous inlet taper and/or bushing, larger than the filament diameter feed stock) and the way the tubing has thermal contact with extruder body and cartridge heaters. The OEM design, apparently, had some thermal epoxy to "bed" the 2 nozzle tubes, which are brazed into the nozzle tip block. The approach, I am using, is Al foil packing around the SS tubes, tight to the Al extruder body (still brazed connection to the nozzle tip block). I had no choice but to recondition the extruder, because of a breached nozzle tube. In any case, with a cleared out nozzle inlet to start each time, I do get transient extrusion at standard temperatures of 250 (support) and 280 (model ABS), and in an adjusted temperature range, with some preliminary experiments. I clear out the nozzle inlet with a metal pin, down to the tube bend (I don't get why the design had this problematic 90 deg bend radius close to the cold end, feed wheel!) For the support, the extrusion goes for about 5 secs, then slows down, and the support filament feed stock stalls and strips out the filament, turning it into white debris.  For the model, the extrusion goes longer for about 20 secs, and also slows down, and, in this case, the model feed stock splits and gets fed outside the nozzle tube inlet, but no white debris in this case. This cycle may be repeated by cleaning out the inlet clogging with the stiff metal pin.

I realize this is not a perfect description of the system, but I am hoping that someone who knows this extruder configuration or a similar one (system is quite old, unfortunately), may chime in here with suggestions. I will add, that I am running the system in a so-called maintenance mode and have some minimal adjustment of the firmware (like the hot end temperatures - defaults mentioned before) for the build mode (which is only during actual part run).

Thanks in advance for your help or suggestions!

Here are some diagrams/link to descriptions for the extruder as well:

My exact extruder (i.e., head) system:
http://www.amtekcompany.com/pdf/dimension_bst_sst_elite_768_head_clog_guide.pdf

A similar extruder (showing heaters, extruder body to isolate model & support paths, tips, and thermocouples)
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwifyLnJsu7OAhVIOCYKHaSIDLQQjRwIBw&url=http%3A%2F%2Fwww.3dprintforums.com%2Fshowthread.php%3Ft%3D2237&psig=AFQjCNGM1BTAiWzUn4fNJ8-z5HDWxa6OEQ&ust=1472824417165187

This site shows another user take apart/redesign the extruder in question (pay attention to the 90 deg bend in the nozzle tubes)
(see attached picture)

I also have a few documents: user manual, service manual, etc. that I may share, if I knew how to upload to this website.

This isn't a "turn this knob and all will be well" answer, because your machine setup sounds pretty unique to what most people will have experience with. Not being familiar with the older Stratasys printheads, but based on my overall experience with 3D printers, there are three things that could be an issue:

The nozzles are obstructed. The way you talk about clearing the jams of pushing a tool up through the nozzle end would not effectively clear a jam, it would only push the debris back into the print head, just waiting to be pushed by the plastic back into the nozzle. It could even be a piece of aluminum foil from the rebuild process. The typical way jams like this are cleared is to do a "cold pull" where you heat up the hot end just enough to be able to pull the plastic out, before it has really had a chance to liquify, hopefully trapping the debris in the plastic, then cut the end of the plastic off and reload. The 90 degree bend in their design may make this very hard if not impossible to do.
Heat creep. The tubes are a slightly smaller diameter, and if heat is creeping up the print head and letting the filament expand in these tubes, it may be expanding enough that it will no longer move through the print head. Diagnose this by letting the printer jam, then cool off for a few hours. If you can print again for a short time period before it jams again, this may be your issue, where as an obstructed nozzle would not allow any more filament out. Either turn down your temps, or increase your cooling on the print head to address (or get the original size tubes if possible).
Print head temperatures too low for the print speed. The Stratasys Fortus 250mc I use runs ABS at about 300 degrees. Many of the reprap printers run even higher than this for ABS. The other thing to remember when ever you see people mention what temperatures they use, is that this is relative, and only a guide, as what the temperature reads at the thermocouple or thermistor is usually slightly off from the temperature that is melting the plastic based on heater location in relation to the plastic and thermistor. This can be diagnosed by printing until it jams, pause the print for something like 30 seconds to let the hot end melt more plastic, and then resume printing. If resumes proper printing this may be your issue (and it will jam again shortly if you do not adjust temps).


Is there an easy way to add rounded edges to semicircle in OpenSCAD? I've put together a flashlight mount for a camera coldshoe in OpenSCAD.  I originally modeled it in FreeCAD and it was easy to round the edges of the clamp with a fillet and that makes it a little easier to get the light in and out of the mount.
I'm not sure how to do it in OpenSCAD.  Naively, I'm sure I could calculate where on my semicircle I would need to add some cylinders in order to round the sharp corners, but it seems like there'd be something a little easier than that.
Am I missing something?
Here's the coldshoe light mount SCAD file and this is what it looks like:

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


Will there be any negative effects on the print process if the printer is outside? If I buy a printer, it will be going on a small table on a front porch so as to keep the smell from the house. The porch has a roof, so precipitation is not a concern. I will find a way to keep the wind out, so that will also not be a factor. The only concern I can see is the lack of climate control. The printer will probably be an Ender 3 Pro. Will this turn out bad for the prints? Do I need to be concerned about dew? Any other concerns? Solutions?

Unless you enclose the printer fully in some way or another, I see problems, even beyond just print quality:

humidity can and will end inside the printer by condensation and destroy the electronics, especially in the fall and winter months.
being accessible, children from the neighborhood might get their stubby fingers into the running machine or throw off the leveling.
being not locked in a box, people might decide to nick your printer.
If the printer is in the sun, the filament might age much more rapidly
Moisture can impact your filaments, making prints impossible with some filaments unless those are kept in a dry container.
Shifting temperatures along a day could lead to prints warping during printing, resulting in deformed prints.


How to connect a Geeetech Prusa I3 Pro B to Repetier-Host on mac My y-axis is running in reverse and slamming into the front of the machine. This is not ideal for my needs.

I need to connect to it with the Repetier-Host software to fix this, and in general. This connects fine via USB, but then says Unknown printer firmw... Waiting for temperature. Sending further commands does nothing as far as I can see.

Does anyone know what I need to install to get this working?

This is not a direct answer to your question, but a solution for your problem.

If a motor is running in reverse, there are at least 2 solutions. You can reverse the connector of the leads to the stepper, or flash new firmware where you reverse the stepper in the configuration file.

The most effective and fast solution is to reverse the connector of rearrange the wires in the connector.