3D Printers @ IAI
We currently (as of 2018) have two Ultimaker printers(2 and 2 extended) and a Prusa i3 MK3.
For slicing, we use the Cura Software (free download), as recommended by the manufacturer. Another commercial slicing software that looks interesting is Simplify3D. (150EUR/license)
For the Prusa i3 MK3, it's recommended to use Slic3r. The right version of Slic3r can be downloaded from the Prusa Website. It comes with all necessary settings so you don’t have to set up anything.
If you want to print an object, please contact Alexis or Patrick.
Ultimaker 2
Single extruder Fused Deposition Modeling (FDM). Print Volume: 223 x 223 x 205 mm
Installed updates:
Original 0.4mm copper extruder (replacing the Matchless that broke at the end of 2018). Also fresh PTFE isolator.
3dSolex 35W block heater
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3dSolex pt100 temperature sensor (the original one broke while taking it out of the original block)
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Firmware: TinkerGnome V17.10.1
Current of E Axis motor was decreased to 1000mA (per instructions for new extruder)
Last good z-offset to buildplate: 19.15mm (with this height the first layer is 0.3mm +-0.02 and the feeder does not miss steps while extruding the first layer, close to perfect). This height will change if the extruder tip is changed or the springs under the heated bed are adjusted.
Ultimaker 2 Extended
Single extruder Fused Deposition Modeling (FDM) printer. Print Volume: 223 x 223 x 305 mm
Installed updates:
Olsson block: The original Olsson block for 2.85mm diameter filament (same one as in the UM2+)
Extruder: 0.4mm brass extruder. Exchangeable for other sizes.
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block heather: Original 25W heater. (A new 3dSolex 35W block heater could be installed).
3dSolex pt100 temperature sensor (the original one broke while taking it out of the original block)
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Firmware: TinkerGnome V17.10.1
Current of E Axis motor was decreased to 1000mA as recommended by the Bondtech upgrade kit.
Fix: The Printer reported often an error on the temperature sensor of the heatbed. The cable connector on the heatbed was not soldered properly from the factory, making the pins have an intermittent connection. Alexis soldered them again and it got rid of the errors.
Door: official transparent front door.
Last good z-offset to buildplate: 16.98mm (with this height the first layer is 0.3mm +-0.02 and the feeder does not miss steps while extruding the first layer, close to perfect). This height will change if the extruder tip is changed or the springs under the heated bed are adjusted.
Prusa i3 MK3
Single extruder Fused Deposition Modeling (FDM) printer. Print Volume: 11.025 cm3 (250mm x 210mm x 210mm)
The printer has received only received one upgrade so far, which is a filament guide: https://www.thingiverse.com/thing:2986472
This helps with springy filament jumping off the spool while printing.
If you carry the printer around, execute „Calibrate Z“. The bed calibration is done every time before printing, so it isn’t necessary to do this manually.
You can print (amongst others) PLA and PETG well with this printer. Using PETG might be interesting to print transparent or more flexible objects, but it suffers a bit from stringing while printing.
If your print stops and the displays says something like „Unloading filament“, it might be that your filament sensor (falsely) detected that you ran out of filament. This especially happened with shiny filament like PETG or transparent PETG. If that happens, turn off the filament sensor in the settings and continue.
Info on components
MK8 drive gear
After calibrating the steps per mm for the E(xtruder) axis, the following value was found: 316.23. The original value with the knurled drive gear was 282.00.
Triffid Hunter's guide was followed for calibration, specifically the section called “E Steps Fine Tuning”. Basically tuning extrusion slowly until the internal layers printed with 95% linear fill have small gaps, while the top layers are perfectly closed.
Firmware for the Ultimakers
Both printers have the TinkerGnome Marlin firmware, from the geek branch, specifically version Tinker V17.10.1 from the release page.
This firmware has many more adjustments and allows for on-the-fly changes to parameters during a print.
Adjustment of feeder spring
Adjust the feeder spring hard enough, but not too hard. The idea is that the filament can be pushed strongly, but that the motor skips back just before stripping the filament. That way, if it is trying to push too much, it will lose some steps, but it will quickly recover the pressure. If that does not happen and the filament gets ground, then it stops extruding altogether, failing the print.
There is an interplay between spring force and current of the E-Axis. Increase current for more motor torque, but that forces to increase the feeder spring force to avoid stripping. At some point the spring force gets too high, and that again makes it more likely to strip the filament. The sweet spot is in the middle, and might even change with a different type of filament.
Typically the extruder motor should try to extrude as much plastic as is needed, so there should not be any skipping. This is not the case with the first layer, that gets over-extruded on purpose to 'push' the material hard onto the glass. So on the first layer some skipping is expected, depending on how close the bed was calibrated to the printing head.
The first layer is set to 0.3mm typically by cura, but depending on the bed calibration, that distance might only be 0.2mm or 0.1mm, so a lot of over extrusion is expected.
Settings for the materials
After each material has been tuned to print correctly, we record the settings that work in this section.
The material on top for each printer should be the one currently installed and ready to use.
Ultimaker 2
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Diameter: 2.85mm
Color: Grey
Temperature: 240 C
Bed temperature: 60 C
Bed adhesion: glue or clean glass
Extruder size: 0.4mm
Approx cost: 24EUR for 750g (90m)
top/bottom thickness: 0.8mm
layer size: 0.1mm
print speed: 60mm/s
travel speed: 120mm/s
fan speed: 50% (set in printer)
retraction length: 6mm (set in printer)
retraction speed: 25mm/s (set in printer)
Ultimaker 2-Extended
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Diameter: 2.85mm
Color: Orange
Temperature: 220 C
Bed temperature: 60 C
Bed adhesion: clean glass
Extruder size: 0.4mm
Approx cost: 30EUR for 750g (90m)
top/bottom thickness: 0.8mm
layer size: 0.1mm
print speed: 60mm/s
travel speed: 120mm/s
fan speed: 25% (at 50% it underextrudes a bit) (set in printer)
retraction length: 6mm (set in printer)
retraction speed: 25mm/s (set in printer)
colorFabb has a list of lengths of their spools here
Prusa i3 MK3
General tips/advice for materials
When your heatbed adhesion is too low with PLA, try to clean the heatbed with Isoprop Alcohol.
When you print PETG it’s advised to NOT clean the heatbed with Alcohol, as this might increase adhesion too much. PETG does stick very well to the heatbed. Important: It is recommended to use some window cleaner to clean the surface which is good enough for cleaning the heatbed while keeping the adhesion low enough. This was noted in the manual for the Prusa.
To get a more transparent print when using transparent PETG, you can try to increase the extrusion rate by 5-10%. This will fuse the material a bit more tightly together, reducing the amount of little gaps that might hinder the light to shine through your print easily.
Material wishlist
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PLA/PHA from ColorFabb. Tested and very good PLA
XT-CF20 from ColorFabb. Very very strong material with carbon fibers (abbrasive, only use on stainless steel extruder tip, not on the normal brass one).
Equipment wishlist