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I am wondering if anyone can help me achieve a good 3d print using polypropylene. I am trying to print custom insoles for shoes and I'm getting some bad warping/lifting (see image).

example of warping using polypropylene

Some details about the print and process:

  • I have a Prusa i3 Mk2S with a Flexion extruder
  • I am using what I believe is a good quality filament (Verbatim PP): https://www.verbatim.com.au/3d-printing/pp-filament/3d-pp-filament.html
  • I am coating my hotbead with clear packaging adhesive (OPP tape) as per the manufacturers instructions. This appears to help quite a bit.
  • Bed heated to 75 degrees. I tried 100 but got hit with the "Heatbed Thermal Runaway" error which I believe indicates that not enough voltage is getting to the bed heater.
  • I've tried printing at 220 degrees and 170 degrees.
  • I've tried enclosing the printer in a makeshift enclosure to reduce the speed that the material is cooling at.
  • Other settings: speed 40mm/s constant, 0.2mm layer height, 20% infill, 3 top bottom and side layers.

The print takes about 5 hours and seems to stay down for an hour or two before starting to warp.

Does anyone have any suggestions of things I should try?

Trish
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Stephen Archer
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  • There is a good answer to the similar question that explains a lot: https://3dprinting.stackexchange.com/questions/938/what-are-the-ideal-print-conditions-for-polypropylene – Mikhail Z Aug 30 '17 at 20:11

3 Answers3

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You should enable the "brim" functionality of your slicer. This adds additional perimeters to the first layer, expanding the base of the model. The larger surface area gives more adhesion.

Tom van der Zanden
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  • Thanks Tom, unfortunately this didn't really help for me. I have used a brim for ABS in the past and it has worked well but it wasn't helpful for PP. – Stephen Archer Aug 30 '17 at 07:06
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Try heating your enclosure to 50C, as well as adding a brim.

Davo
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  • Thanks Davo, I don't have a proper enclosure and the makeshift one that I made enclosed the circuit board as well... I'm a bit worried about the circuit board and components being at 50C. Do you think this might cause a problem? – Stephen Archer Aug 30 '17 at 07:09
  • I can't speak for your equipment. My equipment is rated to run at 55C with no issues. See what the manufacturer says. – Davo Aug 30 '17 at 11:05
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One thing that seemed to help is making sure the heated bed was 100C. I was able to do this on my Prusa by turning off the front fan (for the whole print). If I have both the fan on and the heated bed at 100C I get the "Heatbed Thermal Runaway" error.

This produced a print that was better but still a bit warped.

Stephen Archer
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