Igus I180 material blobbing

General Discussion
1

Basic Information:

Printer Model: Custom CoreXY
MCU / Printerboard: Manta M8P with CM4010000
klippy.zip (3.3 MB)

This is a bit of an atypical question but maybe somebody here has some ideas about what I can try about reducing blobbing on a print using Igus I180 filament for a structural part with an integrated optical rod bearing (I180 has solid lubricants built in and is sold as having good wear resistance against moving parts):

https://www.igus.com/product/700?artNr=I180-PF-0300-0750

In the images below, the white material on the right is I180 and the grey is basic ABS, both done on the same printer with basically the same printing parameters but the I180 produces a fair amount of blobs whereas the ABS has virtually none.

image

image

In trying to get the best possible prints, I altered the following parameters:

  • Nozzle Temperature
  • Bed Temperature
  • Infill
  • Layer Height
  • Retraction
  • Extrusion Factor
  • Print Speed
  • Coasting (Specified in Cura)
  • Pressure Advance (Klipper Feature)
    The only thing I didn’t try (because I don’t currently have the capability) is a heated chamber but I don’t feel like that would contribute to the blobs. The blobs were quite constant throughout the tests except when I reduced printing speed by 50% and they became considerably larger.

I started with the parameters set out in: https://www.igus.com/ContentData/Products/Downloads/iglidur_I180-PF_Printinginstructions_FDM_en.pdf and tweaked them looking for the best quality result.
I used Cura 5.3.1 for slicing and this .stl:
Front_Gantry_Frame_0_04_Bearing.stl (215.0 KB)

For the I180 piece above, I’m running with:

  • 255C nozzle and 100C bed temperatures
  • 60% infill
  • 0.08mm layer height (I found that there was layer separate at larger layer height values)
  • Retraction 0.25mm
  • Extrusion Factor 80%
  • Print Speed, 20mm/s bottom layer, 50mm/s for all others
  • Adhesion: Elmer’s glue stick on PEI (I tried 3DLAC on a glass plate and Elmer’s on PEI sticks just as well and is easy to clean up with Isopropanol)
  • No part cooling
  • No coasting
  • Pressure Advance as setup according to the Klipper instructions for I180

For the ABS piece, I’m running with:

  • 230C nozzle and 100C bed temperature
  • 60% infill
  • 0.08mm layer height (normally I’d run 0.2mm, but I wanted to make it the same as the I180 test)
  • Retraction 0.5mm
  • Extrusion Factor 80%
  • Print Speed, 20mm/s bottom layer, 50mm/s for all others
  • Adhesion: PEI
  • No part cooling
  • No coasting
  • Pressure Advance as setup according to the Klipper instructions for ABS

The I180 doesn’t feel as rigid as the ABS but it seems to be adequately strong and dimensional accuracy is good. Other than the blobs, the only issue I had with printing was layer separation when layer height was 0.2mm and I brought it down as this reduced layer separate to basically nothing.

The blobs come off with a fingernail so they really aren’t an issue, I’d just like to understand how to print without them.

Any ideas what I can do to eliminate these blobs?

2

I suffered lately from big blobs on PET-CF and the vendor told me to enable coasting.

1 Like
3

I tried that (enabled it in Cura) and no difference.

Thanx for the suggestion!

4

Never used the material, but some pointers:

  • Make sure the filament is not wet. Many are incredibly hygroscopic. Dry it to be on the safe side
  • Start from ground up: Disable all bells and whistles (hops, wipes, coasting etc.) and go from there:
    • Determine temperature, e.g. with temp tower
    • Determine extrusion factor
    • Determine PA
    • Print a stringing test to determine minimum retraction
  • Don’t use Cura 5.3. It is known to do stupid things
  • Try playing with the “Wall Ordering”
5

Thanx for the reply.

In terms of your points, I did the first two - put the filament in a dryer for 48 hours at 70C and did the basic characterization. I would have thought that a stringing test would have brought out something with this, but it doesn’t - the towers look nice.

In terms of Cura, that’s why I am comparing to ABS with the same configuration, with the exception of temperatures. I’ve heard about Cura problems but I’ve never experienced any.

I’ll look at “Wall Ordering”.

Thanx!

6

Just ran the test with “Wall Ordering” reversed (from the default Inside to Outside to Outside to Inside) and here are the results (the new print is on the left):

image
image1920Ă—1095 199 KB

The blob positioning seems to change slightly but it’s still there.

It’s been suggested to me to try printing with a lower nozzle temperature (I’m going 10C down), more retraction (from 0.25mm to 0.50mm) and adding some fan (25% starting at 2mm to minimize the chance for loosing adherence - although I suspect it will be a problem).

Thanx for your ideas!

7

That reminds me to a seam position…