Test 3 with Iglidur i150-PF filament

This is the third test of a series with the filament of Igus: Iglidur i150-PF. https://www.igus.eu/product/12404.
I used the following hardware:

• steel sheet (a steel sheet without coating).
• enclosed printer with ventilation control with an ambient temperature of 22C.
• 0.6mm nozzle
• Note that I always store the igus filament in a drybox (with filament buffer inside the drybox, see https://www.prusaprinters.org/prints/39795-mmu2-filament-buffer-and-spool-within-an-ikea-dryb) So even during printing it is in the drybox.

Changes made to test 1 are:

• I did a cold pull with PLA to clean the nozzle (was clean)
• 3 layers of glue with drying in between on one heated bed.
• Lowered the extrusion temperature for the first layer to 240C and for the other layers to 230C.
• Enabled the cooling to a fan speed of 20% (first 4 layers off).
• Retraction Length changed to 1 mm (was 0.6)
• Minimum travel after retraction: changed to 1 mm.

My observations are these:

• Beginning of the first layer does not stick to the bed. (see picture). This can result in a clash with the nozzle, causing a complete ripped off first layer.
• Reduced warping upwards of the sharp gear tips (at the beginning and the end). (increase cooling fan speed?)
• String on the filament tip after unloading (more than test 2)
• Still small holes in the draft shield (why?)
• More stringing between the gears at the top, where the minimum travel between the gears is lowest (reduce the parameter 'Minimum travel after retraction' to zero ?).
• Print sticks good to the print bed and was easy to remove (better than test 2)
• some small blobs on the nozzle during the first layer

This is the reply from Igus (thanks Niklas):

Hi Bas,

thank you for making the effort of fine-tuning your profile and sharing with the community.

• to reduce the amount of stringing, you could further increase the retraction setting (try 1,5 mm).
• to combat the holes at the beginning of lines, you might play around with the "extra length on restart" setting for Retraction. I suppose that, in combination with the oozing and stringing, there might be some material missing at the start of a line.
• While you have kept the material dry at all times, I would still like to see if drying makes a difference - it always does in my experience. There is no 100 % control over moisture in the filament, even with new material.
• how far is print speed decreased for these small islands where the gear teeth run out (top of the print)? There is a very small amount of material deposited which might be difficult to control at higher speeds, so lowering the speed for small sections might help - too slow however, and these small sections will melt and lose form.
Best regards, Niklas

Mit freundlichen Grüßen / Best Regards

Niklas Eutebach M. Eng.
Entwicklungsingenieur Additive Fertigung
Development Engineer Additive Manufacturing
igus® GmbH