FlashErase
Posts: 17
Joined: Thu Mar 03, 2016 1:31 am

Slicer error: Wrong retraction reversion when changing the extruder

Sun Sep 01, 2019 12:57 pm

Printing a jar opener I found an error in the slicer of Simplyfy3D 4.1.2. causing the abandon of the print.
I'm using a FlashForge Dreamer printer with dual head and heatbed.
I print the handle and support out of PETG with the left extruder. The flexible insets are printed out of TPE with the right extruder.
The first three processes in the attached factory file are using the left extruder only for printing the handle and the support. The fourth process prints the insets with the left extruder and the support with the right extruder.
Till line 5140 the handle with the left extruder is printed out of PETG. OK
Starting with the prime pillar for the right extruder from line 5141 now the insets are printed out of TPE till line 7767. OK
But now the problems start: beginning with line 7768 now a new small area of support ist printed out of PETG with the left extruder. But without using the prime pillar before and without reverting the previous retract of the filament in this extruder at the end of the supports print. So the first part of the support lines are missing. Unfortunately the filament will not be retracted after the last support line 8117 with the left extruder.
Beginning with line 8118 on the next layer now a new prime pillar for the right extruder and the insets are printed with the right extruder and TPE till line 10744. OK
With the change back to the left extruder at line 10745 it comes to the crash. The printer tries to revert the retraction which was done after the end of the big supports print. Beause the filament already reached the nozzles end during the print of the small support it is smashed hard into the tube causing a rasping noise and bulging the filament above the PTFE tube. Now the extruder is permanently clogged, the print process must be abandoned and the filament removed out of the extruder with a pliers.

After changing the extruder for the support in the fourth process from left to right the print runs successful because now the PETG is retracted correct. But now a part of the support is printed out of TPE what is not wished.
Attachments
20190901_184705.jpg
bulged filament
Jar_Opener.gcode.7z
(2.3 MiB) Downloaded 11 times
Jar_Opener.factory
(1.23 MiB) Downloaded 10 times

S3D-Alex
Posts: 286
Joined: Thu Aug 30, 2018 1:23 pm

Re: Slicer error: Wrong retraction reversion when changing the extruder

Tue Sep 03, 2019 12:18 pm

Thank you for posting the files! I took a look at your Factory File and resulting gcode and I believe I understand what is occurring here.

So basically you are currently wanting three toolchanges during this layer. The part and support for the first process, then the TPE section for the second process and then a third toolchange to complete the Supports that are actually part of the 4th process here. This is not something that is currently possible in Simplify3D.

For this situation I would suggest turning Supports off in every Process except the Insets Process. This will create Supports without the need for multiple toolchanges per layer.

FlashErase
Posts: 17
Joined: Thu Mar 03, 2016 1:31 am

Re: Slicer error: Wrong retraction reversion when changing the extruder

Tue Sep 03, 2019 1:36 pm

Hi S3D-Alex,
thanks for your response and your hint. But this would mean to print the whole support with the expensive TPE and to dump it than. But your information, that multiple tool changes per layer are not supported by S3D is useful.
Finally I printed the part as described. The most part of the support is printed with the left extruder out of PETG. The problematic small part of the support is printed now with the right extruder out of TPE to avoid the second toolchange in this layer.
Attachments
20190903_192851.jpg
support.jpg

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