IDEX Toolchange Deretraction
Hi all, I am trying to do a multi material print with my vcore4 in IDEX, T0 = PETG @ 260C and T1 = PA6 w/ carbon fiber @ 285C. I quickly discovered that T0 will not properly extrude after resuming printing following a tool change. The extruder makes clicking sounds and doesn't extrude for maybe 5 seconds before resuming normal extrusion. T1 doesn't do this after resuming, I'm guessing because the carbon PA6 is less sensitive to heat creep.
I initially tried various wipe tower settings with mixed results but that doesn't address the root cause of the extrusion issue. I also tried lowering the T0 temp from 260C all the way to 230C and the issue was still present.
After some research it seems that this is due to heat creep and can be addressed with a ~20mm retraction before the tool head is parked. I changed the default IDEX macro settings in printer.cfg for retraction/deretraction to 20mm, but it did not fix the problem due to the tool change deretraction happening immediately after the tool head is parked, rather than immediately before resuming printing as expected.
As a workaround I'm thinking I could set the IDEX retraction to 20, deretraction to 0 and then add custom gcode to deretract in Prusa Slicer every time T0 resumes printing.
Has anyone else encountered this issue with IDEX tool changes? Appreciate any help!
27 Replies
I have no idea the answer but am curious what others have to responsd and what the answer turns out to be. Are you able to print PA6 on T1 if you aren't doing IDEX changes?
Yes PA6 is printing fine, the issue is actually only with T0 and the PETG.
Okay, same question but PETG and T0. Are you able to print like that without tool changes?
Yes no issues, first layer is always fine in IDEX and prints fine in non IDEX or copy mode. Only happens after tool changes
Also I should note that I am trying to print a large part and the tool heads are parked for probably 30 seconds at a time
Maybe a test print that swaps faster? Just throwing out ideas to help narrow down
Yes I've thought about a smaller scale print to confirm it is a heat creep issue, just seems like the retracting the filament out of the hot end at the beginning of the tool change and deretracting when resuming is the obvious solution. There are a lot of tool change settings in Prusa Slicer that I have tried manipulating but it appears ratos overrides most/all of the slicer toolchange gcode in post processing
On the macros section there is macro called ToolShift. I don’t recall if you can change the retract/retraction for individual tool heads or if it is a single setting for both.
But you can add a purge after being parked for a specified length of time. It will purge both tool heads the same before their turn to print.
And you are correct, RatOS preprocessing removes all Prusa Slicer tool change commands.
In ToolShift macro you can also add a park temp, but unfortunately it waits until the other tool head is parked before heating the next tool. So it will add a significant amount of time if you have a lot of tool changes.
I have experimented with the purge variable and it does seem like it could be used to work around the retraction timing issue, but similar to the park temp it adds a significant amount of time to the overall print since there is a tool change on every layer. Unfortunately not a viable solution since I need to mass produce the part
Purging would also waste a lot of PA6 since that doesn't have the same heat creep issue
Helge posted in the Prusa forum when developing the IDEX toolchain (https://forum.prusa3d.com/forum/prusaslicer/making-prusa-slicer-idex-ready/) and made a comment that "Retraction and deratraction in front and after a toolchanges should be optional"
This is not how the toolchange macro has worked for me. Not sure if I'm doing something wrong or if there is an issue with the ratos code
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Helge Keck would be the best person to answer, since I believe he wrote it. I don’t know exactly how the macro works, beyond what little adjustments I have experimented with.
Definitely would like Helge to chime in, but I am going to try adding retract/deretract commands in the custom gcode section of Prusa Slicer before/after T[next_extruder] and see what that does. I'll give that a shot tomorrow and report back!
If you want Helge to respond, you should let him know by adding @Helge Keck in your message. This will give him a notification. Hopefully he'll see my message and read the thread. I am curious as to how to do this as well.
this sounds like a extruder and/or hotend issue. i printed tons of petg with it at the same temps like you and never faced this issue
i highly recommend to check your hotend. most likely a theral issue due to incorrect tightened or loose rapido spacer screws, or the grub screw that presses the hteatink to the tube. if this screw isnt there or loose the heat can not be transferred to the heatsink
or check the extruder screws and the lever
PETG prints fine except for after idex tool changes
I will get a video tomorrow showing what is happening as well
@Helge Keck here is the tool change from T0 to T1. Note that it retracts before going to park position and then deretracts immediately after parking
Here is the T1 to T0 tool change. T0 retracts the same time as T1 and then deretracts right before resuming the print
wasnt the original issue tha thte extruder skips?
also, i dont see anything unusal here tbh. not sure wha tthe issue is. it does what you have configured it for
Issue is that the filament isn't retracted out of the hot end while being parked
i HIGHLY recommend not to change any retraction settings in the config file, use only the tooshfit macro for it
The default settings are only 2mm retract correct?
you also seem to have configured a huge amount of retracting. this will always happen on both toolheds at the same time. use the toolshfit macro to convigure individual retreactions for toolshifts, thats the way to go
Can you explain how to configure the toolshift macro for each extruder? This was the change I made to the config
dont do that there, dont try to configure the retraction in the config file
use ONLY the toolshift macro, thats what it is designed for
if you made any changes in the config file please revert them
Ok changes reverted, is there any documentation on the toolshift macro?
its pretty much self explaining
Nevermind I found it
I'll give it a try and report back
Update- I just turned off toolshift retraction and am using a wipe tower and it seems to be printing fine now.
Regardless, it is clear that the toolshift retraction/deretraction is not working as it should. Both extruders perform synchronous retraction/deretraction and they should alternate based on the tool change being done. Also, the toolshift macro should have different parameters for each extruder to allow for adjustments based on multi material prints
Regardless, it is clear that the toolshift retraction/deretraction is not working as it should.it works exactly as intended
Both extruders perform synchronous retraction/deretraction and they should alternate based on the tool change being donethis is not possbile during toolshift bc toolshift = COPY MODE, you cant control both extruders independelty in copy mode
Also, the toolshift macro should have different parameters for each extruder to allow for adjustments based on multi material printsSlicer -> Gcode Filament -> Set GCODE variable the macro is there for you to tune it under real conditions while its printing, if you have your settings that fits your filament you put these values into your slicer filament gcode reason is its not basef per toolhead, this needs to be tuned per filament