Multimaterial print - lower z-axis after Toolchange

CR3D

Hi Community,

with my IDEX, I always have the issue that after the tool change, despite retract and nozzle cleaning, a small blob gets stuck on the outer wall of the printed object.

I wish I could drive over the object and only then lower the Z-axis or only then do unretraction.

What's the easiest way to do that?

I've already looked at the G1 R0 command, but it lowers the Z axis one layer too late.

Thank you in advance!

oliof

@cr3d it looks like you are trying to avoid a purge tower or a draft shield -- commendable since wasteful. A draft shield / ooze shield would be the easiest solution.

Speaking of G1 R0 -- I assume you already tried applying Z offset here?

CR3D

@oliof said in Multimaterial print - lower z-axis after Toolchange:

@cr3d it looks like you are trying to avoid a purge tower or a draft shield -- commendable since wasteful. A draft shield / ooze shield would be the easiest solution.
Speaking of G1 R0 -- I assume you already tried applying Z offset here?

You are right!

all in all it already works very well and it just fails at this one point, then I would get along completely without any additives

How can I understand that with the offset exactly. I tested it with G1 R0. but it always remained too high for me after the tool change by the set offset. Only in the next layer did he then lower the nozzle again to the correct height.

maybe I'm just using it wrong...

Or is there another approach on the firmware side?

oliof

@cr3d in your tpost#.g, you could do

G1 R0 Z2

to end up 2mm above the stored XY position

and then

G1 R0 Z0 to go down. that should get you to the right height without touching the perimeter printed by the other print head.

Since you're offering your own slicer, another way would be to find the inside of the object, go there with the Z offset as described above, then go down and "wipe" outward to the next position. Computationally expensive but should be possible.

CR3D

Thank you for your answer

@oliof said in Multimaterial print - lower z-axis after Toolchange:

and then
G1 R0 Z0 to go down

And where to do this? When i do this also in the tpost#.g then it will not work.
Should i do that in the toolchange script at the SliCR-3D?

or did you mean that with your last thought then?

oliof

@cr3d https://github.com/oliof/printerconfigs/blob/main/cr20/sys/tpost1.g worked for me.

CR3D

@oliof Thank you a lot! Now it works great

P.S.: Also with downgrade to RRF 3.3