[ITEX] Slow "restore position" move during tfree toolchange

tupp

Hi everyone, I have been working on an ITEX printer. It's fairly unique, with 3 nozzles all sharing the same X axis, all mounted on a crazy looking CR10V2. I haven't been able to find many similar setups, so I'm kind of going in blind here, so I've finally hit a wall and I need some help. I'm using the Duet 2 wifi and Duex 5. The point is, I want to print 3 completely different materials in the same print, for example PLA, TPU, and soluble support.

After some hours of reading documentation and previous forum posts, I've been able to get my setup running well enough to print off a dual-color benchy, leaving my 3rd nozzle unused.

I am thrilled to be at this point, but now there's an issue. I'm just trying to get a hang of the toolchange commands because there is a very slow travel move right after tfree#.g and I can't seem to find a way to fix it. It's causing many issues with print quality.

From my understanding, here's what happens:

//T1 (middle tool) just finished printing, it's somewhere on the bed, say X100 (U100?)
T0; Activate LEFT tool
//tfree1.g begins
G91; relative
G1 Z3 F500;
G90; absolute
G1 U434.6 F6000
//T1 moves all the way to the right side, parking out of the way. Good.
G91 ; relative
G1 Z-3 F500
//T1 moves very slowly at the same time as the Z axis back to where it just was (X100). Bad!
// I don't want this at all, and I don't know why the U axis moves when I just told the Z axis to move.
G91; relative
//tfree1.g ends

//And the print continues normally

This is my tfree1.g:

G91
G1 Z3 F500
G90
G1 U434.6 F6000 ; move U toolhead to the right side, out of the way.
G91
G1 Z-3 F500
G90

And while typing this all out, and doing testing to get a good answer from you guys, I figured out the issue. I'll still post this in case anyone else runs into the same thing.

I added H2 before all the moves so that it forces the motor to move individually. I'm still not sure why the U axis moved to the stored position, that's not how I expected it to work. I'm hoping someone can answer that, because maybe it will cause other problems for me in the future.

This is my new tfree1.g:

G91
G1 H2 Z3 F500
G90
G1 H2 U434.6 F6000 ; move U toolhead to the right side, out of the way.
G91
G1 H2 Z-3 F500
G90

I'm looking forward to asking many more questions. This project is my final project for university and It's due in 1 week!

Diamondback

On my custom toolchanger I have seen similar super slow moves while changing tools. I think they are related to the current position being out of the normal limits, if I set the tool macros to leave the active tool within the allowed area after tfree, it works as expected.

Do you move your tools outside the normal limits for parking by any chance?

tupp

@diamondback The useful print area is X0 to X300

My X is configured to go all the way from X-190 to X700 in config.g

; Axis Limits
M208 X-197.2 Y0 Z0 U-125.9 V0 S1                                   ; set axis minima used to be U-125.4
M208 X700 Y300 Z200 U1000 V537 S0                                  ; set axis maxima

I guess I have weird maximum limits for X and U. I just set them arbitrarily high because I'll never tell them to go that far anyway. I should probably calibrate that