Dual extruder offset macro

tom_lauerman

Hello all, I hope everyone is well. I have a clay printer that uses two extruders, and of course one issue I have is that it can take a lot of time to set the nozzle offsets as they tend to change a little bit (1 or 2mm or less) each time I reload the machine. What I'd like to do is to be able to extrude a little bit of material from extruder 1, then move extruder 2 right over that bit of extruded material and click a button to have that current position recorded as the offset for extruder 2. I hope this description makes some sense. I'm actually basing my idea on something I saw in this video, which may be more clear than my words:
How To: Calibrate Printhead Offset
Of course I'd be very open to other solutions for calibrating offset between two print heads as well if anyone has implementations or ideas that work even better.

Phaedrux

I think you can achieve this with a combination of M291 dialogues with jogging commands and M500 P10 to save an offset.

https://duet3d.dozuki.com/Wiki/Gcode#Section_M500_Store_parameters
https://duet3d.dozuki.com/Wiki/Gcode#Section_M291_Display_message_and_optionally_wait_for_response
https://duet3d.dozuki.com/Wiki/Gcode#Section_G10_Tool_Offset_and_Temperature_Setting

Danal

I've been doing a bunch of stuff to automate tool-to-tool alignment on tool changing printers. That is EXACTLY what you are trying to do. My techniques probably won't be directly applicable, but maybe I can help.

And, hey, before we give up on "Directly Applicable", I'm using an upward looking camera and "Machine Vision" to find nozzles and calculate offsets. There can be absolutely no 'drool' during the process. Nonetheless, I'm curious, would this work for you? Can the nozzles be wiped clean, looked at from below, aligned, and then you start printing? And, how big is each nozzle? The actual hole, and/or the surrounding flat area?

And, you use the word "clay", (and I think I understand why in a broad communication) but, is it really "slip"?

Having said all above, I'm going to assume that cameras and clay/slip/water/etc don't mix. (ha ha). Still may be able to help:

Please tell me more about your environment. Which Duet board? Which release of firmware?

And... Do you switch extruders with T0, T1 and similar commands? Or some other way? Prior to the final tweaking of the offsets, do you start with G10 commands in config.g to define the offset,, or do you do it some other way? Basically what Gcodes manage all this dual stuff?

tom_lauerman

@Phaedrux Many thanks this is, as always, very helpful.

tom_lauerman

@Danal Wow, your setup sounds fascnatng. I may get there eventually, but am presently looking at a simpler solution that maybe later gets more complex. I'm using clay like you would use in an art studio, not a more watery slip. If interested, I've posted some images on this forum of my setup - you can just check my profile to find. I use a Duet Wifi, but may switch to the Duet 3 in the near future (to add more extruders). I use the latest firmware generally. Thanks for your insights and interest!