Bed movement after toolchange dispite lack of commands
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Hi, Im working on a E3D toolchanger and Im having problems with erratic behaviour after a toolchange.
I have disabled all tool offsets in config, like this:
G10 P0 X0 Y0 Z0
G10 P1 X0 Y0 Z0
G10 P2 X0 Y0 Z0
G10 P3 X0 Y0 Z0I start the machine and home all the axes. No tools are selected at this point. I then send T2 to pickup the tool, which initiates the tpre2.g file, containing the instructions to move to the dock, lock the tool to the toolhead and move out. I´ve added a G1 Z150 F2500 in the end of the tpre2, to lower the bed before the move out from the tooldock, to make sure the tool does not crash into the bed.
After this I expect tpost2.g to be run, but I´ve removed all the content so nothing more should happen.
At this point I would expect nothing more to happen until I give further instructions to the printer.
What happens is that the build plate is moved up to the position where it was before the toolchange was initiated. I think this could be a result of a G1 R2 command somewhere, which tells the printer to go back to the position it was when the tool change was initiated. But no such command is present neither in the tpre2 or the tpost2.
I can not figure out what is the origin of this movement is. Am I misunderstanding something or have I stumbled upon a bug of some sort?
Best regards
aze
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Well we need more information.
- firmware version?
- Duet hardware?
Please post your config and homing files using the </> tag, one per file.
I'm using firmware 3.3 on 6HC/3HC combo with the E3D hardware and have not seen any unexpected Z movement.
Thanks.
Frederick
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@aze it's currently standard in the firmware to return to the previous position once a tool change has taken place.
This functionality has been changed as part of 3.4b6.
For the time being, if you're sticking with stable, I would suggest you at least set a z offset that is greater than or equal to the tool offset in Z. I.e. if your tool is 10mm lower than your switch, set it to -11 or something -
Hi, thank your for your answer, I will supply complete files when at work and has access to the files. For hte time being, Im running the toolchanger with a Duet Wifi 2 and Duex expansion board, and RRF3.xx firmware.
@jay_s_uk
Where in the documentation can I find more information about this? I find it odd that that since RRF should be "everything g-code" I would expect to find the actual g-code command instructning the printer that leads to this behaviour. If this is not the case, troubleshooting because very hard in my opinion. If this is a desired behaviour, why not put it in the tpre/post/free so users can identify the source of the behaviour? Im sure there are good reasons for not doing this, but Im just asking out of curiosity.I dont want to apply tool offsets, since im using an automatic tool offset calibration setup as develop by Danal Estes: https://github.com/DanalEstes/TAMV. For me it would be easier if I can start without any offsets applied and let the automatic calibration take care of that.
Anyway, thank your for your input! I´ll supply more information when Im an work.
Best regards
aze -
@aze You can see a bit more about the tool change behaviour here: https://duet3d.dozuki.com/Wiki/Multiple_tools_and_Tool_change_macros#Section_Tool_Change_Macros