Dual X Carriage using M569 for tool change.

Is it possible to use M569 to have dual X motors that are wired to different drives after moving one head to a "parked" position, then M569 to the other drive wired to a "parked" head on the opposite side?

I've worked on a few multi head industrial machines, and can strongly recommend not trying to do flying axis reconfiguration, unless you do a re home each time you can suffer lost counts when you do the switch over, and will possibly need to park the redundant axis into a placeholder in order to maintian hold currents, even if you do do a rehome you can still suffer lost counts if your home switch lacks perfect repeat-ability.

The way I'd do this is configure the first axis as X and the second as U, then in firmware when you do a tool change park the X axis and redirect the commands to the U axis and vice versa.

The next problem will be your compensation, if there is any difference between the X and U axis compensations then you could have problems, solving this could be fun

This will require some work in the firmware

The good thing about this idea, is when your printing with one head your not dragging the other across the job, so will suffer less drool issues, you can also handle different Z height for the tool points

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RepRapPro Mendel 3 Tricolour
RepRapPro Fisher
-Carbon Arms
-Easy adjust Carriage+effector
-axis stiffness mods
HE3D -600 delta
-Duet 0.8.5
-PanelDue
-DC42 Height probe
-RobotDigg metal components
Simplyfy3D
RS Design Spark CAD

Not yet, however dual X carriage support is on the list to be added to the firmware.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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dc42
Not yet, however dual X carriage support is on the list to be added to the firmware.

Thinking about it some more, yes you could achieve this using M569. However, you would lose position by up to 2 full steps unless you re-homed the carriage in the X direction after each tool change. You could do that in the tool change files.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I am going to use small magnets at each park position on the head and the frame that hold the head in an exact position mechanically and use g92 to apply the proper position ( after the m569 to remove error) to the active head since they will both be at their parked position at tool change and are both technically "X axis" just changing the motor and belt driving heads.

Edited 2 time(s). Last edit at 05/25/2016 10:51AM by jmjcoke@gmail.com.

You can also apply needed offsets for z axis and nozzle position in x and y in the tool change g-code.

or I think the offsets for dual extruders in the slicer would still work, because you are still on x axis, it will take some tweeking but it will work.

Edited 1 time(s). Last edit at 05/25/2016 10:48AM by jmjcoke@gmail.com.

Yeah doing setpoint exchange in an 840D control was fun, The best was when we used a torque motor as a spindle and then would change it to an axis to position a right angle head then back to a spindle .

Edited 1 time(s). Last edit at 05/25/2016 11:09AM by jmjcoke@gmail.com.

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[email protected]
I am going to use small magnets at each park position on the head and the frame that hold the head in an exact position mechanically and use g92 to apply the proper position ( after the m569 to remove error) to the active head since they will both be at their parked position at tool change and are both technically "X axis" just changing the motor and belt driving heads.

Unfortunately, that won't avoid the error of up to 2 full steps. The problem is that although the magnet may hold the carriage in position, when the motor is energised the position that the motor want the carriage to be in may still bu up to 2 full steps away form where it is.

The solution is to keep the motor for the idle carriage energised at low current when it is parked. This is what I will be implementing in firmware.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Ok, I will use your setup once it is released.