Only need XY auto level on 4 motor table.
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I have a 600mm x 600mm print bed using 4 lead screws. The bed is made of 8mm machine plate aluminum which is NOT going to twist with a 4 screw auto level. I am trying to find a way to level just on the X and Y axis. I have searched quite extensively this forum and the web and have not found any way to do it.
Equipment:
Duet 2 wifi + duet 5
firmware : 2.02(RTOS) (2018-12-24b1)
BL Touch.My least preferred method would be 4 end stops at the bottom of the Z travel because its 1300mm with single start 2mm pitch lead screws.
Actually my least preferred method would be to install RRF3 if its capable of doing what I need. But if its my only option....
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@foulkn said in Only need XY auto level on 4 motor table.:
firmware : 2.02(RTOS) (2018-12-24b1)
you should update to 2.05.1 then
@foulkn said in Only need XY auto level on 4 motor table.:
BL Touch.
My least preferred method would be 4 end stops at the bottom of the Z travel because its 1300mm with single start 2mm pitch lead screws.the best method would be this
https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors -
Using the probe and the link Veti provided would be the easiest way. Using endstops would be possible in RRF2 but is rather tedious because you need to split each motor into a separate axis, home each, and then recombine. In RRF3 it's much easier to use endstops to level Z. But if you don't already have the endstops and you already have a probe that's the way to go.
And yes you should probably update to 2.05.1 if you want to hold off on RRF3. Though it's really not that bad now days.
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@foulkn said in Only need XY auto level on 4 motor table.:
I have a 600mm x 600mm print bed using 4 lead screws. The bed is made of 8mm machine plate aluminum which is NOT going to twist with a 4 screw auto level.........
You are in for a surprise if you believe that.
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@deckingman well let me rephrase that, mine is not going to twist. I tried several coupler styles and found that these couplers worked best to keep the screws centered with little or no wobble. But they will pull apart.
https://www.zyltech.com/flexible-plum-coupler-shaft-various-combinations-from-5mm-to-12-7mm/ -
So in RRF3 I would be able to level XY only using the BL Touch?
I was always one to have the latest and greatest software versions, but now that I am 55 I under stand the principal of "If it's not broke, don't fix it!"
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@foulkn said in Only need XY auto level on 4 motor table.:
@deckingman well let me rephrase that, mine is not going to twist. I tried several coupler styles and found that these couplers worked best to keep the screws centered with little or no wobble. But they will pull apart.
https://www.zyltech.com/flexible-plum-coupler-shaft-various-combinations-from-5mm-to-12-7mm/Well if the screws are unconstrained so that it doesn't twist, it'll rock. Think beer mat under one leg of a 4 legged restaurant table. Remember that getting the 4 screws synchronised and staying that way within (say) 0.1mm is going to be critical. It might be possible but having one more than the optimum number of screws will make it difficult (IMO).
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@foulkn said in Only need XY auto level on 4 motor table.:
So in RRF3 I would be able to level XY only using the BL Touch?
I was always one to have the latest and greatest software versions, but now that I am 55 I under stand the principal of "If it's not broke, don't fix it!"
You can do it with version 2 firmware.
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@deckingman I do agree with that. I started with 3 screws, but it introduced a slight amount of play that I was not happy with.
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Hi,
Go ahead and upgrade to v3 - I'm using 3.1.1.
I just modified a printer of mine to auto-level using 3 steppers, 3 end stop switches and a Z probe.
The 3 end stop switches take care of getting the bed level enough to use the Z probe.
I had to spend a bit of time getting the 3 switches positioned.
It's a thing of beauty to watch a grossly out of level bed rise up and level out.
Frederick
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You can level with 4 z motors and a probe using this method on RRF2.
https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors
You need to add a command to config.g that defines where the lead screws are physically located in absolute coordinates relative to the 0,0 point.
You need to create a bed.g file that has 4 points to probe as close to the lead screws as possible.
Details in the link.
