1 Topic by 2n2r5 (edited by 2n2r5 2019-02-19 14:43:59)

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Topic: Hardware and Electronics Questions

My latest project will use 3 steppers to drive the z axis. I would like to use the 3 motors to auto level the bed and I want to use a 32 bit.

I can't find any literature that shows that this is currently an option in available firmware.

Or*, I can just use the bed mesh* feature of reprap or smoothieware if the other option isn't available. Seems like it might be a more reliable option anyways. In that case, am I able to split the output of a stepper motor driver to feed 3 motors? Is there another preferred option?

*Edited because I used wrong terminology

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

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2 Reply by carl_m1968

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Re: Hardware and Electronics Questions

I am assuming your goal is to have the motor adjust the bed height similar to the three point design knobs on many beds. If that is the case your current thought will not work. You said you wanted to split the signal from one driver to three motors. All that is going to so is move the three motors in a synchronized fashion. You are going to need independent drive and control of each motor of your goal as well as a form of feedback divided into sectors so the system can plot the regions of the bed and then calculate the needed steps to raise or lower that region to the desired zero point.

Current systems use a Z probe and maps the bed surface using 16 to 24 points. It marks the height at those points and simply adjust the bed height real time when the head is in a region of one of those points to compensate for the bed level. So what you propose is already done on a much simpler system that only needs two motor that do not matter if they work in tandem.

Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
Voxelabs Proxima SLA. 6 inch 2k Mono LCD.
Anycubic Predator, massive Delta machine. 450 x 370 print envelope.

3 Reply by 2n2r5 (edited by 2n2r5 2019-02-19 14:54:28)

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Re: Hardware and Electronics Questions

Thanks for your reply Carl!

carl_m1968 wrote:

I am assuming your goal is to have the motor adjust the bed height similar to the three point design knobs on many beds.

That is the idea behind the first though. Which, I realize now, is probably over complicating the process.

carl_m1968 wrote:

If that is the case your current thought will not work. You said you wanted to split the signal from one driver to three motors. All that is going to so is move the three motors in a synchronized fashion.

This is the 2nd way that I talked about. There was meant to be 2 separate thought processes. Should have been Or not Also. See edits.

carl_m1968 wrote:

Current systems use a Z probe and maps the bed surface using 16 to 24 points. It marks the height at those points and simply adjust the bed height real time when the head is in a region of one of those points to compensate for the bed level. So what you propose is already done on a much simpler system that only needs two motor that do not matter if they work in tandem.

Agreed. I used the wrong terminology when I said mesh mixing. I meant bed meshing which is exactly what this is.

My question was more about how to actually split the stepper driver output to 3 motors. I have seen some parallel modules like this one. But, I have not seen a three-way split. I don't know if that is because there isn't enough current available to split between 3 motors or if it just isn't a common application.

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

2n2r5's Website

4 Reply by heartless

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Re: Hardware and Electronics Questions

can i chime in here?

I am an owner of a 1st generation FT-5 which used 2 steppers for the 12x12 bed..
keeping everything in sync turned into a bit of an issue for a lot of people..

Because of this, Folgertech moved to a single stepper to run both Z axis lead screws in a later revision, for simplicity's sake.

Why you would want to way over-complicate things by putting 3 steppers in the mix is beyond me.
2 is hard enough to keep working in sync, 3 would be a nightmare.

as for the logistics of actually hooking up 3 steppers to the same driver.. you "might" be able to do it (splicing 2 into one), but getting enough current to all 3 motors could be a very real issue.

SD4 #1 & #2 - Lawsy carriages, E3D v6, Rumba controller board, mirror bed plate, X motor fan, upgraded PSU & Mica bed heater
SD4 #3 - in the works ~ Folgertech FT-5, rev 1
Printit Industries Beta Tester - Horizon H1

5 Reply by 2n2r5

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Re: Hardware and Electronics Questions

heartless wrote:

can i chime in here?

By all means smile

heartless wrote:

Why you would want to way over-complicate things by putting 3 steppers in the mix is beyond me.
2 is hard enough to keep working in sync, 3 would be a nightmare.

Over-complicated is my middle name. I love things that are challenging and different. I have done many different projects that were over complicated or difficult to implement and have had pretty good success with some of them. (Notice, I didn't say most tongue)

It looks like the Railcore is running the 3 stepper setup for bed leveling and, as it turns out, uses the same electronics and Core xy.
https://railcore.org/doku.php?id=en:duet_reprap_300zl

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

2n2r5's Website

6 Reply by carl_m1968

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Re: Hardware and Electronics Questions

2n2r5 wrote:
heartless wrote:

can i chime in here?

By all means smile

heartless wrote:

Why you would want to way over-complicate things by putting 3 steppers in the mix is beyond me.
2 is hard enough to keep working in sync, 3 would be a nightmare.

Over-complicated is my middle name. I love things that are challenging and different. I have done many different projects that were over complicated or difficult to implement and have had pretty good success with some of them. (Notice, I didn't say most tongue)

It looks like the Railcore is running the 3 stepper setup for bed leveling and, as it turns out, uses the same electronics and Core xy.
https://railcore.org/doku.php?id=en:duet_reprap_300zl


It is based on Core XY movement so it only uses two motors on the Z. Those would be driven from one drive. Just have to make sure they are level before allowing the machine to move them .

Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
Voxelabs Proxima SLA. 6 inch 2k Mono LCD.
Anycubic Predator, massive Delta machine. 450 x 370 print envelope.

7 Reply by 2n2r5

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Re: Hardware and Electronics Questions

carl_m1968 wrote:

It is based on Core XY movement so it only uses two motors on the Z. Those would be driven from one drive. Just have to make sure they are level before allowing the machine to move them .

Core XY is only for XY movement not Z. The reason I brought that up is because I am using the same thing which means I can harvest that firmware. Doesn't anyone read minds around here???? Sorry, I forgot to mention that piece.

The Z axis is driven from motors 5,6 and 7 so they can be independently driven and therefore autolevel the bed.

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

2n2r5's Website

8 Reply by heartless

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Re: Hardware and Electronics Questions

2n2r5 wrote:
carl_m1968 wrote:

It is based on Core XY movement so it only uses two motors on the Z. Those would be driven from one drive. Just have to make sure they are level before allowing the machine to move them .

Core XY is only for XY movement not Z. The reason I brought that up is because I am using the same thing which means I can harvest that firmware. Doesn't anyone read minds around here???? Sorry, I forgot to mention that piece.

The Z axis is driven from motors 5,6 and 7 so they can be independently driven and therefore autolevel the bed.

which makes the question of how to run 3 motors from one stepper driver moot.. independently driven means 3 separate stepper drivers, not one. wink

and sorry, my mind reading skills have gotten seriously rusty the last few years.. =P

SD4 #1 & #2 - Lawsy carriages, E3D v6, Rumba controller board, mirror bed plate, X motor fan, upgraded PSU & Mica bed heater
SD4 #3 - in the works ~ Folgertech FT-5, rev 1
Printit Industries Beta Tester - Horizon H1

9 Reply by 2n2r5

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Re: Hardware and Electronics Questions

heartless wrote:
2n2r5 wrote:
carl_m1968 wrote:

It is based on Core XY movement so it only uses two motors on the Z. Those would be driven from one drive. Just have to make sure they are level before allowing the machine to move them .

Core XY is only for XY movement not Z. The reason I brought that up is because I am using the same thing which means I can harvest that firmware. Doesn't anyone read minds around here???? Sorry, I forgot to mention that piece.

The Z axis is driven from motors 5,6 and 7 so they can be independently driven and therefore autolevel the bed.

which makes the question of how to run 3 motors from one stepper driver moot.. independently driven means 3 separate stepper drivers, not one. wink

and sorry, my mind reading skills have gotten seriously rusty the last few years.. =P

For now it does, unless something goes wrong and I have all those problems that you forecast. Then I will be hacking together a fix.

SD3 w/ mods:
Glass bed with QU-BD heat pad upgrade, threadless ballscrew w/ 8mm smooth rod, spectra line belt replacement, lawsy MK5 extruder, Lawsy replacement carriage, E3D hotend, Ramps 1.4 w/ reprap discount controller, DRV8825 drivers, 12v 30A PS, Acrylic case, Overkill Y-idlers, Filament alarm, Extruder fan + more.

2n2r5's Website

10 Reply by heartless

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Re: Hardware and Electronics Questions

2n2r5 wrote:
heartless wrote:
2n2r5 wrote:

Core XY is only for XY movement not Z. The reason I brought that up is because I am using the same thing which means I can harvest that firmware. Doesn't anyone read minds around here???? Sorry, I forgot to mention that piece.

The Z axis is driven from motors 5,6 and 7 so they can be independently driven and therefore autolevel the bed.

which makes the question of how to run 3 motors from one stepper driver moot.. independently driven means 3 separate stepper drivers, not one. wink

and sorry, my mind reading skills have gotten seriously rusty the last few years.. =P

For now it does, unless something goes wrong and I have all those problems that you forecast. Then I will be hacking together a fix.

LOL, I will give you this - you are an adventurous soul! I like that. smile

SD4 #1 & #2 - Lawsy carriages, E3D v6, Rumba controller board, mirror bed plate, X motor fan, upgraded PSU & Mica bed heater
SD4 #3 - in the works ~ Folgertech FT-5, rev 1
Printit Industries Beta Tester - Horizon H1