Independently leveled Z axis Issue
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@3DPrintingWorld said in Independently leveled Z axis Issue:
@fcwilt Yes, my current is low but that is because like you I am using planetary reducers. Mine are around 13:1. I keep it low to save my hotend should the probe fail and it crash for some reason. I have tried increasing the voltage previously but it did not make a difference.
13-to-1? That is high. How did you pick that ratio?
Just the same I suggest you up the current setting and see if it makes a difference.
Frederick
Printers: A FT-5 with the 713 upgrade bits, a custom MarkForged style, a small Utilmaker style, a small CoreXY from kit and a E3D MS/TC setup. Various hotends. Using Duets (2 and 3) running 3.4.6
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whats the rated current of those motors?
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@fcwilt Like I said, I tried increasing the voltage previously and I just tired it again but no difference.
I selected 13:1 because I wanted more holding force with the motors off since more reduction magnifies the detent torque of the stepper.
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@Veti said in Independently leveled Z axis Issue:
whats the rated current of those motors?
1A max. Nema 17.
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i think 200 is to low to run 1A motors, even if they are 13:1
you should at least use 50%
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@Veti said in Independently leveled Z axis Issue:
i think 200 is to low to run 1A motors, even if they are 13:1
Ok, great however I have tested and confirmed that the low voltage is not the issue.
Regardless, not sure how you came up with 50% because the minimum voltage is going to be determined by the pulley size, efficiency of the gear reducer, load and acceleration. When a stepper is put on a reducer it can actually run faster at a lower current as its not fighting decay in the pulses caused by too much current.
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@3DPrintingWorld said in Independently leveled Z axis Issue:
Ok, great however I have tested and confirmed that the low voltage is not the issue.
What do you mean by "low voltage" - there is no voltage setting command, only current.
Thanks.
Frederick
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@fcwilt Sorry, I should have said low current.
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at 20% current you will be at 14% holding torque.
pair the 14% holding torque with microstepping and you there is little chance of holding a specific position accurately. -
@Veti Holding torque is not required, detent torque and inefficiently of the gears will keep the axis from moving.
Feel free to review this calculator I made in reference to these regards.
https://github.com/3dprintingworld/MULDEX/blob/master/Resources/STEPPER HOLDING POWER CALCULATOR.xlsx -
Just out of curiosity what you are changing the motor assignment in your homeall routine?
Frederick
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@fcwilt Two motors for Y axis, one belt at each end of the gantry. I split the axis up so I can home to each endstop independently. This is so I can square the gantry up to the frame.
My original plan was to run the y axis into the frame, then run it back to a single switch but I was having a hard time getting the senseless homing to work reliably. Another user has sensorless homing working good so I plan on switching to that.
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@3DPrintingWorld 3.2.2 will home both at same time stopping each at the end stop. There should be no need to do it as you are. At least it works for me.
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@fcwilt Ok, I'll look into it.
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@3DPrintingWorld It's the same as described here, except instead of Z, it's X or Y.
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@3DPrintingWorld said in Independently leveled Z axis Issue:
@fcwilt Ok, I'll look into it.
He is a quick and dirty video I made showing homing of my three Z steppers - I pushed them way out of level first to clearly show the independent axis homing.
My Three Z Steppers Homing Independently
Frederick
Printers: A FT-5 with the 713 upgrade bits, a custom MarkForged style, a small Utilmaker style, a small CoreXY from kit and a E3D MS/TC setup. Various hotends. Using Duets (2 and 3) running 3.4.6
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@fcwilt & @Phaedrux, sorry I forgot that I already tried this but it did not work. Here was the explication from DC.
"On a CoreXY printer, if either the X or the Y endstop switch triggers, all motors must be stopped. Your printer isn't CoreXY, but it has a matrix for which some motors affect more than one axis. If I remember correctly, on MarkForged kinematics, movement of the Y motor causes X (and U) movement too. So when one Y endstop switch triggers, if the other Y motor were to continue moving, it's not clear whether the X and U motors should continue to move if the firmware moves just the other one. That's why the firmware stops all motors when an endstop switch is triggered."
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@fcwilt said in Independently leveled Z axis Issue:
He is a quick and dirty video
That is really slick looking! What are the sensors for, just to get it close before probing the bed?
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@3DPrintingWorld said in Independently leveled Z axis Issue:
@fcwilt said in Independently leveled Z axis Issue:
He is a quick and dirty video
That is really slick looking! What are the sensors for, just to get it close before probing the bed?
Exactly.
The best probing speed is quite slow compared to the homing speed.
So I use the endstop sensors for homing to quickly get the bed close to level.
Then before printing I use G32 to level the bed using the probe.
Frederick
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@3DPrintingWorld said in Independently leveled Z axis Issue:
@fcwilt & @Phaedrux, sorry I forgot that I already tried this but it did not work. Here was the explication from DC.
"On a CoreXY printer, if either the X or the Y endstop switch triggers, all motors must be stopped. Your printer isn't CoreXY, but it has a matrix for which some motors affect more than one axis. If I remember correctly, on MarkForged kinematics, movement of the Y motor causes X (and U) movement too. So when one Y endstop switch triggers, if the other Y motor were to continue moving, it's not clear whether the X and U motors should continue to move if the firmware moves just the other one. That's why the firmware stops all motors when an endstop switch is triggered."
That's good to know.
The fact that by splitting the motors you can achieve your goal suggests that the firmware should be able to do the same when homing using both steppers/endstops.
I may post a firmware request to make this possible.
Frederick
