June 5, 2019 at 1:39 pm #102651
Would it do any damage to the motors, electronics, or anything to intentionally run tandem motors into hard limits, letting them “chatter” and miss steps for a moment, in order to square things up?
What if the standard nema 17s were running at closer to 1.7 to 2 amps ?June 5, 2019 at 2:03 pm #102655
Wow, this is like banging my head against the wall to stop the voices… just kidding, This Old Tony is rubbing off.
If the stepper drivers are set up properly, most have overcurrent/overtemp protection built in – which would only help if your motors are capable of sinking the overcurrent safely. More likely to break something mechanically before your blow up a stepper motor or driver.June 5, 2019 at 2:15 pm #102656
Wow, this is like banging my head against the wall to stop the voices…
Gotta do what you gotta doJune 5, 2019 at 2:31 pm #102665
The torque is low enough, and the parts generally strong enough, that skipping steps on X or Y won’t damage anything. The risk is all mechanical, there’s no real chance of hurting electronics or motors.
The Z axis has more opportunity for damage because of the gear ratio, but even then I have accidentally crashed and lost steps without any apparent damage.
I wouldn’t recommend this strategy for squaring, but that’s a separate discussion.June 5, 2019 at 2:40 pm #102666
I wouldn’t recommend this strategy for squaring, but that’s a separate discussion.
No, that is the discussion! Please discuss!June 5, 2019 at 2:53 pm #102667
Erwin VigiliaParticipantJune 5, 2019 at 2:58 pm #102669
Dual hard endstop semi-autosquare.June 5, 2019 at 4:23 pm #102690
There are some additional thoughts on this topic here: https://www.v1engineering.com/forum/topic/speculation-how-to-rip-off-ideas-from-the-pros/
1 user thanked author for this post.June 5, 2019 at 6:45 pm #102695
The Prusa MK2S uses the minirambo, and to square up the Z axis, you have to run the axis into the upper hard stops. it’ll be fine for a short amount of time.June 10, 2019 at 5:58 pm #103056
Ned van GeffenParticipant
they only do that because they have TMC2130 steppers that detect when they hit the end, and that is their end stop… They dont run them and keep driving into them for any length of timeJune 10, 2019 at 8:39 pm #103069
they only do that because they have TMC2130 steppers that detect when they hit the end, and that is their end stop… They dont run them and keep driving into them for any length of time
MK2S has A4988 because it uses the rambo mini 1.3, like the one that is sold for the mpcnc.
If you do the z calibration on the prusa it tells you to rotate the knob. When you rotate the knob on the lcd, it turns the z steppers and moves it upwards, and you have to move it up until both side hit the stops. It takes less than a second to square it up if you use hard stops on the mpcnc. I did it that way on my mpcnc for 8 months straight before every job, and I had 4-8 jobs 5 days a week.June 11, 2019 at 6:07 pm #103145
Ned van GeffenParticipant
my bad 🙂
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