Stepper motor - loss of steps

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27 Jun 2019 11:02 - 27 Jun 2019 11:03 #137988 by Jocman
Hi all.

As I'm having an huge loss of steps (even 2.8 mm....) more on X (only after few minutes of work....), i've been suggested to change my stepper+driver, as they are not suitable with my structure (home made CNC, heavy aluminium frame - about 150 kg).
Currently I use this combination:
Nema 23 SY60STH88-3008BF + Leadshine M542 (Bipolar Parallel, 40V/3.5A, microstep:5 and step/rev (1.8°):1000)

It has been told me to change the stepper to APM-SB02ADK

At first glance (I'm not an engineer) they look me similar.
Is there some difference between them? It will worth the price (about 300 $ + drivers) to change my old stepper? in case, wich driver should I buy?

I found on ebay this combination of stepper+driver : Kit HSS57 (various prices, more or less about 120 $ each kit); it could be a valid substitute?

Another solution for the loss of steps to try has been to remake all the stepper wiring, using even some ferrite filters, and reduce the acceleration and speed settings (currently the acc is 30mm/s, the max speed 50mm/sec) for the 3 axis.
I think to try first this "cheap" solution.....

Any suggestion?
Thanks
Andrea
Last edit: 27 Jun 2019 11:03 by Jocman.

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27 Jun 2019 14:08 #137999 by persei8
Before throwing money at the problem, I would carefully check the mechanical components. I use the same Leadshine driver with 425 in.oz. Nema23 motors, Max vel is 60 mm.sec., max acc. is 500 mm/sec/sec. When I had what appeared to be lost steps, it turned out to be a slipping shaft coupler.

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27 Jun 2019 15:42 #138001 by Clive S

As I'm having an huge loss of steps (even 2.8 mm....) more on X (only after few minutes of work....), i've been suggested to change my stepper+driver, as they are not suitable with my structure (home made CNC, heavy aluminium frame - about 150 kg).
Currently I use this combination:
Nema 23 SY60STH88-3008BF + Leadshine M542 (Bipolar Parallel, 40V/3.5A, microstep:5 and step/rev (1.8°):1000)


It is always a good idea to post your ini and hal flies from the config folder.

It might be because your acceleration is to high

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27 Jun 2019 16:20 #138003 by PCW
Replied by PCW on topic Stepper motor - loss of steps
Also marginal step timing or wrong step polarity can cause step loss

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28 Jun 2019 00:30 #138062 by andypugh
If everything is set up correctly you would not lose steps even if your motors and drivers were under-specified, as long as they were capable of moving the machine.

For a test make the accell and max speed 10x lower. The machine will move like a slug, but if you still lose steps then it is likely to mechanical (slipping couplers) or step timing being too short.

If that does fix the issue, then you guessed wrong when you configured speed and accel. Where did you get the numbers from?

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28 Jun 2019 13:45 #138118 by Jocman
I got the values from the configuration wizard screen; about the step and micro step values, from the drivers datasheet (compared to the microswitch settings)
Well, In the next days I will check of course the couplers too.

Honestly, trying to avoid the loss, I reduced even the speed (5 mm/s) through the Axis speed slider (80%), but I wasn't lucky....

Attached my ini and hal files.

Andrea
Attachments:

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28 Jun 2019 14:28 #138120 by persei8
setp stepgen.0.steplen 1
setp stepgen.0.stepspace 0
setp stepgen.0.dirhold 44000
setp stepgen.0.dirsetup 44000

Your DIR setup and hold times of 44000 are probably OK but steplen and stepspace should be set to something like 10000 or even 20000. These numbers are nanoseconds so 10000 would give a value of 10 uSec.

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28 Jun 2019 14:36 #138121 by PCW
Replied by PCW on topic Stepper motor - loss of steps
The OP is using the "reset" mode so step time is set by the reset time here:

setp parport.0.reset-time 5000

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28 Jun 2019 14:51 #138122 by persei8
(U32) parport.<portnum>.reset-time -- The time (in nanoseconds) between a pin is set by write and reset by the reset function if it is enabled.

Interesting. I did not realize it worked like that.

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28 Jun 2019 17:32 #138125 by pl7i92
5microstepping is also a steplos killer

better to use externel timingbelts for balscrew it is 20/25 teeth so 1,25 gear
that brings in 0,01mm per step at halfstepping
and gets a full speed full torque running mashine

the
color code is most
A+ RED
A- Blue
B+ Green
B- Black

if you change like most Black /green it will likly loos at higher speed at around 100RPM of the stepper

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