stepper motor control speed

Electronics related to CNC

stepper motor control speed

Postby joskerel » Mon Jan 28, 2013 9:49 pm

hello,

I was lucky to buy a (broken) lasercutter and got this for less then a build would be (shipping kills in Australia, so i bought a thunderlaser 2012 dsp controller, done the install and followed the instructions given on the wiki (thanks to al involved making it :-)
Now ive got it running but the speed is very slow.
So i'm trying to learn everything about the stepper motors, driver and how they work with the software to get the best speeds.
However i can't seem to get it in my head how all the number are calculated so i dont just trow numbers or flip switches without knowing what i'm doing.
I've been looking for about 3 days solid on this and other sites.(call me stupid :-) i can seem to make the wright link)
the motors installed are;57BYGH314 MOTOR,STEP,57MM H,UNIPOLAR,18KG-CM,3V,4A,1 OHM,1.6MH
dan the driver is CW260C set from the factory at 1/32 and 3,71A

Please explain a simple as possible, unless in dutch :-)

Cheers Hans
joskerel
 
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Re: stepper motor control speed

Postby Kellerkind » Mon Jan 28, 2013 10:06 pm

first a warning: i dont know your driver/electronics at all, this is just a guess considering some problems i had in another project.

these motors have a step angle of 1,8°, thats about 200 full steps per full turn of the pulleys.With small pulleys thats about 0,1mm per step, if you use 32x microstepping the driver tries to reduce the stepsize by some pwm magic in the coils to 1/32 of a full step ( = 0,05625° ).
With normal signal frequencies of a stepper controller this is near the timing limits so your logic cant tell your steppers fast enough to move one step forward.
i would suggest to reduce the microstepping to 16X or 8X ( and decrease the steps/mm[inch] setting by 2x or by 4x) and you should be able to move much faster. This way the steps grow 2x or 4x bigger and you should be able to go 2-4x faster.
Kellerkind
 
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Re: stepper motor control speed

Postby joskerel » Mon Jan 28, 2013 11:53 pm

Thanks,

Ive set the steppers to 16 and reset the pulses,the problem i'm having stays the same,
when cutting a vector the laser is very fast, but when doing a engraving its almost as slow as watching paint dry :-(
i think this haze to do with the parameters set in the software.
can someone explain how these work?
the ones in the bios and the ones in settings?
(what are the max settings?)

Cheers hans
joskerel
 
Posts: 15
Joined: Wed Jul 18, 2012 5:51 am

Re: stepper motor control speed

Postby Kellerkind » Tue Jan 29, 2013 4:11 pm

since this seems to be a configuration issue of your dsp maybe check here: viewtopic.php?f=32&t=656
Kellerkind
 
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