Issues With UCCNC software

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Re: Issues With UCCNC software

Postby cncdrive » Sun Jan 08, 2017 10:39 pm

spumco wrote:OP -

Check your "Compensation Acceleration" setting. The default is '240' which I assume is for metric unit setups. This resulted in my Z-axis vomiting when it tried to reverse during spindle synchronization (tapping).

Changing it about 60 (with a max axis acceleration of 50) worked well for my mill in inch units. If you have backlash comp enabled, this is the setting that UCCNC uses to accelerate through the backlash. Too high and it will slam around; for me, it actually caused the Z-axis to go in the wrong direction.


The Comp acceleration parameter plays only in the following functions:

- Backlash, when the backlash is actually being compensated, in other words when a backlash configured axis changes direction, so the backlash needs to be compensated.
- Rigid tapping.
- Thread cutting.
- Softlimits slowing down when the softlimit is reached and the axis needs to be slowed down and stopped.

The Comp acceleration is not used in other circumstances, it is only used when a function is happening (list above) which requires a position compensation which is independent of the PC side software, in other words when the position compensation is calculated by the motion controller itself.
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Re: Issues With UCCNC software

Postby ger21 » Sun Jan 08, 2017 10:43 pm

The M3 command was followed by S6000 and the measured rpm from the super pid was 13000. The UCCNC software showed the same value. I knew this was off so I went back and looked at the gcode. Sure enough the spindle speed shoould have been 6000 not 13000.

If it's off by more than double, then adjusting the speeds won't matter.
I think you need to adjust the PWM duty% settings. Start by lowering the Minimum.
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Re: Issues With UCCNC software

Postby charliem » Sun Jan 08, 2017 11:28 pm

Hi Gerry Thanks I will try what you suggested and post back. Thanks.


Thanks for the reply. I will look at the info and hopefully I can learn something.
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Re: Issues With UCCNC software

Postby charliem » Mon Jan 09, 2017 11:37 am

Hello Everyone,

So I learned a few things. First my jerky movements were associated with the feed rate. I slowed down the feed rate and it smoothed things out a bit. I loaded another Gcode file and all the jerkyness went away. I then set the feed rate back to 100% everything works as expected. It seems that the first gcode file I was messing with has a lot of short segments. I can post the offending file if anyone wants to confirm this.

Also I played with the Min Pwm settings and I have my spindle speed close enough.

Thanks to everyone who helped me on this.
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