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Offline Tef9

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ScrewMapping
« on: May 06, 2013, 02:26:07 PM »
Hi Everyone,

I have DMM tech servos and would like to use the screwmapping function with the servo encoders.  My first question will this work?  Or do I need a DRO installed.

Second how do I get the feedback from the encoder into mach3?

Thanks,

Andy

P.s Interesting that there is little documentation or support on ScrewMapping

Offline Hood

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Re: ScrewMapping
« Reply #1 on: May 06, 2013, 02:52:31 PM »
You need to measure the actual axis travel when mapping the screws so motor encoders are no use.
Hood

Offline Tef9

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Re: ScrewMapping
« Reply #2 on: May 06, 2013, 03:29:22 PM »
Hi Hood,

So a dro is the only way? Shame.

I have new double nut screws (gten) c5 rated and I am getting 100microns backlash.  When set to move 1mm it will always go to 0.9mm but when returning to zero, it hits zero dead on.  I thougth mapping the screw might help!

If any suggestions please let me know!

Cheers,

A

Offline Tef9

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Re: ScrewMapping
« Reply #3 on: May 06, 2013, 03:34:45 PM »
Just to add, if I ask it to move 5mm it goes 4.9mm but always back to zero!

A
Re: ScrewMapping
« Reply #4 on: May 06, 2013, 04:59:52 PM »
That sounds like backlash to me.

Offline Tef9

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Re: ScrewMapping
« Reply #5 on: May 06, 2013, 05:43:53 PM »
Not convinced its backlash as these are C5 rated screws with high preloaded double nuts - should be around 25 microns, or like the other two axis 15 microns.  Unless I am doing somthing daft :)

A

Offline Hood

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Re: ScrewMapping
« Reply #6 on: May 06, 2013, 06:11:10 PM »
If its not backlash then they are not c5 screws ;)
Backlash may be in your bearings or flex in the brackets.
Hood

Offline Tef9

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Re: ScrewMapping
« Reply #7 on: May 06, 2013, 06:14:24 PM »
Lol, I expect some, just not 100 microns...eeek!

Good point, may be the block however the block is rated C5...I am going to have to dismantle the entire thing tommorrow....urgh those motors are heavy and a PITA to take off!

Cheers,

A

Offline Hood

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Re: ScrewMapping
« Reply #8 on: May 06, 2013, 06:16:51 PM »
If you can get a clock on the end of the screw you can see if it moves out and in when you jog one way then back
Hood

Offline Tef9

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Re: ScrewMapping
« Reply #9 on: May 06, 2013, 06:18:30 PM »
Thanks hood, ill give that a go, I do have a little room to try that!

A