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Author Topic: Losing Position  (Read 13936 times)

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Offline mhdale

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Re: Losing Position
« Reply #10 on: March 12, 2007, 08:35:01 PM »
Just an FYI position check came back with x-.0069 y-.056 z-.0012 I can live with the Z and on a bad day the x but the Y is getting bad..

Offline mhdale

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Re: Losing Position
« Reply #11 on: March 12, 2007, 09:40:52 PM »
Ok, Another stupid question if you Home your machine and then go hit verify position I get a bit of variance usually around half a thou, but If I keep hitting verify that number just keeps getting bigger and bigger... is this "normal" behavior is that what other systems do?
Mike

Offline ART

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Re: Losing Position
« Reply #12 on: March 12, 2007, 09:53:08 PM »
Mike:

 Does it lose at 25Khz, you should never go higher than 25Khz unless you have a perfectly workign system.. ?

Art

Offline mhdale

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Re: Losing Position
« Reply #13 on: March 12, 2007, 11:16:05 PM »
Ok, I will try it at 25 K.  Just another not I did run the tests and the results I get are inconsistant, i.e. at 45K I run the same test twice, One one test it will be within tolerances and on the next it will loose 17 thou..... have you ever come across that?


M

Offline mhdale

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Re: Losing Position
« Reply #14 on: March 13, 2007, 01:24:59 AM »
Alrighty, I have my kernel set to 25K Max feed Rates are 180 ipm
I Have adjusted my accel rates from 28 to 16 and I seem to get pretty consitent creep in my x and Y axis, my z seems to be staying within tolerance. I have no idea what tolerance for this type of machine (Gantry) should be but I am taking a WAG at .005 or +/- .0025 The Limit switches definitely are within that as now at the 25K kernel speed I can hit verify till the cows come home and it stays under .001 If I do 100 repeats of a 5Inch Move in either the X or Y Axis I definitely get higher numbers out on that axis up to around .014. Any suggestion on dialing this in any further?

Mike
Re: Losing Position
« Reply #15 on: March 13, 2007, 08:37:25 PM »
That sounds about as good as you can get for a router... Other then that you are going to have to move to servos and use the index to home the machine.
Fixing problems one post at a time ;)

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Offline mhdale

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Re: Losing Position
« Reply #16 on: March 13, 2007, 09:29:30 PM »
Brian, Actually when it is working correctly the system has been able to maintain under .005 the problem is is that the number just keeps getting bigger! The larger the toolpath the worse it is at the end.

M

Re: Losing Position
« Reply #17 on: March 13, 2007, 09:52:14 PM »
Sounds to me like you have a noise problem... are you running steppers or servos?
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Offline ART

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Re: Losing Position
« Reply #18 on: March 13, 2007, 09:54:57 PM »
Hi:

 Have you tried running in Sherline mode as yet? Id be interested ot know if it loses position in that mode..

Art

Offline mhdale

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Re: Losing Position
« Reply #19 on: March 14, 2007, 11:42:54 AM »
Running Steppers, and I have not tried the sherline mode. I too suspect that it is noise in the system but I am uncertain as to where to start. I guess I am just putting off the inevitable and should just get down to re-wiring the whole control box as I think noise has been a problem for a while...

I was hoping and wishing it was anything BUT noise.....
What exactly does the sherline mode do ?