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Author Topic: MISSING STEPS HCIR  (Read 2557 times)

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Offline RICH

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MISSING STEPS HCIR
« on: February 27, 2011, 04:57:48 PM »
Having a problem with missing steps. Figured I would post and seek suggestions.
The complete program code has numerous use of the example problematic code. It is repeated in a simillar
fashion throughout the program.The attached code is just an example  which  may cause skipping ( X axis only).
 I can only run the code reliably at 10 IPM. The mill is very reliable to 80 IPM.  Matters not if run in Cv or exact stop mode.
The code provides small combination X &Z moves. I don't mind running the code at a slow  feedrate for finishing but need to up the IPM
to save hours on the pieces to be done.

N3663X-1.650Z-0.087
N3664X-1.652Z-0.086
N3665X-1.654Z-0.086
N3666X-1.655Z-0.085
N3667X-1.658Z-0.085
N3668X-1.661Z-0.084
N3669X-1.662Z-0.084
N3670X-1.664Z-0.084
N3671X-1.673Z-0.084
N3672X-1.680Z-0.084
N3673X-1.685Z-0.083
N3674X-1.691Z-0.083
N3675X-1.692Z-0.083
N3676X-1.696Z-0.082
N3677X-1.699Z-0.081
N3678X-1.701Z-0.080
N3679X-1.705Z-0.079
N3680X-1.708Z-0.077
N3681X-1.712Z-0.076
N3682X-1.715Z-0.074
N3683X-1.719Z-0.073
N3684X-1.722Z-0.072
N3685X-1.726Z-0.070
N3686X-1.728Z-0.070
N3687X-1.729Z-0.069
N3688X-1.733Z-0.069
N3689X-1.737Z-0.068
N3690X-1.740Z-0.067
N3691X-1.744Z-0.066
N3692X-1.747Z-0.066
N3693X-1.751Z-0.066
N3694X-1.754Z-0.065

 So any thoughts on the above ie; increase kernel speed .............?

The attached pics show the pathing , GREEN LINES, which will be used for testing by doing loops.
RICH
« Last Edit: February 27, 2011, 05:04:41 PM by RICH »

Offline Hood

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Re: MISSING STEPS HCIR
« Reply #1 on: February 27, 2011, 05:12:26 PM »
Tried messing around with the look ahead?
Hood

Offline RICH

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Re: MISSING STEPS HCIR
« Reply #2 on: February 27, 2011, 05:29:53 PM »
Hood,
Tried values from 20 to the recommended 200 still not reliable.

I will explore using my lathe ( by modifying the code for X and Z ) as it is very accurate and can run at higher feedrates reliably.
It could be a machine problem, ie; motor/use higher amp settings, the skipping is a real bear as you don't even hear it happen....can feel it if you keep you hand on the motor.

RICH

Offline RICH

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Re: MISSING STEPS HCIR
« Reply #3 on: February 27, 2011, 07:40:50 PM »
Think I found the problem ....should take my own advice as i so often tell folks it's their machine!  ;)
It's mechanical. Ran the code on the lathe at up to 90 IPM with out a skip or loss of any position. So it's not the code.
The mill is binding more on one side of table travel as compared to the other and thus is enough to cause the skipping.
That was found by trying the code loop at different positions along the bed travel.

Darn.......finaly get the backlash to under .001" after replacing all the bearings in the supports and have to fool more with the
preload and location of the bearing blocks.......PITA.

RICH

Offline RICH

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Re: MISSING STEPS HCIR
« Reply #4 on: March 01, 2011, 09:00:08 PM »
For info,
So I tweaked the amount of bearing preload and adjusted one of the gibb screws  and now can run the code at 60 IPM reliably.
The change in bearing preload put the backlash at .001" which is fine by me. Now I'll change the motor out using ( say 500 or 600 in/oz stepper)  and see how things work. I am not looking for speed as I very seldom machine above 40 IPM. The intent of a different motor would be to have additional torque available when running. The above allows me to reduce part machining time by 12 to 16 hours.
 
RICH

Offline Hood

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Re: MISSING STEPS HCIR
« Reply #5 on: March 02, 2011, 03:05:53 AM »
Good to see you got it Rich :)
Hood