Measuring Features in Tight Spaces

Josh
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Measuring Features in Tight Spaces

Post by Josh » Thu Jul 23, 2015 9:48 am

I am trying to measure a part that has numerous tight spaces with the smallest size probe that I am comfortable using (1.5mm) While setting up the program, I used CAD to get a starting point for the programs path. From there, I tweaked the paths (Start / End Points & Backoff distance) to make it work for the tight space. When I used the "Step Verify" function within the Measure Feature command, the program works perfectly. When I click "Verify", the probe will get an "Unexpected Touch" error. My backoff distance is already minimal at 1mm.

Is there a way to tighten up the target position tolerance when the probe is measuring in tight spaces?

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Re: Measuring Features in Tight Spaces

Post by US_Helpdesk » Thu Jul 23, 2015 12:14 pm

This is handled by controller. What controller make and model is used on your CMM?
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Re: Measuring Features in Tight Spaces

Post by Josh » Thu Jul 23, 2015 12:33 pm

We are using a Cordax 1808 CMM. The controller is a Renishaw PHC 10-2 with a SMP400 processor.

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Re: Measuring Features in Tight Spaces

Post by enpalani » Fri Jul 24, 2015 12:35 am

The following point may cause
[1] Some times variation between CAD and Component is more.
[2] Alignment is not perfect

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Re: Measuring Features in Tight Spaces

Post by US_Helpdesk » Fri Jul 24, 2015 10:03 am

I'm not familiar with procedure to adjust target position on this controller... It is done through a proprietary utility. Have you tried slowing speeds and accelerations down? This will usually improve position capability.
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Re: Measuring Features in Tight Spaces

Post by jpknox » Mon Mar 21, 2016 3:59 pm

We are having this problem also.

We just had a new Altera installed. A program we are using on our older CMM with a renishaw controller has backoffs of less than .25. It seems that when we try to run it on the Altera we get this same error for any backoff distance of less than .7

How can we fix this as we are needing to move these programs to the new cmm?
Last edited by jpknox on Fri Mar 25, 2016 12:44 pm, edited 1 time in total.
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Re: Measuring Features in Tight Spaces

Post by US_Helpdesk » Wed Mar 23, 2016 10:02 am

Check your LKCMMDRV.cfg file... It should be here - C:\ProgramData\Nikon\CMM-Manager 3.5 SP1\Driver

Be sure the min or max settings for motion including approach / backoff are not limited by this file. You can work with Help Desk for details on parameters in this file.

If this does not do the trick you may need to get Service involved, maybe the system needs servo tuning?
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Re: Measuring Features in Tight Spaces

Post by US_Helpdesk » Tue Mar 29, 2016 2:43 pm

Here is an interesting post about sample points (Relative Measure & Find Hole) used for measuring 2D features in tight quarters or with sheet metal / plastic applications that have high deviation.

https://cmmmanager.com/forum/viewtopic.php?f=33&t=545

Also, per the email I sent I suspect you may need to re-Create Path after updating either approach or backoff distance(s) to update Link Path.
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Re: Measuring Features in Tight Spaces

Post by jpknox » Thu Mar 31, 2016 9:02 am

nfrost wrote:Check your LKCMMDRV.cfg file... It should be here - C:\ProgramData\Nikon\CMM-Manager 3.5 SP1\Driver

Be sure the min or max settings for motion including approach / backoff are not limited by this file. You can work with Help Desk for details on parameters in this file.
It isn't limited. Rod has looked at it and has sent a log to the developers.

If this does not do the trick you may need to get Service involved, maybe the system needs servo tuning?

It was just installed 3 weeks ago. wouldn't the servos have been tuned by your tech when it was installed?
Could this and other errors we are seeing be caused by a slow computer. By which It can not communicate fast enough to keep up with the machine movements? I know this computer it is on seems insanely slow.
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Re: Measuring Features in Tight Spaces

Post by jpknox » Fri Apr 01, 2016 2:47 pm

nfrost wrote:Here is an interesting post about sample points (Relative Measure & Find Hole) used for measuring 2D features in tight quarters or with sheet metal / plastic applications that have high deviation.

https://cmmmanager.com/forum/viewtopic.php?f=33&t=545

Also, per the email I sent I suspect you may need to re-Create Path after updating either approach or backoff distance(s) to update Link Path.
Did you post this in the wrong forum?





So, I have established that this is not a touch point issue as I have created planes on these surface with a backoff of .5. No issue. When I try to scan it, I get the error. Weird thing is It scans other holes of similar size without issue.
Capture.PNG
Anyone ever get this error before?
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