Circle in contour function

[[Ri...]]

I have been using this feature on some of our gears with mixed/inconsistent results.
The gear i'm working on right now has 55 teeth and is getting multiple errors depending on the strategy used.

Errors are:
- There are several possible positions for the circle with the contact angle greater than the minimum angle
- Spline calculation not possible (point disorder)
- Error with reference
- System error

Method:
The way i would like it to work is as followed:
- Scan complete gear.(2D curve)
- Recall 1 segment of the 2D curve in a new 2D curve
- Circle in contour function.
- Rotational Pattern ->55 times
- Evaluation( diameters, runout, etc.)

This method seem to give the right visuals on screen but running it on a product gives allot of errors.
Hopefully someone has developed stable and fast method/strategy for these kind of repetitive measurements.

I have a lot of experience in Mitutoyo software and about 8 months in Calypso software. This function has been the most frustrating thing i have encountered so far.

Kind regards,

[[Is...]]

That function is a headache..
In the past I was setting a loop of filters to obtain at least a result.

Now after years of suffering, I have something stable, but not with circle in contour fit, instead of that I look for the contacts with loops (actually it performs better if you use batch or scripts instead of only PCM):

[[Ri...]]

A lot of it depends on how smooth the curve is. I've had a lot of success with it on tactile sensors, but using the camera (especially on dirty parts) I have a lot of issues. Pretty aggressive filtering helps a lot.

[[Cl...]]

This option works very well using the CFS sensor.

[[Ri...]]

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I'm using an Accura with the XTR system. Our products are stamped so they tend to be a bit rough and in some cases contain some defects or burrs.
Maybe finding the contact points is a better option. Could you point me in the right direction on how to do that?

Since its a fairly new machine to us we don't have the PCM licence yet. Is it required to use your method?
Some explanation would be nice.I will need some solid arguments if need to obtain another license.


Kind regards

[[Is...]]

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The Journey could be long, depending your requirements…
If you use it only for gears, I would consider other possibilities instead: maybe probe gage with selcentering or Gear Pro software.

In our case the first solution was to export the curve points and then with an excel macro we were calculating the contact points. This solution allowed our designers to contribute in the measurement method; then after some agreements (Alignment, filters, tolerances, graphics, colors, etc) we generated the calculation in a Visual basic application.

The method that we follow to synchronize the VB application to Calypso is the following:

addToFile(Measurement parameters)        	  			
systemCallWithWait(Application.exe)	
readPCMFile(Measurement results)	

now with the learned skills we generate similar measurements using ellipse, torus or barrel instead of circles.

[[Ri...]]

We need to have a quick way of checking our gears during our production process(SPC).
We produce them in batches of 50k+ in a few days. A complete measurement should be around 10 minutes max.

We need to have a solid way of checking growth and roundness after the hardening process. We already evaluate the profile of each tooth in our program. Maybe best fitting a part of the profile and calculate/measure the distance to our reference is an option?

[[Ri...]]

I would strongly recommend GearPro then.

[[Ch...]]

Do you have Gear Pro? Is it too slow for your production rate?

[[Is...]]

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Depends what you want to achieve .. we have programs that take hours measuring one part for research purposes, or 3 minutes for an specific feature...

For distances between balls I would say the fastest method is the selfcenter using Gage probes (for this is not necessary gear pro)

[[Ri...]]

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We don't have gearpro. We have a Mitutoyo CMM with gear software. A full measurement on this gear will take about 50 min. Excluding the Beta measurement it takes about 20 min. I'm aiming for a program under 10 minutes since we will measure thousands of these gears a year.

I have no experience with self centering probes but i'm guessing it is to slow.
This would require a probe change and will be an extra measurement on top of an already scanned gear.

[[Is...]]

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Selfcentering is fast..., a probe change is around 30 seconds extra but is not necessary with a proper stylus system or if only distance over circles is required..
Something nice using selfcenter scanning: you can generate graphics of taper which normally has big influence in the Fb.