Gap and Flush Evaluation Does Not Match Defined Measurement Points

[[St...]]

Hello,

I am experiencing an issue with the gap and flush evaluation, particularly regarding the flushness calculation. I am unable to reconcile the reported deviations with the individual measurement values.

My current approach is as follows:

• Measure the defined points on each respective component.
• Calculate the flush deviation as the difference between the two measured points.
• This is done irrespective of any nominal shingling (step offset) that may be specified.

However, when I perform the evaluation using the VMB app, the calculated values do not match the deviations obtained from my manual calculations.

Could you please clarify what I might be doing incorrectly? Which parameters can be adjusted to ensure that the evaluation results correspond to the actual correction requirements of the components?

Thank you in advance for your support.

Best regards,
Stefan

[[Ra...]]

Hello,

I would recommend checking the Flush (nominal) parameter, the Side 1/Side 2 assignment, and the evaluation direction, as any of these can cause the reported VMB result to differ from a manual calculation based solely on the measured point values.

[[St...]]

No, there still seems to be another issue in the algorithm.

For the top measurement point, the flush value shows a deviation of 0.6 mm, while the difference between the two measurement points is 0.43 mm. This leaves an unexplained discrepancy of 0.17 mm.

In the second section, the reported deviation is 0.47 mm, whereas the difference between the two measurement points is 0.41 mm. In this case, there is still an unexplained difference of 0.06 mm. While this is an improvement, it is still not satisfactory, especially since both sections were processed in exactly the same way.

 

[[St...]]

I assume that the respective measurement points and the resulting flush values are determined using an extrapolated line. This approach appears to be particularly useful for nominal values. However, when evaluating actual measurements, I am primarily interested in the deviation relative to the CAD zero position, as this makes it much easier to identify the corrections that are required.

As a result, the calculated values understandably differ from those obtained by simply adding or subtracting the deviations of the opposing measurement points. Nevertheless, these are the values that I can plausibly provide to a toolmaker as a correction target. They are also the values that we primarily discuss during our engineering reviews and alignment meetings.

Would it be possible to implement this approach as an additional selectable option within the measurement principle? This would allow users to choose, depending on the application, between the current calculation method based on an extrapolated line and a direct evaluation of deviations relative to the CAD zero position.

[[St...]]

[[St...]]

When I use the following setting – Flush direction: Side 1 → Normal direction of the reference element – I obtain the same result as the automatic calculation, but with the opposite sign compared to what I am used to. At least the value is now understandable and traceable.

Is there any detailed documentation available for the VMB app that describes the calculation logic and the underlying settings? I would like to gain a better understanding of these evaluations and be able to trace the calculation methods used. Thanks.