CASE STUDY: VERIFYING MEASUREMENTS

 In Case Studies

When it comes to high accuracy measurements
it’s best to verify those measurements with multiple tools.

This does two things:

It confirms the data & offers confidence in your tools and measurement methods

Below is an overlay of a high precision machined part. The purple area indicates that the top sphere was cut too deep, but it’s best to be confident before having something like this re-cut.

SCAN DATA

Below is the data provided by one of our scanning systems. This data shows the measured value of the spherical radius, it’s position, and the distance from the highest theoretical point of the sphere to the base of the part.

cylinder-reduced1

CMM DATA

Below is the data set provided by one of our coordinate measuring machines. These values are the same measurements performed using a different system and presented in Excel.

cmm-data

Spherical Radius

Our scanner measured a spherical radius of 48.372mm.

Our CMM measured a spherical radius of 48.384mm.

The difference in spherical diameter? 12 microns.

On it’s own that doesn’t seem very good. The catch is that we were measuring 10% of a sphere and extrapolating that data to measure its full size. This is like grabbing a handful of sand out of a full bucket and accurately quantifying how many grains are left in the bucket.

Distance

Our scanner measured a distance from base to tip of sphere as 134.223mm.

Our CMM measured that same distance as 134.224mm.

The difference in distance from base to tip of sphere? 1 micron. 

This was a real project for a local manufacturer, so there was no funny business involved.

These are real numbers from systems we use every day.
We came away from the project with confirmed data and a new sense of confidence in our technologies and methods.