In our last Metrology Minute post, we demonstrated how Control X can be used to extract feature size and location information directly from the scan, without the use of a nominal CAD model. With this route, a more traditional type of inspection could take place using just the scan of a manufactured part or assembly. We explained how a region’s model may be used to identify and measure analytic features, directly from a scan. And [...]
The optimal workflow in Control X for inspection is to compare the scan of a manufactured part to its corresponding nominal CAD model. This is done by first aligning the scan to the CAD model, typically utilizing datums for the alignment. Once the alignment is complete, any type of dimension, whether feature size, distance, GD&T, etc. may be derived by essentially comparing the dimensions of the scan to those of the nominal CAD model. The [...]
Geometry Deviation is a tool for measuring essentially everything that might be relevant for size, orientation, and location for a specific feature. For example, when measuring geometry deviation for a cylinder, the criteria of interest would likely be the size, location, and centerline axis direction as they all compare to the nominal (exact) CAD model. As you review the data blocks below, Control X can compare the scan data values to the CAD data values [...]
This month's Metrology Minute will focus on a capability of Control X called Color Map Fitting, which is an extremely useful ON and OFF switch to use for analyzing the results of a GD&T callout. GD&T will typically check for a specific criteria to be within an acceptable tolerance and the user is looking for a Pass or Fail response. Consider a connecting arm that looks like the one below. Where Datum A is the top [...]
Choosing a scanner for metrology is a topic that comes up often when companies look to deploy non-contact inspection and question what criteria they should use when choosing a scanner for their company. We have covered this topic in detail at some recent Cimquest events but have had several customers ask more questions. Here are some of the highlights of these presentations. Accuracy vs Resolution Accuracy is the accuracy of the points acquired on the [...]
Cylindricity – Similarities & Differences Between Related Callouts While this month’s segment is focused on Cylindricity we will also review several of the GD&T Callouts discussed previously (and a few not previously discussed but relevant to this month’s discussion) along with some of the similarities, as well as subtle differences between them. Cylindricity is a form of control tolerance that dictates both the roundness and center-axis straightness of a cylindrical part. If you consider the [...]
In continuing our series on GD&T callouts, today's Metrology Minute focuses on Flatness. Flatness is a very simple callout that focuses on just how flat a particular surface is without making reference to any specific datum. Very often, a Flatness callout can determine whether a job shop is able to face mill a surface to its finished dimension or if grinding and perhaps outside services are required to achieve the necessary Flatness. If a specific [...]
In continuing our Metrology Minute focus on GD&T, this month we will discuss Runout and Total Runout. Simply defined, Runout is how much a model feature varies with respect to a datum when the part is rotated about the datum’s axis 360 degrees. The datum in question would necessarily be an axisymmetric feature. It generally involves the analysis of a circular feature that is created when taking a single point tool and rotating it around [...]
