Much of the works of dimensional inspection previously done using hand measurement tools and tactile measurement devices such as CMM's is being done these days by way of scanning a part or assembly. Then bringing the mesh representation of the part into an inspection application such as Polyworks Inspector. The design CAD data is often imported also, but this is not necessary, since the inspection can be performed without the CAD data. An alignment is performed to get the mesh data to align to the CAD in a way that is in accordance with the design and inspection intent of the part. After this, an inspection process can be performed similar to that using a CMM. This process is also known as CAD to part dimensional analysis. Since a complete mesh of the part often exists rather than a few measured points such as gathered from a CMM inspection there are a few advantages of this type of inspection. One, is the ability to produce a "heat map" showing the mesh models deviation from the CAD overall. This provides a quick visual guide to show where a problem with a product may be. The other is the ability to find a defect in the surface of an object that is intended to be flat or to curve in a uniform way. An example of this is a warp in a laminated or annealed auto glass.
* Accuracy specification generated by scanner OEM. Verified on an annual basis by 17025 accredited lab.
Reverse engineering is part art and part science. One takes the scanned mesh data and converts it into CAD surfaces and solid models. Other types of measurement methods may also be applied to compensate for features that are difficult to fully define in the scanned mesh. Such as, small holes, very small features, these can be measured with micrometers, height gauges, calipers, pin gauges, etc. and then this can be added to the CAD model increasing it's fidelity. Finally all this measurement data can then be used to create the final CAD model. The creation of the CAD data is also dependant on if the customer desires that the model reflect the design intent from which special accommodations are taken for wear, damage, warpage, etc. Otherwise the model creation reflects "as built" state where the model is reproduced exactly as found with no allowance for the previously stated conditions.
|STRUCTURED LIGHT SCANNING ||.05MM|
|RED LASER SCANNING||.020MM +.100MM/M|
|BLUE LASER SCANNING||.020MM +.040MM/M|