We have all seen prints with many datum reference frames on them. The fact that there are multiple sets of datum’s is not an issue and is put in place for functional design reasons. There can be so many that they look like an alphabet soup. But what about raw castings? Generally the functional part datum reference frame(s) have not yet been cut into the parts yet. This where casting datums come into play. They are typically designated as X-Y-Z or Z-Y-X.
Many measurement and reverse engineering requirements require more than simple caliper or micrometer measurements. Whether you are conducting a First Article Inspection (FAI), troubleshooting a manufacturing issue or reverse engineering a legacy part for improvements, one or multiple of the modern data collection methods may work – but what is best and what are you compromising on by using any particular method? Do you do this work yourself or hire out an experienced service provider?
Contact measurement devices constitute the majority of what is traditionally used for dimensional metrology. These consist of devices that must be in physical contact with the object to be measured. Below is a listing of general types of contact measurement devices. This covers the vast majority of what is used today and is a good overview on what is possible and what to expect from data taken with these instruments. We freely use these types of devices in our service business where it makes sense for any particular project due to quality, cost and timing.
Non-contact or touchless dimensional measurement devices are the modern new comer to an array of contact devices that have been traditionally used. Contact devices are discussed in this link on Common Contact Measurement Devices. All of the non-contact devices generate a point cloud or voxel data set as their most raw form of data. The exception is the optical comparator which has been around since the late 1920s. It does not expressly produce digital data, but some of the variant equipment that evolved from this equipment does.
3D Engineering Solutions was recently hired to re-engineer military aircraft components, including parts for large helicopters and jets.