Characterization Of Hybrid Coordinate Measuring Machines PDF Download

Any combination of contact and non contact sensors on a single coordinate measuring machine makes it a multi-sensor or hybrid coordinate measuring machine. The ability to change the probing device without re-establishing the part coordinate system is a significant advantage and consequently the reason for their wide acceptance and usage. In addition to the existing three linear stages in a conventional or hybrid coordinate measuring machine, they are augmented with two rotary stages in order to make them more versatile. Augmenting a conventional or hybrid measuring machine with rotary stages not only complicates the metrology loop but also adds a few more parametric errors to an existing list of known twenty one parametric error terms for a three stage conventional measuring machine. Also different probing sensors in the system have different metrology loops. A literature survey reveals that there are no previous or current work on parametric machine modeling, error evaluation, correction for the same and uncertainty analysis for machines of this class with a wide potential for measuring complex parts quickly and with great ease. The current work focuses on developing a parametric model for a five-axis, multi-sensor coordinate measuring machine of a specific configuration. Measurement techniques for estimating the parametric errors, techniques for compensating the same and methods to estimate measurement uncertainty on five-axis, multi-sensor coordinate measuring machines are proposed. A comparison between the results from error budgeting by the method of constraints for such high precision measuring machines with those from conventional methods based on estimates of subsystem errors are also presented.