Optimizing Sampling Parameters of CMM Data Acquisition for Machining Error Correction of Freeform Surfaces

An optimization study using the design of experiment technique is described, in which the surface profile height of a freeform surface, determined in coordinate measurements, is the response variable. The control factors are coordinate sampling parameters, i.e. the sampling grid size and the measuring tip diameter. As a result of the research, an optimal combination of these parameters was found for surface mapping with acceptable measurement uncertainty. The presented study is the first stage of optimization of machining error correction for the freeform surface and was intended to take into account mechanical-geometric filtration of surface irregularities caused by these geometrical parameters. The tests were carried out on a freeform workpiece milled with specific machining parameters, Ra of the surface roughness was 1.62 μm. The search for the optimal combination of parameters was conducted using Statistica software.