Case study: A comparison of error sources in high-speed milling

This paper describes a case study devised to quantify the relative contributions of geometric, thermal, contouring, and cutting force errors to machined part dimensional errors. Measurements were performed to independently evaluate the: (1) quasi-static geometric errors using the laser ball bar; (2) variations in geometric errors due to thermal effects; (3) spindle thermal growth errors using a capacitance gage nest; (4) two-dimensional contouring errors using a grid plate encoder; and (5) surface location error due to (stable) forced vibrations during cutting. The effects of the first three error components were related to part dimensions using a homogeneous transformation matrix approach integrated into a Monte Carlo simulation. A comparison of the individual influences of these error sources showed that the cutting force error was dominant for the high-speed machining center/tool-holder combination selected for this study.