What is the best way to scale my measurements for thermal expansion/contraction?
SA supports many ways to analyze the effect of measuring a part at a different temperature than its design. One common practice that SA facilitates is to enter the part’s average internal temperature and it’s coefficient of thermal expansion when establishing a station, thereby setting a scale factor centered on the instrument (but prior to calculating the instrument’s transform). Another, similar, approach is to use measurements of a scale bar which is both at the same temperature and of the same material as the part. Yet another supported method, when the part reference system has been established at design conditions, is to “let scale float” and calculate it as another degree of freedom during the fit. Another unique situation that SA considers is a non-isotropic scale factor, such as a steel optical table with zerodur components. Which method is best, of course, depends on situation and shop practice.
