Precision Study of a Coordinate Measuring Machine Using Several Contact Probes

Abstract

In this research work, a comparative study between the precision obtained with a touch probe (TP-200) and that obtained with a scanning probe (SP-25) is carried out for a specific coordinate measuring machine (CMM). These two types of probes cover the most commonly used contact probes in CMMs, where touch probes work by making contacts with the part and scanning probes maintain the contact with the part as they scan along its surface. In order to do this, one part was manufactured by machining and a series of measurements were taken over it at distinct locations in the CMM working volume. This part consists of parallel planes with different height values (70mm, 45mm, 25mm and 10mm) from the horizontal plane located on the granite table. The above-mentioned part was measured at five different locations distributed along the working volume and the measurements were repeated three times, where all of them were taken at a temperature of 20°C ± 1°C. Moreover, not only the CMM uncertainty is taken into account but also the variability associated with the manufactured part along with the measuring process of it.