Qualifying Capacitive Sensing Hole Measurement System Technology using Gage R&R Analysis

The Capacitec CMS3 Reader, coupled with the CHP 48 sensor probe, achieves +/−3μm accuracy by mapping 24 diameters in high tolerance drill holes for the manufacture of composite or metal aircraft components. Gage repeatability and reproducibility (gage R&R) studies presented will show better than +/−0.0001 inches (2.5μ m) for this measurement technique. Using noncontact inspection for quality control is a way to perform this inspection more efficiently than traditional contact measuring instruments, while reducing sampling time compared to other methods. Gage repeatability is improved using non-contact methods because capacitive sensing at short distances has a linear and predictable correlation to displacement. Gage reproducibility is also better because different users introduce a different touch using bore gages and other contact measuring devices. In conclusion, using a probe that profiles 24 diameters at the click of a button using non-contact capacitance technology not only saves time but is a significant improvement to overall gage R&R.