Microprocessor-controlled drill analyzer

A microprocessor-controlled instrument was developed for automatic measurement of drill geometry. The position of a reciprocating stylus is measured upon contact with the sample via an analog-digital converter and a linear variable differential transformer (LVDT). Either a guarded stereo phono cartridge or an electrical contact stylus senses contact. Output data are digital readouts plus analog plots. Plots are either polar plots of equal height contours, height versus angle for fixed radius or height, or departures from conical versus position. The sources of error are discussed; achievable accuracy of height measurements is approximately ±1 percent ±25 μm.