Date of Award
With industrial development, precision engineering has a wide range of application. However, in the precision machining of materials, Subtle changes can cause parts to exceed the tolerances. This project is to design a solution that measure the relative parallelism (skew) of 2 sides of the triangular beam during the final milling step. The tolerance of relative parallelism must less than 25 micrometers. The triangular beam is used in Hexagon’s Global S, a coordinate measuring machine (CMM). The air bearings hold the triangular beam and move along with the beam’s surface. The moving direction according to the machine self is X-axis. Therefore, the relative parallelism of 2 sides will affect the measurement accuracy of x-axis. The requirements of the solution need to mount on the milling machine and be non-contact. The parts cannot be moved or touched. Non- contact displacement sensors were considered to be the solution. After thorough and detailed researching and selecting, Omega inductive sensor LD 701-5/10 was be purchased and be tested. However, AR-700 laser displacement sensor from Acuity, LJ-V7060 displacement sensor from Keyence and CapaNCDT 6019 Capacitive sensor from Micro-epsilon were also be considered during the time. By comparing the advantages and disadvantages of displacement sensors from the performance, noise, accuracy, precision, the price and so on, the inductive displacement sensor was chosen. The displacement sensor will measure the side face of the triangular beam and need to be perpendicular to the side face during measuring process. The measuring process is very simple. Before measuring, the first surface needs to be milled. Assume that the first surface is completely horizontal and smooth. After milling first surface, rotating the triangular beam and do the measurement. The sensor will measure the skew of the first milled face. If the maximum and minimum difference displayed by the sensor is within 25 microns, then the position of rotated beam is correct, and the triangular beam can continue to be processed. If it is bigger than 25 microns, it means the position of rotated beam need to be adjusted. It is same principle for second and third face. Through improvement of the triangular beam measurements technology, the processing efficiency is improved, and material is saved.
Liu, Yanchen; Philips, Greg; and Sullivan, Byron, "Hexagon -- On Machine Parallelism/Skew Check" (2019). Mechanical Engineering Capstone Design Projects. Paper 78.