Research And Development Of Stylus Surface Roughness Measurement System

Roughness is an important indicator which reflects the surfacemicro-geometry of mechanical parts. It’s the most widely used parameterrepresenting surface characteristics, and directly affects the performance and life ofequipments. Due to changes in international standards in recent years, a series of newstandards on measurement and evaluation of the surface roughness have beendeveloped in China. As a result, many conventional surface roughness measuringinstruments do not meet the requirements of current international and nationalstandards.A low cost contact style type surface roughness measuring system wasdeveloped in this paper. It included mechanical design, sensor signal collection andcontrolling circuit design, and measuring system application software. In terms ofmachinery, a waste CD-drive mechanism is used as sensor drive mechanism toreduce the cost of driving parts of the system. In the part of circuit, sensor signalconditioning circuit design based on AD698and the application of PCI dataacquisition card and USB motion control card implement the displacement sensorsignal acquisition and the motion control of stepping motors features. The part ofsoftware, an easy-to-use software with beautiful interface was developed to evaluatethe surface roughness parameters. The aspect of surface roughness profile filteringmethod research, for problems of boundary effect of Gaussian filter, a Gaussian filterthat can change border weight function was proposed and realized. For problems oftoo slow running speed of robust Gaussian filter, fast convolution of Gaussian weightfunction was truncated to speed up algorithm running. Results of this research have apositive significance in promoting the development of surface roughness measuringtechnology in our country.