On-line measurement of workpiece surface topography and texture by using laser scattering

摘要

Optical measurements utilise different approaches depending on the application needed. This paper presents an on-line optical experimental method to measure surface roughness applicable for surface finish of metals in a shopfloor environment. The principle of the measurement is based on laser light specular reflection technique with the applications of optical and engineering principles for surface topography measurements. The main components used in this experiment are laser and photosensor. The reflected light is detected and captured by a photosensor which converts light intensities to voltage levels. The intensities of light distributed within the scattered band are correlated to the surface roughness of the specimen. The voltage readings are interfaced to a personal computer via a data acquisition card. They are then quantified and presented by sampling techniques into a surface profile. The approach and system have been tested on a computer numerical controlled XYZ stage which emulates a CNC milling centre. The preliminary results show the approach and system are very promising albeit more industrial trials need to be undertaken. The paper concludes with a discussion on the potential and applications of the system for broad manufacturing engineering applications.