TABLE OF CONTENTS Surface finish and texture can be measured in a large number of ways ranging from simply tracing a fingernail across a surface to the use of scanning electron microscopes (SEMs). Each particular method has its own advantages and disadvantages. If all techniques were to be covered in this book, there would be little room for anything else so we need to restrict ourselves. We will be concentrating on profilometry techniques because these are the most common.
The range of surface topography measuring equipment can be divided into two classes, those used on- or in-line and those used in the laboratory. The former are quick and convenient, being typically two-dimensional (2D) profilometry and light scattering. The latter are mostly expensive and slow, being typically three-dimensional (3D). Some of the latter techniques are exceedingly expensive and are only found in the larger laboratories, typically scanning electron microscopes (SEMs) and atomic force microscopes (AFMs). Areal techniques are growing in use but, apart from light scattering, are generally not used on-line. In view of this range, the emphasis in this chapter will be on stylus instruments, although towards the end, mention will be made of microscopy techniques.
The most common method of assessing texture involves mechanically drawing a stylus across a surface. The principal elements for a 2D system are shown in Figure 3.1. The pickup supports the skid that rides over the surface. The stylus moves over the surface, driven by the traversing unit. The transducer signal is amplified and processed...
