Appendix: Surface finish of a machined part; main aspects and factors

As the quality of the surface finish increases, so do machining costs. That's why it's vital to specify surface structure parameters, taking into account the specific requirements of the parts concerned. Most machining methods leave characteristic traces on the surface of the part that are both visible and measurable, underlining the need for ocular inspection methods adapted to the part's design criteria. A surfaced part may show well-defined visible traces due to the cutting edge, but still remain within the limits of measurable design criteria.

Modern cutting tool technology has established a relationship between the conventional criteria frequently used and the surface structure of the machined part, although these criteria are not particularly precise.

Take, for example, the distinction between metal cutting and grinding. Here, current...