Comparisons between different measuring strategies were made on three types of smooth tool steel surfaces. Three replica materials were tested to study possibilities within replication techniques. An optical interferometer as well as a mechanical stylus was used to evaluate the surfaces. The results showed that the tested replica materials generated good representations of both the form and the surface roughness (Sq > 300 nm). The evaluated surfaces were quite homogeneous, thus, few measurements are needed to get representative results. However, it was found that caution must be taken regarding manually polished surfaces which can be less homogenous and therefore require more measurements to get representative results.

This study is based on several tests of a robot assisted polishing equipment, the Strecon RAP-200, which was recently developed by Strecon A/S in purpose to polish punches and dies for metal forming. The main part of the study was a 4-factor 2-level design of experiment, where the influence of pressure, pulse, repetitions and linear speed on the final surfaces were studied with help of both a mechanical stylus and an interferometer.

The number of repetitions seemed to be the main factor affecting the final surface quality, but also the rotation speed seemed to affect the surface roughness. Further evaluations will be performed in the forthcoming three years.

Manual polishing is a common method to accomplish a mirror-like mould surface, although it is a cumbersome and time-consuming process. It is, thus, of great interest within the industry to find faster and better polishing techniques to decrease the costs and lead times. A key factor towards improved polishing techniques is to find ways to characterize polished surfaces; which parameters and instruments can be used and what is the definition of polishability? This paper summarises a study where three steel grades were analysed with five different measuring devices. The results showed that mechanical stylus instrumentations are not enough to describe very smooth surfaces, but measurement devices with better resolution are needed, such as interferometers.