Methodology and Adjustment of the Test for Determining the Polishing Difficulty Degree of Hardened Steel Surfaces, Previously Obtained by High- Speed Milling Processes

In the moulds and dies manufacturing it is important to reduce the manual polishing time after end milling processes. The polishing difficulty is related to surface topography shape and roughness values obtained in the previous end milling processes. It is interesting to develop a methodology and a test to evaluate the polishing difficulty. The aim of the present work is to establish a methodology and a test for quantifying the difficulty degree for polishing hardened steel that is used for moulds and dies, manufactured by high-speed milling. An automatic polishing machine was used. First, the test parameters to be used were defined: rotation speed of the pad, force between the workpiece and the polishing disk, type of abrasive material, grain size of abrasive and elemental polishing time corresponding to an elemental polishing operation. Second, a parameter that will allow the quantification of the difficulty degree for polishing was determined: either the total necessary polishing time or the number of elemental polishing operations that are necessary to obtain the final roughness defined. Third, a roughness pattern was manufactured of each one of the materials to be studied, in order to materialize the final roughness to be obtained after polishing.