Sabina Rebeggiani

A quantitative method to estimate high gloss polished tool steel surfaces

Visual estimations are today the most common way to assess the surface quality of moulds and dies; a method that are both subjective and, with today’s high demands on surfaces, hardly usable to dis ...

Quantitative evaluation of the surface finish of high gloss polished tool steels

Standardized procedures to measure and estimate surface qualities of moulds for injection moulding of plastic components do not exist. Instead, steel producers as well as polishers and mould-users need to rely on master plaques for tactile comparisons and/or their own visual estimations for surface quality controls. This paper presents an overview of various surface evaluation methods of steels, including existing standards and available surface metrology. A new method to evaluate high gloss polished tool steel surfaces, based on a three-dimensional non-contacting measurement technique, is presented. The suggested method is based on defect extraction, and should be useful for both specifications and quality controls. Included defects were found to be quality criteria for polished tool steel surfaces. The surface acceptance levels and defect classification are based on interviews and questionnaires, as well as literature studies and visual estimations of test samples made by experienced polishers.

Factors influencing the surface quality of polished tool steels

Today’s demands on surface quality of moulds for injection moulding of plastic components involve no/low defect contents and roughness levels in the nm-range for high gloss applications. Material p ...