Polibilidade de aços para moldes de plásticos

Abstract

The polishing is a key feature for selection of material for the manufacture of molds and dies for plastics. This feature is associated mainly to the need of the roughness of the finish manufactured part, such as lens glasses or car headlights. This work aims to characterize the polishing materials and compare the result for three different types of steel used in the manufacture of injection molds for plastics. The characterization of polishing was made by evaluating the surface roughness measured by different procedures. The materials were evaluated steels VP20, VP80 and 304 UF, produced by Villares Metals. Were prepared 45 samples for each of the three steels. The samples were subjected to different levels of finishing using grinding and polishing. Measurements of roughness were performed using a laser interferometry, mechanical profilometer to probe reflectivity measurements and the technique of photoluminescence. Considering the results made a comparison and evaluation of three methods of measuring surface finish. In this comparison, we tried to show the relationship between the roughness and reflectivity of the technique of photoluminescence. The results obtained in the comparison of methods showed a good correlation for steel VP80. The higher the roughness measured by profilometer and interferometry, the lower the index of reflectivity achieved. Steels VP20 ISO 304 and UF did not show a good relationship. Was also carried out tests for evaluation of roughness according to the time of polishing. The results show that the steel VP80 again demonstrated its roughness lower than the other steels studied.