Avaliação da preparação de gume através do processo de escovação para aplicação em fresamento de topo reto

Abstract

The condition of the cutting edge is of great importance to the machining process. After the wedge is made, the cutting edge may be defective, burr, and micro chipping. Edge preparation is an alternative that can be performed with the objective of removing these defects from manufacturing resulting in increased mechanical stability of the cutting wedge reflecting increased tool life. This paper deals with the process of cutting edge in straight end mills through the brushing process used by the Machining Group (GUS) of the University of Caxias do Sul (UCS), which uses pneumatic mini-grinding and surface finishing sheets composed of microabrasives. This process was investigated and parameter configurations were proposed in such a way that symmetry-prone or slightly shifted roundings to the face of the cutting wedge were generated, according to the theoretical basis for milling. Brushing test was developed by applying the special tool brushing process, with linear edge along the cylindrical surface, in order to facilitate the evaluations and the tests in search of the best parameters to be performed later in the preparation of the helical straight end mills, which will be subjected to machining tests. In the brushing test, the radii and the transition profiles generated at the edges were evaluated through the contact technique and SEM images. The chosen configuration presented an average radius of 6.71 µm and an estimated form factor of 0.94, slightly shifted to the flank. Two original milling cutters were subjected to an AISI P20 steel machining test, later re-sharpened and prepared for further testing. For both original and brushed cutters, the flank wear and surface quality generated were evaluated for comparisons. Flank wear follow-up has returned a 21.35% longer life for brushed cutters and minimal incidence of microlanding. The textures obtained in general do not appear to differ greatly and the roughness decreased from 1 to 2 µm to Ra values. Brushing edge preparation proves to be efficient, and based on this research, better results can be obtained depending on the subsequent machining applied (sic).