Antiabrasive coatings: application for wood processing

The aim of the study was to examine how a modification of the tool surface influences the knives blunting for wood processing. The process was conduct ed with a laboratory Micro-lathe test apparatus. The cutting tools used in the experiments had an edge angle of 20 degrees a nd were made of 60SMD8 low-alloy steel and Z90WDCV high-speed steel. The mo dification of the working surface of the tool involved covering it with ant iabrasive coatings: TiN, (Ti,Zr)N, CrXNY W-C:H(DLC) and Cr. 60SMD8 steel wa s also nitrided. The lowest reduction of the cutting edge has been observed for CrXNY coated knives. The CrXNY coated knives seemed to have the best adhesion to steel: resisting scratching Lip to 4000 m of the cutting path. The obtained results demonstrate that the modification of a knife with hard coatings delays drawbacks of a knife wearing out processes. The relatively high values of friction coefficient between coatings and wet wood (up to 0 .4) require a very large extent of adhesion between coatings and tools surf aces. It seems that for wood rotary peeling with a knife with an edge angle of 20 degrees, it is not enough to increase the edge hardness but it also needs a complete study of the geometry of the edge. It appears that a low value of friction, a good resistance to abrasion and, to some extent, a good adhesion between a coating and a steel knife are th e most important factors in wood knife modification. (C) 1999 Elsevier Scie nce S.A. All rights reserved.