Electrical effects in woodcutting tool wear

Abstract

Recent work [Klamecki 1977] has indicated that a useful way to investigate the wear of wood cutting tools is to try to separate wear phenomena which depend on the time of fool-work contact from those which seem to be related to a number of discrete events. Specifically, the work mentioned above con-> pares tool wear in turning tests wher~ thc cutting action is (a) continLiou.s mid (b} interrupted. In the interrupled cutting trials using relatively brittle tool materials (carbide and ccr~.inlic/ tee anloui l i of tool Flank wear is approximately linearly related to the number of impacts the tool is su/zjected to during cutting and no clear relationship is sho,.vn between the ~,,ear and the length of cutting path. i.e.. the time of tool work contact . ()n the other halld, the study of conlitluous cutting processcs me.,, lead to understanding tb.e \',ear mechanisms ,.\ hiclt depcnd on the time of tool-work contact. In the interrupled cutting tests the primary catlsc of tool wcaF seems to be the mechanical loading of thc tool and any related clTects, such as thermal cycling. During cont inuous cutting other v, car mechanisms appear to bc acting. Tool wear vxlnich depends on the time of contact between the tool and u o l k material can be explained by mechanical abrasion of the tool. by chemical or electrical action between the Iool and lhe work, or by various COlnbir~atior~s of these wear n~cchanisi-ns. f h e probable importance of wear mechanisms c~thelthan those associated v, ith mechanical loading oCthc tool b', the v, ork material is pointed out ill the work under discussion where \ \ear data are presented for the cutting of green and alE-dry incet~se cedar. Smaller cutting forces, it',wei tool temt-,eratures, and some lnbricalion :ire expected in the cutting of green v, ood when 9 " These considerations indicate contrasted to cultmg dry wood. that tool \\eat shotild be less when green x\ood is cut ~l coi1clusion which is not completel_\ snpported by experin!ental data. A po,,sible expluuation [or tile observed wear behavit~r is that \'~hen cutting green wood chemical and or eleclrical cfIects ha \e :.ul overriding elTcct in determining tile \\cur rate of the cutting tool. This paper describes work ~.thich \\as undertaken to clarily the role of electrical action bct\'~een the work and tool materials in tile cutting of wood and tile ilrq-Jorlance of this inle~ acl ion on I ool wear.