铣削硬质纤维板时不同材料木工刀具的磨损形态

借助显微照相和对刀具磨损过程中的刀刃退缩量、刃口圆弧半径、前、后刀面磨损区的宽度、前、后角变化量以及负间隙等磨损参数的测量分析,研究了高速钢和硬质合金刀具在一般切削条件下铣削硬质纤维板时的磨损形态。结果发现,两种刀具的刀刃退缩量虽然都随切削路程的增加而增加,但磨损后的微观几何形状却各有特点:高速钢刀具在初期磨损阶段后,刀口圆弧半径基本不再加大,磨损主要集中在后刀面,表现为负间隙的不断加大;硬质合金刀具的刃口圆弧半径随切削路程的增加基本成线性增加关系,同时负间隙也不断加大。研究表明,可以用刀刃退缩量来表示刀具的磨损程度,以负间隙表示刀具的变钝程度,以磨损参数的集合来描述刀具的磨损形态。本文建议重磨应以刀具磨损后的微观几何形状变化为依据。

A Preliminary Study of Wearing-profiles of Woodcutting Tools Made of Different Materials in Milling Hard Board

Wearing-profiles of woodcutting tools made of high speed steel and tungsten carbide were investigated in the milling of hard board under common conditions by means of micrography and measurements of edge recessions, edge radii, front wear land widths, back wear, land widths, changes of rake angles and clearance angles as well as negative clearances of the worn tools. The results indicated that although the edge recession of the tools increased with the length of cut,the wearing profiles of the tools were different: the radius of high speed steel tools did not increase almost after the first stage of the wear, which mainly happened on the back face of the tools and indicated that the negative clearance of the tools increased gradually with the length of cut. The radius of the tungsten tools exhibited a near linear increase with the length of cut, and at the same time the negative clearance of the tools gradually increased also. The study indicates that the extent of wear of tools can be indicated by the edge recessions. The extent of bunting can be indicated by the negative clearance of the tools. And, wearing profiles of the tools can be described by parameters used in the test. It is proposed that resharpenning should be conducted according to the mi-crogeometris of worn-out tools.