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A STUDY OF CHIP FORMATION AND CUTTING FORCES IN DRILLING OPERATION

钻削加工中切屑形成和切削力的研究

基本信息

批准号：
60550097
负责人：
HIROTA AKIHIKO
金额：
$ 1.15万
依托单位：
SEIKEI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60550097/
关键词：
Drilling Operation Chisel Edge Chip Formation Process Cutting Model Cutting Forces Oblique Cutting Up-curl Of Chip 切りくずの横向きカール

项目摘要

1. A CUTTING MODEL TAKING ACCOUNT OF THE VARIATION OF WORKING NORMAL RAKE ANGLE, CUTTING VELOCITY AND OTHERS ALONG THE CHISEL EDGE IS DEVELOPED FOR THE CASE THAT THE CHISEL EDGE PORTION IS THINNED TO BE A UNIFORM TOOL-CHIP CONTACT LENGTH. THE MODEL INCLUDING SEVEN VARIABLES WITH RESPECT TO THE GEOMETRY OF DEFORMATION ZONE AND VELOCITIES REPRESENTS THAT THE WHOLE CHIP PRODUCED BY THE CHISEL EDGE IS TO BE A HELICAL ONE.2. A MODEL OF OBLIQUE CUTTING, IN WHICH BOUNDARY OF THE CHIP AND WORKPIECE IS CONSTRUCTED BY TWO CIRCULAR ARCS AND TRANSLATIONAL VELOCITY IS CONSIDERED FOR EXPLAINING THE DIRECTION OF CHIP FLOW, IS DEVELOPED FOR PREDICTING THE CHIP FORMATION SUCH AS UP-CURL OF THE CHIP AND CUTTING FORCES. BY SPECIFYING VALUES OF THE MEAN FRICTIONAL STRESS, FRICTION ANGLE ON THE TOOL FACE AND OF TOOL-CHIP CONTACT LENGTH, ONE SITUATION HAVING A RADIUS OF UP-CURL OF THE CHIP IS DETERMINED AS THE SITUATION TO BE REALIZED BY MINIMIZING THE RATE OF ENERGY CONSUMPTION.3. A CUTTING MODEL INVOLVING UP AND SIDE-CURL OF THE CHIP AND THE VARIATION OF CUTTING VELOCITY ALONG THE CUTTING EDGE IS ALSO DEVELOPED. IN THE MODEL IT IS ASSUMED THAT THE WHOLE CHIP FORMATION PROCESS CAN BE TREATED AS A COMBINATION OF ELEMENTAL OBLIQUE CUTTING ALONG THE CUTTING EDGE. CALCULATED VALUES OF SIDECURL OF THE CHIP CHANGE WITH THE DIFFERENCE OF CUTTING VELOCITY ALONG THE CUTTING EDGE FROM INFINITY IN OBLIQUE CUTTING TO THREE OR FOUR TIMES WIDTH OF CUT.4. CONDITIONS OF GEOMETRIC SIMILARITY BETWEEN DRILLS OF VARIOUS DIAMETERS ARE ESTABLISHED. FROM THESE AND BY CONSIDERING THE VARIATION OF SPECIFIC CUTTING FORCES CHANGING WITH RAKE ANGLES AND THE CONDITION OF TOOL-CHIP CONTACT ON THE TOOL FACE, THE EQUATIONS FOR TORQUE AND THRUST ARE DERIVED.

1.本文建立了考虑工作前角、切削速度等因素沿刃口变化的切削模型，并将刃口部分减薄到一个正常刀-屑接触长度。考虑到变形区和孔隙的几何形状，七个变量的模型表明凿刃产生的切屑为螺旋切屑.本文提出了一种斜切削模型，该模型将切屑与工件的边界线构造成两条圆弧，并考虑了切屑流动方向的平移矢量，从而可以预测切屑的上弯和切削力等切屑形成过程。通过确定平均摩擦应力、刀面摩擦角和刀-屑接触长度的值，将一种具有切屑上卷曲半径的情况确定为通过使能耗率最小化而实现的情况.建立了考虑切屑上弯、侧弯及切削速度沿切削刃变化的切削模型。在该模型中，假设整个切屑形成过程可视为沿着切削刃的基本斜切削的组合。计算了切屑侧切角随沿刃口切削速度差的变化规律，从斜切时的无限大到三、四倍切宽时的切屑侧切角.建立了不同直径钻头之间的几何相似条件。在此基础上，考虑到比切削力随前角的变化和刀-屑在刀面上的接触条件，导出了扭矩和推力的计算公式。