1、Effect of Tool Rake Angle on Machining Vibration Abstract： Effect of tool rake angle on cutting vibration by experiments are done at different cutting speed in machining operation, and corresponding theoretical analysis is conducted. Result indicates, amplitude of machining vibration gradually decre
2、ases with tool rake angle increasing； while rake angle 00, the biggest unidirection amplitude occurs at V=5070m/min； While 00, it is at V=160180m/min. Moreover, quarding measures is presented on avoiding the biggest amplitude range so as to guarantee quanlity in precision machining at high speed. Ke
3、ywords: machining,vibration,amplitude,tool rake angle In machining operation, tool character is not only decided by material, to a certain extent, it depends on resonable geometrical parameters. Tool rake angle is one of the specialest geometrical parameters, directly affects cutting zone deformatio
4、n, chip morphology, chip break effection, cutting force, tool head strength and machined surface, quality it is researched by foreign scholars. Relative study points out1: tool rake angle also has considerable effect on machining vibration. But what is present situation about research of tool rake a
5、ngle affecting machining vibration? What is the relation exsits between arke angle and amplitude of vibration at different cutting speed and what is the law ? These and others questions have not yet integrated coferences and exact data. For this reason, choose general machine tool, fairly used workp
6、iece and tool material in experimental research on the relation between rake angle and amplitude of machining vibration at different cutting speed, and theory analysis of the result is producted, in an attempt to get relevent datas and corresponding material, and then perfect relevent theory of rela
7、tion between rake angle and amplitude of vibration. This research provides theorecial basis for adopting resonable rake angle in practice, avoiding largest maplitude zone and guaranteeing quality in practice. 1 Experimental Material,Equipment and Instrument 1.1 Workpiece Material Different metal mat
8、erials have different physical mechanical characters. In this experiment, choose general used workpiece material 45# steel in cylindrical machining. 1.2 Tool Material According to piece material, choose YT14 hard alloy tool tip is choosen and drill weld it on to 45# steel tool. Precision and utrapre
9、cision machining are strict on quality of spare surface, while vibraltion affects is mostly. Therefore, the geometrical parameters and corresponding machining quality of six tools are selected in this experiment rake angle 0 is made:-20,-10,0,10,20and 30, tool cutting edge anglekris 45, tool minor c
10、utting edge angle kr is 15, tool orthogonal clearance0 is 8, tool cutting edge inclination 0 is 0, corner radius r is 1.52.0mm, cuting speed V is 2030mmin-1, feed per revolution 0.2mmr-1, and beck engage mentap is 0.5mm. 1.3 Equipment and Instrument In experiment, choose CA6140 lathe (Shenyang First
11、 machine Tool Plant Made), electric eddy-current sensor and riameter WFC- . Electric eddy-current sensor can be used in dynamic untouched survey, survey range is 01500m, resolving power can reach 1m； Measure range of WFC- is 0.2300m (Unidirection vibration value), this viameter fairly resists interf
12、erance, measured data has quite accurate. 2 Experiment Method and Measured Data Considering up limit of vibration in machining opration, clamp wordpiece on lathe CA6140 with cantilever of three-jaw-chuck. Experiment test device sketch map in Fig.1 indicates: Distance from sensor untouched testing po
13、int ( its surface roughnessRa=2.2m)to end surface of chuck is 200mm. Sensor is fixed on lathe tail stock, the measured amplitude (only measure the sensitive direction of work- piece in machining) is an absolute value of piece relative to lathe guide. Distance between cutting part and outter end of c
14、huck is 50190mm. Relation between rake angle and amplitute of vibration measured in machining operation see table 1. With measured data in table 1, relation curve of tool rake angle and cutting speed affecting amplitute of vibration is given in Fig.2. Fig.2 indicates: The measured amplitudes of vibr
15、ation differently correspond to dif- ferent tool rake angle； with rake angle changing, amplitude varies even at same rake angle, while 0 0, the biggest amplitute occurs at V=5070m/min； while 00, it is at V=160-180m/min. To each tool, three repeat experiments are done to verify the reliability of above testing data, its trend of vibration is roughly the same, only the amplitude of vibration changes a little all (relative error less 5%).
