Metallic cutting is basic regular application (3)

The function of tool cutting edge angle and choice 　 　 (1) the specific value that the function tool cutting edge angle of tool cutting edge angle basically affects each cutting component of force, also affect cut sectional appearance and workpiece face figure. Reduce when tool cutting edge angle, ff is reduced, Fp increases, the generation when carrying curved workpiece and cutting on the head possibly thereby is oscillatory. But should slant horn is reduced, when feed F and Ap of quantity of back penetration of a cutting tool are changeless, cutting width increases, medicinal powder hot condition improvement, cutting tool durability rises. (2) the chooses 　 tool cutting edge angle choice principle of tool cutting edge angle is, below the premise that allows in machining complex stiffness, choose lesser tool cutting edge angle. The tool cutting edge angle of requirement of referenced value work of the tool cutting edge angle of 2-16 of referenced value watch that expresses 2-16 to be tool cutting edge angle penetration of a cutting tool of big, back measures tigidity of κ R system lesser, feed ～ of ° of tall 10 of hardness of material of bigger, workpiece tigidity of 30 ° system big, treatment dish ～ of kind of ° of spare parts 30.

Deputy slant horny function and choice 　 　 (1) deputy slant function 　 of horn deputy slant horn basically affects the surface roughness that already machined the surface, also affect the specific value of cutting component of force. Deputy slant horn is reduced, the value of exterior surface roughness is little, but can increase back force Fp.

(2) deputy slant choice 　 of horn deputy slant when horn chooses, basically press processability to pledge, general and desirable 100 ～ 150, cut off a knife to assure intensity of point of a knife, desirable 10 ～ 20. 3.

What 2-35 of graph of 　 of form of point of a knife is point of a knife is multiform. A) graph is linear model point of a knife pouring wine cup, also call transfer blade. R of κ of =1/2 of ε of general κ R, b ε ≈ (1/4 ～ 1/5)ap, this kind of point of a knife is used at thick car or graph of B) of the 　 on puissant lathe tool is point of a knife of circular arc blade. ε of R of radius of circular arc of point of a knife increases, average tool cutting edge angle is reduced, the value of exterior surface roughness is reduced, cutting tool durability can rise, but Fp force increases, the meeting in cutting produces vibration. C) graph is parallel blade, also call Xiu Guangren. It is the simultaneous where a thing can be put to best use that grinds a R/=0 of a paragraph of small κ in place of close point of a knife of deputy cutting blade. ε of B of length of the blade that repair light / =(1.

2-1.

5)f. Xiu Guangren can reduce the cost of exterior surface roughness, but B ε causes vibration easily greatly too. D) is point of a knife of big circular arc. Its are average tool cutting edge angle and deputy slant horn all lesser, cutting tool intensity and durability all taller, workpiece surface surface roughness is worth lesser. (4) 　 of blade dip 　 1.

The function of the dip of function 　 blade of blade dip basically is to control the flow direction that cut bits, make the crucial point sharp while, change the working position of cutting blade. The control that if pursue,2-36 place shows the dip that it is blade to be flowed to to cutting bits. Orthogonal cutting (λ S =0 0) when, cut bits to be poured out of approximately along the normal direction of cutting blade. And bevel angle cutting (0 0 of ≠ of λ S) when, the normal direction of blade of cutting of the deviate that cut bits is poured out of. When 0 0 of λ S ﹤ , cutting flow direction already machined the surface, consequently meeting cut already machined the surface; 0 0 of λ S ﹥ , cut the change that bits flows to, make act well actually before horn increases, raised the sharp rate of cutting blade. If graph 2-37 place is shown, below the condition of interrupted cutting, bevel angle cutting can make cutting blade is cut smoothly gradually cut, but when λ S ﹥ 0 when, point of a knife can contact workpiece above all, easy collapse blade; And λ S ﹤ 00 when, the cutting blade that is far from point of a knife contacts workpiece first, protected point of a knife already, rose to bear again percussive ability. But negative blade dip can make back force F P increases, bring about workpiece to be out of shape vibration produces in reaching cutting. 2.

The choice 　 blade of blade dip chooses obliquitously to answer the basis produces a condition concrete analysis, can press processability to be chosen character usually, ～ 5 0 of S =0 0 of fine vehicle λ ; ～ of S =0 0 - 5 0; Intermittent ～ of turning λ S =-30o - 45o; Should not be when machining complex tigidity is poorer choose negative blade dip. 5, the choice 　 　 of reasonable cutting dosage (one) when the principle 　 that cutting dosage chooses determines cutting dosage, should be to be in assure to machine quality (the surface is rough with treatment precision) below the condition that requirement and machining complex tigidity allow, in make full use of machine tool power and the quantity of the biggest cutting when developing property of cutting tool cutting. When rough machining, semifinished product surplus is large, the technical demand such as the geometrical precision of workpiece and exterior surface roughness is low, because this answers in order to develop the cutting property of machine tool and cutting tool, reduce motor-driven time and auxiliary time, rise productivity and raise cutting tool durability, regard a choice as the main basis of cutting dosage. When finish machining, mental allowance is not big, treatment precision is tall, exterior surface roughness is worth a requirement small, because this answers to regard a choice as in order to improve treatment quality the main basis of cutting dosage, consider to improve productivity as far as possible next. (2) the order that the dosage of choice 　 cutting of cutting dosage chooses should be to decide back penetration of a cutting tool measures Vc of speed of F of again A P, affirmatory feed, final affirmatory cutting first. Because be in cutting dosage in 3 element, a P of quantity of back penetration of a cutting tool is the smallest to the influence of cutting tool durability, and cutting speed Vc is the biggest to the influence of cutting tool durability. 1.

The choice 　 that carries penetration of a cutting tool on the back to measure A P should choose generous to carry penetration of a cutting tool on the back to measure, take a knife in as far as possible in, the mental allowance that should excise this working procedure treatment is excised. If be when rough machining, pass when mental allowance when big or machining complex tigidity is poorer, also can divide second: 3/4)A of ～ of Ap1 A P1 =(2/3 of first time feed (2-12) 　 1/4)A of ～ of A P2 A P2 =(1/3 of the 2nd feed (2-13) the A in 　 type -- -- unilateral surplus (Mm) . 2.

The intensity that the main factor of F of the biggest feed is arbor and razor blade, intensity of feed orgnaization reachs the rough machining of choice 　 limitation of feed F the tigidity of machining complex. Expressing 2-17 is the feed when the round end panel outside thick car of hard alloy and high-speed steel lathe tool. Express the feed that 2-18 allows for intensity of hard alloy razor blade. The main factor of the biggest feed when restricting finish machining is the exterior surface roughness that machines the surface. Watch 2-19 is the when semifinishing machining of round lathe tool feed outside hard alloy. 3.

The main factor of the Vc of speed of cutting of the limitation when choosing 　 rough machining of cutting speed Vc is cutting tool durability and machine tool power. The main factor that cutting speed Vc limits when finish machining is cutting tool durability. Force of the cutting when finish machining is lesser, machine tool power can be satisfied commonly. After already should deciding back penetration of a cutting tool measures Ap and feed F, press T of durability of reasonable cutting tool, when begging cutting to spend Vc, in order to issues formula: (The Vc in type of 2-14) 　 -- -- , cutting speed (M/min) ; T -- -- , durability of reasonable cutting tool (Min) ; M -- -- , index of cutting tool durability (the 2-9 that check a watch) ; C V -- -- , cutting speed coefficient (the 2-20 that check a watch) ; X V, Y V -- -- measure A P to carry penetration of a cutting tool on the back respectively, the feed F influence to V C index (the 2-20 that check a watch) ; K V -- -- , cutting speed amends coefficient (～ of the 2-21 that check a watch expresses 2-24) . According to N= of 　 of 　 of N of rotate speed of workpiece of computation of D Wn/1000 of V C= π (1000v C) / (the N in type of 　 of π D W) (2-15) -- -- , workpiece rotate speed (R/mim) ; V C -- -- , cutting speed (M/min) ; D W -- -- , diameter of workpiece work surface (Mm) . According to machine tool manual, choose the rotate speed N with cheaper close. CNC Milling CNC Machining