With tap of synchronism of high speed of tap of integral hard alloy

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Heat in metal cutting of Css" Type=text/css Rel=stylesheet> is the archenemy of cutting tool. But unfortunate is, in cutting tool / workpiece interface place, cutting tool often needs to bear enough shortens cutting tool life and the cutting high temperature that limit cutting tool function. To solve this one problem, people developed various cutting tool material, among them the most commonly used is high-speed steel and hard alloy. High-speed steel cutting tool has very remarkable intensity and tenacity, and hard alloy cutting tool is mixed with taller hardness red rigid (the ability that retains hardness below cutting high temperature) and more get the better of one prepare. Generally speaking, the cutting speed of cutting tool of integral hard alloy can achieve the 4 times above of high-speed steel cutting tool at least, and cutting tool life is longer. But, compare with photograph of high-speed steel cutting tool, of hard alloy cutting tool rupture tenacity is poorer, restricted its to be in certain treatment domain (especially tap is machined) medium application. Mix with major turning, milling auger cut cutting tool to differ, the cutting blade of tap is more fragile, its whole intensity is inferior also. Although processing the workpiece data of opposite easier cutting (be like steel) when, the cutting blade of hard alloy tap is incidental also collapse blade, bring about cutting tool invalidation. When undertaking tap to mild steel, successive length cuts bits to may jam the chamfer holding bit of tap, the workpiece material that limitted hard alloy tap to apply at a few easier than steel even tap thereby (be like aluminium and cast-iron) . Steel and other iron a group of things with common features material is the material that the commonnest need adds tool to deserve to use screw, accordingly, tool manufacturer is preventing the tap of blade of cutting blade collapse and damaged in development of land of do one's best. In view of hard alloy and high-speed steel photograph comparing has congenital performance advantage, because tap of this hard alloy already made development focal point. The precision that the dimension precision of whorl decided to whorl is assembled inside and comfortable match a gender. When the whorl inside treatment, tap normally by drilling machine or of flexible those who attack thrum is asynchronous machine tool drive, flexible tap head can drive tap to rotate, ask in order to receive at place nearly inside the rate feed of whorl lead. These vintage machine tools coordinate feed and whirligig accurately hard when tap, and this kind cooperates with the requirement that the gender is thread machining. Accordingly, must use flexible tap head in order to control error limits. When tap, flexible tap head can make tap produces radial beat, those who restricted whorl precision rise. These elements bring about treatment rigid and inferior with tap load inhomogenous. The success application of hard alloy tap depends on the control precision that the clip of cutting tool holds stiffness and feed. To most treatment means, these treatment conditions are of course. But to tap, these conditions just just turn into reality. In recent years, technology of machine tool control progresses ceaselessly, already can realize the synchro control of main shaft roll and feed, thereby can need not reuse is flexible tap head. In addition, type of use shrinkage fitting and collet of cutting tool of fluid pressure type can raise the clip of cutting tool to hold tigidity, radial and jumpy error is more flexible than using also reduce considerably when tap head. When these cutting tool collet rotate homocentric degree in 3µm less than. Although nicety covers barrel type to place the high accuracy that hold power greatly (the function of TGHP) collet inferiors to be mixed at shrinkage fitting type a bit collet of cutting tool of fluid pressure type, but application adds man-hour at tap very effective also. Be not all numerical control machine tools to be able to come true " synchronous " tap (namely " rigid " tap -- press whorl lead when main shaft rotates accurate feed) . Accordingly, the axial displacement for minim of be patient of in order to compensate the small error with synchronous tap inherent machine tool, need collet of pair of shrinkage fitting type, fluid pressure type and cutting tool of sleeve type TGHP to undertake improvement. The petiole public errand of industrial standard tap is relatively comfortable (it is commonly + 0.

0000/-0.

0381mm) . The tap that makes work as a result of city can be in flexible use on tap head, the requirement of dimension public errand that jumps to controlling way accordingly is not strict. For example, according to industrial standard, the diameter of the petiole of tap of 1/2 ″ high-speed steel and whorl diameter jumps the error can be achieved 0.

04mm, and what do not ask to control whorl diameter and blade of oblique plane cutting and tap petiole directly is homocentric degree, this allowed diameter to jump bear of sum of errors is inhomogenous phenomenal existence. Actually, these measure oppose a center to undertake metrical relative to the clip at tap is made. To disentomb the full benefit of material of hard alloy cutting tool, agree the new-style tap that offer company designed a kind to be able to produce tall rigid machine tool and advantage of collet of high accuracy cutting tool adequately, mix with broach of efficient hard alloy like establishing milling cutter, hard alloy tap also uses completely columnar power, in order to ensure homocentric spend and effective clip is held (most tap uses the columnar handle) that carries all directions head. In addition, the petiole size of the petiole dimension of this tap and other cutting tool is same, for example, the petiole dimension of tap of 1/4-20 hard alloy and use at getting to cut 1/4-20 whorl bottom outlet, diameter normally for 5.

The size of petiole of hard alloy broach of 1054mm is same. To produce the advantage of collet of cutting tool of shrinkage fitting type, fluid pressure type or TGHP of accurate sleeve type adequately, the petiole dimension precision of tap of this kind of hard alloy reachs the H6 level of German standard DIN 7160. Accordingly, the petiole dimension public errand of 1/2 ″ tap is + 0.

0000/-0.

0101mm, circularity public errand maintains in 0.

0030mm less than. Tap handle does not need to contain square head, because these cutting tool collet are when tap,be, have enough clamping force to satisfying the tap of afore-mentioned petiole dimension public errand. In addition, what tap takes the cutter hub of whorl part and cutting cant and petiole is homocentric degree in 10µm less than, can raise tap to bear the uniformity of bear. When using tap of this kind of hard alloy and collet of accurate cutting tool together, can form the system of tall rigid tool that can reduce tap diameter to jump, it can satisfy two requirements of tap of success application hard alloy: The uniformity of tall tigidity and tap bear. In the past, just was introduced when broach of integral hard alloy when aperture treatment, to reduce cutting blade bear is mixed prevent collapse blade, the user must reduce every to turn feed (compare) with photograph of high-speed steel broach. Nevertheless, hard alloy broach can use rapidder cutting rate. Get the progress that cuts brand and broach design as hard alloy, the possibility of blade of cutting blade collapse is reduced greatly, make the actual feed rate of broach of integral hard alloy rises ceaselessly thereby. To tap, be counted by head of whorl lead, whorl only and cutting blade cant will control the load that cut bits, the negative charge that the ambient conditions of tap drops action to go up at tap cutting blade further hard. But, to avoid collapse blade, the improvement that broach of integral hard alloy is designing (make its can obtain taller feed to lead) can apply at tap of integral hard alloy as much. These improvement include KC7542 of new cutting tool brand, the matrix of high strenth hard alloy that this kind of brand will develop technically for tap and the coating of accept rice TiAlN that are new development of hard alloy broach are united in wedlock faultlessly together. The improvement of brand of collet of system of treatment machine tool, control, cutting tool, hard alloy and tap design extended the workpiece that can realize efficient tap greatly material limits, include the short material that cut bits not only among them (like aluminium and cast-iron) , also included to grow the material that cut bits for the first time (the steel that be like carbon and alloy steel) (refer to) issueing a list. The hardness of material of example of material of category of material of workpiece of cutting speed limits that when the watch processes different data with hard alloy tap, recommends mild steel of cutting speed *(sfm) (C<0.

25%)1018<220HB300 ～ 400 cut steel 12L14<275HB250 ～ easily 350 common medium / steel of high-carbon steel, tool 1040, 4340, 300 ferrite of ～ of H-13, D-2<32HRC200 stainless steel of steel, martensite steel, PH 430, 410, 17-4 PH<32HRC150 ～ 400 casting pig of ～ of A-47 of 210 nodular cast iron, malleable iron, A-536<300HB250 50 class of 20 ～ , shrinkage fitting type, fluid pressure type or collet of cutting tool of TGHP of accurate sleeve type are used on the machine tool of CNC numerical control that can realize synchronous tap when clip holds tap, new the hard alloy tap that roll out can in order to compare high-speed steel tap hurry up the speed of 5 times undertakes machining, can improve tap productivity substantially thereby. But, making must notice when tap to blind aperture, be not machine tools of all CNC numerical control to have identical synchronous tap capacity. Because machine the tap when the hole bottom of blind aperture and main shaft must decelerate is exited, may appear when tap inverts lead error, cause effect thereby the side direction thrust at tap, cause out of tolerance of the dimension when whorl detects. In addition, as a result of tap decelerate, when invert and be being quickened afresh, still be together with workpiece joint, accordingly, the speed of blind aperture tap should compare recommended via tap rate to reduce 40% the left and right sides. Agree offer company collected a few treatment data that concern tap of new-style hard alloy. For example, be in in cutting experiment, with M12 × 1.

The tap of 75 is right 4340 steel (hardness undertakes via tap for 32HRC) workpiece. Tap of TiN coating high-speed steel can machine 1500 aperture normally with the groovy tap speed of 50sfm; If raise tap rate 300sfm, can machine 158 aperture only. And in this experiment, after hard alloy tap machines 1700 aperture with the tap speed of 300sfm, tap did not wear away almost. In the cutting experiment that processes 4340 steel another times, high-speed steel tap machines the invalidation after 1300 aperture with the tap speed of 50sfm; And M6 × the hard alloy tap of 1 is OK the tap rate treatment of 300sfm exceeds 6000 aperture. Supplier of component of a car uses the discovery when tap of new-style hard alloy machines A-536 nodular cast iron, tap rate can rise 400sfm from 110sfm, can make tap cycle time shortens thereby 65% . Because tap life increased 40000 opening, it is pulverous metallurgy (4 times of life of tap of P/M) high-speed steel, because this is below the case that considers finished cost and cutting tool cost, total tap cost can be reduced 66% . Another manufacturer discovers, hard alloy tap is OK the tap speed of 300sfm processes A-36 steel, can shorten handling time thereby machine 4 3/8 - the aperture of 16. In addition, tap of a hard alloy can be finished need normally 3 - the treatment job that ability of tap of 4 high-speed steel finishs. CNC Milling