Summary: Introduced to use cutting, the method of the whorl inside trail of workpiece of stainless steel of treatment of extruding combination craft, actor or actress the mental allowance that chose craft parameter and cutting tap and extruding tap allocates. 1 foreword machines all through the ages of small whorl aperture on stainless steel workpiece is a difficult problem. Be out of shape as a result of plasticity of stainless steel material big, tenacity is good, treatment is sclerotic and serious, cutting fights muscularity, and tap treatment is to be in close partly undertake below the state, medicinal powder hot condition is poor, discharge bits difficulty, the intensity limit that cutting torque often exceeds tap and bring about tap to break off. We pass pair of cutting tap and the problem that the extruding that do not have bits appears when the whorl inside tap treatment to undertake an analysis, use cutting, means of extruding combination treatment machines small whorl aperture on stainless steel workpiece, obtained idealer result. The trade off study of craft of 2 different treatment is in on stainless steel workpiece under treatment M3 when small whorl aperture, conventional treatment craft is it is a group with 3 tap, with tap of handiwork of lever of bore with a reamer. Repair 3 grind the cutting tap that is different external diameter to be 3 awl to large fraction as a child, attack head drill above all, next ordinal attack 2 awl, 3 awl to shape. Cutting quantity is pressed do not give 3 tap prorata together, can make torque of cutting of every tap susceptive is reduced. But when using this kind of means to machine, sometimes tap still hard to avoid breaks off, and machine aperture of a whorl to need manual tap 3 times, treatment efficiency is very low. Use tap of the extruding that do not have bits to replace the whorl inside cutting tap treatment to have tap strength tall, need not blade is ground, treatment precision tall, efficiency the characteristic such as stability of tall, quality. To aluminium kind of material inside thread machining, want bottom outlet measure only the choice is logical, can use extruding tap cold extrusion. But to stainless steel material inside thread machining, because the cold extruding torque of material is too big, cannot extrusion, do not exceed extruding tap intensity to assure extruding torque, must enlarge bottom outlet diameter, the whorl tooth that this certainly will causes extruding to form height is insufficient, out of tolerance of thread inside diameter. Cutting, the characteristic that extruding combined tap method to combine two kinds of afore-mentioned technique, use two tap to undertake machining, use the cutting tap tap that grinds via repairing on bottom outlet of make choice of above all namely, next reoccupy does not have cold extrusion of bits extruding tap. In machining a process, because head awl is in bigger bottom outlet (compare with photograph of cutting tap tap with sheet) aspirant travel cutting, and 2 awl are in not complete tooth foundation aspirant travel squashs, no matter be,regard the cutting of head awl as tap accordingly, still regard the extruding of 2 awl as tap, torque of its susceptive tap all is reduced greatly, tap breaks off not easily. Use cutting, the whorl inside treatment of method of extruding combination tap has the following advantage: ① treatment precision is tall, dimension is stable; ② whorl intensity is high, exterior wearability is good; ③ extruding tap need not blade is ground, the save labour when the province; ④ tap torque is small, realize motor-driven tap easily; ⑤ machines efficiency to rise apparently. 3 cutting, the choice of parameter of craft of extruding combination tap uses cutting, when extruding combines a method to machine small whorl aperture on stainless steel workpiece, main craft parameter (diameter of bottom outlet of external diameter of tap of the cutting angle that is like cutting tap, cutting, whorl) the choice is crucial. To achieve inside the treatment precision requirement of whorl, relevant craft parameter must match each other, cutting quantity and extruding quantity must reasonable allocation. The whorl inside the M2-6H via that 5mm is with machining deepness below is a choice that shows main craft parameter. The choice basis of angle of cutting tap cutting cutting, the torque of head awl cutting of extruding combination craft not very big characteristic, m2 cutting tap can choose following cutting angle: Before horny G=15 ° , hind horny A=8 ° , ° of cone angle F=17. Because bottom outlet diameter is bigger, volume of head awl cutting is minor, because this chooses bigger cutting angle,won't bring about tap to wear away more quickly, collapse tine and break off. Treatment practice makes clear, the M2 cutting tap that chooses angle of this groups of cutting attacks the cutting in the process in the head smooth. The chooses to choose bottom outlet diameter size of diameter of whorl bottom outlet is mattered to directly inside the treatment precision of whorl. When sheet uses cutting tap tap, because tap trail does not attend cutting, accordingly bottom outlet diameter is equal to thread outside diameter normally subtractive pitch, bottom outlet diameter is namely after shaping inside the internal diameter of whorl. And use cutting, when extruding combines craft to machine, bottom outlet diameter is more than after shaping inside thread inside diameter, because squash,this is tap 2 after attacking cold extruding, diameter of primary bottom outlet produces systole to become inside the trail of whorl, namely whorl tooth apophysis is outspread. Accordingly, according to the extruding of extruding tap the amount chooses bottom outlet diameter correctly to become the key that assures thread machining precision. Of D0 of diameter of whorl bottom outlet choose formula to be D0=d-(0.
6 ～ 0.
In 7)P(1) type: D -- P of thread outside diameter -- pitch classics for many times cutting experiments, can be in certainly on workpiece of 1Cr18Ni9Ti stainless steel inside treatment M2 when whorl, quantity of 2 awl extruding is 0.
1mm, bottom outlet diameter takes Ø1.
75mm; Cutting of awl of head of bottom outlet classics and 2 awl extruding (surplus is 0.
After 1mm) , the diameter is contractible for Ø1.
62mm, accord with the requirement of internal diameter dimension of the whorl inside M2-6H. The choice of cutting tap external diameter has the calibration share of cutting tap shovelling grinding along all whorl profile, in order to reduce the external diameter of tap, the head that can reduce cutting tap already so attacks cutting quantity, reduce cutting torque, can undertake for extruding tap again 2 attack leave certain extruding amount. Of D1 of cutting tap external diameter choose formula to be D1=d-(0.
2 ～ 0.
3)P(2) pursues 1 cutting quantity and the allocation that extruding measures sketch map expresses diameter of 1 whorl bottom outlet and cutting tap external diameter to be worth norms P(mm)d0 (mm)d1(mm)M30.
52.
7 ～ 2.
652.
9 ～ 2.
85M2.
50.
452.
23 ～ 2.
1852.
41 ～ 2.
365M20.
41.
76 ～ 1.
721.
92 ～ 1.
88M1.
60.
351.
39 ～ 1.
3551.
53 ～ 1.
495M1.
40.
31.
22 ～ 1.
191.
34 ～ 1.
31M1.
20.
251.
05 ～ 1.
0251.
15 ～ 1.
The shovel of tap of cutting of 125 right choices grinds quantity and external diameter of affirmatory cutting tap, its purpose is reasonable special rotary valve attacks cutting quantity and 2 attack extruding quantity, make extruding tap attacks formation not complete tooth in cutting tap head model (external diameter is too small, internal diameter is too big) aspirant travel cold extruding, form thereby those who accord with dimension precision requirement is complete inside whorl. The head is attacked cutting is measured and the 2 allocation that attack extruding quantity are like a graph 1 is shown. Experiment via undertaking cutting repeatedly, the external diameter shovel that can decide M2 cutting tap grinds a quantity for 0.
1mm, cutting tap external diameter is Ø1.
9mm, the 2 extruding that attack extruding tap to be in in external diameter are measured for 0.
1mm. Ø1 is in the diameter of make choice of by this parameter.
Cutting undertakes on the bottom outlet of 75mm, extruding combines tap, formation M2 screw accords with the dimension precision requirement of M2-6H. Cutting, the suitable scope of extruding combination craft is in on stainless steel workpiece under treatment M3 when small whorl aperture, want craft parameter only the choice is proper, all can use cutting, extruding combines technology. The cutting angle of cutting tap can be chosen by M2 cutting tap; Diameter of whorl bottom outlet and cutting tap external diameter press type respectively (1) , (2) is chosen. Attack M1 of the ～ that make M3.
The diameter of whorl bottom outlet when 2 whorl aperture and value of cutting tap external diameter see a table 1. The measure that provides to make shaping whorl aperture internal diameter is achieved asks, bottom outlet diameter and cutting tap external diameter concern into inverse ratio commonly, namely if bottom outlet diameter is chosen a few bigger, criterion cutting tap external diameter should be chosen a few smaller; Vice versa. Because the physics of all sorts of stainless steel material is mechanical function is different, should use cutting, extruding combination craft is attacked when making different stainless steel material, cutting is measured and the allocation of extruding quantity also should differ somewhat, bottom outlet diameter and cutting tap external diameter also will be distinguished somewhat, but all can be in the watch lists data range 1 times inside reasonable choose. After head of tap of workpiece classics cutting is attacked, whorl aperture must be cleaned clean, lest the influence cutting bits of the remain inside aperture squashs quality. The head is attacked cutting and 2 attack extruding to all need to join proper lubricating fluid, can choose commonly industrial soya-bean oil or 20# engine oil. The cutting of aperture of the whorl inside trail of workpiece of 4 epilogue stainless steel, extruding combination treatment is comprehensive cutting treatment and the characteristic that extruding machines, the advantage that achieved cutting tap and extruding tap is complementary, choose each craft parameter through actor, can machine the small whorl aperture on stainless steel workpiece smoothly, it is a kind of quality good, loss the advanced treatment technology with small, high efficiency.
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