The whorl inside alloy of aviation domain titanium uses the design of tap

26 times, 1 of high strenth aluminium alloy.

38 times. Inside limits of 400~550 ℃ temperature, of titanium alloy than long-term strength, mix than creep intensity than fatigue intensity excel heat-resisting stainless steel. Titanium alloy can divide titanium of the photograph that it is α from metallic textural alloy of alloy, β photograph titanium and (α + β ) photograph titanium alloy. Hardness and intensity press α photograph, (α + β ) the order of photograph, β photograph increases, and cutting processability drops by this order. The hardness of alloy of titanium of characteristic of treatment of cutting of 2 titanium alloy is more than 350HBS or 300HBS undertakes cutting is machined hard, but difficult reason does not depend on hardness respect, and between function of the mechanical, chemistry that depends on titanium alloy itself, physics integrated, cutting machines characteristic expression to be: Be out of shape coefficient is small; Cutting temperature is high; Advocate cutting force is small and back force is large; Cut bits to show crowded split state, treatment surface is easy build hard fragile degenerative layer; Phenomenon sticking a knife is serious. Characteristic of tap of the whorl inside 3 titanium alloy because a lot of character of titanium alloy, tap of the whorl inside travel is entered on titanium alloy material, it is the most difficult process in treatment of titanium alloy cutting, especially more difficult to the treatment of alveolus whorl, and cannot leave tap to attack make. Main show is attack whorl total torque is big, attack 2 times of whorl torque for 45 steel about; Tap tooth wears away too quickly, collapse blade, even by " bite dead " and break off. Its are main the reason is titanium alloy flexibility modular amount is too small, the whorl surface that already machined can produce very big spring back, tine is reached at the back of the side that gives tap tooth at the back of the top very big law Xiang Li, cause very big attrition torque thereby; Temperature of together with cutting is high, cut bits to phenomenon sticking a knife eliminates not easily, cutting fluid arrives at cutting area not easily to wait; Treatment surface produces stress easily to center, form hard fragile layer, be machined whorl surface quality is poorer. The whorl inside titanium alloy is the special sex requirement of contented aviation industry with the design of tap, solving afore-mentioned keys that machine a problem is the treatment performance that improves tap of the whorl inside titanium alloy to use tap, the geometrical parameter that must use tap to titanium alloy tap undertakes optimizing designing, accept proper treatment condition. Undertake improvement from respect of parameter of the configuration of tap, cutting tool, this is very important step, wait for a lot of and different condition according to condition of requirement of precision of workpiece screw form, screw, machine tool at the same time design, choose appropriate tap. Of 1 tap material choose use hard alloy to serve as cutting tool, in order to improve productivity. Should choose property of as small as titanium alloy affinity, heat conduction the fine grain tungsten with good, high intensity is cobaltic kind of hard alloy. At the same time tap also can choose the high-speed steel with good high temperature capability: W2Mo9Cr4VCo8 (M42) , W6Mo5Cr4V2AI (501) reach pulverous metallurgy high-speed steel. Next, to raise the performance characteristics of tap, still can undertake to tap surface coating aggrandizement is handled. Can choose the TiAlCN, TiCN, TiAIN, coating such as TiN, the cutting tool surface after coating has hard layer, wearability is good, with be machined the coefficient of friction between material is small, but the tenacity that does not reduce base material, the durability of cutting tool rises significantly. The design of 2 tap structure is in tap structure respect, what should improve cutting tool data above all is rigid, good stuff combines proper cutting tool form, ability play gives better performance. Can choose straight chamfer tap according to need, jump a variety of forms such as tooth tap and tap of horn of correction flute profile. (1) straight chamfer tap. A.

The influence of the horn after the horn before tap is mixed to its processability. The basis produces the observation of the spot, when machining titanium alloy, titanium alloy by easy generation flexibility is out of shape when cutting and flexibility restores, make attrition force and cutting force increase, cutting tool wears away accelerate, loss of accuracy of the whorl that be cut. Of tap before damage of knife face collapse is serious, happen on cutting awl more near adjacent and oriented part, beginning is individual snail tooth dies, then is tooth of a few snail before knife face is connected piece die. Because the cutting blade of this place is close to external diameter of Yu Luo grain,this is, tooth becomes pointed, intensity is abate. When current part is larger, intensity is abate more apparent, edge suffers force to be centered in the part between snail tine, easier collapse caustic. Because of this tap reasonable before horn should choose according to be being come to by the fabricating characteristics of material of treatment titanium alloy, should the horn before the choice is lesser, the horn before be being chosen for this is 5 ° left and right sides. Horn chooses after undeserved also have certain effect to tap collapse tine, if of cutting awl hind part is too large, criterion tap answers what when attacking, did not fall off to cut bits and already fell off petty cut bits to be squeezed easily from blade valve backside, is not by cut away, produce intense friction and extruding with tap the reverse side, also can cause the collapse damage of face of the knife before tap sometimes. To reduce attrition force is mixed attrition torque, avoid tap to stick bits, improve whorl surface quality, the horn after treatment titanium alloy uses tap is increased for ° of 4 ° ~8. In the meantime, whole tap tooth face should age the shovel is carried on the back completely, the horn after assuring tine side is ′ of 30 ′ ~40. B.

When tap of average data via, choose the L5=2P of cutting awl length of tap normally, ° of cutting taper Kr=17, sinKr/N of · of Ac=P of ply of every tine cutting (N is counted for tine) , n =3, when P=1, ac=0.

09745mm. When tap of titanium alloy via is machined, to reduce tap cutting force, choose L5= of cutting awl length (10~20) P. Enter whorl bottom outlet to assure to guide smoothly, press TanKr= (0.

7~0.

8) P /L 5 chooses cutting taper, namely ° of ~2 of Kr=4 ° , ply of every tine cutting: N=3, when P=1, ac=0.

023~0.

012mm; Ply of every tine cutting decreases considerably. C.

To reduce the enlarge tensor of attrition and whorl aperture, increase the role after calibration part tooth, fall those who machine titanium alloy to use tap taper to increase to (0.

04~0.

08) Mm/25mm. D.

Awl of essence of life is tap adds man-hour to cut make a final and complete tooth model finish machining cutting tool, to improve the whorl dimension precision of titanium alloy tap and exterior quality, must improve the dimension precision of awl of essence of life and exterior quality, reduce cutting load. E.

The groovy form to treatment influence of tap. Tap allows bits chamfer appearance to have very big effect to cutting the figure of bits, the chamfer that hold bit should make sure those who cut bits is successful and curly, and have the larger space that hold bit, to blind aperture tap, this especially important. (2) jump tooth tap. A.

To reduce the attrition force that whorl already cut on tap and workpiece, in straight chamfer tap or section of job of helix chamfer tap, the tine every other on same blade valve a take out ages, again the edge the place that adjacent of photograph of direction of same corkscrewed yarn ages on 2 blade valve is accomplished stagger one ages each other, this kind of tap is become jump tooth tap. The flexibility that as a result of interval take out ages and the space of put apart gives titanium alloy work is out of shape put apart space, reduced the attrition force between tap whorl surface and workpiece whorl surface, reduced tap torque and decreased to stick tooth phenomenon, improved cutting condition; At the same time take out interval ages and the space of put apart can contain juice of one part cutting, make refrigeration sufficient, reduce heat in metal cutting, improved cutting condition further. Use this kind of improvement tap to machine the whorl on titanium alloy, improved the treatment of whorl, the effect is very apparent. Nextpageb.

Treatment jumps when tine tap, its go aging the form is: Maintain whorl of cutting awl ministry changeless (do not change cutting graph and cutting ply namely) , from the 2nd after cutting awl ministry complete tine begins, each a tooth-like part of anything that makes calibration part corkscrewed yarn lies between circuit of circuit take out, make tap cutting condition is improved somewhat, can avoid to produce frit apply phenomenon in calibration part. When age, the biggest diameter of part of tooth form remain, approximate tap trail or allow to be more than trail 0.

1mm, had better not be more than the bottom outlet diameter before tap. Should notice to avoid emery wheel to come up against tooth flank of two side dentiform. C.

The attention still answers in the meantime, the classics in answering to be measured with 3 needles before tap goes aging, measure hard otherwise. Because cannot be found,be in with tap already in near meridian tangent, the standard that does not meet with tooth form of the remain after age again 3 needles. (3) tap of horn of correction flute profile. A.

The tooth body part of common tap and be machined whorl face tooth part is equal. The unoccupied place horn of such tap side edge is 0, when workpiece of cutting titanium alloy, because flexibility is out of shape,restore with flexibility, make tap side edge and workpiece attrition bigger, cutting torque is bigger. To improve this kind of condition, can use tap of horn of correction tooth form. The tooth of horny tap horn is less than correction flute profile to be machined the tooth of whorl horn, it is 60 ° when whorl tooth horn namely when, the tooth of tap of horn of correction flute profile horn is taken commonly for 55 ° . When because tap uses part of 55 ° flute profile,machining whorl of 60 ° tooth horn, can assure tap and workpiece tooth model have ample backlash part, the flexibility that is used at improving work is out of shape and flexibility restores, make cutting force drops in order to reduce attrition. B.

The taper of tap whorl part. The tooth of horny tap horn is less than correction tooth form to be machined the tooth of whorl horn, pass theoretical analysis, go out to make tap is machined correct be machined whorl tooth, must make tap the crown that every cutting ages all falls in be gotten on by the tooth of treatment whorl face. For this, grinding when making tap tooth form, need the last tooth depth that gets on tap cutting awl to age at the first, make cutting awl ages each carry same plane comes grinding, the taper that makes what whorl of ministry of tap cutting awl face has to increase gradually bigger, the retrorse taper that asks namely, it is tap of horn of correction tooth form and common tap this bit the biggest different, whorl of ministry of awl of common tap cutting face is a taper that reduces gradually. When machining titanium alloy cutting cone angle takes 6 ° , the retrorse cone angle of tap of horn of correction tooth form can be 39 ′ . C.

The screw center diameter of tap. After filar taper thread grinding gives retrorse taper, of every tine in diameter is not identical, what measure the first finishing teeth commonly is medium diameter, use 55 ° horn to be measured with 3 needles. When machining titanium alloy in the computational type of diameter is: D20=d2-0.

07P. The figuration law instead that this kind of tap is the tap of level of figuration primary reason whorl becomes a law gradually, when using this kind of tap to attack whorl on titanium alloy, compare with common tap photograph, cutting torque can reduce 30%~35% ; With jump tooth tap is compared, can reduce 20%~25% .

Demand of precision of this kind of tap is high, make more complex. When the 3 notes in be being used actually attack titanium alloy whorl, of cutting fluid choose special important. General better with containing the cutting fluid effect of CI, P, but with the spare parts must be cleaned after containing CI pole to press cutting fluid, corrode in order to prevent between brilliant. Of diameter of the bottom outlet when titanium alloy attacks whorl choose particularly important, can lead high by the tooth (screw is actual the percentage of the ratio of tooth height and academic tooth height) do not exceed 70 ％ to choose size of bottom outlet diameter for the basis: Small diameter and tooth of thick tooth whorl are led high but somes small, attack whorl deepness to be less than whorl can increase appropriately when basic diameter control high rate. The tooth has led congress high to increase attack whorl torque, fold awl of fracture of wire even. The last word regards Chinese aviation industry as enterprise of scientific research of only whorl industry measure, specialization of production, the research and development that devotes oneself to the war industry such as aerospace to use whorl industry measure, make, detect with the experiment, the whorl tool that in the light of aerospace industry treatment titanium alloy, high temperature alloy uses, machinist of nicety of Shaanxi aviation Hong Feng provided a company to already accumulated rich experience, pass the machine tool of advanced high accuracy numerical control on the world that introduces after technical reformation, and import partly detect equipment compose built good platform, assured the use demand of coupling of aerospace company whorl. The company still will continue to increase technical innovation strength, make full use of the enterprise machines an advantage, only design of research and development gives the cutting tool with difficult treatment applicable material, ability becomes contemporary aerospace to make the supplier of first selection tool of the enterprise. CNC Milling CNC Machining