Broach of chamfer of tenon of dynamical eddy turntable is designed

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Turntable of 0 introductive eddy is the part with very important part of turbine of whole motive force, its precision difficulty of tall, machining is great, a difficulty also is in whole turbine treatment. And in eddy turntable machining, workload the biggest, difficulty is highest is treatment of turntable tenon chamfer. Material of dynamical eddy turntable is GH698 character, belong to nickel radical alloy, ni content is more than 70% , treatment is sclerotic and serious, cutting processability is very poor. And turntable precision demand is high, machining difficulty is very great, have character to the structure of broach and material very strict and special requirement. The alternative with 1 broach simple material pledges as a result of turntable material is GH698 of high temperature alloy, processability is poor, and turntable precision demand is high, although hard alloy cutting tool waits for respect excel high-speed steel in hardness, wearability and cutting dosage, but its defect is very outstanding: Cannot bear bigger wallop, intensity is low, 1/3 be high-speed steel only, heat treatment difficulty; Cutting tool of integral hard alloy creates difficulty, machinability is poor, the shovel of molded lines is ground must use diamond emery wheel. Because common high-speed steel waits for respect function index in intensity, hardness low, cannot use, and pulverous metallurgy high-speed steel is like CPM-42, although tenacity, hardness is mixed but high-speed steel of other of grinding sex excel, but price on the high side, accordingly, also do not use. Pass trade off study, broach material chooses M42(W2Mo9Cr4VCo8) cobaltic high-speed steel character. The hardness after M42 heat treatment is 67-69HRC, rise when temperature in treatment to 600-620 very tall red rigid is had when ℃ , have very tall wearability, very high intensity reachs good technical properties, consequently material of tenon chamfer broach pledges choice M42 is accurate. Of the length of affirmatory thick broach of structure of 2 thick broach the special broach that deciding round of groove broach is treatment turntable, because cutting tool flute profile is special, broaching machine, pull the element such as clamping apparatus to consider integratedly, use broach of integral structure whole set. Every cover 9, 8 thick broach, broach of a compound essence, broach locates dimension is 40mm × 40mm. The accident of broach should be decided according to actual condition, broach is too short, the amount is much, machine heavy and complicated, workload is big; Too long to sheet broach charge costly, once damage, the loss is too big. To turntable broach, prove via relapsing, use 1000-1200mm more reasonable, decide finally: Length is ordinal it is L1, 2, 4, 5=1185mm, l3, 9=1200mm, l6=1025mm, l7, 8=1145mm. The allocation of cutting surplus of tenon chamfer shaping come true according to graph of two kinds of cutting, be not molded lines part and molded lines part namely, the broach of molded lines part has taller treatment precision than be not the broach of molded lines part. Tenon chamfer is not molded lines part to shape come true by broach of N1 ～ N6, molded lines share achieves by N7 ～ N9. Graph the 1 broaching surplus that is broaching tenon chamfer distributes a plan. Graph the geometrical parameter Af of 1 broach cutting part raises an amount for tine, namely before cutting ministry, hind tooth (or group) high difference; P is pitch, namely the axial distance between two-phase adjacent tooth; Ba1 is first flank, use at tooth dimension is being controlled when production broach, also to raise scale of the knife before broach finishing teeth can wear a number again, improve the life of broach. Had first flank, return the stability that can increase broaching; G0 is the horn before broach; A0 is the horn after broach. Parameter of geometry of thick broach cutting part ages Af raising an amount is below certain broaching surplus surely really, af is bigger, the tooth that cuts need of overall surplus place is less, the length of broach is shorter also, can save cutting tool stuff not only, it is easy that broach is made, and can improve broaching productivity; But Af is too big, cutting force also increases, can bring about broach to break off or the machine tool is overweighted, surface of the workpiece after pulling also is couldn't get assure. What because this tine rises,measure is affirmatory must consider broach intensity, machine tool is tensile, and workpiece surface quality. According to the ply of turntable, the broaching place of each thick knife, use respectively 0.

05-0.

The tine of 07 raises an amount. Pitch P pitch is the important design element of broach, p is too big, criterion broach is too long, make cost not only tall, and broaching productivity is low. In addition, p is too big, working tine number is too little at the same time, broaching process is not smooth, affect broaching surface quality. P is too small, the space that hold bit is little, cut bits to jam easily; At the same time the job ages number is met overmuch, cutting force increases accordingly, the likelihood brings about broach to break off reach machine tool overload; P is too small, still can grind to blade bring difficulty, emery wheel cuts the risk that collides with photograph adjacent tooth from time to tome. Pitch P can press following experience formula to calculate: P=(1.

25 ～ 1.

9)L½(L is broaching length) eddy turntable place needs to machine 4 class turntable, every class 76 chamfer, groove is wide it is respectively 50.

55, axial is obliquitous 20 ° , total cutting length is 17m. The broaching length of every chamfer is: L1=50/cos20 ° =53.

20, l2=55/cos20 ° =58.

53. Before horny G0, hind horny A0 and first flank Ba1 are told to turntable, its material qualitative GH698 is agglutinant big, hardness is tall, flexibility is big, before horn is desirable G0=10 ° , to reduce cutting force, reduce spring back to be out of shape, horn should increase A0=3 ° after, ba1=0 of cutting tine first flank, ba1=0 of finishing teeth first flank.

1 ～ 0.

3. The geometrical parameter of other cutting part allows bits chamfer: The choice is lengthen pitch model. Ministry of this kind of bottom land that hold bit mixes a paragraph to be comprised point-blank by two paragraphs of circular arc, pitch is bigger, have the enough space that hold bit, facilitate the treatment below the quantity rises in very big tine complex model the tenon chamfer of the face. Divide bits chamfer: What pledge in the light of workpiece material is characteristic, tooth flank of thick broach of N1 ～ N4 is wide and tine raises an amount big, break up certain width to will cut bits, facilitate curly and accommodate in the chamfer that hold bit, after broach cutting ages knife face hands in wrong ground to grind a deepness to divide bits chamfer for Hk=1. Because process of broaching of broach of essence of life is the final shape that tenon chamfer shapes,parameter of geometry of cutting part of 3 essence broach is decided really, want to assure the high quality of tenon chamfer surface consequently, the design of broach of essence of life is having crucial effect. The following notices on the design: Compound essence broach by annulus round plane shapes outside groove broach, annulus groovy bottom land shapes broach, tenon chamfer outline shapes 3 parts comprise broach. The tine of each part broach rises Af, pitch P each are not identical, broach of essence of life ages Af raising an amount wants small, when cutting of whole flute profile more want small, to whole essence broach, before tine raises an amount big hind small. Tenon chamfer outline shapes corrective tine wants broach much, pitch wants big, to dynamical eddy turntable, 3 pitch are more than turntable to be in finally tilt the ply on 20 ° direction, form odd tine cutting, such making that turntable has sufficient flexibility to answer shrink time, a corrective tine after making is again new smooth one knife, assure the outline quality of tenon chamfer surface. To improve the service life of broach of essence of life, assure model of face outline correct, when the design, broach outline takes the Least Material Condition of round of groove outline, such broach substance are in the upper limit of round of groove outline. When cutting of whole flute profile, pulling force increases suddenly, broach produces vibration, easy collapse ages or broach breaks off, not only workpiece discards as useless, and the loss that can cause broach, to avoid the happening of this kind of circumstance, the design wants the tine when computation gives cutting of whole flute profile to count when broach of essence of life, bottom of the tine root that ages these, tine opens the slot that divide bits, assure to be able to break bits effectively. The production of 4 broach because annulus all sorts of performance demands with groovy qualitative to cutting tool material broach are very high, because of this pair of semifinished product forging, heat treatment requirement is very strict, especially the tooth form treatment of part of molded lines of broach of essence of life has very great difficulty. Add man-hour to want to notice the following: Mix before tooth chamfer of roller seating space must pliable join, do not want occurrence needle part, the influence discharges bits. Face of the knife after tooth is bright and clean degree be close friends, can reduce cutting resistance so, prevent stress concentration, reduce or avoid the vibration of the machine tool. Cutter hub and part of knife handle join should assure integral linearity, flatness, make with pull clamping apparatus to direct groove cooperates good. Flaw detection wants 2 times when broach is made, eliminate flaw. Of 5 broach long grind blade to grind the meeting when conditional broach is being used gradually wear away, wear away to affect the life of the quality of tenon chamfer and broach to the meeting when particular case when broach, be necessary to grind condition and blade to grind a method to make to the blade of broach so elaborate. Broach judges the condition that broach blade grinds in broaching process: The exterior surface roughness that broaching shapes drops suddenly; Pulling force increases quickly; The first flank width of broach cutting blade exceeds 0.

01mm; Unusual situation appears in treatment, if broach vibration increases,wait. The blade of broach grinds broach material qualitative M42, grind through trying quite, CBN(cubic nitrogen changes boron) when emery wheel grinds broach, want to observe notch carefully, notice the following: Broach is ground not grinding of move back and forth is too fast, can burn broach tooth paste otherwise, cause anneal, make tine dies when broaching. To broach of essence of life and circular arc of bottom land of thick broach tooth! Different, want to have different appropriative emery wheel, assure circular arc and linear and smooth join. Thick broach should be the CBN emery wheel of 100 with granuality, round horn is R2.

5; Broach of essence of life should be 148 ～ with granuality the CBN emery wheel of 180, round horn is R1. When wearing corrective tooth, want a foundation already broaching chamfer number, detect measure result, all places data undertakes a few grinding. Face of the knife after corrective tine must use broach of essence of life marble oilstone is repaired, in machining a process, every play a slot, must face of the knife before corrective to all broach tine undertakes blowing grinding, tumour of bits of take out accumulating (GH698 sticks) quite. After blade has been ground, every knife must degauss. The broach that afore-mentioned methods design 6 conclusion undertook broaching is carried out, the product that broaching gives accords with the design of chamfer of eddy turntable tenon to ask, use method is simple, long grind convenient, it is the broach structure with first-rate chamfer of tenon of broaching eddy turntable. CNC Milling CNC Machining