Of broach of the high-speed steel when blade wears different stuff auger cut

Cast-iron -- hardness is low (it is 175-250HB) commonly, intensity is low, brittleness is big, plasticity is out of shape small, heat conduction rate is inferior, the organization is more loose, cut bits to become smash shape, of broach wear away to go up at the back completely almost, round corner office wears away outside the biggest, block up cutting tool life rises with what manufacture efficiency. To above the problem can adopt following measure: A.

Broach uses corner of the predestined relationship outside double vertex angle part is easy wear away, so flat first abrasion and form double vertex angle, can improve broach life 1 ～ so 2 times. B.

The horn after be being increased appropriately. The horn after blade uses 16 ° of 13 ° ～ to chafe in order to decrease outside, improve broach life. C.

Auger feed should be increased when cutting, lower cutting rate appropriately, and unfavorable use small feed of high rotate speed. D.

If use cooling fluid, must not intermittent use, at the same time discharge wants proper, otherwise, the quantity is mixed less intermittent the local sclerosis that will create hole, and pulverous shape cuts bits abrade point also can accelerate broach to wear away. 2.

High strenth steel -- wait like steel of tool steel, cementite steel, spring steel, bearing, refractory steel. When bore, broach cutting blade wears away faster, life is briefer. To above problem, can use following method: A.

Choose the bit that high-powered high-speed steel or hard alloy make. B.

To hard and fragile rolled steel, the horn before can reducing those who get department of the blade outside the head, be opposite in order to raise point intensity; the steel products with hard and fine plasticity, need not reduce. C.

Vertex angle chooses 118 ° to control can. D.

Use phosphorous cutting oil to make cooling fluid. 3.

Stainless steel -- wait for 3 kinds of stainless steel for martensite, ferrite and austenite commonly. Martensite stainless steel can fight atmospheric corrosion t, mechanical performance is good, handle ameliorable cutting function character via tone, if 30HRC of hardness prep above, criterion broach wears away faster. The volume containing chromium of ferrite stainless steel is higher than martensite stainless steel, cause heat treatment cannot aggrandizement, its cutting performance is poorer than martensite stainless steel. The mechanical intensity of austenite stainless steel and close of medium carbon steel, and its plasticity, tenacity is taller, when cutting negative charge is very big, phenomenon of sclerosis of the treatment in cutting process is serious, heat conduction is poor, heat in metal cutting is in the point point of broach centrally, easy in cutting process generation accumulates bits tumour, and contain in its organization a few carbonization titanium, cause broach to wear away very quickly. To above problem, can use following method: A.

Choose bigger feed and inferior cutting career appropriately, such is helpful for that cut bits to break off, can improve broach life effectively. B.

Vertex angle is increased (140 ° of ～ of ° of 2 φ =135) , can improve broach life. C.

When blade grinds broach vertex angle, two plunge knife must symmetrical. D.

Machine tool and the tigidity of the collet that hold clip are close friends. E.

Cooling fluid wants sufficient. 4.

Titanium alloy -- have high strenth, proportion small, anti-corrosive, be able to bear or endure microtherm and high temperature resistant the character of intensity. By its the organization after anneal can divide alloy of titanium of the photograph that it is α , alloy of β photograph titanium, α + alloy of β photograph titanium. Alloy of α photograph titanium (TA kind) cannot heat treatment aggrandizement, performance of reason room temperature is not high, have medium plasticity, but cutting sex is passable. Alloy of β photograph titanium is passed quench ageing treatment, can acquire taller room temperature property. α + alloy of β photograph titanium (TC kind) bits and the osculatory length in front are cut when treatment shorter, cutting master piece is used around point, because coefficient of thermal conductivity is very small, cutting point temperature is higher, quickened broach to wear away, and because treatment is sclerotic the phenomenon is more serious, stretch coefficient is lesser, the contractive amount of bore is accordingly larger, also affect the life of broach. To above problem, can use following settle way: A.

Be out of shape as a result of titanium alloy flexibility bigger, aperture contracts easily, reason will get a needle to be ground a bit slant, measure 　 B with increasing the dilate of aperture appropriately.

Increase advocate of cutting blade hind horn and the attrition that reduce first flank width to get head and hole wall in order to reduce. C.

Office of corner of outer predestined relationship grinds the transition of a small vertex angle to repair Guang Ren, come loose in order to improve hot condition. D.

Advocate cutting blade point, the horn before be being reduced appropriately. 5.

Brass -- drilling spare parts is to cast brass normally, its characteristic is wear-resisting, fight corrode, but hardness and intensity are inferior, cutting bear is lesser, and plasticity is poorer, the asunder that cut bits (but the plasticity of forming brass is better, cut bits to break) not easily. Getting regular meeting of the classics in cutting brass course to happen " plunge into a knife " phenomenon, namely broach cuts a phenomenon automatically, especially when shortly will drill bore a hole more below can automatic change, very insecure, make aperture exit delimits bad and take burr or make broach dies blade, weigh a broach to break off. To above problem, can accept following means of settlement: A.

Should decrease " plunge into a knife " the problem should make cutting blade not quite sharp, 8 ° of ～ of ° of =6 of τ of the horn before reducing what the predestined relationship outside cutting blade is in so. If get,cut forming brass work, so τ =10 ° . B.

Repair the blade that grind a horizontal stroke to make its narrow, but want semmetry, can drill idealer hole so. 6.

Aluminium alloy -- basically be cast aluminium alloy, easy generation accumulates bits tumour when bore, bore surface roughness is poor, it is more difficult to discharge bits when drilling deep hole, make hole wall is touched gently, cut bits to be blocked up inside broach chamfer again, cause broach to break off. The stretch coefficient of aluminium alloy is small, and linear expansion coefficient is bigger, because this is in,the meeting in bore produces aperture systole. Silicon is contained in casting aluminium, the compound of silicon is very hard, can make broach wears away aggravate. But aluminium alloy intensity hardness is low, low, cutting negative charge is small. Outside dividing aluminium, the plasticity of general aluminium alloy is small, outspread rate is low, because this breaks bits more successful. To above problem, can adopt following settle way: A.

To prevent bore medium aperture contracts, the horn after can be being increased, get a needle to be able to be ground slant slightly a bit. B.

Get deep Kong Shi, vertex angle can choose ～ of ° of 2 φ =135 160 ° . 2, 　 of a few clew in using 1.

Must the broach with reasonable formulate grinds blunt standard, grind in time again, in order to restore its cutting ability. For example: Auger cut general composition steel, the wear limit that is in with corner of the predestined relationship outside broach will decide to be ground again, its wear extent △ =(0.

7 ～ 1.

0)fo millimeter (Fo is) of first flank width. 2.

Should reasonable choose cutting fluid, the attrition in decreasing bradawl effectively to cut and improvement come loose hot condition. Bore serves as rough machining commonly, the main effect of cutting fluid is to improve broach life, cool namely function is close friends, employ emulsification grease solution normally, its thermal capacity is large, coefficient of thermal conductivity is taller, have good cool performance. If bore surface roughness and precision ask somewhat, should use the cutting oil that gives priority to with lubricating so, the miscella that if machine aluminium alloy,engine oil and kerosene use when workpiece is advisable. 3, the cutting effect that wants to obtain ideal and taller manufacturing efficiency must accomplish: 1.

Be chosen by treatment material by what differ get suitably cut cutting tool. 2.

Tigidity of treatment facilities system is better, main shaft has enough power, workpiece clip is held firm and reliable. 3.

The needle is gotten to be in radial circle to beat after cutting tool clip is held should be in 0.

02mm less than, machine means to what workpiece rotates, workpiece rotates the deviation of center and line of cutting tool center should be in 0.

02mm less than. 4.

Cutting tool clip is held dangerous extend a part to answer as far as possible short, install tigidity in order to enhance its. 5.

When means of the refrigeration outside using, cooling fluid must sufficient. CNC Milling