The design of hollow broach is analysed to the influence of cutting function

Hollow broach is a kind of aperture that suits portable tool to use relatively machines cutting tool. But the workmanship as a result of hollow broach is more complex, and cannot machine blind aperture, be used in metallic cutting treatment accordingly and unpopular, machining a few big diameters only normally or just use. Finalize the design without the standard as a result of hollow broach product, because this much is used at special material,the hollow broach of treatment all needs to be developed by oneself. We ever were used one kind at machining the special and hollow broach of difficult treatment material for user development. By U-Mn of treatment material code name, main and chemical composition includes: Carbon (0.

56% ～ 0.

68%) , manganese (1.

35% ～ 1.

65%) , silicon (0.

2% ～ 0.

35%) ; ≥ of data tensile strength 882N/mm2, hardness and wearability all taller. Does this broach use the treatment on the material of Yu Zaihou 17mm? 30+0.

5mm via, <1000W of power of portable drilling machine, requirement broach life > 30min, broach material is W6Mo5Gr4V2. In developing this hollow broach process, adjust the design parameter of broach through relapsing, hand-in-hand travel bore experiments, decide broach geometry parameter is finally: Before horny G=12 ° , hind horny A=9 ° , deputy hind horny A1=3 ° . The design of hollow broach is opposite below the influence of cutting function makes one brief analysis. 1, before the deformation that the change of the horn before the influence of the horn before the horny change influence to broach cutting function to cutting force can affect the data that cut bits, make cutting force produces change thereby. Cut bits to be out of shape bigger, cutting power is greater; Cut bits to be out of shape smaller, cutting force is smaller. Current part is in when 0 ° ～ changes inside 15 ° limits, the span of cutting force correction coefficient is 1.

18 ～ 1. Horn is opposite before when the horn before the influence of broach durability increases bit, can make intensity of point of a knife and radiator are accumulated reduce, at the same time meeting influence point of a knife gets force case. Current part is when be worth, point of a knife suffers pull stress; When current part is negative worth, stress of press press of point of a knife. Like what choose before part is too large, although can add bit sharp degree, reduce cutting force, but place of point of a knife suffers pull stress bigger, intensity of point of a knife is reduced, break off easily. In a lot of broach in cutting experiment all because of before part is too large and attaint. But, because be machined material hardness and intensity are higher, the main shaft of portable drilling machine reachs together with overall and rigid inferior, like what choose before part is too small, of force of the cutting when bore add congress to make main shaft produces vibration, treatment surface appears apparent Zhen Wen, broach durability also can be reduced. 2, hind the attrition between face of the knife after the horn after horny change increases to the influence of broach cutting function can be reduced and cutting material, reduce the extruding that already machined the surface to be out of shape. But the part after be like is too large, can drop the crucial point intensity and medicinal powder heat energy force. Horny size affects broach durability directly after. In bore process, of broach basically wear away the form changes for mechanical abrade and photograph wear away. Consider mechanical abrade to wear away, when cutting life is certain, horn is jumped over after big, usable cutting time is longer; The consideration changes wear away, horn adds congress to make broach comes loose after heat energy force is reduced. After broach wears away, as hind knife face wears away of the belt gradually broaden, cutting power is increased gradually, the quantity of heat that attrition produces can increase gradually, make broach temperature elevatory, lift when temperature broach photograph changes after temperature, broach will appear to wear away quickly. Oil of essence of look line tea tree goes to pop chart of collagen albumen pink blain imprints dispel spot the beautiful shell tool with good good effect of what eye film which kinds of good external use reduces weight good 　 of the which rehabilitate after basking in 3, the influence that broach designs pair of blade to grind treatment is hollow broach dosage is less, treatment batch is small, because this designs Lv of the take an examination when broach,its machine technology issue, machine equipment and treatment of implementation of commonly used cutting tool and blade to grind with commonly used machine as far as possible. Face of the knife before the classics that cut bits is poured out of, because the form of face of the knife before this is direct,the influence cuts bits appearance and platoon bits function. Face of the knife before cutting bits to get in pouring out of a process squashs and chafe, farther generation is out of shape. Deformation of metal of the ground floor that cut bits is the biggest, and face of the knife before the edge produces slippage, make length of the ground floor that cut bits longer, form all sorts of curly appearance thereby. When using hollow broach drill, the hope cuts bits to become drossy or banding bits, with benefit at discharging bits. To facilitate treatment and blade are ground, knife face must be designed before for plane, and do not open bits slot. In use does not need knife face to be ground again before. Knife face is the face that hollow broach wears the most easily again after, also be to wear away the face with the rapiddest rate, because this is hollow,the blade of broach is ground is face of the knife after be being ground with blade will come true. Deputy hind knife face cent is inside deputy hind knife face and outside deputy hind knife face. From grind angle again for, grind again inside, outside deputy hind knife face comes true not easily, because of this pair hind knife face should be designed grind a form to be not weighed. According to above analysis, this hollow broach edge the design is a graph 1 shows a form. Treatment carries out a proof, this design can satisfy use requirement and cutting tool completely to worry a demand again. 4, cutting fluid uses the main characteristic that reachs hollow to the influence of broach cutting function bit is the aperture when treatment inside core not by cutting, because of this cutting of hollow broach the quantity compares twist drill to decrease apparently, the quantity of heat of the generation in needing borer power and cutting is lesser also. With high-speed steel when hollow broach bore, because machine area temperature,affect to broach hardness very big, drop in temperature because of cooling fluid must be being used in this bore process (be like need not cooling fluid, broach wears away to give priority to and will wear away quickly with changing at the beginning) . Begin us to use exterior gush to drench cooling means, but because broach is versed in machine for horizontal axes direction, cooling fluid enters broach edge share not easily, cooling fluid is used up bigger, cooling effect is not ideal. Via redesigning structure of change borer main shaft, will exterior gush drenchs refrigeration turns into in-house gush drenchs cooling, cooling fluid is joined by ministry of hollow broach core, refrigerative fluid can reach broach cutting part smoothly, reduced cooling fluid wastage apparently thereby, improved cooling result. 5, the hollow broach with perfect design of hollow broach use effect should satisfy the following respects to ask at the same time: ① facilitates make, can use general accuracy machine tool and treatment of general cutting tool; ② facilitates new blade is ground, can use common grinder to undertake blade is ground; ③ production efficiency is tall, service life is long; ④ price is low. The hollow broach that we develop basically achieved above requirement. In be used actually, broach durability can be stabilized achieve 50 minutes, surface roughness of bore diameter public errand, surface all achieved design requirement. Because need to weigh face of the knife after grinding only, the horn after broach is controlled more easily, can realize blade to grind conveniently on common grinder. CNC Milling