Hard alloy broach is repaired grind the applied exploration with coating technology

Enough hardness. The hardness of broach must is more than by the hardness of treatment workpiece. 2.

Enough strength and tenacity. Because broach is bearing when processing work very big turn round force and axial force, because this must have enough strength and tenacity. 3.

Enough wearability. Because be machined material tenacity is good, the edge when requirement cutting wants enough and sharp, accordingly cutting tool material must have enough fighting to wear away ability, such ability reduce treatment sclerosis. 4.

Cutting tool material and workpiece affinity want difference. As a result of this workpiece chemistry character wants tall, because this asks cutting tool material and titanium alloy affinity want difference, lest the journey diffuses and cause stick a knife, break get a phenomenon. Current, apply to the material sort that makes cutting tool extremely various, include tool steel, hard alloy, exceed hard data to wait. At first, the attempt uses broach of common high-speed steel to undertake coating has a test, price of broach of common high-speed steel is low, after using coating technology, can reduce the coefficient of friction of cutting tool and workpiece apparently, improve cutting tool life. But because machine tool rotate speed is higher, intensity of place use broach is insufficient, broach is caused to break off in machining a process, the effect is not ideal. Hard alloy is the material of a kind of cutting tool that newest development rises, apply to the thick finish machining of most material, include steel, cast-iron, special material and plastic. For this, the decision uses bit of integral hard alloy. 3, broach is repaired those who grind each parameter is affirmatory 1.

The main and auxiliary ichnography of twist drill assists plane a few times of 1 standard twist drill by the graph 1 see, a few of twist drill main and auxiliary plane are: (1) tool reference plane: If take no account of auxiliary motion, twist drill head advocate the bit more aleatoric tool reference plane on cutting blade, it is to pass this to nod and the plane that includes broach center line. As a result of the framework characteristic of twist drill, broach advocate the tool reference plane that orders each on cutting blade is change. (2) tool cutting edge plane: Advocate the bit more aleatoric tool cutting edge plane on cutting blade, it is to include direction of speed of this bits of cutting and cut the plane that machines the surface at this bits. Tool cutting edge plane and tool reference plane are perpendicular, and advocate the tool cutting edge plane that orders each on cutting blade all not identical. (The section plane in 3) : The central line that passes broach and with two advocate the plane of cutting blade parallel is called in section plane, section plane has only in. (4) column section plane: Advocate the bit more aleatoric column section plane on cutting blade is the columnar range that pass this to nod and makes, advocate the columnar face that the different column section plane on cutting blade is different radius. 2.

Of the main geometry parameter of twist drill broach choose a plan basis of parameter of geometry of cutting part of 2 twist drill pursues 2, the main geometry parameter of twist drill broach chooses to include: (1) broach carries horny choice on the head. Vertex angle is two advocate cutting blade is in in the umbriferous included angle on section plane. The vertex angle of broach of standard twist drill is 118 ° . When broach vertex angle is lesser, cutting knife is long, cut cut bits wide, broach torque is consequently bigger, axial fights force big also. Cut rate of state of helix of bits roll into at the same time big, the space that the place that cut bits occupies is large also, platoon bits is not smooth, the influence is cooling. Broach vertex angle decides to cut the size of the horn before bits width and broach. When broach diameter and feed are certain, increase vertex angle, criterion scrap narrow, the bear on unit cutting blade is reduced. In the meantime, the horn of point of a knife outside broach is reduced, reduced knife sharp-angled to wear away speed, be helpful for coming loose at the same time hot, durability also gets rising. The horn before vertex angle is right has very big effect, increase vertex angle to be helpful for improving the cutting condition of the place that get a heart accordingly. Vertex angle influence cuts the way that bits pours out of. Vertex angle is bigger, cut bits curly the rate that becomes helix is minor, and flatter, easy eduction, improved platoon bits performance namely. Cutting tool designs a material related the basis, hardness of product of combinative place treatment is not tall, but agglutinant bigger characteristic, choose this broach vertex angle to be 140 ° . (The choice of the horn after the horn before blade of 2) broach cutting is mixed. The horn before Nextpage is located in advocate the make choice of on cutting blade nods advocate inside section plane, be in front with the included angle between tool reference plane. Cutting tool designs a material related the basis, advocate nod arbitrarily on cutting blade before the computational formula of 0 is horny λ : In type by on type can see, of twist drill before horny λ 0x is decided by the other geometry parameter of broach. Of twist drill before horn is in place of the predestined relationship outside its normally + 30 ° , jump over toward the center more small, central part is - ° of 64 ° ~ -60. When the machine tool undertakes high speed cutting, horn is out of shape to cutting before the influence that reachs cutting power is minor, use at the same time lesser before strength of point of a knife can enhance when horn. Through external predestined relationship place is + the horn before 30 ° and the comparative experiment of the horn before 25 ° can see, before of horn reduce apparent to raising cutting tool life to have effect. For this, the predestined relationship is in outside before horn is taken for 25 ° . Hind horn and before horn is located in same advocate inside section plane, be advocate from the back with the included angle between tool cutting edge plane. To twist drill, advocate nod arbitrarily on cutting blade hind measure in the column section plane that horn orders in this, it is the included angle of face of the knife after be being mixed through tool cutting edge plane of this bits. Outer predestined relationship manages part after the biggest, approach a center more smaller, of the standard twist drill that nominal diameter is 17mm hind horn is ° of 9 ° ~12. Design a material according to cutting tool, horny action is face of the knife after reducing cutting tool and the attrition force that already machined the surface after, obtain taller exterior surface roughness thereby. After current part is certain, horn is jumped over after big, point is sharper, but can reduce wedge horn to affect cutting tool accordingly intensity and medicinal powder hot area. For this, what choose the actor after broach is a few smaller, take for 8 ° . (3) broach helix angle is analysed to the influence of broach life. By the appearance characteristic of twist drill each bits of helix angle on knowable cutting blade is change. Round place helix angle is bigger outside be being stood by more, horn also is jumped over before big, cutting blade is sharper, cutting performance is better also. And approach the point that get a heart helix angle is the smallest, cutting performance is poorer, can become here grinding ball arc state, in order to improve cutting condition. Helix angle is affected directly advocate of cutting blade before horn. Helix angle is bigger, criterion point is sharper, cutting is lighter, can cause serious treatment sclerosis phenomenon to make the crucial point very sharp otherwise wear away. Helix angle increases, cutting blade intensity is abate, wear away fast, can produce the phenomenon such as cutting blade burn down even. Cutting tool designs a material related the basis, take helix angle to be able to satisfy use requirement for 30 ° , facilitate large quantities of quantities are produced at the same time. (The relevant processing of 4) point. The processing of point includes horizontal blade to amend, arris and pour the measure such as blade. Among them B = -0 of horizontal blade amendatory.

025 × Dc, c value is taken 0.

32, r = 02 of the S in horizontal blade circular arc × Dc. In addition internally λ of the horn before blade and feed horn β had relevant consideration. Be aimed at by treatment material, the machine tool machines function, machine parameter, clamping apparatus operating mode, undertook appropriate passivation to the point of broach, improve bit auger cut function, reduced cutting tool wear extent. Graph 3 fall in identical cutting condition to pass passivation and the point that do not pass passivation, cutting is identical the microcosmic analysis after quantitative workpiece. Can see from inside the graph, the point that handles through passivation wears away lesser, and character be yielded by treatment measures stability. Graph the point state after processing of 3 courses passivation and the bit that do not handle through passivation are processing same amount work is comparative 4, the application of coating technology is below the circumstance with cutting changeless parameter, produce cost to rise to manufacture efficiency and be reduced, use coating technology to cutting tool, reduce cutting tool to wear away, in order to raise cutting tool durability more and more make a kind of trend. Cutting tool coating is to point to better in intensity and tenacity hard alloy or high-speed steel (HSS) matrix apparently, use the difficult frit metal with good wearability of layer of Tu Fuyi of method of gas phase deposit or metalloid compound. Coating regards a chemistry as protective screen and hot protective screen, reduced cutting tool and workpiece between diffuse to react with chemistry, reduced cutting tool to wear away thereby. Coating cutting tool has exterior hardness tall, wearability is good, chemical function stability, heat-resisting is able to bear or endure thermal conductance of Xiaohe of factor of oxidation, attrition is low and characteristic. Deposit of physical gas phase (PVD) it is gas phase of a kind of physics reaction grows law. Deposit process is to be below vacuum or condition of low pressure gas discharge, undertake in microtherm plasma namely. The corporeal source of coating is solid state material, through " evaporate or splash shoot " hind, the new solid state that differs completely with base material function is made in workpiece surface corporeal coating. PVD coating material basically is TiN, tiCN, crN, tiAlN, alTiN, alCrN, WC/C, the component such as DLC and diamond, different applied domain, need to choose different coating material. The ply of coating has a few micron only normally, hardness is steely however 2 to 5 times. Cooperate through company of coating of as top as the world level, used its HELICA of coating of newest generation broach, its are coating of class of rice of the 6th acting accept, top job temperature can amount to 1100 ℃ , with the friction of steel coefficient is 0.

25. Next watches are in cutting parameter and cutting tool parameter identical requirement falls, the contrast that after experimenting through several, makes expresses: Can see from this, through the broach after coating treatment amount had apparent promotion, odd cost is reduced greatly. 5, conclusion 1.

Fall with use environment in parameter of relevant treatment data, cutting, broach is relevant of parameter optimize improve, machine efficiency to improving a product, reduce effect of side of cutting tool cost remarkable. At the same time technology of cutting tool coating is decreasing small cutting tool to machine the coefficient of friction in the process, reduce cutting tool cost, raised the respect such as cutting tool life to have apparent effect. 2.

The correction home application that grinds parameter to be being repaired related broach is not much, need to undertake relevant exploration and experiment study further. 3.

This technology application got popularizing stage by stage, initial effect already was obtained in showing to already processed application in the bore of product of the other inside the company. CNC Milling