Technology of dry type cutting processes medium application in milling

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The metallic cutting treatment with 1 introductive major nowadays is in order to use cutting liquid wet means undertakes. Cutting fluid is had cooling, lubricant, clean, platoon bits, antirust wait for a function, to prolonging cutting tool service life, assure to machine quality to having main effect. But take seriously to environmental protection increasingly as human society in last few years, a series of negative effect that people begins to pay close attention to cutting fluid place to bring. On one hand, use extensively of cutting fluid need to drain many energy resources and resource, raise finished cost. According to Germany data of a lot of company statistic calculative make clear, charge of use cooling fluid occupies the 16 % of total production cost, and the 3 ～ that the charge that cutting cutting tool spends holds cost only 4% . On the other hand, cutting fluid is relatively serious to environmental pollution, endanger worker health even. Produce pollution less as far as possible to make metallic cutting is machined, people put forward " cleanness turns production " this one concept. Dry cutting is to eliminate cutting fluid pollution, reduce product cost, implementation cleanness changes the most efficient way of production. Want to realize dry type cutting, must material of logical choice cutting tool, design parameter of reasonable cutting tool geometry. Technology of dry type cutting already became metallic cutting to machine one of trends of development. In recent years, its application in turning and milling is increasingly general already, getting cut, boring and gear hobbing respect also obtained major breakthrough. Article union work is real, do type cutting technology to undertake treatise in the application in stainless steel milling only. The function of the requirement cutting cutting tool that cutting of 2 dry type machines pair of cutting tool depends on cutting tool material and cutting tool structure and geometrical parameter. Different treatment method emphasizes particularly on to the design of cutting tool the dot differs somewhat. To doing type cutting to machine cutting tool must have undermentioned property: (1) cutting tool should have taller hear resistance and good wearability. (2) cuts the coefficient of friction between bits and cutting tool to want as far as possible small. (Appearance of 3) cutting tool should make sure a bits is fluent and come loose easily hot. (4) cutting tool should be had higher intensity and impulse withstand tenacity. In actual production, should mix according to the physics of workpiece material, mechanical function working procedure characteristic, reasonable choose cutting tool material, coating, optimize cutting tool structure and geometrical parameter, notice cutting tool material and workpiece material match, ability is designed and make a cutting tool that applies to dry type cutting. Material of the cutting tool when the cutting tool data that dry type cutting processes does type cutting is the most important is to must have each tall red rigid and tall impact resistance. The cutting tool material that applies to treatment doing type at present has exceed fine grained hard alloy, coating hard alloy, pottery and porcelain and cermet material, diamond (PCD) and cubic nitrogen change boron (CBN) . The brittleness of common hard alloy that exceeds fine grained hard alloy to be used normally dies greatly, easily blade. Exceed fine grained hard alloy to be able to raise the tenacity of common hard alloy, have very good wearability and high temperature resistant function, usable Yu Xi is cut and get cut treatment. Cutting tool of coating of coating hard alloy most apply to treatment of dry type cutting, can bear already because of appropriate coating high cutting temperature, reduce cutting tool / cut bits and cutting tool / the coefficient of friction between workpiece surface, reduce the quantity of heat that cutting tool wears away and produces, still can make cutting tool has coriaceous matrix and the cutting blade that contented cutting asks or workpiece face. Accordingly, one of crucial technologies that the coating engineering technology with appropriate matrix and coating combination and feasible economy is treatment of dry type cutting. Commonly used coating base material basically is hard alloy. Coating material basically has TiC, TiN, TiAlN, diamond to wait. Among them TiAlN coating is one of best coating when dry type cutting is machined. The bit of uses at doing type milling coating hard alloy that develops like SECO company: T150M, T25M, F20M, F40M. See a table 1. The sort that expresses razor blade of 1 coating hard alloy and material of coating of sort of knife of applied limits knife apply cutting fluid to use T15OMTi(C, n)+Al2O3 grey mouth is cast-iron / nodular cast iron does cutting T25MTiC/Ti(C, n)+TiN carbon steel / stainless steel is wet / dry cutting F20MTi(C, n)+(Ti, al) N+TiN stainless steel does cutting F40MTi(C, n)+(Ti, al) N+TiN stainless steel is wet / because dry cutting pottery and porcelain and cutting tool of cermet pottery and porcelain are tall hear resistance and good chemical stability, special agree with treatment doing type is cast-iron and quench steel. Dan Jiren gets the better of difference, yi She is broken, restricted its application in dry type cutting greatly. To solve this one difficult problem, abroad already developed razor blade of pottery and porcelain of a few new-style alumina. If Japanese scholar is developed,one kind uses imperceptible grain (0.

22µm) , tall purity (99.

The bit of pottery and porcelain that the powder of new-style alumina pottery and porcelain of 99 %) makes, in dry car, Gan Xi carbolic steel is mixed cast-iron when have superior cutting performance. The sort that cermet is hard alloy, it contains titanium radical compound, binder is nickel or nickel photograph. Cermet cutting tool agrees with dry type cutting. Grind to horniness before use grinding or electric spark treatment normally, cutting tool of usable now cermet undertakes Gan Xi is machined, improved work efficiency not only, exterior quality also got rising. It is good that CBN CBN material has tenacity, stability of high temperature chemistry is good, the characteristic with tall hardness, hardness is as high as 3200 ～ 4000HV, be next to diamond. Because this suits dry type cutting very much cast-iron and quench steel. SECO company was developed a series of CBN razor blade, if apply to the CBN20 razor blade of hard steel of temper by dipping in water of high speed milling; Apply to dry type pearlite of mill of thick, essence is grey the mouth is cast-iron the CBN300 razor blade with nodular cast iron. CBN300 is change what particle size size gets to defy concussion name with special technology from CBN30 foundation, its grain dimension is 22µm. Body of this kind of pure agglomeration, PCBN content (90%) is taller, have very good wearability, admirable thermal conductivity and impact resistance, with former already some PCBN product photographs are compared, it is a kind of new more mature PCBN product. PCD PCD cutting tool has hardness tall, hot conductivity the characteristic with small coefficient of big, linear expansion. PCD cutting tool applies to copper alloy of dry type precision work, aluminium and aluminium alloy, composite material to wait. With PCD cutting tool dry type machines aluminium alloy to be able to reach very high cutting rate and very long cutting tool service life. But PCD cutting tool and iron element response are big, can use at cutting to be not iron spare parts only. Additional, PCD cutting tool cannot endure cutting area to exceed the high temperature of 600 ℃ , accordingly, it cannot extend sexual material cutting tenacity, high. When cutting tool structure and geometrical parameter do type cutting, point of a knife and thermic load of point material susceptive increase greatly, produce all sorts of point loss easily. Bring about cutting tool invalidation finally. Machine quality and cutting tool life to assure workpiece, the cutting force of the generation when when cutting tool is designed, the requirement should consider to machine and attrition force want small, the effect that discharge bits is close friends. Cutting tool of dry type cutting must written guarantee to cutting tool compose and geometrical parameter undertake optimizing designing, if ① design makes,cutting tool is the horn before losing or make around knife face raised, be opposite in order to defer crescent moon depression the harm of edge. ② increases negative blade dip, improve what edge reachs point of a knife to cut position, with raising cutting tool fight concussion and heatproof shake ability to wait a moment. The cutting tool that manufacturer of a few tool already developed can be offerred choose. The octagonal mill razor blade of the ME that designs like SECO company chamfer that break bits used can effective control to cut what bits is formed and discharge bits break bits chamfer, apply to dry type milling technically. The refrigeration of cutting of 3 dry type and lubricant in some circumstances (if deep Kong Zuan is cut, tap) should come true need not the cutting of completely dry type of cutting fluid is difficulty, accordingly, the applied limits of craft of cutting of completely dry type has certain restriction, can use least quantity to lubricate at this moment (the means of cutting of standard dry form of MQL) and air cooling cutting. Least quantity is lubricant, also say sparge is lubricant, it is to use compress air to make the plant of minim oily pulverization, and with very tall speed gush the cutting area to high temperature, can have the cooling, effect that lubricate and discharges bits. The dosage of vegetable oil is wet of cutting extremely one of. The quantity of heat that coequal dosage place absorbs is 1000 times of the law more pouring, consequently greatly bring down cutting fluid cost. Air cooling cutting is to use compress air to undertake cool and discharging bits, the part replaced the function of cutting fluid, but use with MQL commonly, in order to improve lubricant result. The application of cutting of 4 dry type in milling usually we are used to be especially in milling in treatment establishing mill add note cooling fluid, but the intense change that notes cooling fluid to be able to make cutting tool produces temperature is added in milling, when workpiece is cut, milling cutter razor blade cools oneself, cut again fashionable temperature rises again. Temperature changes quickly to produce stress in bit, can bring about the generation of crackle. Although also have when Gan Xi,heat and cooling loop arises, but want under photograph comparing small much, can get settlement through parameter of material of logical choice cutting tool, structure and geometry. To milling treatment uses dry type cutting to be able to get the cutting result of ideal of cutting of specific humidity type. The representative application example that is treatment of dry type milling below. Gan Xi of F20M of coating hard alloy does not lure portal of steel a powerful person (workpiece material: CF -8M, do not become rusty acid-proof cast steel) the uses SECO firm formerly T25M(CVD coating when some factory is machining underside of portal of stainless steel a powerful person) bit is wet thick mill He Jingxi, because rise quickly of production lot, the contradiction of cutting tool life appears more outstanding. This factory is R220 with the model of milling cutter bit body at thick mill.

43-0080-07W(tool cutting edge angle 43 ° , diametical 80mm) , chooses bit coating grade is T25M, bit model grows the) of mill razor blade of 7mm for OFER070405TN-ME15(octagonal edge. Parameter of thick mill cutting: Vc=130m/min, fz=0.

1mm/z, ap=2 ～ 3mm, ae=80% , the cutting tool life of every cutting blade 4 ～ 6. Parameter of cutting of mill of essence of life: Vc=250m/min, fz=0.

16mm/z, ap=0.

7 ～ 0.

8mm, ae=80% . The cutting tool life of every cutting blade: 12 ～ 16. The factory asks thick iron treatment improves cutting tool life, after be being improved for the first time, choose with former and identical cutting parameter, the F40M(PVD physics coating that uses SECO firm) bit is wet thick mill, cutting tool life is 9 ～ 10. This result still did not achieve the goal that the manufacturer hopes. According to abroad introduction of person of the same trade is used do cut way to machine stainless steel to be able to make life of its cutting tool rises greatly, can exceed 20. The F20M(PVD physics coating that uses SECO firm finally) thick mill of bit dry type, bit model breaks bits chamfer to be D18 for OFEN070405TN-D18(, difficult treatment) . Cutting parameter: Vc=180m /min, fz=0.

16mm/z, ap=2 ～ 3mm. The cutting tool life of every cutting blade: 24 ～ 28. Its are cutting tool life rises substantially as a result. Analysis: The metabolic relation of cutting force and cutting temperature is curve of a hump. When cutting temperature Gao Zhichao jumps over hump, as cutting temperature rise further, cutting force can drop, make cutting becomes opposite easy, life of reason cutting tool rises. And if adding person cooling fluid right now, can make cutting area temperature drops, bring about cutting force to rise, wear away aggravate, make cutting tool life is reduced. And the Zun Fang in hump of curve of relation of temperature of cutting force, cutting, the circumstance is contrary, add cooling fluid to meet those who cause cutting strength reduce, make cutting light definitely. Cutting tool life is improved. But the project that through cutting the experiment decides this relation curve is huge of a workload, the workpiece of this respect remains further ground is thorough. Company of treatment of component of some car of Shanghai of cast-iron vent-pipe end panel is machining cutting of dry type of T150M of coating hard alloy when company of Shanghai general motors does not overcome the vent-pipe of the car, the Gan Shixi of razor blade of hard alloy of T150M black coating that uses SECO firm cuts cast-iron vent-pipe end panel. Compare with the photograph of razor blade of pottery and porcelain that uses another firm formerly, manufacturing efficiency rises apparently, every point exceeds cutting tool life 100. Bit body model: R220.

43-0088-S(diameter 88mm, tine number: Z=5) ; Bit coating grade: T150M; Bit model: OFET070405TN-16; Cutting parameter: N=11OOr/min, ap=1 ～ 1.

2mm, vf=600mm/min. The cutting tool life of every cutting blade is more than 100 workpiece. The razor blade of pottery and porcelain of all directions form has 4 point only, the price is higher than the octagonal razor blade of hard alloy, and the in part that point has anise bit only, economy is poorer. The CBN300 of the set of razor blade of integral structure PCBN that company of SECO of plane of cast-iron cylinder body develops grey mouth of dry mill of PCBN cutting tool cuts grey mouth in Gan Shixi behaved when cast-iron cylinder body is planar get the better of uncommonly especially, life of its cutting tool is general PCBN razor blade 4 times and to razor blade of pottery and porcelain, CBN300 can improve life of 50 times cutting tool. CBN300 uses the engine that builds at company of Shanghai general motors successfully already flexible the Gan Shixi on product line cuts grey mouth cast-iron cylinder body is planar, milling rate can amount to 1600m/min, improved the treatment efficiency of engine greatly. Bit model SNMN090312S; Bit body model: R22033-0100-12CT(z=8) , cutting parameter: Ae=80mm, ap=4 ～ 5mm, fz=0.

15mm, vc=1600m/min. The cutting tool life of every cutting blade: 170. The clean workmanship method that treatment of cutting of 5 conclusion dry type is a kind of ideal. The research that abroad machines to doing type cutting and application are wider already, our country is the same as the difference with foreign very bigger than having look on this technology. But the success application example of above can make clear, below existing technology condition, doing type cutting treatment to be in our country can come true, and as the wide application in turning and milling, be sure to drive the application in other treatment method. Of course, do the development of type cutting technology, must rely on provide structure and cutting tool data at advanced knife. Believe the thorough research as technology of dry type cutting and promotion application, the cutting of our country machines efficiency and treatment quality to will reach a new level. CNC Milling