Move toward compound treatment -- the inevitable trend that engine crankshaft machines

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After entering 21 centuries, engine crankshaft produced tremendous change in the respect such as workmanship, cutting tool. The craft of much knife turning that led nearly half many century and manual grinding craft, because treatment precision is low,mix flexible the reason such as difference, exiting historical arena stage by stage. High speed, efficient compound processing technique and equipment enter car and component manufacturing industry quickly, efficient and compound processing technique is in high speed crankshaft already had in treatment production quite the application of degree, will be its develop a tendency necessarily. Current situation of equipment of crankshaft processing technique is current, majority of product line of domestic crankshaft stale is comprised by general accuracy machine tool and special machine tool, manufacturing efficiency and automation degree are relatively inferior. Rough machining equipment uses neck of main shaft of crankshaft of turning of much knife lathe and connecting rod journal commonly, stability of working procedure quality is poor, produce greater treatment stress easily, achieve reasonable mental allowance hard. Finish machining uses the common crankshaft grinder such as MQ8260 generally to undertake kibble, half essence is ground, essence of life is ground, polishing, rely on artificial operation normally, consistency of not stable, size differs treatment quality. Vintage product line a main characteristic is common device too much, by treatment crankshaft of nodular cast iron is calculated, a product line has 35 ～ 40 equipment. Author Ceng Kao has checked product line of crankshaft of domestic some forged steel, rough machining is used common outside neck of mill treatment main shaft and connecting rod neck, next neck of main shaft of vehicle of numerical control fine and connecting rod neck, the grinding of working procedure of repass much talk just turns into finish machining working procedure. So equipment of this product line amounts to many 60, cause product turnover string long, field takes up the area is large, its manufacture efficiency rely on much stage equipment to decompose working procedure and surplus to rise completely. And what manufacturing industry of current car engine crankshaft is faced with is the following problems however: Much breed, small lot is produced; Date of delivery shortens greatly; Reduce manufacturing cost; The occurrence of difficult cutting material makes machine difficulty to increase apparently, the task that a lot of need solve offerred in treatment, be like hard cutting; To protect an environment, the requirement is used less or need not cutting fluid, realize dry type cutting or cutting of standard dry form namely; Be based on above circumstance just about, be in since entering 21 centuries, high speed, high spirit, efficient compound processing technique and equipment are in car crankshaft manufacturing industry received rapid application, manufacturing efficiency got very big rise, because equipment is produced in product line of this engine crankshaft,the amount is able to decrease. The author ever saw in product line of crankshaft of some car engine, all fronts equipment (include aggrandizement of heat treatment, surface) only 13 equipment are controlled, product turnover line efficiency of short, treatment is tall, easily quality controls government. Crankshaft is compound the development of processing technique 20 centuries 80 time later period, the crankshaft car that German BOEHRINGER company and HELLER company development gave to perfect - the car pulls a machine tool, this treatment craft is crankshaft turning craft and crankshaft car help technology perfect union, manufacturing efficiency precision of tall, treatment is good, flexible degree of strong, automation the tall, time that change a knife is short, suit to have the treatment of the heavy crankshaft that cut groove particularly, the crankshaft after treatment can undertake essence of life is ground directly, working procedure of leave out kibble. Accordingly, crankshaft car - the car helps treatment technology is one of treatment craft that at present midstream of rough machining of the crankshaft on international goes. 20 centuries machine tool of the mill outside the crankshaft of new-style CNC high speed that 90 time metaphase appears makes craft of crankshaft rough machining went up again a new chance to extricateoneself from an awkward position. The mill outside the mill inside CNC crankshaft and crankshaft of CNC high speed is comparative, mill puts in the following defect inside: Be opposite not easily speed of knife, cutting is inferior (do not be more than time of cutting of 160m/min) , blame normally longer, machine tool invests cycle time of more, working procedure longer. And the mill outside crankshaft of CNC high speed has the following advantage: Cutting rate is high (can be as high as time of 350m/min) , cutting cycle time of shorter, working procedure force of shorter, cutting temperature rise of lesser, workpiece life of inferior, cutting tool is tall, the time that change a knife is little, treatment precision is taller, flexible better. Accordingly, the mill outside crankshaft of CNC high speed will be the development direction of crankshaft rough machining. The author from motor-car limited company in Jiangsu South Asia car crankshaft product line sees Feiyate two facilities of German BOEHRINGER company, among them car of crankshaft of aperture of an amount to - the car pulls a machine tool, additionally 1 is the mill outside crankshaft of CNC high speed, experienced personally " cut iron to be like mud " feeling. According to expert introduction, crankshaft car - the car pulls a machine tool special agree with journal has heavy the crankshaft that cuts flank of groove, balance piece to need not be machined; And the mill outside high speed cannot machine axial to have heavy the crankshaft that cuts groove. This milling machine lets the milling machine outside moving for the high speed of VDF 315 OM-4 of German BOEHRINGER company, it is German BOEHRINGER company what be design of car engine crankshaft to make only is flexible CNC Milling, this equipment applies workpiece circumgyrate and servo of milling cutter feed to use control technology repeatedly, can install clip not to change crankshaft centre of turning circle, follow move dog the connecting rod journal of milling crankshaft. High speed of VDF 315 OM-4 uses lathe bed of structure of composite material unifinication along with the mill outside moving, workpiece synchronism of two upright electrons rotates drive, have precision of dry type cutting, treatment efficiency of tall, cutting is advanced characteristic; This milling machine uses SIEMENS 840D CNC to control a system, through the input the basic parameter of the spare parts can create machine program automatically, can machine length to be in in diameter of 450 ～ 700mm, circumgyrate all sorts of crankshaft of 380mm less than, error of diameter of connecting rod journal is ± 0.

02mm. By on can see, the craft with crankshaft more popular rough machining is: Main shaft neck uses a car to help the mill outside craft and high speed, connecting rod neck uses the mill outside high speed, and apt high speed follows the mill outside moving, use dry type cutting entirely. Because price of this kind of foreign equipment is high, product finished cost is very high, a few machine tools of domestic produce manufacturer (like Qinghai the 2nd machine tool creates finite liability company) developed milling machine of crankshaft of high speed of lathe of numerical control crankshaft, numerical control in succession, car of numerical control crankshaft pulls the special machine tool such as the machine tool. Crankshaft finish machining uses case of grinding of grinder of domestic numerical control quite general already, product treatment precision already had quite of degree rise. The treatment that improves increasingly to satisfy crankshaft asks, raised very tall requirement to crankshaft grinder. Contemporary crankshaft grinder besides wanting to have very tall static state, dynamic stiffness and very tall treatment precision, still ask to have very tall grinding efficiency and more flexible. In recent years, more the treatment precision that asks crankshaft grinder has stability, for this, set Cp ≥ to the process capability coefficient of crankshaft grinder 1.

67, the effective treatment common difference that this means requirement crankshaft grinder should compare crankshaft given tolerancepublic errand small in part. Mix as contemporary drive control technology, measure cubic nitrogen of control, CBN(to change boron) the application of emery wheel and advanced machine tool component, for the high accuracy of crankshaft grinder, efficient grinding treatment created a condition. A kind say follow the technology that uses grinding for connecting rod neck. Reflected the material gain that these new technologies apply integratedly just about. Along with the grinding efficiency that moves grinding craft to be able to raise neck of crankshaft connecting rod significantly, treatment precision is mixed this kind treatment is flexible. When undertaking following moving grinding to connecting rod neck, crankshaft undertakes gyral for axes with main shaft neck, place next grinding in outfit neck of all connecting rod. In grinding process, wheelhead implementation moves feed toward compound pendulum, dogging neck of prejudicial revolving connecting rod undertakes grinding is machined. Want implementation to follow move grinding, x axis besides must have tall dynamic property, still must have dog enoughly precision, the appearance public errand that with ensuring place of connecting rod neck asks. The application of CBN emery wheel is to realize connecting rod neck to follow the fundamental condition that changes grinding. Because wearability of CBN emery wheel is tall, the diameter in the emery wheel in grinding process is changeless almost, nap but grinding 600 ～ 800 crankshaft. CBN emery wheel still can use very high grinding rate, can use the grinding rate that is as high as 120 ～ 140m/s commonly on crankshaft grinder, grinding efficiency is very tall. With Yu Qu axis the machine tool of compound treatment mentions compound processing technique, must mention compound treatment machine tool, the definition of compound treatment machine tool also changes along with the times. Called machining center compound treatment machine tool in the past, but the breed that exchanges treatment because of the tool is restricted, and the field that also does not take to give cutting to machine, had been what general machining center says compound treatment machine tool no longer now. Compound machine tool should have process market to become a function, a variety of treatment are compositive function. From manufacturing industry located environment looks, compound treatment machine tool will be one of machine tool products that develop mainly all the time, the function expands ceaselessly, can side with " a machine tool makes plant of a coolie " directional stride. Neck of crankshaft connecting rod is followed move graph of grinding machine principle to be in crankshaft is compound in machining a machine tool, compound machining center has the horizontal car mill that Austrian WFL company produces certain representative. WFL company put forward " hold card, all and finishing " concept. Center of mill of M40G this car is compositive center of turning of double main shaft, 5 axes machining center, deep aperture boring, mill, get and 3 coordinate function at a suit, the Che Xi that has double main shaft in can undertake be machininged completely to crankshaft on compound machining center, the crankshaft after treatment can turn into finish machining working procedure directly. At present home also rolled out similar compound machine tool, during CIMT2005, machine tool of Shenyang numerical control is limited the machining center of CKZ80-5 Che Xi that liability company exhibits is a compound machine tool, represented the top level of our country congener machine tool. Axis of the X in 5 axes, Y, Z, B uses this machine tool linear grating feet or circularity grating feet detect, can realize closed-loop control. Stock of this machining center 96 labour of 48 ～ Kukeshi shows the knife to change a knife automatically, outfit card can have car, mill, auger, boring, tap the treatment that wait. In respect of crankshaft finish machining, also appeared the grinder of CBN numerical control with compositive working procedure, install clip grinding namely neck of all crankshaft main shaft and connecting rod journal, this kind of grinder matchs head of double emery wheel to wear commonly. Brave of project machine, Germany overcomes Japanese TOYADA (the grinder of this kind of numerical control of the production such as NAXOS of JUNKER) , Germany is more mature equipment. Here is brief the function that introduces the GF70M-T crankshaft grinding machine that Japanese TOYADA is versed in machine development produces: This machine tool is to satisfy much breed, low cost, high accuracy, big batch the grinding machine of numerical control crankshaft that production needs and designs, applied workpiece circumgyrate and linkage of servo of emery wheel feed control a technology, can hold clip and do not change crankshaft centre of turning circle to be able to finish the grinding of all journal, include to follow move dog journal of grinding connecting rod; Use static pressure main shaft, static pressure slideway, static press feed guide screw (emery wheel head is worn) with linear grating closed-loop control, use TOYADA is versed in the GC50 CNC of engine production controls a system, precision of grinding journal circularity can be achieved 0.

002mm; Use CBN emery wheel, grinding linear velocity is as high as 120m/s, match head of double emery wheel to wear, grinding efficiency is extremely tall. Of function of cutting tool of cutting of diversification of material of the cutting tool in crankshaft treatment rise to machined development to offer possibility for efficient, high speed, besides high-speed steel, hard alloy, the development that exceeds hard data had main effect. The treatment that wait created the cutting of material of embarrassed treatment of PCD, PCBN, dry cutting, hard cutting condition. Change to get used to crankshaft to machine high speed, the demand of cutting of efficient, dry type, use coating cutting tool in great quantities at present. The material of coating develops to wait for Al2O3, TiC, ZrO2 from TiN, according to the requirement of treatment, to improve high temperature resistant performance, developed TiCN, TiAlN, TiSiN, CrSiN to wait again. PVD(physics gas phase is deposit now) , deposit of CVD(chemistry gas phase) technical ceaseless get rid of the stale and bring forth the fresh, by monolayer development becomes multilayer, 1000 layer, compound coating, develop accept rice coating again now; The treatment of deep oily aperture uses a gun to get treatment to replace broach of common lengthen high-speed steel, bore and tap replace the high-speed steel data in the past with hard alloy material. At present the finish machining of crankshaft also begins to use treatment of CBN emery wheel gradually, price of CBN emery wheel is high, but because treatment efficiency and durability are tall, the common emery wheel with the cutting tool lower than using the price instead fare to every workpiece wants share low. The material that seizes mill of German NAXOS grinder shows, use handling time of CBN emery wheel to be able to shorten normally 50% , and process charge but managing 50% above. Epilogue above basically discussed the progress that crankshaft machines from crankshaft machining respect, can reach from this the following conclusion: Craft of turning of crankshaft much knife will exit historical arena stage by stage, although this one period is longer; High speed is efficient treatment already had in crankshaft manufacturing industry quite the application of degree; Agree with the compound processing technique of much breed, small lot will be henceforth the direction of a development that crankshaft machines; Of function of cutting cutting tool rose to provide technical safeguard for development of efficient, high speed, compound treatment. CNC Milling CNC Machining