Summary: Numerical control machine tool manufactures efficiency with it the tall, characteristic that can machine spare parts diversification, more and more the advantage that shows it, because how this transforms general accuracy machine tool numerical control machine tool, already became machining equipment to transform working key. Keyword: Numerical control transforms necessity to improve a method one, the general accuracy machine tool with original now foreword already cannot suit more and more market competition is intense, at present efficient with changeful requirement, so, numerical control machine tool already more and more get the favour of the market. Experts are fatidical: The competition of manufacturing industry of 21 centuries machinery, it is the competition of numerical control technology character actually. Numerical control technology is automation of manufacturing industry implementation, flexible change, compositive the foundation that turns production; Numerical control machine tool basically is mixed by orgnaization of numerical control device, servo composition of machine tool main body. The program that inputs numerical control device dictates the record is on information carrier, read in device to receive by the program, or by the clavier of numerical control device direct hand uses an input, numerical control machine tool machines a spare parts not only efficiency is tall, can changeful, and, need to undertake modification to the program only, with respect to the treatment requirement of OK and contented client. But to save fund, do not eliminate equipment of original general accuracy machine tool, try to transform to this. Such already but managing cost, can have property of numerical control machine tool again, satisfy manufacturing need. 2, numerical control of general accuracy machine tool changes transformed necessity often need to process a few form in production the spare parts that complex, precision asks to taller, general accuracy machine tool is machined hard or cannot be machined. It is easy that with numerical control machine tool treatment is compared, because amount to charges a machine tool,have the advantage that highlights below than general accuracy machine tool. 1. Can machine the complex part such as the curve that gave general accuracy machine tool to be not machined, curved surface. Because the computer has excellent operation capacity, can instantaneous is calculated well and truly the athletic amount that gives instantaneous of every reference axis to should move, because this is OK and compound,become complex curve or curved surface. 2. Can realize treatment flexible automation, thereby efficiency can raise 3 ～ than traditional machine tool 7 times. Because the computer has memory and storage capacity, can remember the course of the input coming down with memory, the order that sets according to the program next is carried out automatically, implement automation thereby. General accuracy machine tool can rely on the implementation automation such as cam or link stopper, but cam is made reach adjust very take time. When undertaking large quantities of quantities are produced only, ability economy is sound, automation of the tigidity that be called. And numerical control machine tool should change only a program, with respect to the automation that can implement another workpiece to machine, can make odd with pre production be able to automation, because this is called,came true " flexible automation " . 3. Treatment precision is tall, dimension is spent dispersedly small, assemble easily, need no longer " make repairs and supply replacements " . Because machine process automation, the computer still can undertake cutting tool life manages automatically, won't wear away because of cutting tool and affect workpiece precision and its consistency. Machine tool error, machining error increased to amend compensatory function in numerical control system especially, make machine precision to get rising further. 4. Can realize the concentration of multitask foreword, decreased to be in by treatment spare parts between the machine tool carry often. The result that automation brings (OK and automatic change cutting tool) . After workpiece outfit has been placed, can realize the treatment of multitask foreword. Already appeared now the machine tool that other working procedure centers. 5. Have call the police automatically, a variety of self-discipline functions such as automatic monitoring, automatic compensation, can come true consequently long unmanned guard treatment, in deploy a variety of sensor conditions to fall, of computer power reflect, somebody of implementation day shift attends to and can have made sufficient preparation work, make 2, 3 undertake be machininged automatically below unmanned condition, the worker works 8 hours only, and the machine tool can work 24 hours. Of the labor productivity that brings accordingly rise to shorten with what produce cycle equivalent beneficial is very apparent. In addition, machine tool numerical control is changed or carry out FMC(flexible production system) and C IMS(CIMS) the foundation that waits for enterprise informatization to transform. The numerical control that introduces general accuracy machine tool from 3 link next time is changed transform. 3, numerical control of general accuracy machine tool changes numerical control of transformed main link general accuracy machine tool transform main from advocate 3 link undertake system of transmission part, feed drive part, numerical control plan is made and be transformed carry out. 1. Advocate transmission is transformed. Main shaft component drives workpiece directly or cutting tool attends cutting to move, it is divided bear outside itself weight, still need to carry on bigger cutting load, the tigidity of main shaft itself and rotate precision and the tigidity that prop up machine what affect a part directly precision, because the numerical control of part of this main shaft is transformed, the tigidity that should assure itself above all and rehabilitate and the whirl that raise itself precision. To medium, Bench Machine Tool advocate transmission majority uses common communication electric machinery, its gearshift carries main shaft case, achieve different rate, satisfy treatment requirement, because mechanical archives number is average more, make gear-box structure complex, volume is huge, to the spare parts treatment precision can produce undesirable effect. But as a result of medium, Bench Machine Tool, itself value is inferior, if its advocate transmission instead communicates gearshift, its cost is too high, accordingly, be in usually, still hold this share changeless. Advocate transmission is transformed outside dividing transmission case, still need to consider bearing, slideway. Be being propped up as a result of main shaft of general accuracy machine tool is scroll bearing or sliding bearing more, when transforming, choose high accuracy bearing to replace former bearing; to be able to convert to big, medium-sized machine tool more to Bench Machine Tool static press bearing. 2. Of feed drive transform. Treatment gives the component that accords with a requirement, be: commonly to the requirement of feed drive? Whoop hammer of caries knocks at mu of ㄎ tan1huan4 group sew of of tan1huan4 of ㄎ of Tuo thoroughfaring cook a meal makes an appointment with sunken commonplace ち to weary mires? of of a surname free time is high quality, answer namely fast, frequency band is broad, movement condition fast fall small, high speed of timing scope wide; is spent, can locate quickly namely, in order to raise efficiency; high-power, can output large moment of force and power namely, in order to satisfy treatment requirement. Feed drive machinery is transformed partly basically is the flexibility that increases athletic component, reduce or eliminate transmission gap, reduce backlash especially, transform a component to be slideway normally box of deputy, feed and transverse reach fore-and-aft feed component to wait. Slideway of general accuracy machine tool uses sliding slideway more, as a result of its coefficient of friction changes along with speed and change, attrition loss is big, appear easily when low speed creeping phenomenon, affect the fixed position precision of athletic component directly. Because this is in,can roll sliding slideway instead slideway or static press slideway, or slideway is used stick receive soft ribbon. Former transform workload big, transform expense more, latter transforms workload small, cycle is short, expense is little. Box of feed of general accuracy machine tool is gear structure more, as the grow in quantity of progression of feed motion commutation, not only feed box structure is complex, and backlash increases, reduced retrorse precision, when undertaking counting accusing to change transforming accordingly, often be to cancel former feed box, or change only the feed box of one class decelerate, and with the join that do not have key. In catenary of drive of machine tool feed, need to turn whirligig into linear exercise, although have a lot of advantages,general accuracy machine tool often uses common guide screw, but its attrition resistance is great, transmission efficiency is low (η = 0.
20 ～ 0140) , activity coefficient of friction differs big, appear easily when low speed creeping, and the mobile component sensitivity of part of feed of requirement of numerical control machine tool is good, precision is tall, reaction is sharp, without crawl. Use ball guide screw deputy may contented requirement, is deputy characteristic ball guide screw: ? = 0 of η of? of arrow of .
92 ～ 0196) , attrition loss is small, guide screw of scroll of service life long; deputy belong to rolling friction, attrition resistance is little, move, static friction coefficient is very adjacent, reason motion is smooth, without crawl, after deputy classics of guide screw of ball of transmission precision tall; is tightened beforehand, can eliminate whorl gap, retrorse when without dead band of light locomotive trip, precision of retrorse fixed position is tall. 3. Electric part is transformed. The electric part of the machine tool is transformed basically control for main shaft and feed part, to medium, small machine tool, main shaft maintains original system, electric part transforms concentration to control a part to transform to feed, numerical control system is main the task is to realize feed drive control. This part task is to decide servo of control means, choice is mixed measure component. Means of control of numerical control system basically can be divided for open loop, closed circuit, half closed circuit 3 kinds of means. Machine tool numerical control is changed transform a choice which kinds of means, need to decide according to particular case. The machine tool with general Bench Machine Tool or precision inferior requirement, use open loop to control fashion more, big, medium-sized machine tool uses means of half closed-loop control more. Change in machine tool numerical control in transforming, bench Machine Tool uses a pace to take system of electric machinery drive more, price of this kind of system low, structure is simple, but control precision and rate are low. Use communication servo more in big, medium-sized machine tool, be like HSV -- drive of servo of synchronism of 11D communication permanent magnetism and servo electric machinery, according to the enterprise transform a requirement to also can use formula of domestic and international of all kinds imitate servo. The position measures component is the one part in numerical control system, with the displacement quantity that will measure athletic component to be worth shift by the instruction, give numerical control the system its feedback. Current, use the most extensively in numerical control machine tool to come back transition measures component, among them photoelectricity pulse coder and rotate code converter receives wide application.
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