CNC technology applies

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  • source:BAGANZ CNC Machining
The development of CNC technology is quite rapid, this improved the productivity that the mould machines greatly, among them the core that the CPU with operation quicker speed is CNC technology development. The improvement of CPU is operation speed not just rise, and the improvement that speed itself also involved technology of other respect CNC. because in last few years CNC technology produced so big change, just be worth us to be in to current CNC technology the applied circumstance of mould manufacturing industry makes an overview. Program block handles what time and other treat rate as a result of CPU to rise, and CNC manufacturer uses high rate CPU height compositive in the CNC system that change, the function of CNC had marked improvement. Those who react faster, more acute system comes true is higher program processing rate not just. In fact, a system that can handle spare parts machine program with quite high rate resembles processing system of a low speed likely also in moving process, because even if the CNC system with complete function also is existing a few potential problems, these problems control the bottleneck that machines speed into in the limit of likely. What at present most mould factory realizes high speed machines need is time of shorter machine program processing not just. In a lot of respects, of this kind of circumstance and racing bicycle drive very similar. Can the racing bicycle with the rapiddest rate win the contest certainly? Even if now and then the audience that just watchs car game knows to eliminate rate beyond, still a lot of elements are affecting the result of the match. Above all, car hand is very important to the understanding degree of circuit: He must know where has make a radical change, so that can appropriate ground decelerate, adopt curved method safe and efficiently thereby. In using tall feed speed to machine the process of the mould, CNC waits for technology of treatment contrail monitoring mediumly to be able to get the information that acute curve appears beforehand, this one function is having similar action. Same, car hand is acute to movement of other vehicle hand and the reaction that cannot determine an element the number that the servo in degree and CNC feedbacks is similar. Feedback of the servo in CNC basically includes positional feedback, speed feedback and voltaic feedback. Drive when car hand when circling circuit travel, behavioral continuity, whether the adroitly brake, it is very main to face an expression to having effect that waits for pair of car hands quickly. No less, the bell form of CNC system is quickened / decelerate and wait for function of treatment contrail monitoring to use slow quickly / decelerate will replace abrupt speed change, quicken smoothly of the machine tool in order to assure. Divide this beyond, cycle racing and CNC system still have the place of other likeness. The power of cycle racing engine is similar to the actuating device of CNC and electric machinery, the weight of cycle racing can place on a par with the weight of the moving link in the machine tool, the stiffness of cycle racing and intensity are similar to the intensity of the machine tool and stiffness. The ability that CNC corrects error of specific ways and means and car hand have control cycle racing the capacity inside driveway extremely similar. Another with at present the circumstance of CNC likeness is, those speed are not the fastest racing bicycle often needs the car hand with full-scale technology. Only high-grade CNC ability was in in the past high speed cutting while assure taller treatment precision. Nowadays, the function that medium, cheap CNC place has completes the work satisfactorily likely also. Although high-grade CNC has the optimum behavior that can obtain at present, but also existing this kind is likely, namely the cheap CNC that you use is had with the like high-grade CNC fabricating characteristics in congener product. In the past, restricting a mould to machine the element of highest feed speed is CNC, today is the rigid structure of the machine tool. Below the circumstance that already was in function limit in the machine tool, better CNC also won't make function rises again. It is current under the immanent character of CNC system a few basic CNC in mould treatment process are characteristic: The blame of curvilinear curved surface is even justifiable B batten (this technology uses NURBS) interpolation the means of edge curve interpolation, is not to use a series of short will plan add up to a curve point-blank. The application of this one technology has comparatived general. The CAM software that a lot of mould industries use at present offerred an option, create the part program of NURBS interpolation format namely. In the meantime, the CNC with powerful function still offerred function of 5 axes interpolation and the character related to this. These function improved the quality of exterior precision work, those who improved electric accident travel is smooth degree, raised cutting rate, make spare parts machine program smaller. The CNC system of smaller instruction unit great majority delivers motion and the unit that fixed position dictates to not be less than 1 micron to machine tool main shaft. In make full use of after CPU handles ability to improve this one dominant position, the unit of the smallest instruction of system of a few CNC can achieve 1 accept rice even (0.

000001mm) . After dictating the unit is 1000 times more contractible, can obtain taller treatment precision, can make electric machinery moves more smoothly. What electric machinery moves is smooth make below the premise that a few machine tools can not increase in lathe bed vibration, move with taller acceleration. Bell form curve is quickened / decelerate also says to be quickened as S curve / decelerate, or creeping control. With use quicken means photograph to compare point-blank, this kind of means can make the machine tool is obtained better accelerate the effect. Quicken means photograph to compare with other, also include linear means and exponential kind, use means of bell form curve to be able to obtain smaller fixed position error. Wait for treatment contrail monitoring this one technology already was used extensively, this technology has numerous function difference, make its are in medium working way is able to distinguish the working way in cheap control system and high-grade control system to come. Will always tell, CNC realizes the pretreatment to the program namely through machining orbit monitoring, will ensure with this can obtain more exceedingly good acceleration / decelerate control. According to the function of different CNC, the program block amount that needs place of treatment contrail monitoring to need differs to about a hundred from two, this basically depends on the shortest handling time of part program and quickly / the time of decelerate is invariable. Generally speaking, want to satisfy treatment requirement, need 15 to need treatment contrail monitoring program at least piece. The development of servo of number of digital servo control is so rapid, so that manufacturer of most machine tool selects this system,control a system as the servo of the machine tool. After using this system, CNC can control servo in time, and CNC also becomes more accurate to the control of the machine tool. The action of digital servo is as follows: the sampling rate that raises voltaic annulus way, plus improvement of voltaic annulus pilot, reduce electric machinery temperature rise thereby. Such, can prolong the life of electric machinery not only, still can reduce the quantity of heat that delivers ball guide screw, raise the precision of guide screw thereby. Besides, of sampling speed accelerate the gain that still can increase speed return, these conduce to the integral performance that improves a machine tool. Because a lot of new CNC use high speed alignment and servo loop to be linked together, because this passes communication link, CNC can obtain the working information of more electric machinery and actuating device. The maintenance that this can raise a machine tool function. Successive positional feedback allows to have the treatment of high accuracy below the circumstance of high speed feed. Of CNC operation speed accelerate make the rate that the position feedbacks becomes the bottleneck that restricts machine tool traversal speed. In traditional feedback pattern, as the change of the sampling speed of the exterior coder of CNC and electronic equipment, feedback speed gets of signal type restrict. Use serial feedback, this one problem will get very good settlement. Although the machine tool moves with very high rate, also can achieve accurate feedback precision. Linear electric machinery in last few years, the character of service of linear electric machinery and welcome are spent had rise significantly, so a lot of machining center used this one device. Up to now, fanuc company had installed 1000 linear electric machinery at least. A few advanced techniques of GE Fanuc make the force of the biggest output of the linear electric machinery on the machine tool is 15, 500N, the biggest acceleration is 30g. The application of another some of advanced technique makes the dimension of the machine tool is able to reduce, weight is able to reduce, cooling efficiency rises greatly. All progress on these technologies make linear electric machinery is in with rotate when electric machinery photograph is compared, the dominant position is stronger: Taller add / decelerate rate; Exacter location is controlled, taller stiffness; Higher reliability; In-house dynamic apply the brake. Exterior and add character: The machine tool development that opens type CNC system to use system of open mode CNC is very rapid. The communication rate of the communication system that can supply a choice at present is higher, appear consequently the structure of open mode CNC of a variety of types. The functional photograph of the open sex of the PC the standard and traditional CNC integrates the open mode system of great majority. Do the biggest gain to depend on so: Although the hardware of the machine tool already was passed when, the CNC of open mode still allows its function to ask to change along with existing technology and treatment. Have the aid of at other software, still can add other function to the middle of open mode CNC. These function can be machine with the mould closely related, also can be not as big as mould treatment concern. Normally the circumstance falls, the system of open mode CNC that mould workshop uses has the following these commonly used function choices: The network news report with low price; Aether net; From adaptive control function; But for joining reader of number of serial of a form code reader, cutting tool is mixed / or the interface of system of tray serial order; Save and edit the function of a large number of part program; The collection of information of memory programme controll; File processing function; Of CAD/CAM technology compositive plan with the workshop; General operation interface. Last bits very important. The demand that because mould treatment is right,handles simple CNC is bigger and bigger. In this concept, the most important the CNC that differs namely has identical operation interface. general situation, the operation personnel of different machine tool must groom apart, because of the machine tool of different type, and the CNC interface that the machine tool that different manufacturer manufactures uses is not identical. System of open mode CNC is used for whole workshop same control interface created a CNC opportunity. Now, of the machine tool possessory although do not know C language, also can operate the interface that designs oneself for CNC. In addition, the controller of open mode system allows the need according to the individual, the machine movement kind with different set. Personnel of such handlers, process designing and the demand that the person that maintain can press him undertake installing. When use, the specific information that they need appears only on screen. Use such means to be able to reduce needless page to show, conduce to simplify CNC operation. 5 axes treatment is in the process that makes mixed pattern, the application that 5 axes process becomes wider and wider. Use 5 axes treatment, can reduce treatment the tool that place of a spare parts requires or / the amount with the machine tool, the facility amount that treatment process place requires will be decreased to come lowest, also reduced total handling time meanwhile. The function of CNC is stronger and stronger, this makes CNC manufacturer can offer more 5 axes character. There was the function that high-grade CNC ability has only once upon a time, also be used to be in nowadays intermediate on the product. Never had used 5 rods to those the manufacturer of processing technique, these characteristic application make 5 axes treatment becomes simpler. Will current CNC technology is used at 5 axes treatment, make 5 axes treatment has the following advantage: Reduce the demand of special tool; After allowing to completing part program again of set cutting tool slant buy; Support the design of general purpose program, the program of such course aftertreatments is OK between different machine tool crossing-over is used; Improve the quality of finish machining; Can use at the machine tool of different structure, need not explaining in the program so is main shaft or workpiece are circling center to turn. Because this will come by the parameter of CNC,solve. We can explain with the compensatory example of globose milling cutter why 5 axes are special apply to a mould to machine. When spare parts and cutting tool circle center axle to rotate, slant for what accurate ground compensates globose milling cutter buy, CNC must can be in X, Y, Z3 the compensation that direction adjusts cutting tool dynamicly. Those who make sure cutting tool cuts contact is successive, be helpful for improving the quality of finish machining. In addition, the utility of 5 axes CNC returns expression to be in: With circle main shaft to rotate the character related cutting tool, with circle main shaft to rotate the character related the spare parts, and the character that allows handlers to use a hand to move means to change cutting tool vector. What should use cutting tool is medium when axes regards rotor as the line, the cutting tool length of direction of original Z axis slants buy will be divided into X, Y, Z3 directional heft. Additional, the tool diameter of direction of axis of original X, Y slants buy also is divided to be axis of X, Y, Z the heft of 3 direction. Because be in cutting project, cutting tool can do feed to move along direction of runner shaft coming back, these all slanting buy must trends is updated, so that show the trend of the cutting tool of successive change. CNC is called another times " process designing of cutting tool center " characteristic, allow process designing personnel to define the method of cutting tool and center rate, CNC passes the command of runner shaft coming back and linear axis direction to make sure cutting tool moves according to the program. This one character makes the center of cutting tool follows the change of cutting tool no longer and change, this also means: 3 axes can be resembled to machine what input cutting tool directly euqally to slant in 5 axes treatment buy, still can pass again the change that postposition program will come to show cutting tool length. The athletic character that through making main shaft rotates this kind to realize runner shaft simplified the processing of process designing postposition of cutting tool. Use same function, make workpiece circles center axle to come back, the machine tool also can obtain whirligig. The CNC of new development can be secured through be being adjusted dynamicly slant buy and rotate the motion that reference axis will come to cooperate a spare parts. What use a hand to move means to realize a machine tool when operation personnel is slow when fast feed, CNC system is having main effect likewise. The CNC system of new development allows an axis likewise the direction along cutting tool vector is slow feed, below the premise that changes without position of point of a knife, the way that still allows to change vector of point of a knife (the illustration) that enters settle on area. These character make the process that operation personnel is using 5 axes to machine a machine tool medium, can use the method of 3+2 process designing that uses extensively in mould course of study at present easily. However, develop to chase short for Zhejiang Province to be accepted with this kind of function gradually as what new 5 axes machine a function, right 5 axes pattern machines a machine tool may more general. CNC Milling