Shunt-wound machine tool and can reframe the development of the machine tool

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The article was analysed and online bed mixes the current situation of coupling compose and development trend among them especially, and still introduced can reframe the basic idea of the machine tool. Shunt-wound machine tool is based on the shunt-wound machine tool of Stewart platform principle, call shunt-wound kinematic machine commonly in the world at present (ParallelKinematicMachine, PKM) , past China also call his 6 legs machine tool machine tool of fictitious perhaps axis. Because shunt-wound machine tool is the major shake-up of machine tool structure and have a lot of advantages, from 1994 American Giddings&Lewis company exhibits first on exhibition of Chicago international machine tool the name mutates for VARIAX(model) since this kind of machine tool of machining center, times suffer each country to take seriously, for instance the European Union established PKM scientific research special, the new product that a few courses improve exhibited in succession on the exhibition of international machine tool in all previous name, chinese institution of higher learing and machine tool manufacturer also cooperate the shunt-wound machine tool that rolled out a few kinds of forms. Anyhow, what no matter international still is home,advancing shunt-wound machine tool energetically now is practical change. Graph the metallic cutting machine tool of 1 tradition, it is substantially " establish ties " orgnaization. And 6 freedom spend the is based on Stewart platform typical pure parallel connection that the graph shows 1 times machine tool, for relatively traditional machine tool, have following advantages: Hardware structure is simple, stiffness / weight comparing is big, production cost is relatively inferior; Athletic part is small, inertial small, answer speed fast, yi Wushi shows high rate and acceleration; Configuration is agile, moving the working head that deserves to differ can be picked on platform (rotate cutting tool head, high-energy bundle of treatment head, survey first class) the exercise that will undertake differring; Theoretic motion and fixed position precision can be achieved very tall, because 6 lengthen,this is the error that lever length varies is opposite the influence that uses precision of platform space position, not be to resemble traditional machine tool in that way accumulative total alternate is added have leveling tendency however. Nevertheless, shunt-wound machine tool also is put in a few defect and problem, for example: Its use the platform campaign in working space, should open space of associate empty axis (nonexistent athletic coordinate axis) to solid axle (lengthen lever length) of the space nonlinear map will come true, and coupling of deepness of existence of solid axle space, accordingly its control software to want to compare traditional machine tool complex; Below same exterior size, its work effectively the space should compare traditional machine tool small much and not intuitionistic, the part of the biggest gesture that uses head of platform main shaft to be able to come true especially is less than 30 ° commonly; Although the precision of dimensional fixed position of shunt-wound machine tool is theoretic,can achieve very tall, but get a few factors actually restrict, the design of joint of bore with a reamer makes high accuracy of more crucial than if element still relatively the reason such as difficulty, its change to date the level that the dimensional position precision of platform still basically is in 10 micron class. To solve space of work of shunt-wound machine tool small, especially part of stance of main shaft head is not worth the issue that affects process capability of 5 axes linkage badly, the alleged machine tool mixing couplet that all sorts of different series-parallel connection combine was rolled out in succession on the world, among them the commonnest is be spent by 3 freedom and translation of online compose implementation and the machine tool mixing couplet that realizes roll by orgnaization of traditional series connection, make translation and roll solve Ou thereby. With pure paralell connection 6 freedom spend machine tool photograph to compare, this kind of machine tool works not only the space is larger and can undertake CNC Machining of big obliquitous much coordinate, and because the position and speed are going against Jiejun existence is analytic solve, created advantage for numerical control process designing and error compensation. The Tricept of machine tool of 3 lever paralell connection of Swedish NEOSROBOTICS company, it is the shunt-wound machine tool with the most application in be being produced actually at present. The Tricept845 machining center that develops on shunt-wound orgnaization foundation here, each of X, Y, Z3 by degree by 3 levers paralell connection the orgnaization is finished, two rotational freedom are spent come true by traditional compound revolving stage. By the main shaft head of drive of orgnaization of 3 lever paralell connection, speed of the biggest feed can amount to 90m/min, acceleration 2g, electric main shaft is highest rotate speed 24, 000 or 30, 000r/min, power 30/45kW. This machine tool is modular structure, divide optional outside matching compound revolving stage, optional also match revolving stage of common workbench, odd coordinate or pallet changer, main shaft also has vertical, horizontal and 45 ° setup 3 kinds of forms. Precision of its space fixed position is not tall (already rose by original 50 μ M allegedly to 25 μ M) , but already had economic value. The series-parallel connection combination of this kind of type still has structure of another kind of distribution, namely 3 mobile axes still come true by orgnaization of 3 lever paralell connection, and two axis of rotations are finished by the main shaft head that uses the series connection below platform. Germany is worn the company of DeckelMaho of machine tool manufacturer of the name permits after in what acquire use Tricept structure, rely on the experience that oneself accumulates in machine tool domain, redesigned the important part such as lever of head of lathe bed, all-purpose main shaft, drive and ball bore with a reamer, development goes Tricenter(DMT100) milling center (graph 3) . Workbench of this machine tool is fixed do not move, by 3 lever paralell connection the orgnaization realizes X/Y/Z axis to move, the journey amounts to 1500/800/700mm, 100/50/50m/min of corresponding speed of the biggest feed, acceleration 2g, feed force 5kN. The corner of axis of A of main shaft head of series connection 0 ° - 120 ° , 180 ° of ± of C axis corner. Uses electric main shaft is highest rotate speed 24000r/min, power 27kW, pitching moment 90Nm, knife handle HSK63A. This machine tool works not only the space can implement large stance part with main shaft head greatly, and by at used laser demarcate, the positional precision of space of main shaft head can amount to 4~12 μ M. Alleged laser demarcate, it is to use measuring instrument of high accuracy laser to be in to main shaft head the dimensional position of whole treatment area undertakes metrical (should measure 200 dot) commonly, refinance aids the demarcate algorithm that develops technically, go against solution model parameter mediumly by controller of CNC of nap of actual measurement information, in order to undertake precision is compensated. Tricenter not only comfortable the aluminous ability part that machines complex curved surface at high speed, and can undertake to steel and cast-iron workpiece efficient treatment. DeckelMaho company plan made this machine tool 2002 the world's well-known Airbus company is used actually. The 5 axes linkage of group of Chinese Dalian machine tool and Tsinghua university joint development is shunt-wound machine tool DCB510, also be 3 mobile axes confuse coupling form by what move implementation of orgnaization of the series connection below platform by two shunt-wound orgnaization implementation, axis of rotation (graph 4) . Journey of its X/Y/Z axis is 630/630/500mm, a shaft is the largest corner 140 ° , c shaft is the largest corner 380 ° . Nevertheless it is to use slide and fixed length lever to replace but adjustable lever, every pay fixed length lever to be comprised by double lever (also can comprise) with 3 lever, and the bore with a reamer of one aspect of the matter of fixed length lever is raised fixed go up in slide, such although structure a little a bit more complex, but the stiffness of tall machine tool of advantageous Wu Di and precision. In addition, the drive of slide of this kind of configuration can use ball guide screw not only, usable also and linear electric machinery is direct drive. String, the machine tool mixing couplet of shunt-wound combination still has other configuration, the CNC MillingHyperMach of high speed of dragon door movable type that for instance American Cincinnati company develops in the light of aviation industry, distance of its X axis is the longest 46m, 2m of Y axis journey, by drive of linear electric machinery, but the series connection orgnaization that still is a tradition, the head of its distinctive Z3 main shaft that used development of German DST company at Wu Cai. Head of this kind of main shaft is comprised by orgnaization of 3 axes paralell connection and main shaft component, besides main shaft can outside high speed roll, oneself of main shaft head realizes Z axis by shunt-wound orgnaization drive feed and circle A axis and B axis to turn (± 40 ° ) . The applied domain of shunt-wound machine tool still is expanding, expand development target to lathe again recently. The V100 convert type that for instance German Index company develops establishs a car, platform of its main shaft is in on, by 3 lever paralell connection orgnaization drive can realize the shift of axis of X, Z not only, and the automatic fluctuation makings that a many freedom spends bed of usable still Wu Che. Its turn tower tool carrier is in lower part of main shaft platform, only rotational not mobile. Theory and practice prove, shunt-wound machine tool is very comfortable machine spare parts of complex curved surface at high speed, at present also to practical change directional development, but in wanting to be in a factory truly, more general application still needs to pass tough effort to just can come true. The working space that although the structure mixing couplet of series-parallel connection combination is in,enlarges a machine tool, be in especially increase respect of part of stance of space of main shaft head to already obtained bigger effect, but the carrying capacity of shunt-wound machine tool, especially main shaft head is returned in positional precision of the space extremely wait for rise. This besides from kinematic outside undertaking study to improve with kinetic angle, the weak point that improvement restricts stiffness of shunt-wound machine tool and precision, the function of articulatory structure also is urgent affairs, must take structural dimension seriously so small, carrying capacity is mixed by force the development of the compound scroll joint with tall precision and production. In addition, kinematic demarcate namely precision compensation also is the important step that raises precision of shunt-wound machine tool, outside the exterior demarcate method that narrates measuring instrument of laser of use high accuracy except above paragraphs place, still can install sensor to get information to undertake in machine tool interior from demarcate (it is on driven joint installation precision is mixed high commonly the detecting element) with interference rejection strong capability. Although still have afore-mentioned a variety of problems need to solve, but the important complement that shunt-wound machine tool becomes traditional high speed to machine a machine tool already by a definite date is not far. Can reframe the machine tool is current, numerical control machine tool asks to satisfy the treatment craft of more and different spare parts, increasing treatment function ceaselessly, but in actual batch production, the functional utilization rate of machine tool of general numerical control is quite low. One professor ever was opposite Germany the rigid production business that 370 batch produce 22 countries has undertaken investigating, the machining center that discovery has nearly 80% uses his only the function of 20% . The production that the method that uses compound treatment function blindly apparently will come to improve machine tool facility is flexible with manufacturing efficiency not certain economy is sound, because this people put forward again,can reframe machine tool (the concept of ReconfigurableMachineTool) . Just as its name implies, can reframe the core of the machine tool is use process is medium can reframe quality, the user can produce the change of the product to have a change to the structure of the machine tool, layout and even treatment function according to place, and reframe to want do one's best to accomplish every time basically do not have redundant function. Clearly, of the machine tool reframe need comes true through altering ability of certain function component, because this can reframe,the machine tool is modular certainly machine tool, and ought to be what be a center with the user is modular machine tool. Alleged it is a center with the user, it is to point to what the module of soft, hardware that comprises a machine tool must abide by country or industry is not the criterion that the enterprise revises oneself, the interface of standardization should be had between each module especially, of course the interface with production system also ought to be standardization. Although can reframe the machine tool is theoretic can reframe often, but in applying actually, should decrease as far as possible reframe frequency and when reframing, should avoid to change main structure as far as possible, just accord with economy principle and advantageous at maintain machine tool precision. This is involved can reframe the delimits classify commands respect of multiple compose strategy problem of the treatment target with potential machine tool, function that should have and functional module, still need to have the research of thorough system to these problems. Nevertheless the author still thinks, can reframe the machine tool may suit to be in more big, medium batch is used below manufacturing condition. Other side sees not hard also, use can reframe the user of the machine tool should lay in module of function of particular spare machine tool, this may affect its promotion to use. Somebody thinks to build service centers of a certain number of regional storage of machine tool function to be able to solve this one problem, of course this returns those who remain to be carried out in the future to examine. Can reframe the machine tool still is in research phase at present, heretofore still is made without accepted archetypal machine come out, the graph is shown 5 times is the United States the person such as university YoramKoren puts forward Mixigen can reframe graph of machine tool concept. Although can reframe,the machine tool leaves practical change still have a paragraph of space, but it serves as can recombine production system quickly (a of RRMS) important and unit technology, can form the batch productivity to replacing a product quickly, have development latent capacity for certain. Sentimentally attached of Ying Weiyu of machine tool manufacturer, give enough attention now. CNC Milling CNC Machining