Author: Lai Jiankang of Zhongyan sharp edge turns stick from: The technology that shares in each segment that fictitious production technology is designed through analysing the computer to assist injection mould and produce and information, the article announced the essential connotation of the compositive technology of injection mould CAD, raised its research heat and trend. 0, compositive technology of foreword mould CAD is an important pattern advanced production technology, it is an important and crucial technology that transforms mould tradition technology with hi-tech. Begin from 65 plans, our country has a lot of pattern companies to use CAD technology, especially in recent years, the application of CAD technology is mixed more and more generally thorough, shortened greatly mould design is periodic, improved the engineering capability of patternmaking quality and mixed pattern. However, because a lot of companies are right knowledge of mould CAD compositive technology is insufficient, investment contains blindness, cannot produce effect well, created very big waste. The article provides CAD with respect to plastic pattern compositive technology and its application express a few point of views, consult for everybody. 1, plastic pattern provides what compositive technology plastic pattern provides CAD to make, cut of treatment of the CNC Machining(milling of the modelling design that includes plastic product, structure design of the mould and analysis, mould, report, line) , polishing and deserve to try model and fast figuration to make etc. The CAD unit technology that each link place involve has: Modelling and structural design (of appearance of CAD) , product beg instead quickly (analysis of RE) , structure and optimize a design (CAE) , auxiliary make (process of CAM) , treatment is fictitious emulate (the fast figuration of SIMULATION) , product and mould (RP) , auxiliary process (CAPP) . Plastic mould CAD is compositive technology, create plastic pattern namely each unit technology that process place involves is compositive rise, unified database and file transmit a format, implementation information is compositive share with data resource, shorten greatly thereby the design of the mould makes cycle, improve patternmaking quality. 2, of the CAD design of plastic product and appearance begging the first situation that undertakes plastic pattern provides a design to make instead quickly is model the design of the product. Method of traditional products plan is the architect three-dimensional conception to the product with 2 dimension ichnography paper expression comes out, craft and construction method indicate on blueprint, the simple sex that this kind of method decided to design a graph and cannot control production quality directly. Contemporary design method is the three-dimensional model that the architect builds a product directly on computer, according to the product three-dimensional model undertakes mould structure design is reached optimize a design, design three-dimensional model to undertake process designing and staff technology plan machining according to mould structure again. This kind of method makes process designing of product model design, mould structure design, treatment reachs technology design to be a foundation with 3D data, implementation data is shared, can improve design efficiency quickly not only, and can assure quality, reduce cost. Computer model the origin of product model has 3 kinds: Use CAD system software to undertake product model is designed, use objective to measure undertake be turninged over quickly begging proposing the model, standard form that uses other CAD system file. Be aimed at the origin means of model of these 3 kinds of products, already excogitated all sorts of technologies to improve the design efficiency of product model and quality at present. The connotation of all sorts of technologies and characteristic are analysed further below. Use CAD system software to undertake product model is designed, design of modelling of design of the design that its technology basically includes the scale of graph of 2 dimension geometry, 2 dimension parameter to change a figure, three-dimensional hypostatic model, three-dimensional feature, three-dimensional parameter turns hypostatic model of the exterior apply colours to a drawing of design of design of modelling of design, three-dimensional curved surface, dimensional freedom modelling, product, product. These software have a lot of typical delegates. 2 dimension software has: The; three-dimensional software such as ME10, CADKEY, AUTOCAD, DHCAD, Genis, Sigraph has: The modelling of; product freedom such as UGII, PRO/E, IDEAS, CATIA, EUCLID and the software that advertisement designs have: Alias, CDRS. The scale of graph of 2 dimension geometry is to use figure of spare parts of scale of planar CAD software, replace manual plot; with the computer namely and 2 dimension parameter is changed, namely the variable design that the computer realized a graph, the actual figure that makes revise three-dimensional model of more convenient; to design the product that is digitlization is designed, it conveyed a product completely, can be mould design, analysis and treatment to provide space of necessary mathematical model; further the artistic design that free modelling design is product appearance, make the product is functional product not only, the exterior apply colours to a drawing that also is artwork; product is the effect design of the product, making the dynamic advertisement of all sorts of more beautiful, demand; products that color can cater to people more designs the product is the result products plan makes advertisement directly, undertake the market is popularized. Use objective to measure one of heat that undertake the model is to study at present be turninged over quickly begging building, it is the vital technology that undertakes the product modifies a design on product copy foundation. Its fundamental is to pass 3 coordinate to measure machine, laser to measure machine or electron to copy several appearance to undertake scanning metrical to objective, in nodding the mass data that measures obtains digitlization those who send advanced CAD software to beg module or appropriative to beg software instead instead, beg software to be able to read data extraction a place directly instead group, can occupy to check the number group have an edition, filter, arrange, beg essence of life, sort, local revise with recombine, generate curved surface automatically next, obtain what agree accurately with objective finally or via transformed computer model product model. Type of this one party but great raise rate of new products plan. At present more mature curved surface begs the software that build a model to have instead: Surfacer, cimatronrenge, strim100. The standard format document that uses other CAD system will build a model, form of this one party is more convenient. As a result of the development of the globalization of the market and INTERNET network technology, the CAD technology communication of pattern company and collaboration have a lot of passing CAD file means undertakes. Because CAD system is phyletic more, because the format of this file must follow international standard, wait like DXF, IGES, STEP, VDA, STL. Product model is built after taking standard format to the file will be built directly or be revised through reading, can accelerate already, the communication that deepens user and die manufacturer, also can shorten products plan is periodic. 3, the CAD design of the mould and the CAD design that analyse a pattern, analysis, the design that includes to have mould cent side according to product model, affirmatory model antrum and model the detailed design of structure of core, mould, plastic fill up a few respects such as process analysis. If the very easy ground such as PRO/E, UGII defines cent area,use advanced diagnostic modelling software, make fluctuation model antrum and modular core, have flow path, runner and cooling hose again decorate etc. After deciding these design data, recycle mould analyses software, if MOLDFLOW, CFLOW undertakes plastic figuration process analysis. According to library of MOLDFOLW software and its rich material, technical data, through inputting figuration craft parameter, movable condition emulation analysis is plastic the condition of injection process flow inside antrum of the model that note model (the plastic converge grain when containing much runner to inject is analysed) , circumstance of change of analytic temperature pressure, analysis notes model leftover stress, the quality problem of the rationality that will examine mould structure according to analysing a case, rationality of flow condition, product. More unreasonable than denying existence gating system so, occurrence flow path and runner position dimension are undeserved, cannot be full of evenly model whether is antrum; put in product structure unreasonable or mould structure is unreasonable, occurrence product fills dissatisfaction (namely short shoot a phenomenon) ; is cooling inhomogenous, whether do influence production efficiency and product quality; exist the technology that note model is wrong, the warpage of occurrence product. The mould passes CAD design and analysis, can eliminate the error in design phase, rise to try a model to be led successfully. Be designed in plastic mould and analysed this one phase to apply a lot of new computer to assist a technology, if parameter changes technology, diagnostic modelling technology, database technology,wait. There are a lot of standard components in plastic mould, the parameter that if standard mould bases, top gives orgnaization, gating system, refrigeration to be able to be used the system,is based on database management changes diagnostic modelling to design method undertakes designing or build standard component warehouse, can realize data to share already so, can satisfy an user to be revised to the design at any time again, make the design analysis of the mould fast, accurate, efficient. Parameter changes diagnostic modelling to describe the geometrical graph information of the product thoroughly not only, and the precision that can acquire a product, material and assemble wait for information, the product model that its build is one kind is handled easily, the model that can reflect design intent and treatment feature. Accordingly, parameter changes diagnostic modelling technology is one of techniques with mould production the mainest process. 4, the application of the CAM technology of the mould, treatment emulates the CAM that reachs production mould (CAM) technology basically applies in the respect such as treatment of numerical control milling, line cut treatment, electric spark treatment. CAM technology is in especially of mixed pattern model antrum, model the milling of core and electrode is having more main effect in treatment. Its main technology characteristic includes: (1) the optimizes program and NC instruction generation of contrail of cutting tool of thick, finish machining, (Of sort of 2) cutting tool, character and material library build, (3) cutting machines craft parameter to be decided really, (4) common cutting and the character that high speed cutting machines are controlled, (5) cuts examination and the precision control that machine the surface too, (6) machines the computer substance of the process to emulate cutting, (The application of the DNC technology of machine tool of numerical control of 7) computer control and group control technology is waited a moment. Need data of model of CAD three-dimensional product particularly in the application of CAM technology. If when the MASTERCAM, UNIMOD, CIMATRON process designing in much curved surface is machined, software of more professional computer process designing is opposite the curved surface model of the product has higher demand, the high accuracy of the consistency of direction of the U that is like photograph adjacent curved surface, V, curved surface and curved surface plans to close, curved surface slope changes continuously etc. In system of advanced CAD/CAM unifinication (be like UGII, PRO/E) , because used parameter to change diagnostic modelling design and same database technology, make of product model data, mould model antrum and model data of core model data, cutting tool contrail is having immanent connection, the contrail of modification cutting tool of product model also is revised automatically. It is more and more mature that the mould processes hypostatic emulation technique, also more and more get the attention of people. Processing hypostatic copy is the treatment process that imitates a machine tool on computer really, the result that can intuitionistic report machines, can assess the quality of the spare parts after treatment directly, can check the mistake that gives treatment. When the quality of the spare parts after the examination is machined, can go up to undertake to machining the hypostatic model after aleatoric analyse is cut in computer, measure its dimension and precision directly. Accordingly, it can eliminate the error in design phase of treatment craft process designing, after reducing treatment repair and do poorly done work over again, improve the production efficiency of the mould and quality greatly. 5, after the fast figuration of plastic product and its mould makes plastic product and its mould be finished with design of computer CAD technology, can be made through fast figuration technology. This is a kind brand-new production technology of the concept, its slam the door traditional machining method. Its figuration principle is disperse of hypostatic model of will three-dimensional CAD become set ply a series of piece layer data, use laser forming machine or other figuration equipment to read take these data, add law skill with material, ordinal rise every accumulation figuration. This one technology calls skill of fast and automatic figuration (Rapid Prototype) . It also is the main component of CAD compositive technology. Equipment of the first fast figuration is born at was in American 3D company 1987, because its characteristic is,have nothing to do with the complex degree of production product, bring to manufacturing industry shake tremendously. After this 10 years, fast figuration technology gets flying development, the sort of equipment also emerges in endlessly, can divide from material solidify method for law of agglomeration of laser and blame laser (law of model of surface layer of SLS) , solid (SGC) , layer piece production law (fused and LOM) , deposit law (law of felt of FDM) , electorate (law of deposit of gas phase of DSPC) , laser (SALD) . All sorts of method characteristics are: SLA law is the fast figuration technology that uses the earliest, youth market has larger cent specified number, but because material range is narrow, cost is higher, figuration heat-resisting, be able to bear or endure bear and chromatic capacity are small, be replaced by other method place gradually in recent years. FDM law because figuration rate is rapid, cost is low, better application receives in plastic product industry, because the size of the spare parts is small, precision is poor, also be restricted certainly. Because LOM law uses paper chip perhaps and plastic, cost is low, and laser illuminate each outline brim, figuration rate is consequently rapid, but product surface quality is poor. SLS law is to use laser to undertake agglomeration, adoption data is more extensive, wait like makings of plastic, candle, pottery and porcelain, metal all but figuration, figuration heat-resisting, be able to bear or endure bear and chromatic capability are stronger, have wide applied perspective. Other method also gets applied in certain non-traditional machining. According to afore-mentioned figuration law characteristics, the action of fast figuration technology basically depends on: Make the product model that is used at design and experiment, make the pattern that is used at small lot production and small lot the treatment of special spare parts. The product model that the product model that makes into form technology quickly pledges in material the respect machines a method to make than the tradition somewhat difference, but outer form and measure respect almost just the same, and have particular mechanical strength, can make functional sex experiment, pass finishing at the same time, look like real product, can make advertisement propaganda paterial. The pattern that fast figuration technology creates, the figuration model that basically is weak data at present (alloy of model of wax-pattern, epoxy resin, silicon balata model, low melting point casts a model to wait) with pottery and porcelain or metal base synthetic data is hard model antrum model. Spare parts of usable and fast figuration makes master mold when production die, make the soft model of epoxy resin model or other material first, pouring in soft model pottery and porcelain or plaster mold, irrigate cast steel to become steel model; next pouring in soft model perhaps mix the steel white that has chemical binder, undertake agglomeration becomes steel model. The steel model that makes into form technology quickly requires the treatment after doing polishing to wait further, make what produce into small lot note model model. Because the mould is the pink that use steel pouring or agglomeration and into, material has certain difference with common mould steel character, accordingly, life is briefer, can do trial-produce product or small lot production only. Additional, fast figuration technology also can make special part, if use metallurgy powder,the law makes metal electrode, accurate casting make cupreous electrode, grind modular legal system makes black lead electrode wait. Become what form technology makes mould and product to shape quickly equipment, all be to read the file format data such as the STL that takes CAD system generation or CLI, different file format data has bigger difference to made product precision, accordingly, the file format output of research CAD system to fast figuration equipment has quite important sense. 6, the development of mould CAD compositive technology is narrated on trend put together, the computer that mould CAD compositive technology uses at the mould to produce each segment namely assists technology and implementation the technology with each segment compositive information. Apparent, information is compositive as centralized as data management is crucial. The information of the product is perforative at design, analysis, treatment, detect, assemble wait for each phase, the fluent, solves data format standardization that realizes each segment information and data are safeguarded with sharing is the stress that compositive technology develops prospective CAD. The occurrence of PDM system brought dawn to solve this one problem. Of PDM system the main task that carrying out is compositive technology of CAD of pattern company application. The field is created in the design of the mould, treatment of cutting of the research that contains the intelligence of rich expert knowledge to change mould CAD/CAM system, high speed and its process designing is the trend that future studies to develop. Main bibliographical reference [1] Ren Zhonggui. CAD/CAM principle. Tsinghua university press. 1992. 11 [2] Dai Tong. CAD/CAPP/CAM basic tutorial. Machinist trade publishing house. 1997.
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5 CNC Milling
CNC Machining