Current situation and development of enterprise's digital manufacturing technology of the mould

In modern industrial production, 60%-90% of the industrial products need to use the mould , the industry of the mould has already become the foundation of industrial development . According to the prediction of the international production technology association, 75% of part rough machining of machine building industry in the 21st century, 50% of finish machining needs to finish through the mould , among them such trades as the automobile , electric apparatus , communication , petrochemical industry and building ,etc. are the most outstanding .

The mould , as the skill-intensive products of a kind of high added value, its engineering level has already become the important evaluation index to weigh level of a national manufacturing industry. Still in initial stage of development in CAD/CAM technology, CAD/CAM is competitively absorbed application by the mould manufacturing industry. Present domestic there are about 20000 mould manufacturing companies, and grow at a high speed of 10%-15% every year. In the value of industrial output of mould of about 40 billion yuan, enterprises producing the personal mould by oneself account for 2/3, 50%-60% of the enterprises use CAD/CAE/CAM/PDM technology well. CAD/CAE/CAM technology that the mould is correlated with has been research and development , education and training and focus popularized and applied all the time .

First, the degree of mould CAD/CAM system melts special-purposly improves constantly

One that is with mould industry development and importance, CAD/CAM of technology extensive be approved by mould of circle at full speed, CAD/CAM developer invest heavy manpower and material resources in developing special-purpose CAD/CAM system , point to all the characteristics, have put out the pleasant melting , integrated and intelligent special-purpose system, well received by vast mould worker. For example the Quick series products which the Israeli Cimatron Company put out , can be under unified serial environments, use the unified database, finish the product design , produce the three-dimensional entity's model, carry on the automatic classification on this basis, produce the protruding , concave mould and intact structural design of finishing the mould , can process automatic NC to the protruding, concave mould conveniently . And for another example PowerSHAPE system that DELCAM Company of Britain put out , including PSMoldmaker module, face mould assembly that mould makes design the expert system, very automatic to mould , is it is it establish mould structure and smoke core organization , is it divide mould to produce automatically to mould to blow for complicated note, processing information automatic encapsulation, and can direct output reach to PowerMILL module , produce the procedure of processing automatically. Have increased the special-purpose design module that moulded in the note too in three-dimensional CAD/CAM systematic SpaceE of Corporation of information system of Japan's shipbuilding. Japan special-purpose to have much characteristics too on plastic mould design and CADCEUS of the manufacture system, this comprehensive plastic product design of system produces all functions needed from form design of the products , mold design to the mould , the ones that placed on the three-dimension and designed with the two-dimentional view are related especially, reflect the technological progress of the pleasant melting and integrated respect

Second, face the system integration scheme of CAD/CAE/CAM technology of mould enterprises

One that is with the scientific and technological progress of the industry of the mould and international competition is fierce day by day, mould industry requisition for CAD/CAM system is it is it support since the design to demand to turn from simple modeling tool into too, analyse , manage and process the overall integrated system of information management of products. In recent years , many research units and companies have all developed CAD/CAE/CAM system integration scheme facing mould enterprise, demonstrate higher practical level. If made in digitization in project centred of the national mould of Shanghai Communications University, system integration , reverse project , fast prototype / such respects as the mould and auxiliary application technology of computer ,etc. have already formed the ability of the omni-directional solution, can offer the mould to develop the business with the project service , heightenning the level of mould enterprise in an all-round way and product quality . And for example the scientific and technological developing company of the rising sun of Zhejiang University, can offer the product design for enterprise , three-dimensional model and NC programming, reverse project, 3 coordinates measure , mold design and analysis , technical training and omni-directional technical support of mould CAD/CAE/CAM technological development. CAXA brand serial CAD/CAE/CAM software that Haier software Co., Ltd. of Beijing Institute of Aeronautics puts out can offer the omni-directional solution about project of the mould to user too.

Third, plasticity forming process computer modelling technique has made remarkable progress

Have obtained the development advancing by leaps and bounds too in the past two years in forming process computer modelling technique of plasticity, Central China University of Science and Technology mould technology that national key laboratory develop to is it take shape simulation software and sheet metal that Hunan University develop is it take shape the simulation software to press to mould plastics, modeling at mathematics, algorithm, in front and at the back of dealing with and experiment will be put by proving, factory using respect, two school make remarkable progress, this indicate our country in mould plastics shaping , board material forming process computer simulation have been close the international most advanced level. These two achievements are chosen as the science and technology great progress project of Chinese mechanical industry of 2002 .

The plastics inject the development and application of the artificial system of forming process is new developing discipline that machinery , mechanics , material and computer cross that the plastics inject forming process emulation , because plastic melting body whether Newton is it flow course the stable state , not warm to inject, the course has very great degree of difficulty to adopt the computer simulation melting body and take shape. Though there are a lot of units that the countries all over the world study, two families to form the influential and commercialized and systematic one finally: Australia Moldflow Company and U.S.A. ACTech Company. The national key laboratory of the mould technology of Central China University of Science and Technology is improved, used and popularized constantly under national natural science fund and subsidy of other subjects fund, have gone through it from analysing two-dimentionally that analyses to the three-dimension, the course popularized and applied that reach from some pilot project by a large scale. Through 10 efforts for one year, is it show unique characteristics to develop, with international most advanced level at present three-dimension mould plastics the artificial system of shaping.

A traditional one mould plastics shaping artificial software based on products in the center one layer of models, and mold design adopt the three-dimensional entity's model , the nonconformity because of the two model more, the modeling two times is unavoidable. It is a very difficult job but the centre aspect appears abstractly from the three-dimensional entity, it is tedious and time-consuming to draw the course, so the designer has fear of difficulty to the artificial software, this has already become and injected the bottleneck that the artificial software popularized and applied This system can divide the net on the three-dimensional entity's model directly , mate and introduce the new border condition to guarantee the corresponding and superficial coordination flows through the surface, realize the analysis based on three-dimensional entity's model, show the three-dimensional analysis result, have broken through the bottleneck that the artificial system popularized and applied. Have solved the key technological difficult problem of one layer of models in the centre of replacing with three-dimensional entity's model.

The products are mostly the products of thin wall to mould plastics, the size of the direction of thickness of the products is smaller than the size of other two directions far, temperature physical quantity direction very heavy change have in thickness, adopt simple finite element or limited difference divide method certainly will is it analyse time to be too long to cause, actual need unable to meet mold design and making. This system is flowing in the level and adopting the law of finite element, the thickness direction adopts limited difference to divide the law, set up and flow level and thickness direction net that size meet and ask and solve coupling separately, base on the premise that calculate precision make the full foot project of the computational speed need, have adopted and controlled the volume law and solved the movement border problem in shaping. As to inside and outside surface not corresponding the products more,not divide into volume of two parts of and not last equation of controlling each, through hand over place go on person who insert is it guarantee two coordination of part to compare with, realize finite element / limited difference divide / control comprehensive application , volume of method.

The rationality of inputting the parameter is that the number value analyses the prerequisite which obtains the correct result, this system has got optimization which injects time and optimization that injected in grades through the artificial intelligence technology , guarantee the rationality of the introduction parameter, adopt the technology of expert system to turn into the analysis result report automatically, shorten user's needs and distance that analysis result exist , promote the artificial software for the " active optimization system " by the traditional " passive form " computational tool.

Generally adopt the round cylinder unit in a system of artificial midstream, and what the products are adopted is triangular unit, this system adopts half an analytic method to solve the integrating and asking the problem of solving of the unit of mixing, can not only analyse a mould and a of large-scale and complicated products but also can analyse a mould and more than of small-scale accurate products , widen systematic scope of application greatly , realize products with flow a systematic three-dimension flow and protect that pigeonhole and integrate analysing.

Alloying the line will have important influence on intensity , appearance of the products ,etc. , predict accurately that it is a difficult problem of the artificial software too to alloy the line position, this system has raised accuracy and efficiency that the line predicts of alloying greatly through adopting the model method of the nodal characteristic , its accuracy is higher than the advanced level of the like product in the world. Utilize the method of the neural network to determine the nature on appraisal to the influence degree which alloys the line, have offered the direct criterion for user's evaluation in shaping quality.

Development and application of this system, the fictitious manufactures of products and mould have established the solid theory and technological foundation in order to mould plastics, is it mould plastics products take shape key technology that quality control in an all-round way to form. At present , should already systematically form the commercialized software product , and popularize and apply among such more than 60 users as Haier , Kelon ,etc., have produced the considerable economic benefits.

In existing research, it is mainly a method to adopt number value and analyse that the craft of shaping based on CAE is optimized, but because of the characteristic of the shaping craft itself, it is very difficult to provide continuous and regular optimization to ask and solve the space. And number value analytical method have heavy, low optimizing goal form first-class shortcominging efficiency of calculating etc. also, this has influenced the popularization of CAE technology to a great extent. . Knowledge engineering method and technology solve number value and analyse the inherent and insufficient effective waySince 1990s, the research of knowledge engineering was unusually active, relevant method and technology emerged in an endless stream , deepening and expansion studying with knowledge engineering, include the producing type rule through setting up, instance , sample ,etc. integrate the knowledge base of the expression way of many knowledge and regular reasoning (RBR ) , the case-based reasoning (CBR ) , artificial neural network (ANN ) ,etc. integrate many intelligent agents of dealing with more ways, set up the intelligent system supporting CAE to use the course in an all-round way, use artificial intelligence and expert system technology, analysing and appraising to the shaping scheme automatically basically in analysis result of number value, propose the optimization suggestion of the scheme, it is the material science at present and make scientific front field and research focus .

On the basis of mould CAD/CAM, CAE technology that combine the artificial intelligence technology and use materials and take shape thoroughly , it is the shortcut that enterprises of our country can mount the new step of the modern digital manufacturing technology as soon as possible .