The mould CAD technology development

1, mould CAD technology development

Early in the early 1960s, foreign automobile manufacturing company started mould CAD. This study began in automotive design, on the basis of complex surface design method was developed, and the major automotive company has established its own CAD/CAM system, and its application in the mold design and manufacturing. Computer software and hardware technology, for the rapid development of mould CAD/CAM application to a higher level of development.

Based on geometric model, a box of CAD system model aircraft and the development and application of automobile manufacturers. Example: the company and McDonnell Douglas Lockhead plane aircraft company before the automobile company, which CADD CAD system, system, AD2000 system, which promoted the development of mould CAD technology.

Since the 1970s, surface modeling and solid modeling technology develops rapidly, a new generation of CAD software is solid modeling and surface modeling, the system can be applied in mold design and manufacturing, in the mold has been used widely in the world. Ford motor company like America of CAD/CAM system including the mould CAD/CAM, replaced manual design and manufacture, design human-computer interaction are using 3d graphics processing, analysis and design calculation, complete production parts, 2d graphics, materials and processes, norm, watch cost, and other documents. System includes some professional software, such as design, process of complement of elastic-plastic deformation analysis, the springback control and surface parts of appearance, etc, has been used in the production of part in research and improvement. TOYOTA automobile company in Japan from 1980 to arm the mould CAD/CAM system, this system includes covering the mold processing software and Die - Nebuchadnezzar the convex, concave Die TINCA software etc. By tri-ordinate measuring machine model will measure the data obtained after the processed into a computer data for the car to cover design, mold design and manufacturing. The system of three-dimensional graphics functions, can be repeated revision on the screen surface shape, make in stamping workpiece when not produce various process defect, thus ensuring the quality of workpiece, DIECOMP company developed mould CAD system, make whole production preparation period by 18 weeks shorter for six weeks.

Meanwhile, a few countries of Europe in dies CAD/CAM application and research also made a lot of progress, such as French Renault automotive company Euclid application of CAD/CAM software system as the leading software, existing 95% of the software design work, and Renault automotive company in Euclid leading software was developed based on the demand for many automobile industry, such as modules for the interference Megavision and analysis of sheet metal forming OPTRIS etc.
At present, there are many enterprises to adopt CAD technology, and computer technology in automatic programming has gained rich experience and skill, make the mold accuracy and productivity greatly improved. With the introduction Autodesk from the company for a number of drawing AutoCAD software is mould industry gradually popularization, computer graphics is gradually replacing manual drawing. Domestic large and medium-sized enterprises of automobile and household appliances (in), has introduced from abroad a considerable amount of CAD system, and the allocation of some special software design, analysis, and made the obvious economic benefit. However, due to various reasons, there are still many enterprises still stays in the mould design stage of manual, although some have dumped story-board is realized, and the mould CAD drawings, the work is also just use the Computer drawing (Computer Aided design Draft) and 2d, only extremely individual enterprise auto mould design and manufacturing ability to international advanced level. In 1989, the chengdu been used abroad, auto mould CAD/CAM technology, nc machining and CNC digital transmission technology, design and manufacture YiWeiKe successfully complete the main model of car body.

In addition, although some domestic with independent copyright software, such as Shanghai jiaotong university national mould CAD project research center, the development of cold dies CAD system, wuhan huazhong university of science and technology of state key laboratory mould technology development of plastic injection mould CAD/CAE/CAM system HSC2.0 and Beijing university of aeronautics research development are mould CAD/CAM system, solved CAXA production of some problems, but haven't been very good promotion and use.

Now a new models and need 48 months, Japan is only 30 months. Our new model of car in the car models, especially the design technology development is relatively backward, one of the important reasons is covering mould design efficiency is low. The traditional mould design has not adapt to the development of automobile industry, and introduce foreign covering mould products not only will cost a lot of foreign exchange, and will seriously hindered the upgrading of automobile products. To solve these problems, it is necessary to research and develop our own mould CAD technology. While the introduction of foreign advanced universal modelling software development is a necessary and effective method.

2 the mould CAD technology characteristics

(1) the mould CAD face

Usually covered in stamping must pass the drawing, trimming, plastic, flanging and punching process etc. First step, namely the drawing process is the most important in the design process added. Process design to supplement directly affect the mould design can pull out qualified mould parts, can reduce the time, shorten the commissioning of the mold production cycle.

(2) the mould structure characteristics of CAD

Large mold structure are generally more complex, a pair of large covering mould has hundreds of parts, mould shape size is larger also. The mould structure design can generally be divided into 2d and 3d design design two, two kinds of method has its advantages and disadvantages.

Computer 2d is designed with manual drawing design, graphic drawing is similar, its advantage is design speed and occupy the computer memory of computer hardware configuration, small, small investment, is a kind of effective method, It is designed by mistake, can't directly for analysis and processing. 3d design has many advantages, such as parameter can be based on the characteristics and the related, etc., products made in the design phase to modify, also make the concurrent engineering. 3d design, structure design, and visual image is reasonable to be clear at a glance. At the same time, the design of automatic 3d dimension reduced design error, but the three-dimensional mold design is also exist some problems, such as: computer software occupies speed, low drive and memory space, die structure and design projection lines slow speed, etc.

3 the automobile covering mould CAD application of existing problems

In automotive body covering occupies an important position in the mold, and covering the main production technology and equipment, quality of body plays a decisive role. Foreign automobile covering mould CAD/CAM technology development has entered the stage of applications, not only the substantial increase the overall quality of the mould design, and greatly shortened mold production cycle. In recent years, our country in the mould CAD technology applications have achieved remarkable progress, but some problems still exist below:

(1) the design efficiency is low

Because our country CAD technology, professional level is low, both professional and familiar with CAD/CAM application technology, and lack of talent development ability is poor, independent development of CAD software quality is not high, low efficiency of design.

(2) low degree of standardization

Due to the various sectors of the standard, each have each enterprise, the enterprise standard mould manufacturer must have formed between the design and manufacturing standard, thus causing existing stamping cover of CAD/CAM system integration and intelligence are relatively low.

(3) current CAD software specificity

At present domestic independent development of CAD software less, and the most advanced software manufacturer introducing more for general-purpose software development, without the specificity.

(4) covering dies CAD/CAM technology development is relatively backward, means of CAD/CAM system in quality, reliability, and to guarantee the long period of development.

(5) existing dies CAD system of the man-machine interface can not meet the requirements of users.

(6) is mainly used for 2d CAD design, and mostly stay in computer graphics instead of manual drawing with the basis.

The mould CAD's future development trends

Mould manufacturing technology is one of the fastest growing technology, its characteristic is very large, batch number, generation very fast. Theoretically, it can bring out the best of CAD technology is of advantage. But the present achievements of mold CAD is remarkable, especially in the mould CAD technology application, the technology of the huge potential is still not fully play out to solve this problem, the key is to improve the mould design efficiency. Now in the mould CAD technology development exist several trends:

1 mold CAD parameterization

Parameterized modeling method is more advanced CAD technology, but also improve the modelling method is an effective means of CAD work efficiency. It is the overall structure of stamping mould in general are standard form for each part of the characteristic, the basic sizes, the corresponding parameter in the real geometry, topology based on various parts of the relationship between elements. When because of the mould structure resulting mould parts size change, change the parameters related files of variables, and the relevant parts of the model BiaoZhuZhi size also change accordingly, through the driver module size after treatment can generate the dimensions actual size.

2 mold CAD of intelligence

The stamping mould design difficulty is mainly manifested in the design theory of incomplete and only needs to express and experience of experts on use. With manual design, using gm CAD software (including new integrated CAD software) for covering mould design, largely must rely on mould expert intervention. In order to realize the automation of die structure design, and to reduce the dependence of mould expert, must develop the special automobile covering mould structure design of the software, intelligent some previous experience in the design, manufacture, application of success in the mould design, to form the computer knowledge and intelligence library, expert system, thereby CAD system capable of working mould design experts, designed to meet the requirements of automobile covering mould, this also is the so-called mould CAD of intelligence.

Intelligent CAD in understanding human thought theoretical basis, the design personnel at logic, synthesis reasoning ability of thinking in images, with computer, accurate calculation capacity, thereby combining CAD system capable of working, mould design expert design meets the requirement of stamping mould.

3 the integration of CAD

The integration of CAD is from the traditional design methods to CAD/CAE/CAM integration development direction. Mould design process is an exchange of information processing, distribution and management of the process by elas-plastics large deformation finite element simulation technique can analyze the material of plastic forming process, improve process analysis and mould CAD/CAM system function, to create a more advanced CAD/CAM system, therefore, CAD/CAE/CAM integration to design and the manufacture process of information, conversion, storage, distribution management analysis and control, will they organically "integrated" together, it helps to achieve optimal performance.

4 mold CAD professional

The future of the mould CAD will lead to more specialized road. Some common due to its various functions of software, professional, already cannot satisfy the needs of large mould CAD. A better method is software company specialized in close cooperation with the factory, the development of the mould CAD software strong specificity, such as the PTC software company with TOYOTA automobile company in Japan PRO/E based on software development of the mould design module PRO/DIEFACE etc, it is also a developing direction of mould CAD. For domestic manufacturers of mould in introducing foreign advanced CAD software (such as UG, Pro/E, etc), and on the basis of using the secondary development technology, aiming at the characteristics of product development department for mould CAD system is an effective and economical way.