The first chapter is introduction.

1. 1 basis of topic selection

Mould plays an important role in the product manufacturing process. The level of mold design, to a large extent.

Determines the level of productivity. Effective mold design can reduce the adjustment times and time of resources and make a living.

Production planning and scheduling provide more optimization space to improve production efficiency [1]. Mold design is a job.

As an important part of assembly system, it affects the efficiency and quality of product production. In-depth mold design

It is of great significance to study it.

Mold industry is the basic industry of industry, and molds are widely used in various fields of industry. In electronics,

In automobiles, motors, electrical appliances, instruments, meters, home appliances, communications and other products, 60% to 8% of the parts must meet the requirements.

Molding by mold. High precision, high complexity, high consistency and high precision of mould production parts.

Productivity and low consumption are unmatched by other processing and manufacturing methods. Mold is also a "benefit amplifier",

The value of the final product produced by the mold is often dozens or even hundreds of times the value of the mold itself. Shaping students

The level of production technology largely determines the quality and efficiency of products and the ability to develop new products.

And it has become an important symbol to measure a country's product manufacturing level [3]. Mold is the foundation of industrial production.

Basic technology and equipment play an important role in the national economy. In the past 10 years, mold CAD technology has developed rapidly.

The application scope is expanding day by day. Mold CAD technology provides an efficient, economical and fast tool for mold design and manufacturing.

This rapid method greatly improves the quality of the mold, shortens the design and manufacturing cycle of the mold and reduces the cost.

Reduce mold cost ['].

At present, there are many mold CAD systems at home and abroad, although these systems have strong analysis and calculation capabilities.

With graphic processing ability, it can provide interactive design 5] L. But in these systems, the mold design process mainly adopts

Using human-computer interaction, most of the design depends on the design experience of the operator, and only one computer is used.

Some rules are matched and calculated, but the mold successfully designed by predecessors can not be used effectively, which leads to the mold.

Long design cycle, high cost and low development efficiency.

Mold design based on case-based reasoning is beneficial to designers.

Using the past design experience, by combining and modifying the previous design scheme, a new design scheme is constructed; Simultaneously at

In actual production, there are already many mold families with exactly the same mold part types and assembly relationships, which can be

Become the basis of new design 6] 1. CRB technology abandons the construction and calculation of abstract knowledge rules in the past.

Solve the problem directly with the help of existing examples, and design a new mold by confirming and modifying the old examples.

Meter [7]. In the case-based reasoning system, past experiences are saved in the form of examples according to a certain organizational structure.

In the case base 8]t, when a new problem is to be solved, an appropriate algorithm is used to retrieve the case base through related attributes.

Find one or several examples that are most similar to the new problem, and then modify the examples to solve the new problem [9l.

CRB method is applied in mold design, and computer is used to shape the thinking activities of human brain in design.

It has become a task completed by designers in the past, which not only makes full use of the design experience of mold experts, but also applies to engineering.

The actual situation inside is also in line with human thinking habits. At the same time, the mold obtained by this method is based on the previous

A successful example was designed, which reduced the possibility that the new mold could not work normally and shortened the mold opening time.

Hair cycle.

1.2 Development Status and Trend of Mould CAD

1.2. 1 mold CA. Overview of system development at home and abroad

Mold CAD system is developing with the development of three-dimensional technology and modern design theory and method.

From the initial system based on two-dimensional graphics technology to the current system based on three-dimensional graphics technology and feature configuration.

As the main feature of the stage 1 10, Sichuan.

In the late 1960s, foreign countries began to use D to research molds, and put them into production in the early 1970s.

For example, 1973, Diecomp Company of the United States successfully developed the PDDc system for computer-aided design of progressive dies ['2 1].

The system already includes the input of product graphics and material characteristics: on the basis of the input, the molding is carried out.

Structural selection, die layout, punch and other insert design; Finally, draw the mold assembly drawing and parts drawing.

And numerical control programming.

1978, Japan Mechanical Engineering Laboratory developed a CAD system for blanking progressive dies, which consists of product drawings.

Input, mold selection, blank layout, layout, mold layout, process calculation, drawing, etc. 10.

Modular composition.

In 1980s, with the development of computer technology, the number of manufacturers adopting mold CAD technology increased greatly.

Increase. In the CAD system of bending progressive die and automobile panel die, the plastic forming simulation technology is applied.

Surgery. The representative is the D/ M system of bending progressive die developed by Hitachi in Japan in 1982, which adopts manual and

Batch mode combined with computer design.

Many commercial CAD/CAM systems appeared in 1990s, such as Pro/E and SolidWorks.

Due to the late development of computer technology in China, the research of mold CAD began in the 1980s. Huazhong University of Science and Technology

Science, Mechanical and Electrical Research Institute, Shanghai Jiaotong University and other units have begun to study the blanking die system. The 1990s.

In the mid-1970s, the CAD system of progressive die based on feature design in Huazhong University of Science and Technology was the representative product of this period.

mouth

Word of mouth.

1.2.2 development trend of crystallizer CAO

In recent years, the global manufacturing industry is shifting to the Asia-Pacific region, and China is becoming an important base of the world manufacturing industry.

[3] Li. The change of manufacturing mode will inevitably produce the demand for new technology and promote the development of CAD technology;

The popularization of network technology will change our way of life and production to a greater extent. along with

China's entry into WTO requires our products to be innovative, with higher quality and lower cost.

And provide it to users in a faster time [4l 1. As an important process equipment for product manufacturing, it is the foundation of national economy.

As one of the basic industries, the mold industry will face the forefront of competition. In addition to the need for "high-tech" practitioners, the mold industry

Personnel, but also need more "high-tech" to ensure.

(1) Collaborative innovative design will become the main direction of mold design.

The vertical integration mode of manufacturing industry makes the worldwide product sales, product design, product production and model

The division of labor in manufacturing industry is more clear. In order to shorten the product listing cycle, mold design can fully understand the significance of product design.

In the picture, in the product design stage, mold design also begins at the same time, product design engineer and mold design engineer.

Teachers need to enter the collaborative design state as soon as possible. In addition, mold standard parts required by mold manufacturers are generally made of molds.

Standard parts factory, it is best to refer to various standards in the mold design stage and make full use of the mold standard parts factory.

Used for data design. Because the CAD system used in every link of the manufacturing process is not necessarily the same,

This requires D system to have coordination ability, exchange upstream and downstream data at any time, and handle it.

This kind of data, data generation and processing standardization.

At present, mold manufacturers have widely adopted CNC machining technology. In order to ensure the processing quality, extraction

With high machining efficiency and improved manufacturing technology, quite a few mold manufacturers began to use multi-coordinate NC machining.

High-speed milling and die manufacturing based on rapid prototyping. Due to the abundant manufacturing equipment, the manufacturing industry

With the increase of information, the future manufacturing information will not only be the code of NC programming, but also come from.

The design considers the manufacturing process from the beginning, that is, it provides the mold manufacturing process, which not only includes the process table,

Processing parameters include fixture design, clamping technology and codes of each process. Ge gong

The sequence process is simulated and the network is used to realize * * *.

(2) The mold CAD technology based on ASP mode will become the development direction.

Today's mold industry has become a high-tech intensive industry. Any enterprise must first master everything.

Advanced technology, the cost will be very high, and it will be very difficult to train and retain talents who master these technologies.

Difficult. As a result, APS mode of mold CAD came into being, that is, the application service of various specialized technologies.

Business units provide technical services for mold enterprises. In this way, the whole society has formed a large mold manufacturing enterprise.

According to the division of labor between value chain and manufacturing process, manufacturing resources will be optimized. Application services include rapid prototyping.

Manufacturing, CNC outsourcing, mold design, mold forming process analysis, etc.

In the past 20 years, due to the continuous adoption of new technology, mold manufacturing is far from what people think of as "manual"

Workshop ".

2.3 Characteristics and advantages of crystallizer CAO system

Characteristics of (1) mold design

Different from the traditional design of a single part, the mold is the assembly of multiple parts, and the mold design is integrated.

Extremely complicated process, including product modeling, process analysis, making mold scheme, selecting mold base and mold.

General assembly drawing design, working parts design, auxiliary device design and detailed parts design, etc. , required to be able to

Enough to generate assembly drawings, assembly drawings and mold parts drawings. The particularity of mold modeling has the following points:

A. Most molds are complex parts, and mold modeling is complicated.

B, general mold processing parts of the process is very few, most of them are formed at one time, so the shape of the mold must be.

All the details of the machined parts must be described.

C mold design has a high repetition probability, and the geometric model of mold CAD should be updated repeatedly and repaired in time.

Reply.

(2) Modeling characteristics of mold cAD [4]

Mold CAD modeling technology is an accurate modeling technology, which can be divided into solid modeling and curve modeling:

A. Solid modeling technology has been able to meet the design requirements for molds with simple structures, but for structures,

For complex parts with high detail description accuracy, such as drawing surfaces and fillet transitions,

The design of cavity is limited to some extent.

B surface modeling technology is to generate smooth surface models from different surface construction features. Mainly includes many

Equivariant fillet transition processing technology, automatic surface trimming technology, surface editing technology, surface analysis technology and

The core technologies, such as fairing, can assist solid modeling technology to complete all the details description in mold design.

Rice. Surface modeling technology is suitable for product mold design with complex appearance and high detail description accuracy.

(3) Advantages of mold CAD

The superiority of mold CAD endows it with infinite vitality, which enables it to develop rapidly and be widely used.

Whether in improving productivity and quality, or in reducing costs and reducing labor intensity, D

The superiority of technology is incomparable to the traditional mold design method.

A.ACD can improve the quality of mold design. In the computer system, the comprehensive information of various related majors is stored.

Technical knowledge provides a scientific basis for mold design and process formulation. Computers and designers

Interaction is beneficial to give full play to the respective advantages of man and machine, and make the mold design and manufacturing process more reasonable.

B.CAD can save time and improve productivity. Greatly shortened the automation of design calculation and drawing.

And the design time is saved. The quality is improved, the reliability is enhanced, the decoration time is obviously reduced, and the delivery time of the mold is greatly shortened.

Shorten.

C.CAD can greatly reduce the cost. The high-speed operation of computers and automatic drawing greatly save labor.

Power. The optimized design saves raw materials.

D.CAD technology liberates technicians from tedious calculation and drawing and engages in other creative work.

Move it.

1.3 research contents of the paper

The theory and method of die design based on case-based reasoning are systematically put forward, and the application of CRB technology in die design is discussed.

In-depth research on the application of. On the basis of theoretical research, a case-based reasoning model is developed.

The design system strongly proves that the application of CRB technology can improve the efficiency of mold design. The main content of this paper is

Including:

The first chapter is the introduction: it summarizes the research significance of the paper, introduces the source and background of the topic, and briefly introduces

The application of CRB technology in mold design is expounded, and the general situation and development trend of mold CAD at home and abroad are studied.

Potential.

The second chapter is the overall design of mold CAD system, which mainly includes the process analysis and system requirements of mold CAD.

Analysis, as well as the customization of architecture and the division of functional modules.

The third chapter expounds the key technology of case-based reasoning, and introduces the actual case in detail.

Key technologies such as case representation, case retrieval strategy and case storage.

Chapter four: Case-based die design: The contents and methods of die case representation are introduced, and the dies are compared.

A storage and retrieval scheme is proposed and an example is given.

The fifth chapter is the development of the prototype system: it introduces the UG development platform and tools, and introduces the business process of the system.

Okay, describe it.

Chapter VI Conclusion and prospect. Summarize and prospect the research content of this paper.