Who knows how to write the graduation thesis of Mold Manufacturing and Design?

Practice and discussion on graduation design mode for mold students

Cheng Rong, Li Jibin, Wang Xiankun, Wang Hongzhi, School of Engineering and Technology, Shenzhen University (Shenzhen, Guangdong, 5186O)

[ Abstract] Taking the reform of graduation design mode for 99 mold students in Shenzhen University as an example, the application scope, steps and results of computer technology in graduation design for mold students are discussed, and it is clearly pointed out that the combination of mold design theory and advanced design methods is applied in graduation design teaching for mold students.

Keywords Mold Design Graduation Design Computer Technology

1 Introduction

Mold is a technology-intensive and capital-intensive product, and its position in China's national economy is also very important. Mold industry has been officially identified as a basic industry in China and listed as a key supporting industry in the Tenth Five-Year Plan. Due to the continuous development of new technologies, new materials and new processes, mold technology has been continuously improved, and the requirements for talents' knowledge, ability and quality are also constantly improving.

According to the new requirements of social development for students majoring in mold to teach students, the College of Engineering and Technology of Shenzhen University has greatly revised the graduation design of students majoring in mold design of grade 99, and achieved good results.

2 Training objectives of mould major students

The mould design major of Shenzhen University is affiliated to the mechanical manufacturing and automation major of the School of Engineering and Technology of Shenzhen University, mainly engaged in the design and manufacture of injection moulds. In order to make clear the training goal of this direction, we conducted a relatively extensive social survey on the mold enterprises in the Pearl River Delta, especially in the surrounding areas of Shenzhen. The survey results show that employers require graduates to have high ideological quality and moral cultivation, love their jobs and have good ability to coordinate with others, require graduates to have a solid basic theory, focus on mastering basic skills and relearning skills, and require graduates to master foreign languages skillfully and have certain computer software application and development capabilities.

according to the analysis of the survey results, we have positioned the specification of mold professionals training as: training applied engineering and management talents who are dedicated to various types of enterprises, have basic knowledge of machinery and various mold design and manufacturing, have strong relearning ability and creativity, and can engage in mold design and manufacturing, technology development, applied research and sales in the front line of mold production. Based on this, the basic guiding ideology of teaching in this direction is to broaden the professional caliber, make the curriculum system reasonable, optimize the teaching content, have strong experimental research ability and wide social adaptability, and integrate the theory, practice and computer application of mold design into one.

3 Application fields of computer technology in injection mold

Plastic products from design to molding production is a very complicated process, which includes several important aspects such as plastic product design, mold structure design, mold processing and manufacturing, and plastic parts production. It needs the concerted efforts of product designer mold designer, mold processing technicians and skilled operators, and it is a process of repeated iteration and continuous optimization of design, modification and redesign. Traditional manual design has become increasingly difficult to meet the needs of fierce competition in the market. The application of computer technology is replacing the traditional manual design method in all aspects and has achieved remarkable economic benefits. The application of computer technology in injection mold is mainly manifested in the following aspects:

(1) Design of plastic products: 3D modeling software based on features provides a convenient design platform for designers, and various physical parameters such as product quality and volume lay a good foundation for subsequent mold design and analysis.

(2) structural analysis: the strength and stress of products can be analyzed by using finite element analysis software to improve the structural design of products.

(3) mold structure design: according to the shape, precision, size, technological requirements and production batch of plastic products, the mold design software will provide corresponding design steps, parameter selection, calculation formula and standard mold base, and finally give a full set of mold structure design drawings.

(4) Simulation of mold opening and closing movement: CAD technology can be used to simulate the whole process of mold opening, closing and product being pushed out, so as to check out the irrationality of mold structure design and correct it in time to reduce mold repair time.

(5) Numerical analysis of injection process: CAE method can be used to simulate the flow and pressure holding process of plastic melt in the mold cavity, and the results are of great guiding significance for improving the gating system of the mold and adjusting the injection process parameters, and can also test the rigidity and strength of the mold, the warpage of the product, the cooling process of the mold wall and so on.

(6) NC machining: The NC programming software can simulate the real-time machining process of the cutter on the three-dimensional curved surface and display the shape data of the curved surface, and at the same time, it can automatically generate NC wire cutting instructions, three-axis and five-axis NC milling tool paths of the curved surface, etc.

at present, the mainstream CAD software for injection mold in the world includes Pro/E, I-DEAS, UGⅡ, SolidWorks, etc. Structural Analysis software includes MSC, analysis, etc. The numerical analysis software of injection process includes MoldFlow, etc. CNC machining software includes MasterCAM, Cimatron, etc.

4 graduation design mode for mold major

mold major students require strong comprehensive knowledge and practical ability, which is not only the comprehensive application of basic technical courses and specialized courses such as mechanical drawing, engineering materials, tolerance fit and technical measurement, plastic molding technology and equipment, but also the need for students to understand a lot of practical experience.

Through graduation project, students should be trained and trained in the following basic abilities: ① the design of plastic products and the selection of molding technology; (2) the design ability of general plastic products molding die; ③ The ability of quality analysis and process improvement of plastic products and improvement design of plastic mold structure; ④ Understand the common commercial software of mold design and the combination with actual design. < P > The previous graduation design can only be regarded as the course design of mold design strictly; Teachers designate a plastic product, and sometimes even product model drawings are given to students. Students follow the steps of mold design in the spy book step by step. Without practical experience, it is impossible for the school to turn students' designs into actual products. Therefore, students don't know whether the designs are reasonable or not. Even if experienced teachers can't point out the irrationalities, students have no perceptual knowledge, and they can only talk on paper. When students step into society and engage in actual product design, they often find that they can't start. Even if they design it, it is a piece of waste paper, and it usually takes one to two years to get started. Therefore, students often sigh: nothing has been learned at school, which is a failure of our education.

In order to change this situation, in the graduation design of Grade 99, we closely combine the contents of mold design with CAD/CAM/CAE. Through advanced software simulation, students can find out their own irrationalities in each step of design at any time, and find out various solutions to make the design more reasonable. At the same time, they have mastered the most advanced design and analysis technology, which has improved students' interest in learning and innovation ability, and made the graduation design truly become students' actual work. The design flow is shown in Figure 1.

In order to ensure the quality of graduation design, we set up a mold design steering group composed of four teachers, each of whom is responsible for one step of the design process. There are ***15 students who participated in the graduation project of mold design this time. We are divided into 5 groups with 3 students in each group.

First of all, when arranging graduation design topics, students are told to make a switch button without giving specific plastic products. Students can determine their own design products according to their own interests: game console handle button, glasses case switch button, light wall switch button and mouse button. Through market research and consulting a large number of documents, we can determine the shape and internal structure of our plastic parts. The three-dimensional modeling software Pro/E is used to design the internal and external structures of plastic parts, and AutoCAD is used to draw two-dimensional drawings. In the process of structural design, the structural analysis software MSCPatran is used to analyze the structural strength, stiffness and stress after the button is stressed, and the structure is constantly revised. Students will find that the knowledge of mechanical design, industrial product design, material mechanics, theoretical mechanics and other courses is reflected at this stage, which is also a comprehensive application process for the previous courses. Fig. 2 is the assembly diagram and explosion diagram of the button of a game machine designed by Xueniu, and fig. 3 is the maximum deformation and maximum stress diagram when the button is stressed at two diagonal points.

after the design of plastic products is completed, the mold structure is designed, and the mold design module under Prom/E is used to classify, divide and extract the products to obtain the core and cavity files; The standard die holder parts and other accessories such as sliders and oblique pins are established through expert die holder system EMX(Pro/E, one of the plug-in programs of the system). In fact, this process is not over. It is closely related to the numerical analysis of the subsequent injection process. The injection flow analysis software MoldFlow is adopted. According to the dynamic diagram of the flow process of melt in the gating system and cavity, the gating system of the mold is improved and the injection process parameters are adjusted, so that the design of each system of the mold can be optimized. Fig. 4 shows the optimal pouring position analyzed and the result of injection molding with circular runner arrangement. Fig. 5 is an assembly drawing and an explosion drawing of the button die.

after the mold structure is completed, NC machining is carried out. MasterCAM8. processing software is used to complete the virtual machining process of the mold, and the NC code of NC machining is automatically compiled. The rationality of the machined workpiece can be checked by using the simulation module.

Finally, students should provide detailed design instructions and complete 2D and 3D drawings. In the thesis writing stage and the defense process, students also used ACDSee image software to intercept the design images and help introduce the whole design process. Office software is used to process words and write analysis reports.

after the completion of the whole design, each student must make a summary of his own design process and results, and put forward the innovation and characteristics of this design. For example, in the modeling part or runner design part, we should also consider the problems existing in the design and the corresponding solutions. From the summary of most students, students urgently realize the lack of practical experience. Therefore, in the graduation design of the next student, we strive to invite more designers from enterprises to communicate with students and let students get in touch with the actual design and production process.

At this point, students have completed the whole process of a project: plastic product design-mold juice design.

5 Conclusion

Through the reform of this graduation design mode, students have not only made a summary of their four-year college courses, but also mastered the most popular design and processing methods that are closest to social reality. Therefore, the graduates of this year's mold major have been welcomed by the society, and the mold department of a large Taiwan-funded company in Shenzhen is willing to accept 5 graduates from our school at one time, which has achieved good social benefits.

References

1 Zeng Pan attached importance to the teaching reform of traditional courses to cultivate high-quality talents, Beijing Degree and Postgraduate Education, 2,(1)

2 Zhou Huamin's lecture notes on modern mold design method, injection mold part and modern mold design method, 1988

3 Zeng Xiaohong's injection mold design for the handle direction button of game machine, Shenzhen University's graduation design collection, 23.