Three development stages of the hottest injection

2022-08-14
  • Detail

Three development stages of injection mold software Abstract: This paper focuses on the working characteristics, existing problems and development trends of the three development stages of injection mold software, and introduces the achievements of the Key Laboratory of mold technology of Huazhong University of technology in this regard

key words: injection mold simulation software integrated three-dimensional solid model OpenGL cad/cam/cae

Introduction

the importance of plastic mold cad/cae/cam technology is gradually recognized by the mold industry, in which the development of plastic injection mold application software is very eye-catching, forming a unique situation in the industry. The development of injection mold software can be divided into three stages. The first stage is the development of independent injection process simulation software, the second stage is the integration of two-dimensional mold design software and simulation software, and the third stage is the integration of three-dimensional mold design and manufacturing software and simulation software. This paper focuses on the work content, characteristics, existing problems and development trend of each development stage

figure 1hs_ The organizational structure of cae97 system

2 injection process simulation software running independently

the one-dimensional commercial flow analysis software mf1.0 based on the finite difference method introduced by Moldflow company of Australia in 1978, and AC of the United States_ Two dimensional commercialized flow analysis software C based on finite element method launched by tech company in 1986_ Flow1.0 is two milestones in the development of injection mold software at this stage. In the following 10 years, MF and C_ Flow software has been continuously improved and perfected, and has formed a series of analysis software including flow simulation, pressure maintaining analysis, cooling analysis, internal stress analysis, molecular orientation and warpage deformation prediction, which enjoys a high reputation in the mold industry at home and abroad. The injection process simulation software HS currently launched by the State Key Laboratory of mold technology of Huazhong University of Technology_ Cae97 has independent copyright. Figure 1 shows HS_ The organizational structure of cae97 system. The system runs in the windeow95/nt environment. Supported by OpeGL/GUI software, the object-oriented programming method and surface modeling method are adopted. In the software structure design of the system, a general user management system UIMS that can run on multiple software and hardware platforms is formulated, which can completely shield the application software and system development resources, and ensure good portability and maintainability. HS_ The main functions and characteristics of cae97 are: it is an instrument used to test the mechanical and physical functions of various material components (1) advanced three-dimensional surface modeling system. (2) Automatic division and optimization of triangular lattice. (3) Unified window interface style. (4) Integration of injection flow, pressure maintaining and cooling process analysis software. (5) The calculated results are in good agreement with the experimental measurements. Figure 1hs_ The organizational structure of cae97 system the software developed at this stage is limited by the mathematical model and algorithm, whether it is MF or C abroad_ Flow, or domestic HS_ Cae97 has the following shortcomings and problems:

(1) although all the software uses three-dimensional visualization technology, the mathematical models based on these software are essentially two-dimensional models. Because the mathematical model is too simplified, the analysis results are inaccurate. In many cases, the analysis results obtained can only be qualitative, not quantitative, and the warpage analysis software becomes passive water

HsCAE 3.0

(2) due to the limitations of the algorithm, the flow, pressure maintaining and cooling software need to use the neutral surface to analyze. The so-called neutral surface is an imaginary layer located between the mold cavity and core. Users directly construct the neutral surface of the car from plastic products. It is very difficult to generate such a situation when the car is driving. It is even more difficult to generate the neutral surface based on the cavity and core graphics. For a long time, the generation of neutral surface has been a stumbling block in the operation of injection process analysis software

hscae 3.0 pressure distribution of plastic melt in the mold cavity

hscae 3.0 temperature distribution of plastic melt in the mold cavity

(3) when running the flow and cooling analysis software, you must know the layout scheme and injection process conditions of the mold pouring system and cooling system in advance. In the absence of these initial data, the use value and efficiency of the analysis software will be greatly reduced, Relying solely on the trial and error method, even running these analysis software repeatedly, may not necessarily obtain the appropriate technical scheme and process conditions

(4) the surface modeling and functions of these independently developed analysis software have considerable limitations, and their modeling convenience and application coverage are far from being compared with the famous commercial cad/cam systems (such as pro_e, CADDS5, UG Ⅱ)

(5) the geometric model of plastic products or the geometric model of cavity and core generated by commercial cad/cam software generally cannot automatically generate the neutral surface, and the secondary input is inevitable, which often consumes a lot of energy and time of users

hscae 3.0 distribution of shear rate of plastic melt in the mold cavity

hscae 3.0 distribution of shear force of plastic melt in the mold cavity

3 integration of two-dimensional mold design software and analysis software

in the past 10 years, computer graphics and automatic programming technology have become more and more popular in the mold industry. In the 1990s, with the rapid development of cad/cam technology, people are no longer satisfied with using computers only as drawing and programming tools, It is urgent to have the functions of drawing, design, calculation, analysis and processing in the same software environment, so the integrated system of mold cad/cam/cae came into being. Based on the successful development of injection process analysis and simulation software, the State Key Laboratory of mold technology of Huazhong University of technology has adopted the most widely used commercial two-dimensional software AutoCAD in the plastic mold industry to realize the integration of two-dimensional mold design software and simulation software. All programs of hscad 2.0 are written in C language on the ads development platform provided by AutoCAD, providing users with a unified man-machine interface. In addition to the functions of AutoCAD itself, hscad 2.0 includes modules such as mold structure design subsystem, structure and process parameter calculation and verification subsystem, plastic injection flow, pressure maintaining and cooling simulation subsystem, CNC wire cutting programming subsystem, database building tools and design process management, Therefore, the program can be integrated and run in the environment of AutoCAD. Figure 2 shows the structural block diagram of hscad 2.0

Figure 2 HSC 2.0 structure block diagram

hscad 2.0 main functions are shown in the following five aspects:

(1) convenient and practical graphic input mode. The system provides an input method based on graphic size. With the help of size superposition, the automatic conversion from product to cavity diagram or core diagram can be realized

(2) flexible and diverse parametric design process. In hscad 2.0, parameterization method runs through the whole process of die structure design

(3) conceive novel database building tools. Users can easily establish and modify the material library, mold base library and drawing library that meet the characteristics of our factory. The two signs of novelty are the parameterization of mold base structure and the relevance of mold base parts

(4) calculation and verification function combining theory with practice. Hscad 2.0 not only adopts relevant theoretical calculation formulas, but also takes full account of the empirical formulas and practical principles that have been proved to be effective in practice. It has developed unique software for mold stiffness verification, mold cost calculation, launch system calculation, injection machine verification, cavity number calculation, cooling system and gating system calculation, which can be called by users at any time in the design process

(5) plastic injection molding process simulation integrated with mold structure CAD

HsCAE 2.0 software in the second stage is unique in the following aspects:

(1) running HsCAE 2.0 can obtain initial data such as gating system, cooling system, mold structure scheme, injection process conditions, and create good conditions for the successful implementation of injection process simulation

(2) according to the cavity diagram and core diagram generated by HsCAE 2.0, the elimination method of running mode can be easily generated: take out the triangular lattice required by the damping pin fitting software, avoiding the secondary input of the geometric model

(3) the software function is expanded from simple process simulation to the integration of mold structure design, wire cutting and injection process simulation

however, the HsCAE 2.0 software developed in the second stage still has the following shortcomings:

(1) using the cavity surface and core surface to divide the lattice, although the problem of constructing the neutral surface is avoided, it affects the analysis accuracy. Using this simplified method to establish the pouring system and cooling system of the mold is appropriate, but it cannot be used for warpage analysis

(2) the mathematical model of flow process simulation is still a two-dimensional model

(3) due to the weak ability of AutoCAD surface modeling, the application scope of HsCAE 2.0 is limited

(4) the mode of three-dimensional modeling and two-dimensional design cannot meet the needs of the development of a new generation of injection simulation software

hscad 2.0 hscad 2.0 mold assembly drawing design based on AutoCAD R12

4 integration of 3D mold design and manufacturing software and simulation software

the so-called new generation injection mold software is an injection mold integrated manufacturing system (CIMS) established by using computer integrated manufacturing Technology (CIM). This highly integrated system should support the whole process of mold design and manufacturing, Therefore, the application of 3D geometric modeling and 3D mold design and manufacturing is very important. In the 1990s, the western advanced industrial countries have preliminarily integrated the commercialized cad/cam system with the injection process simulation software, and achieved remarkable results. However, no matter CADDS5, UG Ⅱ or pro_ E. At the beginning of development, it was conceived as a general mechanical design and manufacturing tool, not for plastic molds. Therefore, when using these general CAD software to design plastic molds, it will feel inefficient, cumbersome operation and lack of functions. Therefore, the development trend in recent years is to develop a new generation of injection mold cad/cam special system, or carry out targeted secondary development on the basis of cad/cam general system. For example, the special system camold software developed by technocal company can automate many routine work of injection mold design. Camold software establishes the relationship model between the components of the injection mold, and can automatically assemble and modify the structure and size of the injection mold. Another example is parametrictech in Pro_ Based on E software, a special software pro/molddesign for injection mold design is developed, which preliminarily realizes the integration of mold structure design, injection flow process simulation and injection mold opening and closing action simulation. In view of China's national conditions and our strong strength in mechanical CAD, in the third stage of injection mold software development, we chose to develop a new generation of injection mold integrated manufacturing system on the three-dimensional parametric feature modeling cad/cam system Intesolid 1.0 independently developed by our school

the main functions and characteristics of HsCAE 3drf 5.0

new system based on 3D solid model are as follows:

(1) 3D solid modeling ability. On the basis of two-dimensional sketch design, three-dimensional entities can be generated interactively and the surface information of the entities can be easily extracted for automatic mesh generation

(2) three dimensional parameterization function. 3D entities and 2D views are related to each other. During the design process, the size of 3D entities or any view can be changed at will. The change of the size will lead to the automatic change of 3D entities and all views

(3) visualization function. 3D graphics can be shaded and rendered at any time, and can be hidden

Copyright © 2011 JIN SHI