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1 Int J Adv Manuf Technol (2003) 21:807819 Ownership and Copyright 2003 Springer-Verlag London Limited A Parametric-Controlled Cavity Layout Design System for a Plastic Injection Mould M. L. H. Low and K. S. Lee Department of Mechanical Engineering, National University of Singapore, Singapore Today, the time-to-market for plastic products is becoming shorter, thus the lead time available for making the injection mould is decreasing. There is potential for timesaving in the mould design stage because a design process that is repeatable for every mould design can be standardised. This paper presents a methodology for designing the cavity layout for plastic injection moulds by controlling the geometrical para- meters using a standardisation template. The standardisation template for the cavity layout design consists of the configur- ations for the possible layouts. Each configuration of the layout design has its own layout design table of all the geometrical parameters. This standardisation template is pre-defined at the layout design level of the mould assembly design. This ensures that the required configuration can be loaded into the mould assembly design very quickly, without the need to redesign the layout. This makes it useful in technical discussions between the product designers and mould designers prior to the manu- facture of the mould. Changes can be made to the 3D cavity layout design immediately during the discussions, thus saving time and avoiding miscommunication. This standardisation tem- plate for the cavity layout design can be customised easily for each mould making company to their own standards. Keywords: Cavity layout design; Geometrical parameters; Mould assembly; Plastic injection mould design; Standardis- ation template on it and provides the mechanism for molten plastic transfer from the machine to the mould, clamping the mould by the application of pressure and the ejection of the formed plastic part. The injection mould is a tool for transforming the molten plastic into the final shape and dimensional details of the plastic part. Today, as the time-to-market for plastic parts is becoming shorter, it is essential to produce the injection mould in a shorter time. Much work had been done on applying computer techno- logies to injection mould design and the related field. Knowl- edge-based systems (KBS) such as IMOLD 1,2, IKMOULD 3, ESMOLD 4, the KBS of the National Cheng Kang University, Taiwan 5, the KBS of Drexel University 6, etc. were developed for injection mould design. Systems such as HyperQ/Plastic 7, CIMP 8, FIT 9, etc. are developed for the selection of plastic materials using a knowledge-based approach. Techniques have also been developed for parting design in injection moulding 1012. It has been observed that although mould-making industries are using 3D CAD software for mould design, much time is wasted in going through the same design processes for every project. There is great potential for timesaving at the mould design stage if the repeatable design processes can be standard- ised to avoid routine tasks. A well-organised hierarchical design tree in the mould assembly is also an important factor 13,14. However, little work has been done in controlling the para- meters in the cavity layout design; thus this area will be our main focus. Although there are many ways of designing the 1. Introduction Plastic injection moulding is a common method for the mass production of plastic parts with good tolerances. There are two main items that are required for plastic injection moulding. They are the injection-moulding machine and the injection mould. The injection-moulding machine has the mould mounted Correspondence and offprint requests to : K. S. Lee, Department of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260. E-mail address: mpeleeks .sg Received 8 January 2002 Accepted 16 April 2002 cavity layout 15,16, mould designers tend to use only conven- tional designs, thus there is a need to apply standardisation at the cavity layout design level. This paper presents a methodology for designing the cavity layout for plastic injection moulds by controlling the parameters based on a standardisation template. First, a well-organised mould assembly hierarchy design tree had to be established. Then, the classification of the cavity layout configuration had to be made to differentiate between those with standard con- figurations and those with non-standard configurations. The standard configurations will be listed in a configuration database and each configuration has its own layout design table that controls its own geometrical parameters. This standardisation 2 808 M. L. H. Low and K. S. Lee Fig. 1. Front insert (cavity) and back insert (core). template is pre-defined at the layout design level of the mould assembly design. 2. Cavity Layout Design for a Plastic Injection Mould An injection mould is a tool for transforming molten plastic into the final shape and dimensional details of a plastic part. Thus, a mould contains an inverse impression of the final part. Most of the moulds are built up of two halves: the front insert and the back insert. In certain mould-making industries, the front insert is also known as the cavity and the back insert is known as the core. Figure 1 shows a front insert (cavity) and a back insert (core). Molten plastic is injected into the impression to fill it. Solidification of the molten plastic then forms the part. Figure 2 shows a simple two-plate mould assembly. Fig. 2. A simple mould assembly. 2.1 Difference Between a Single-Cavity and a Multi-C a vity Mould Very often, the impression in which molten plastic is being filled is also called the cavity. The arrangement of the cavities is called the cavity layout. When a mould contains more than one cavity, it is referred to as a multi-cavity mould. Figures 3(a) and 3(b) shows a single-cavity mould and a multi-cavity mould. A single-cavity mould is normally designed for fairly large parts such as plotter covers and television housings. For smaller parts such as hand phone covers and gears, it is always more economical to design a multi-cavity mould so that more parts can be produced per moulding cycle. Customers usually deter- mine the number of cavities, as they have to balance the investment in the tooling against the part cost. 2.2 Multi-Cavity Layout A multi-cavity mould that produces different products at the same time is known as a family mould. However, it is not usual to design a mould with different cavities, as the cavities may not all be filled at the same time with molten plastic of the same temperature. On the other hand, a multi-cavity mould that produces the same product throughout the moulding cycle can have a bal- anced layout or an unbalanced layout. A balanced layout is one in which the cavities are all uniformly filled at the same time under the same melt conditions 15,16. Short moulding can occur if an unbalanced layout is being used, but this can be overcome by modifying the length and cross-section of the runners (passageways for the molten plastic flow from the sprue to the cavity). Since this is not an efficient method, it is avoided where possible. Figure 4 shows a short moulding situation due to an unbalanced layout. A balanced layout can be further classified into two categor- ies: linear and circular. A balanced linear layout can accommo- date 2, 4, 8, 16, 32 etc. cavities, i.e. it follows a 2n series. A balanced circular layout can have 3, 4, 5, 6 or more cavities, but there is a limit to the number of cavities that can be accommodated in a balanced circular layout because of space constraints. Figure 5 shows the multi-cavity layouts that have been discussed. 3. The Design Approach This section presents an overview of the design approach for the development of a parametric-controlled cavity layout design system for plastic injection moulds. An effective working method of mould design involves organising the various subas- semblies and components into the most appropriate hierarchy design tree. Figure 6 shows the mould assembly hierarchy design tree for the first level subassembly and components. Other subassemblies and components are assembled from the second level onwards to the nth level of the mould assembly hierarchy design tree. For this system, the focus will be made only on the “cavity layout design”. 3 Fig. 3. (a) A single cavity mould. (b) A multi-cavity mould. A Cavity Layout Design System 809 3.1 Standardisation Procedure Fig. 4. Short moulding in an unbalanced layout. In order to save time in the mould design process, it is necessary to identify the features of the design that are com- monly used. The design processes that are repeatable for every mould design can then be standardised. It can be seen from Fig. 7 that there are two sections that interplay in the stan- dardisation procedure for the “cavity layout design”: component assembly standardisation and cavity layout confi guration stan- dardisation. 4 810 M. L. H. Low and K. S. Lee Fig. 5. Multi-cavity layouts. Fig. 6. Mould assembly hierarchical design tree. Fig. 7. Interplay in the standardization procedure. 3.1.1 Component Assembly Standardisation Before the cavity layout configuration can be standardised, there is a need to recognise the components and subassemblies that are repeated throughout the various cavities in the cavity layout. Figure 8 shows a detailed “cavity layout design” hier- archy design tree. The main insert subassembly (cavity) in the Fig. 8. Detailed “cavity layout design” hierarchical design tree. second level of the hierarchy design tree has a number of subassemblies and components that are assembled directly to it from the third level onwards of the hierarchy design tree. They can be viewed as primary components and secondary components. Primary components are present in every mould design. The secondary components are dependent on the plastic part that is to be produced, so they may or may not be present in the mould designs. As a result, putting these components and subassemblies directly under the main insert subassembly, ensures that every repeatable main insert (cavity) will inherit the same subas- semblies and components from the third level onwards of the hierarchy design tree. Thus, there is no need to redesign similar subassemblies and components for every cavity in the cavity layout. 3.1.2 Cavity Layout Configuration Standardisation It is necessary to study and classify the cavity layout configur- ations into those that are standard and those that are non- standard. Figure 9 shows the standardisation procedure of the cavity layout configuration. A cavity layout design, can be undertaken either as a multi- cavity layout or a single-cavity layout, but the customers always determine this decision. A single-cavity layout is always considered as having a standard configuration. A multi-cavity mould can produce different products at the same time or the 5 A Cavity Layout Design System 811 Fig. 10. The standardization template. design table. The configuration database consists of all the standard layout configurations, and each layout configuration has its own layout design table that carries the geometrical parameters. As mould-making industries have their own stan- dards, the confi guration database can be customised to take into account those designs that are previously considered as non-standard. Fig. 9. Standardisation procedure of the cavity layout configuration. same products at the same time. A mould that produces different products at the same time is known as a family mould, which is a non-conventional design. Thus, a multi- cavity family mould has a non-standard configuration. A multi-cavity mould that produces the same product can contain either a balanced layout design or an unbalanced layout design. An unbalanced layout design is seldom used and, as a result, it is considered to possess a non-standard configuration. However, a balanced layout design can also encompass either a linear layout design or a circular layout design. This depends on the number of cavities that are required by the customers. It must be noted, however, that a layout design that has any other non-standard number of cavities is also classified as having a non-standard configuration. After classifying those layout designs that are standard, their detailed information can then be listed into a standardisation template. This standardisation template is pre-defined in the cavity layout design level of the mould assembly design and supports all the standard configurations. This ensures that the required configuration can be loaded very quickly into the mould assembly design without the need to redesign the layout. 3.2 Standardisation Template It can be seen from Fig. 10 that there are two parts in the standardisation template: a configuration database and a layout 3.2.1 Configuration Database A database can be used to contain the list of all the different standard configurations. The total number of configurations in this database corresponds to the number of layout configur- ations available in the cavity layout design level of the mould design assembly. The information listed in the database is the configuration number, type, and the number of cavities. Table 1 shows an example of a configuration database. The configur- ation number is the name of each of the available layout configurations with the corresponding type and number of cavities. When a particular type of layout and number of cavities is called for, the appropriate layout configuration will be loaded into the cavity layout design. 3.2.2 Layout Design Table Each standard configuration listed in the confi guration database has its own layout design table. The layout design table contains the geometrical parameters of the layout configuration and is independent for every configuration. A more complex layout confi guration will have more geometrical parameters to control the cavity layout. Figures 11(a) and 11(b) show the back mould plate (core plate) with a big pocket and four small pockets for assembling the same four-cavity layout. It is always more economical and easier to machine a large pocket than to machine individual smaller pockets in a block of steel. The advantages of machin- ing a large pocket are: 6 S01 Single 1 L02 Linear 2 L04 Linear 4 L08 Linear 8 812 M. L. H. Low and K. S. Lee Fig. 11. The back mould plate with pocketing. Table 1. Sample of the configuration database. Configuration number Type Number of cavities L16 Linear 16 L32 Linear 32 L64 Linear 64 C03 Circular 3 C04 Circular 4 C05 Circular 5 C06 Circular 6 1. More space between the cavities can be saved, thus a smaller block of steel can be used. 2. Machining time is faster for creating one large pocket compared to machining multiple small pockets. 3. Higher accuracy can be achieved for a large pocket than for multiple smaller pockets. As a result, the default values of the geometrical parameters in the layout design table results in there being no gap between the cavities. However, to make the system more flexible, the default values of the geometrical parameters can be modified to suit each mould design where necessary. 3.3 Geometrical Parameters There are three variables that establish the geometrical para- meters: 1. Distances between the cavities (flexible). The distances between the cavities are listed in the layout design table and they can be controlled or modified by the user. The default values of the distances are such that there are no gaps between the cavities. 2. Angle of orientation of the individual cavity (flexible). The angle of orientation of the individual cavity is also listed in the layout design table which the user can change. For a multi-cavity layout, all the cavities have to be at the same angle of orientation as indicated in the layout design table. If the angle of orientation is modified, all the cavities will be rotated by the same angle of orientation without affecting the layout configuration. 3. Assembly mating relationship between each cavities (fixed). The orientation of the cavities with respect to each other is pre-defined for each individual layout configuration and is controlled by the assembly mating relationship between cavities. This is fi xed for every layout configuration unless it is customised. Figure 12 shows an example of a single-cavity layout con- figuration and its geometrical parameters. The origin of the main insert/cavity is at the centre. The default values of X1 and Y1 are zero so that the cavity is at the centre of the layout (both origins overlap each other). The user can change the values of X1 and Y1, so that the cavity can be offset appro- priately. Figure 13 shows an example of an eight-cavity layout con- figuration and its geometrical parameters. The values of X and Y are the dimensions of the main insert/cavity. By default, the values of X1 and X2 are equal to X, the value of Y1 is equal to Y, and thus there is no gap between the cavities. The values of X1, X2, and Y1 can be increased to take into account the gaps between the cavities in the design. These values are listed in the layout design table. If one of the cavities has to be oriented by 90, the rest of the cavities will be rotated by the same angle, but the layout design remains the same. The user is able to rotate the cavities by changing the parameter in the layout design table. The resultant layout is shown in Fig. 14. Fig. 12. Single-cavity layout configuration and geometrical parameters. 7 A Cavity Layout Design System 813 4. System Implementation A prototype of the parametric-controlled cavity layout design system for a plastic injection mould has been implemented using a Pentium III PC-compatible as the hardware. This prototype system uses a commercial CAD system (SolidWorks 2001) and a commercial database system (Microsoft Excel) as the software. The prototype system is developed using the Microsoft Visual C V6.0 programming language and the SolidWorks API (Application Programming Interface) in a Windows NT environment. SolidWorks is chosen primarily for two reasons: 1. The increasing trend in the CAD/CAM industry is to move towards the use of Windows-based PCs instead of UNIX workstations mainly because of the cost involved in purchas- ing the hardware. 2. The 3D CAD software is fully Windows-compatible, thus it is capable of integrating information from Microsoft Excel files into the CAD files (part, assembly, and drawing) smoothly 17. Fig. 13. Eight-cavity layout configuration and geometrical parameters without cavity rotation. Fig. 14. Eight-cavity layout configuration and geometrical parameters with cavity rotation. A complex cavity layout configuration, which has more geometrical parameters, must make use of equation to relate the parameters. This prototype system has a configuration database of eight standard layout configurations that are listed in an Excel file. This is shown in Fig. 15(a). Corresponding to this configuration database, the layout design level, which is an assembly file in SolidWorks (layout.sldasm), has the same set of layout configurations. The configuration name in the Excel file corre- sponds to the name of the configurations in the layout assembly file, which is shown in Fig. 15(b). Every cavity layout assembly file (layout.sldasm) for each project will be pre-loaded with these layout configurations. When a required layout configuration is requested via the user interface, the layout confi guration will be loaded. The user interface shown in Fig. 16 is prior to the loading of the requested layout configuration. Upon loading the requested layout configuration, the current layout configuration infor- mation will be listed in the list box. The user is then able to change the current layout configur- ation to any other available layout configurations that are found in the configuration database. This is illustrated in Fig. 17. The layout design table for the current layout configuration that contains the geometrical parameters can be activated when the user triggers the push button at the bottom of the user interface. When the values of the geometrical parameters are changed, the cavity layout design will be updated accordingly. Figure 18 shows the activation of the layout design table of the current layout configuration. 5. A Case Study A CAD model of a hand phone cover, shown in Fig. 19, is used in the following case study. Prior to the cavity layout design stage, the original CAD model has to be scaled according to the shrinkage value of the moulding resin to be used. The main insert is then created to encapsulate the shrunk part. This entire subassembly is known as the main insert subassembly (xxx cavity.sldasm), 8 814 M. L. H. Low and K. S. Lee Fig. 15. The configuration database and layout template for prototype system. Fig. 16. The user interface prior to loading of the requested configuration. where “xxx” is the project name. Figure 20 shows the main insert subassembly. After the main insert subassembly is cre- ated, the cavity layout design system can be used to prepare the cavity layout of the mould assembly. 5.1 Scenario 1: Initial Cavity Layout Design In a mould design, the number of cavities to be built in a mould is always suggested by the customers, as they have to balance the investment in the tooling against the part cost. Initially, the customers had requested a two-cavity mould to be designed for this hand phone cover. After the creation of the main insert subassembly, the mould designer loads a layout configuration that is of a linear type which has two cavities using this cavity layout design system. The corresponding configuration name is L02 and is listed in the user interface as shown in Fig. 21. 5.2 Scenario 2: Modification in the Cavity Layout Design Technical discussion sessions between the customers and mould designers are common. This enables changes to be made to the 3D CAD files of both the product and mould as soon as possible, prior to mould manufacture. Changes are almost always inevitable and mould designers are never given any extension in the lead time. In this case, during a technical discussion session, the cus- tomers changed their minds and needed a linear four-cavity mould instead of a two-cavity mould so that the production 9 A Cavity Layout Design System 815 Fig. 17. The user interface after loading of the requested configuration. Fig. 18. The user interface with the layout design table. 10 816 M. L. H. Low and K. S. Lee Fig. 19. The CAD model of a hand phone. rate of the hand phone covers can be increased. The mould designer can use the cavity layout design system to modify the existing cavity layout design to a linear four-cavity mould. The required new layout configuration can be selected from the available layout configurations that are listed in the con- figuration database. This is shown in Fig. 22. Fig. 20. The main insert encapsulating the shrunk part. 5.3 Scenario 3: Gap is Required Between Cavities Finally, in another technical discussion session, the mould designer is required to introduce a gap of 20 mm between the cavities in the longitudinal direction, as shown in Fig. 23. Fig. 21. A linear two-cavity configuration. 11 A Cavity Layout Design System 817 Fig. 22. A linear, four-cavity layout configuration (after a change in the layout configuration). Fig. 23. The introduction of a gap between the cavities. 12 818 M. L. H. Low and K. S. Lee Fig. 24. Modifying the value of Y1 in the layout design table. Fig. 25. The final design after the addition of the gap. 13 A Cavity Layout Design System 819 In the cavity layout subassembly level, the mould designer uses the cavity layout system to activate the layout design table of the current layout confi guration. The value of Y1 is changed from 50 mm to 70 mm to introduce a gap of 20 mm between the cavities in the longitudinal direction. Figure 24 shows the change of the value of Y1 in the layout design table. The result of the final design, after addition of the gap, is shown in Fig. 25. 6. Conclusions In this paper, an approach using a standardisation template is proposed for the development of a parametric-controlled cavity layout design system. Since this approach makes use of stan- dardisation, it can be further applied to other components for mould assembly design if their design processes are repeatable or they have features that are commonly used for every mould design. The advantages of the developed cavity layout system are as follows: 1. The developed system has user-friendly interfaces. 2. Since it makes use of databases, it is highly flexible, and mould-making industries that have their own standards can customise the databases to suit their needs. 3. Because a pre-defined standardisation template is available in the layout design level of the mould assembly design, the required layout configuration can be loaded very quickly into the mould assembly design without the need to redesign the layout. 4. This system enables product designers and mould designers to have more useful technical discussions prior to mould manufacture as changes to the layout can be made immedi- ately during the discussions. 5. This system saves time in the mould design process because it removes redundant work. This is very important for the mould-making industries since the lead time for mould making is decreasing. The developed system has some limitations. Although the databases and layout design tables can be customised, customis- ation will be more difficult for more complex non-standard configurations because the correct geometrical parameters have to be determined. We are currently working on applying a standardisation template for other components in mould design. References 1. K. S. Lee, J. Y. H, Fuh, Y. F. Zhang, A. Y. C. Nee and Z. Li, “IMOLD: an intelligent plastic injection mold design and assembly system”, Proceedings of the 4th International Conference On Die and Mould Technology, pp. 3037, Malaysia, 46 June 1997. 2. K. S. Lee, Z. Li, J. Y. H, Fuh, Y. F. Zhang and A. Y. C. Nee, “Knowledge-based injection mold design system”, CIRP International Conference and Exhibition on Design and Production of Dies and Moulds, pp. 4550, Turkey, 1921 June 1997. 3. C. K. Mok, K. S. Chin and John K. L. Ho, “An interactive knowledge-based CAD system for mould design in injection moulding processes”, International Journal of Advanced Manufac- turing Technology, 17, pp. 2738, 2001. 4. Kwai-Sang Chin and T. N. Wong, “Knowledge-based evaluation for the conceptual design development of injection molding parts”, Engineering Application of Artificial Intelligence, 9(4), pp. 359 376, 1996. 5. Rong-Shean Lee, Yuh-Min Chen and Chang-Zou Lee, “Develop- ment of a concurrent mold design system: a knowledge-based approach”, Computer Integrated Manufacturing Systems, 10(4), pp. 287307, 1997. 6. A. A. Tseng, J. D. Kaplan, O. B. Arinze and T. J. Zhao, “ Knowledge-based mold design for injection molding processing”, Proceedings of the 5th International Symposium on Intelligent Control, pp. 11991204, 1990. 7. K. Beiter, S. Krizan and K. Ishii, “HyperQ/Plastics: an expert system for plastic material and process selection”, Proceedings Computers in Engineering, ASME, 1, pp. 7176, 1991. 8. W. R. Jong and K. K. Wang, “An intelligent system for resin selection”, Proceedings ANTEC89, SPE, pp. 367370, 1989. 9. M. Wiggins, “Expert systems in polymer selection”, Proceedings ANTEC86, SPE, pp. 13931395, 1986. 10. L. L. Chen, S. Y. Chou and T. C. Woo, “Parting directions for mould and die design”, Computer-Aided Design, 25(12), pp. 762 768, 1993. 11. A. Y. C. Nee and M. W. Fu, “Determination of optimal parting directions in plastic injection mold design”, Annals CIRP, 46(1), pp. 429432, 1997. 12. B. Ravi and M. N. Srinivasan, “Decision criteria for computer- aided parting surface design”, Computer-Aided Design, 22(1), pp. 1118, 1990. 13. X. G. Ye, “Feature and associativity-based computer-aided design for plastic injection moulds”, PhD thesis, National University of Singapore, 2000. 14. X. G. Ye, J. Y. H. Fuh and K. S. Lee, “Automated assembly modeling for plastic injection moulds”, International Journal of Advanced Manufacturing Technology, 16, pp. 739747, 2000. 15. G. Menges, How to Make Injection Molds, Chapter 4, Hanser, Munich, 1986. 16. Joseph B. Dym, Injection Molds and Molding: A Practical Manual, Chapter 7, Van Nostrand Reinhold, New York, 1989. 17. SolidWorks 2001 Training Manual, “SolidWorks Essentials parts assemblies and drawings”, SolidWorks Corporation, Concord, Mas- sachusetts 01742, 2001. 14 参数控制型腔布局设计系统 今天,塑料制品 的生产 时间正在 变 短,因此,筹备时间使注射可用模具正在减少。有潜力的省时模具设计阶段,因为设计过程中的重复每个模具的设计都是 标准 的 。本文提出了一种通过使用注塑模具标准化模板控制腔布局几何参数 的 设计方法。在标准化模板腔布局设计 中 包括可能布局的配置。每一个布局结构设计 都有 其自身所有的几何布局设计表参数。这种标准化的模板是预定义为 模具装配设计 的 布局设计的水平。这将确保,所需的配置可以 很快 装入模具装配设计,而不需要重新设计布局。这使得制造前模具的产品设计和模具设计之间有用的 技术讨论。可以在讨论过程中立即改变三维腔布局设计,从而节省时间,避免误 差 。这种腔布局的设计标准化模板 使 每个模具制造公司可以很容易地定制自己的标准。 关键词 :腔体布局设计 ;几何参数 ;模具装配,注塑模具设计 ;标准化模板 1.导言 注塑是一种大众 生产高精度塑件的 通用的方法。有两种可用于注塑所需的主要项目。他们是注塑成型机,注塑模具。模具安装在注塑成型机 上 注塑成型机并提供了溶化的塑料 流到 机器的模具,模具的夹具应用压力和形成的塑 件注射压力 的一部分。注射模具 是表达 熔融塑料 在 最后 阶段塑件 的形状和尺寸的 三维细节的工具 。 今 天,塑料件 的生产 时间,是越来越短,必须在较短的时间 里生产出 注塑模具。在注塑模具设计及相关领域已经做了许多应用计算机技术 的研究 。知识系统( KBS)的如 IMOLD 1,2, IKMOULD3, ESMOLD 4,全国程康的 KBS 大学,台湾 5,在德雷克塞尔大学 6等韩国 的 注射模具设计 已经发展 。系统,如 HyperQ /塑料 7, CIMP 含量 8,飞度 9等,都 以 制定塑料材料的选择使用知识为基础 正在发展 。技术也已经 成 为设计注塑 模具的发展趋势 10-12。据观察,虽然模具制造行业正在使用的模具设计 ,三维 CAD 软件, 许多 时间 被 浪费 是 每 个项目的 同样设计过程。同时,如果重复的设计过程可以标准化 就能 避免日常任务,则模具 的 设计阶段巨大 的 省时的潜力。 在 模具装配 中 一个组织良好的分层设计树也是一个重要因素 13,14。然而,腔布局设计控制参数 的部分工作已经完成,因此这方面将是我们的主要重点。虽然腔布局有许多设计方法15,16, 但 模具设计人员往往只使用常规设计,因此有必要 使 腔布局设计水平标准化。 15 本文介绍了 一种 基于标准化模板通过控制参数设计注塑模具的 型腔 设计 的方法 。首先,组织严密模具装配层次设计树已经建立起来。 然后,腔布局配置的 分类 必须 作出标准配置和那些非标准配置之间的区分。那个标准配置将列在配置数据库 并且 每个配置都有自己的规划设计表控制其自身的几何参数。这种标准化模板 被预定义为模具装配设计的布局设计水平。 图 1 前插入(腔)和后插入(核心) 2. 塑料注塑模具的腔布局设计 一个注塑模具 是表达 熔融塑料 在 最后 阶段塑件 的形状和尺寸的 三维细节的工具 。因此,模具包含最后部分 的 逆印象。对模具大多建立了两半:前插入和背部插入。在某些模具制造工业,前面插入也被 称为 腔和背部插入被称为核心。图 1 显示了前面插入(腔)和背部插入 (核心)。熔融塑料注入印象填充 。熔融塑料的固化,然后 形成塑件 。图 2 显示了一个简单的两板模装配。 16 图 2 一个简单的模具装配 2.1 很多时候单腔和多腔模具之间的差异,印象中,塑料 模具的填充 也被称为填补了腔。腔的安排被称为腔布局。当一个 模具 包含 多个腔时 ,它被称为是一个多腔模具。图 3( a)和 3( b)显示了一个单腔模 具 和多腔模具。一个单腔模具通常是相当大的设计部分,如绘图仪封面和电视外壳。对于较小的如手手机盖和齿轮部件,它总是 采用 更多经济设计的多腔模具,使更多的地方可以形成 生产成型周期。客户通常确定 腔 的 数量 ,因为要 平衡投资成本。 2.2 一个多腔模 具在同一时间 生 产 不同的产品,作为一个 组合 模具。然而,它不是 模具不同腔的普通 设计,由于腔未必都是 熔融塑料在同一时间和同样的温度 填补。另一方面,多腔模具的生产在整个成型周期同样的产品可以有一个平衡布局或不平衡的布局。均衡布局在其中一腔都统一 用 相同条件下熔体在同一 时间 填补 15,16 时间 。短成型如果不平衡的布局正在使用,但是这通过修改的长度和跨节茎加以克服(为熔融塑性 从 浇口流动腔 的通道 )。由于这不是一种有效的方法,尽可能避免。图 4 显示了短期 注塑 情况是由于不平衡的布局。均衡 布局可进一步分为两类:直线和圆弧。线性均衡布局可容纳 2, 4,8, 16, 32 等 型腔 ,即它遵循一个 n2 系列。均衡的圆形布局可以有 3, 4, 5, 6个或更多腔,但有一腔的数量限制,可安置在一个平衡的,因为圆的空间布局限制。图 5 显示了 已经被讨论的 多腔布局。 3.设计方法 本节介绍的设计方法 是 一个注塑模具参数控制腔布局设计开发系统的概述。建立有效的工作模具设计方法是 建立 各种部件和组件到最适当的层次结构设计树。图 6 显示了模具装配第一级组件和部件 的 层次设计树。其他部件和组件的装配 是从 第二级开始到第 n 模具装配水平层次设计树。对于这个 系统 ,重点将仅在 “ 腔布局设计 ” 。 3.1 标准化程序 为了节省在模具设计过程中的时间,有必要确定设计通常功能 的 使用。每一个 重复模具设计过程,然后可以标准化。图 7 可以看出,在标准化 “ 腔布局设计 ” 的相互作用程序 中 有两个区段:组件装配标准化和模腔布局配置标准化。 17 3.1.1 组件标准化 腔布局配置 前 可以标准化,但必须认识到部件和组件 是通过腔布局中各种腔被重复的 。图 8 显示了详细的 “ 腔布局设计 ” 等级设计树。 主要插入组件(腔中)层次结构设计树 的 第二层有 许多 部件和组装部件 从层次结构的设计树第三层开始直接 插入 。它们可以被看作是主要部分和次要组件。主要部分存在于每一个模具设计。次要组成部分依赖于塑 件的 生产,所以他们可能 存在 或可能不存在在模具设计。因此,把这些元件及部件 归于 主要插入组件,确保每 一个 重复的主要插入(腔)继承从第三级开始层次设计树 的 相同的部件和零部件。因此,没有必要重新设计类似的部件和组件中的每一个腔腔布局。 18 布局设计 809图 3 ( a)单腔模具 ( b)多腔模具 图 4 在短成型布局不平衡 810 杂木低和堪萨斯州利 19 图 5 多腔布局 图 6 模具装配分层 设计树 图 7 在标准化的相互作用过程 3.1.2 腔布局配置标准化 有必要 把那些有标准的,哪些是非标准 的 腔布局配置 进行 研究和分类。图 9 显示了腔布局配置 的 标准化程序。腔布局设计,也可以采取为多腔布局或单腔布局,但始终 由 顾客确定这一决定。一个单腔布局 20 总是视为标准配置。多腔模具可以在同一时间 生产 不同的产品 或 在同一时间 生产 同一产品。腔布局设计系统 811 图 8 详细的 “ 腔布局设计 ” 分层设计树 模具 在同一时间生产 不同的产品被称为 组合 模具,这是一个非传统的设计。因此,多腔 组合 模具有一个非标准配置。生产同一种产品 的 多 腔模具包含一个平衡的布局设计和失衡 的 布局设计。不平衡的布局设计是很少使用,因此,它被认为 是一个 非标准配置。不过,均衡布局的设计也可以包括任何线性布局设计或圆形 布局 设计图。这取决于那些根据客户要求的模腔数。必须指出, 虽 然,有任何其他腔 非 标准的数 量 也 被 列为一个非标准配置。 在 标准的布局设计分类后 , 其详细信息可以 被列入 标准化模板。这种标准化的模板 被 预定义 为在 模具装配设计和支持所有的标准配置的腔布局的设计水平。这将确保所需的配置可以很快加载进入模具装配设计布局而不需要重新设计。 3.2 标准化模板 从图 10 可看出 ,有两个 部分标准化模板:一个配置数据库和布局设计表 。 21 配置数据库包括所有布局 的 标准配置,每个布局结构 都 有自己的布局设计表 的 几何参数。由于模具制造行业有自己的标准,配置数据库可以 将 那些以前采取定制 的 视为非标 准 设计。 图 9 标准化程序腔的布局配置 22 图 10 标准化模板 3.2.1 配置数据库 数据库可以 被 用来包含的所有不同标准配置的名单。在这个数据库 中的 配置总数相当于 在模具配置的腔布局设计水平中可用的布局配置的数量 。在数据库中所列出的 信息 是配置数量,类型和 腔的 数量。表 1 显示了一个配置数据库的例子。 配置数量是相应 类型可用布局配置的每一个名字的腔的数量 。当布局的特殊类型和数量 被定义时 ,适当的布局配置将被加载到腔设计 中。 3.2.2 布局设计表 在 配置数据库中 的 每一个标准配置 都 有自己的布局设计表。布局设计表包含 每一个配置的 布局结构的几何参数 并且 每个配置 是 独立的。一个更复杂布局结构将有更多的几何参数 去 控制腔布局。图 11( a)和 11( b)显示回模具板(核心板)与大型腔和装配四个小型腔相同的四腔布局。它总是更经济,容易加工,而不是机器个别一大型腔在钢块小型腔。机械加工的优势一个大型腔是: 812 杂木低和堪萨斯州利 23 图 11 凹模板 1、可以节省 腔之间更多的空间,因此,小钢块都可以使用。 2、 相对于加工多个小型腔加工大型腔更快 一些 。 3、相对加工 多个较小的型腔 加工 一个大型腔 有更高的精度。因此,几何参数的默认值在布局设计中 由表腔之间的距离决定 。然而,为了使系统更加灵活,几何参数的默认值可以修改以适应每一个有需要的模具设计。 3.3 建立几何参数 几何参数有三个变量: 1、 腔之间的距离(弹性)。腔之间的距离 要在 布局设计表中列出他们可以由用户控制或修改。那个距离默认值, 使得 没有腔之间的 没有 距 离 。 2、单型 腔 的圆角 方向(弹性)。 单型腔的圆角方向 也要在布局设计表中列出 ,用户可以 更改 。 对 多腔布局,所有的腔 的圆角方向都必须和 布局设计表所示 的相同 。如果修改 圆角方向 ,所有的腔 的圆角都必须改变相同的角度 ,而不影响布局配置。 3、 各腔之间的 组装 关系(固定)。 腔的圆角方向要相互配合,在单独的布局设计中被预定义,而且被各腔之间的相互组装关系控制,除了定制的,这适用于所有的布局设计 。图 12 显示了一个单腔布局 设计 例子和几何参数。主要插入 /腔的起源是在该中心。 x1 的默认值和 Y1 为零,使腔是该布局 的 中心(两个相互重叠的起源)。用户可以更改 X1 和 Y1 的 默认值 ,使腔可以适当地 弥补 。图 13 显示了一个八腔布局结构例子和几何参数。 X 和 Y 的默认值 是主要插入尺寸 /腔。 在 默认情况下, x1 和 X2的默认值 等于 x, 1 值等于为 Y,因此腔之间不存在距 离 。 X1, X2 和 1 可 被提高 以适应设计中 腔之间的距 离 。这些 默认 值 会 在布局设计表 中列出 。如果 某个 腔 被调整 90 , 那么其他 腔 也必须跟着调整相同的角度 ,但布局设计 仍保持不变 。用户可以通过改变布局设计表格 中 的参数 来改变腔的角度 。布局如图14。 24 图 12 单腔布局结构和几何参数 腔布局设计系统 813 图 13 八腔布局结构和几何参数无腔旋转 一个复杂的腔 布局配置,有更多几何参数,必须使用的相关方程的参数。 4.塑料模具的控制腔布局设计 参数原型用奔腾三 PC 兼容的硬件执行 。这个原型系统使用了商用 CAD 系统( SolidWorks2001)和商业数据库系统( Microsoft Excel) 等 软件。该原型系统的开发使用微软的 Visual C + + V6.0 的编程语言和 SolidWorks 的 API(应用编程接口) 在 Windows 25 图 14 八腔布局结构和几何参数与腔旋转 NT 的环境 中 。 SolidWorks 的选择主要有两个原因: 1。 主要由于硬件的采购成本,在 CAD /CAM 行业的上升趋势已经转向以 Windows 为基础的个人电脑 的使用而不是基于 UNIX。 2。三维 CAD 软件完全兼容 Windows,从而它能够从Microsoft Excel 中 顺利整合 信息 到 CAD 文件 中 (零件,装配和绘图) 17。这个原型系统有 8 个标准布局配置数据库在 Excel 文件中列出。 如 图 15 所示。( 1)。与此相应的配置数据库,布局设计水平,这是一个具有相同的布局配置SolidWorks( layout.sldasm) 的装配文件 。 与 Excel 文件中的配置名称 相 对应的 布局配置文件名称,如图 15( b)所示 。 每腔布局文件( layout.sldasm)项目将预先加载这些布局配置。当所需的布局配置是通过用户的要求接口,布局结构将被加载。用户界面如图。 16 装载要求 的 布局配置 要事先下载 。在加载要求 的 布局配置 后 ,当前的布局配置信息将在列表框中 列出 。然后用户可以改变当前的布局配置 以适应在配置数据库中建立的任何相应布局设计 。 如 图 17 所示。 当用户按下用户界面底部的按钮包含几何参数的布局结构的布局设计表会被激活 。当几何参数的 默认 值改变 时 腔的设计亦相应更新。图 18 显示了当前的布局配置激活 的 布局设计表。 5.案例研究 手机外壳 CAD 模型,如图 19 所示 , 是用在下面的案例研究。 原始的 CAD 模型要根据使用的模具树脂的收缩默认值来缩放设计插入件来阻止收缩部分,这 26 整个组件被称为主要插入组件 (三十 cavity.sldasm), 814 杂木低和堪萨斯州利 图 15 配置数据库和布局模板原型系统 图 16 在用户 登陆 界面之前加载所要求的配置 其中 “xxx” 是项目的名称。图 20 显示的主要插入组件。主要插入 件 创建后,腔布局设计系统,可用于制备模具装配 的 腔布局。 5.1 方案 1:初步腔布局设计在模具设计 中 , 所设计的 模具总是 由 客户 决定 ,因为他们要平衡 设备投资 和最初的预算 。客户已经 要求设计一个两腔模具生产 手机外壳。创建主要插入组件 后 ,模具设计 师会下载一个使用此腔设计系 27 统的两腔线性布局配置 。相应配置的名称是 L02,并在用户界面中列出如图 21所示。 5.2 方案 2:腔布局设计改造与客户 与 模具设计者 之间的 技术讨论会是常见的。这使得 对模具制造的 三维 CAD 文件 都要尽可能快的做出调整 。变化几乎总是不可避免的,模具设计人员从来没有 多余 的时间。在这种情况下,在技术讨论会 上 ,为客户改变了主意,需要一个四腔线性而不是两腔模具使 该 甲腔布局设计系统 815 图 17 加载所要求的配置 后 的 用户界面 28 图 18 与布局设计表的用户界面 816 杂木低和堪萨斯州利 图 19 手的手机 CAD 模型
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