插座蓋的注塑模具設(shè)計(jì)【proe和CAD圖紙】,proe和CAD圖紙,插座,注塑,模具設(shè)計(jì),proe,以及,cad,圖紙 附錄 1 附錄 英文原文 Vo l. 44 Issue 4 2004 Jour nal of The Inst itution of Engineers, Singapore 3D RAPID REALIZATION OF IN ITIAL DESIG N FOR PLASTIC INJECTION MO ULDS ABST RACT Ma ria L.H. Lowl and K.S. Le ez To provide an initial design of the mould assembly for customers prior to receiving the fina l product CAD data is a prelimina ry work of any final plast ic inject ion mould design.Traditionally and even up till now, this initia l design is always created using 2D CAD packages.The information used for the initia l design is based on the technical discussion checklist, in which most mould makers have their own standards. This technical discussion checklis t is also being used as a quotation. This paper presents a met hodology of rapid realization of the initia l design in 3D solid based on the technical discuss ion checklist, which takes the role of the overa ll standard template. Infor mationare extracted from databases and coupled with the basic information from customer,these information are input into the technical discussion checklist. Rules and heuris tics are also being used in the initia l mould design. A case study is provided to illustrate the use of the standard template and to exhibit its real applica tion of rapid realization of the initia l design,for plastic inject ion moulds. INTRODUCTION The most established met hod for producing plast ic parts in lar ge quantities is plast ic inject ion mould ing. This is a highly cost- effective, precise and competent ma nufactur ing met hod, which can be automated. However, costly tooling and machiner y are needed in this ma nufactur ing process. The design of a plast ic injection mould is an integral part of plast ic inject ion mould ing as the quality of the final plast ic part is greatly relia nt on the injection mould. A plastic injection mould is a high precision tooling that is being used to mass produce plast ic parts and is by itself an assembly of cavities, mould base and standard components etc. An example of a n inject ion mould assembly is shown in Figure 1. 36 徐州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論文 ) Over the years, much research work using computer- aided techniques had been done from studying the ver y specific areas of mould design to studying mould design as a whole integrated system. Knowledge-based systems such as IMOLD (Lee et al. 1997), ESMOLD (Chin et al. 1997), IKMOULD (Mok et al. 2001), etc were developed for injection mould design. Many commercia l mould design software packages such as IMOLD, UG MoldWizard, R&B MoldWorks, etc are also available today in the market for mould makers. However, the systems and software packages mentioned above did not consider the initia l design prior to actual mould design. These software packages assist in the preparation of the detailed mould design that includes the core/cavity creation, cooling and ejection design. As a result, mould designers hardly used the mould design software packages when they are doing their initial design because the software does not catered for such a design process. There is not much research being done on the initial design of plast ic injection moulds except for Ye et al. (2000) who presented a n algor ithm for the initial design. The researchers first deter mine the parting line for the plast ic part followed by the calculation of the number of cavities required. The cavity layout is created based on the input information of the la yout patter n and the orientation of each cavity. The mould base is loaded automa tically to accommoda te the la yout. The researchers also proposed to use their initia l design as a guide tool for the quotation of the mould. However, the research that is being done may not be applicable for most plast ic inject ion mould ing industr ies. The calculation of the number of cavities required is mostly deter mined by the customers who provides the product CAD file and they seldom seek opinion 37 徐州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論文 ) from the mould makers, thus this step could be omitted to save time. Although exter nal undercuts are identified in the product, the research did not consider the standard components that are required in producing such undercuts, which in this case, the use of sliders. The research also did not consider inter nal undercuts where lifters are required. Thus, the quotation derived would not reflect the correct costing of the mould, and thus could be ver y misleading, since the use of these types of standard components can increase the cost of producing such a mould substa ntia lly. Alter natively, the authors (Low et al. 2002) proposed a methodology of standardizing the cavity la yout design system for plastic injection mould such that only standard cavity layouts are used. When only standard layouts are used, their layout configurations easily be stored in a database for fast retr ieva l later in the mould design stage. research is being incor porated into the rapid realiza tion of the initia l design for plastic injection mould in this paper. There is a need to introduce a faster method of mould design since there are fewer very exper ienced mould designers and coupled with the fact of today's market dema nds of having shorter lead-time and higher quality products. This is fulfilled by the introduction of standardization into mould design, since the design processes are repeatable for ever y mould design project. This paper presents a met hodology of rapid realization of the initia l design in 3D solid instead of 2D drawings using standardization method. The initia l design in 3D solid will be based on the technical discuss ion checklist that acts as the overa ll standard template. Every sub- design such as cavity layout design, gating system, mould base design etc will have its own respective standard template. This is to enable timesa vings in the design stage as the fina l mould design can be obtained directly by making minute changes to the initia l design. INITI AL DESIGN OF PLASTIC INJECTION MOULD The customers and the mould designers have to work closely together to obtain a mould that could produce what is desired suitably. It would be costly to rectify the errors after the mould is ma nufactured completely. Thus the initia l pla nning of how the la yout design of the mould is likely to be is important. A typica l mould design project workflow chart is shown in Figure 2. When the customers have decided to engage a particular mould- maker, the CAD file of the product have to be provided to them. However, the mould-maker is always prepared to receive newer versions of the product CAD file as changes are consta ntly made to it. The downside of this is that the lead- time given to complete the mould still rema ins as it is. Thus, the time that was lef t to complete the fina l mould design and ma nufacture the mould becomes shor ter. When the product CAD file is first received, the assigned project engineer or mould designer fills up a technical checklist during their first technical discussion with the customers. The checklist records information such as the resin materia l to be used and its shr inkage value, the number of cavities required by customers, the gating system, and the mould ing machine to be used, the required type of mould base and other information needed to provide the basis of the 38 徐州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論文 ) initia l design of the mould. Since this checklist contains most of the basic infor mation, it doubles up as a quotation. This allows customers to decide whether to modify their product CAD file to produce a simpler mould that is cheaper. After that, the mould designer prepares an initia l design based on the product CAD file and infor mation in the checklis t Traditionally and even up till now, mould designers are using 2D CAD packages to create the initial design, although 3D CAD packages are readily available. Ironically, mould designers would then use the 3D CAD package only in their fina l mould design. When this initial design is completed, it will be presented on the next technical discussion. Modifications made to the initia l design are nor ma lly done by marking and sketching the changes o n the printed drawing paper. Though there is no fina l product CAD file at this stage, the mould-maker could go ahead to purchase the raw materials and standard components subject to approval of the customers. After the final product CAD file has been received, the mould designer would start the actual mould design afresh using the 3D CAD package that they have. This is a time consuming met hod since the initia l design is not related to the fina l mould design. THE DESIGN STRUCTURE Figure 3 shows the overa ll structure of the proposed system. In the proposed approach, the 39 徐州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論文 ) standardization method utilizes standard mould designs, which are derived from the information listed in the technical discussion checklist. This checklist takes on the role of the overa ll standard template and must be used for every new mould project. The sub- designs will have their own templates. Databases are used to record information such as types of standard components, types of design, geometrical parameters and project data etc. Mould- making industries can easily adopt the proposed approach since they are able to customize the databases to include their own standards. A standard mould design uses only standard components such as the mould bases; ejector pins and other accessories. Standard configuration of cavity la youts, that produces only the same products in a bala nced la yout are used in a standard mould design. Calculations used in a standard mould design are based on rules and heuris tics, which can be applied universa lly to any organizations. Rules and heur ist ics make up a n impor tant sector of mould design since they deter mine if the mould that is designed, is able to fit into the specified moulding machine or be able to mass produce the product without any problems due to bad design. The hierarchical organization of the assembly files of a standard mould design should also follow a single mould assembly structure. Provision had been made in this system to present representations of the core, cavity, slider 40 head and lifter head as blocks 徐州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論文 ) in the initia l design. These blocks can be edited to trim to the profile only when the fina l product CAD file design, ejector pins/blades and cooling lines has been received and confir med. Dur ing the initial are still not included because these depend greatly on the final product CAD file. Since this paper focuses on the rapid realization of initia l design, core/cavity parting, profile creation, addition of ejector pins/blades and cooling lines will not be discussed here. 3D solids would be used as they have their advantages. The advantages of solid modeling are better visua lization, simplified simulation, improved producability, faster drawing product ion and facilitates an integrated design process. Standardiza tion met hod Standardiza tion met hod involves using standard mould designs, standard components and a standard working met hod of mould design. This mea ns that every mould designer will design moulds in exact ly the same met hod, use the same design assembly hierarchy tree, and use standard components from a specified supplier. This allows the different teams involved in the mould project to speak the same la nguage. The advantages are as follows: a) Easy follow ing-up of mould project, b)Lower cost and faster deliver y of components and c) Proper mould project ma nagement. Databases Four different types of databases are used in this system (Figure 3): a) LibYaYy database is a collection of a ll standard components commonly used by the mould- making industry. b) CoufiguYatiou database is used for a ll standard components and cavity la yout design. All the different configurations are already pre-defined in the 3D solid files and only the required configuration will be activated. c) PYOject database is a collection of a ll data that is input into the technical discussion checklist and sub- designs inter faces, thus enables tracking and retrieval of information that are unique to a particular project. The quantity of the var ious components and their types that are to be used in the project are also recorded here, thus enabling an easy generation of a n initial bill of mater ia ls (BOMs) when desired and d) Geometr ical paYameteYS database is utilized where there is a need to change the geometrical parameters such as distances between different cavities and locations of standard components etc. SYSTEM IMPLEM ENTATION A prototype of the rapid realization of initial design system for plastic injection mould has been implemented using a PIII PC-compatible as the hardware. This prototype system utilizes SolidWorks 2001 as the CAD software, Microsoft Visual C++ V6.0 as the programming language and the SolidWorks API in a Windows environment. The rules, heuristics and formulations used in this prototype system are based on the local mould making industr ies in Singapore. 41 徐州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論文 ) Technical discussion checklist& mould assembly str uct ure Before the sub- designs are utilized, the overall standard template, "Technica l Discussion Checklist ",must be used first (Figure 4). This enables the mould design to follow a standard mould assembly str uct ure using the initial product CAD file, the basic information and requirements from customers. It is impor tant to adhere to the same mould assembly str uct ure for every mould design project within a n organization to ensure ever y mould designer follows the same working met hods of designing. It also enables other mould designers to be able to locate a certain design of a component easily. The section "Project Tracking" records down the basic details of the project. In the section known as the "Moulding Material", the resin to be used is chosen from the list. The shr inkage value of the resin is entered into the space provided so that the initial product CAD file can be scaled accordingly prior to mould design. The section on "Moulding Machine Details" allows users to select the moulding machine to be used. The customers provide this information. Upon select ing the required machine from the list, it extracts data from the mould ing machine database and reflects the releva nt dimensional information onto the appropr iate spaces in the inter face. A short extraction of the injection moulding machine database is depicted in Table 1。The section on 42 徐州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論文 ) "Mould Information" records down information such as the type of cavity la yout and the number of cavities that is required. All these information in this section will eventually be used in their own individ ual sub-designs templates where users are able to input more infor mation or to edit the current selection or the geometr ica l parameters. The last section records down the mould materia ls and the type of surface finishing required. This information is needed for the initial quotation and the procurement of mater ia ls for the mould project. Finally, enter ing the person's name that had recorded the infor mation and the date when the information is recorded ensures that a proper project database. record is kept. All the infor mation that is entered is listed into a mould Shrinkage factor&core/ca vity creation A representation of the core and a representation of the cavity in the for m of blocks are simultaneously created to encapsulate the scaled product CAD file. A default- offset value is applied to the range box of the scaled part to give the approxima te size of the blocks (Figure 5). These values are commonly used by mould designers loca lly and can be edited. Other accessories/secondar y components The secondary components that may need to be selected during the initial mould design are sliders, lifters and special inser ts. Sliders and lifters will be the source of concer n in the la yout assembly level as they pla yed a part in determining the overa ll size of the la yout assembly. They are initially categor ized into the general types and are available in three basic sizes: Small (S), Medium (M) and Large (L). The respective sub- design templates for the sliders and lifters are 43 徐州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論文 ) used to place the components to the appropr iate undercuts. They also functions as an inter face to allow users to edit the geometr ica l parameters or configurations of the secondar y components. As this is the initial design, ver y accurate positioning is not required but the secondar y components have to be at its correct location and orientation. the Cavity layout Only standard types of cavity la yout are used in this types of available la youts are fixed, the different prototype system (Low et al. 2002). As types of layouts can be listed into a configuration database that enables the required la yout to be activated in the mould assembly dur ing the mould design. This provides a faster method of designing. The desired new configuration can be reloaded via the sub-design template for cavity layout. In addition, the orientation, the dista nces between cavities, which are known as geometr ica l parameters be edited through the same inter face. Selection of mould base size can also The secondar y components and cavity layout are assembled in the la yout assembly. The overa ll size of the la yout assembly needs to be known in order to select the appropr iate mould base size. The system automa tically loads the sma llest possible mould base from the available configurations of the specified model of mould base that has been selected. Simulta neously, the system has to check the compatibility of the chosen mould base with the targeted inject ion 44 徐州 工 程 學(xué) 院 畢 業(yè) 設(shè) 計(jì) (論文 ) mould ing machine that is to be used for mould ing the products. Parameters that are checked are the tie-bar dimensions, platen dimensions, mould height and ma ximum daylight of moulding machine. A representation of the cla mping unit of the chosen inject ion moulding machine can be activated to allow the user to verify the design visua lly. Gating&r unner design The standard design of gates and runner are pre-created and store in a library database. Depending on the number of cavities that are indica ted ear lier, the appropr iate configuration will be activated in the initial mould design. In this prototype system, some rules and heur ist ics are also set for the gating and runner design. The available options can be selected only after the type of mould base has been chosen since they are dependent on the type of mould base. The rules for selection of the gating are: 1. For 2-plate mould, types of gating that can be used are a ll but pin- point gat