This paper presents an Internet-based intelligent mould design system using Internet technology and knowledge- based approach。 The system can shorten the design cycle of injection mould and can effectively aid the design and development works of injection moulds in the small- and medium-sized enterprises to meet the increasing pressure of the current competitive world market。 The rest of the paper is organized as follows。 Section 2 gives a brief introduction of injection mould design。 Section 3 introduces earlier research works on mould design and related fields。 The architecture of the Internet-based mould design system is presented in section 4。 The knowledge-based part of the mould design system is described in section 5。 Section 6 discusses the development of the system。 A practical design case is demonstrated in section 7。 Conclusion is made in section 8。

2。 Injection mould design

The basic features of an injection mould consist of cavity number and layout, feed system, cooling system, ejection system and mould construction。 Fig。 1 shows the general procedure of mould design [1]。 It can be seen that how interrelated the conditions are and which boundary and secondary conditions have to be met by the main functions。 A mould design project normally starts with economic considerations, namely the question of how many parts can and should be produced in one mould in one shot in order to meet the delivery date and other requirements。 This is followed by consideration of the arrangements of the cavities in the mould frame, which might directly include thoughts on the ease of ejection and subsequently, the connection between mouldings and runners and part quality (number, position and shape of gates)。 The feed system accommodates the molten plastic material coming from the injection nozzle of the moulding machine and distributes it into each cavity。 To remove the heat from the moulding, it is necessary to provide the mould with a cooling  system。  After  the  moulding  has  solidified    and

cooled down, it has to be removed from the mould by the ejection system。 Mould is normally constructed by stacking several metal plates to form a rigid body。 It has to house various mould components in correct positions for the proper functioning of the mould。 Mould construction normally involves the selection of mould bases and standard mould parts。 For complicated plastic parts, some other mechanisms such as slides, unscrewing device, etc。, might also be involved in the whole mould structure。

3。 Related research

A number of research activities have been carried out on mould design and its related field over the years using computer-aided techniques。 These research activities range from studying specific areas of mould design to investigat- ing mould design as a whole integrated system。 They can broadly be classified into three areas: the functional and initial mould designs; the algorithms to automate mould generation; and system development of mould   design。

Hui and Tan [2] presented a heuristic search approach based on sweep operations to develop automated mould design systems for determining parting direction, parting line, side core, etc。 Huang et al。 [3] used solid modelling techniques to build mould plates and library of standard mould components。 Chen and Liu [4] have  developed a cost model, which depicts the relationships between cost factors and product development activities as well as their relationships with product geometry, for cost-effectiveness design for injection moulding。 Fu et al。 [5] proposed an efficient methodology which systematically presents the undercut feature definition, classification, undercut feature parameters, and the recognition criteria of all types of undercut features for undercut feature recognition in an injection mould design system。 Chen et al。 [6] presented a method for determination of parting direction based on dexel model and fuzzy decision-making。 Li JC [7] presented a neural network approach for modelling and optimization of injection mould gate parameters。 Li CL [8] used a feature-based approach to design the cooling system of injection moulds。 Chung and Lee [9] proposed a frame- work of collaborative design environment for injection moulding in which geographically distributed, multi- disciplinary designers can collaborate with one  another。 Ma et al。 [10] described the development of a standard component library for plastic injection mould design using an object-oriented approach。 Low and Lee [11] introduced a methodology of providing the initial design in 3D solid model instead of 2D drawings using the standardization method。 Ashaab et al。 [12] described a supporting plastic engineering development system to facilitate the sharing of injection moulding information and knowledge between interested parties via the Internet for the collaborative design of injection mould。 Li et al。 [13] used graph-based technique and developed a heuristic search algorithm to automate the layout design of plastic injection mould cooling system。