A mold base is a set of fixturing components for mounting the mold onto an injection machine. Since the components have been highly standardized, mold base designers usually select components from a catalog and integrate them into complete mold bases. One of our goals is to support this way of a mold base design process. A system can help a designer by generating product data of a mold base from relative positions of components and by rearranging the whole specification of the mold base according to designer’s modification. The system should be so flexible that it can provide operations corresponding to many kinds of components. This is the other goal of our study. The paper proposes a scheme of a mold base CAD system which allows a user to design a mold base in a natural way and has flexibility to handle various kinds of components.
A mold base consists of plates and other kinds of components, e.g., cavity/core inserts, bolts, pins, etc., which are all embedded into the plates with some assembly and machining information. Therefore, a feature of an embedded component such as a bolt screw should have a mate feature in the corresponding component such as a threaded hole in a plate. A pre-paired feature, a key concept proposed in this paper, consists of two features; an intrinsic feature of a component to be embedded and a mate feature to be machined in a corresponding component. A component defined with a set of pre-paired features may have its own shape as well as assembly and machining information. The system based on object-oriented scheme can generate and maintain the product data of a mold base with this kinds of components. We examined mold base components for categorizing their features and made some experiments with a prototype system.