Knowledge – based method for gate and cold runner definition in injection mold design

The quantity of plastic parts in mechanical and electronic industry during past 2-3 decades has a tendency to grow up. Mechatronics systems, in particular, apply many parts of plastic materials. A plastic, which is one of the most versatile materials in the modern age, is widely used because this is an easiest way to get parts of complicated geometrical form and properties. The injection molding process is the most common process for making plastic parts. In plastic parts manufacturing business the three types of small and medium enterprises (SMEs) are involved: 1) design, manufacturing engineering and production of injection molds, 2) production of plastic parts, 3) development of products and components from various plastic materials. These enterprises, in general, are located in different towns, even countries and are very specialized and must survive with high work productivity because they feel strong competition. The work productivity of mentioned SMEs depends on the created value, therefore, the intelligent systems related to design and manufacturing of plastic parts and appropriate techniques allow increasing work value. It involves the minimization of plastic parts and molds dimensions, mass and improvement of design and manufacture processes. There are many research publications related to the developments of knowledge-based and object oriented approaches of injection molds and their design features as feed system, cooling system, ejection system and whole mold construction. An object-oriented approach to computer-aided design (CAD) of a plastic injection mold [1] considers the design of mold feed system. There was developed CADFEED to efficiently design the type, location and size of a gating system injection mold. It generates acceptable solutions at a lower cost than the most traditionally and commercially available analysis packages. The developed system can be used to verify designs proposed by the design engineers. CADFEED, unfortunately, was oriented to the AutoCAD and 2D input of a product, which are not competitive in new manufacturing environment. An interactive knowledge-based CAD system for mold design in injection molding processes [2] presents a practical prototype of artificial intelligence design method in molding manufacture. The application of case-based reasoning in die-casting focuses die design [3] on storing the knowledge and experience as cases, and modifies the previous case to satisfy a new situation. The proposed framework is also generally adaptable for injection mold design. A parametric controlled cavity layout design system for plastic injection mold [4] considers a methodology for designing the cavity layout by controlling geometrical parameters using a standard template. The standard template for cavity layout design consists of the configurations for the possible layouts. This ensures that the required configuration can be loaded into the mold assembly design very quickly, without the need to redesign the layout. An object-oriented design tool for associative cooling channels in plasticinjection molds [5] describes an associative design approach embedded in cooling channel module of mold design software package. It gives a set of comprehensive object definitions for cooling circuits, and addresses balanced or unbalanced design. Optimization of gate location with design constraints [6] considers an automated gating synthesis, taking advantages of the functionality of both CAD and CAE systems. Design of the runner and gating system parameters for a multi-cavity injection mold using FEM and neural network [7] presents the simulation method of optimal runner system minimizing the warp of injection mold. Since for plastic parts and manufacturing techniques are raising distinctly higher claims, the purpose of this work is to develop knowledge-based method for gate and cold runners definition of injection mold. The engineering data and facts available in various references and companies involved in molding plastic parts as well designing and producing molds is systemized. Developed knowledge – based (KB) method is oriented towards personal computer and standard CAD systems (Solid Works, Solid Edge) and is able surely define the gate and cold runners of injection mold, because most of reviewed methods can work only with specialized mold design systems or software.