Wire Path Rapid Tooling Process and Supporting Software Development

Recent developments in Computer Aided Design (CAD) have drastically reduced overall design cycle time and cost. In this paper, wirePATH, a new method for rapid direct tooling, is presented. By using specialized interactive segmentation computer software and wire electrical discharge machining (wire EDM), wirePATH can reduce manufacturing time and cost for injection molds, casting patterns, and dies. Compared to other conventional-mold making methods, wirePATH can reduce fabrication time by as much as 40 to 70%. Wirepath can use a combination of wire EDM and other processes. Our method provides a new means to produce a greater variety in products by changing only portions of the tooling. Segments allow a part of a mold to be replaced to accommodate design changes and repair. WirePATH enables new applications of wire EDM to more complex shapes by bridging the gaps between CAD, our method, wire EDM and conventional manufacturing processes. INTRODUCTION With the increasing competition in the global market place and with the growing number of products being introduced, today’s industry is under pressure to reduce the time and cost of new product development. Faster product development often means getting to the market faster, establishing a stronger market position, and setting premium pricing. In many industries, rapid product development is now a key aspect of competitive success. In injection molding and other molding processes, the design and fabrication of the mold consumes a significant portion of production lead-time. The plastic injection molding industry is estimated at $20 billion dollars per year and the current tool and die-related industry is estimated to have annual revenue of about $10 billion [1]. In order to shorten design and manufacturing lead-time, many industrial firms have employed mold analysis software and CAD/CAM packages. However, the mold manufacturing process still relies on conventional moldmaking technology, and a significant amount of time is spent on machining, sinker EDM, and labor-intensive polishing. Many researchers have developed new technologies to speed up mold making processes [1-9]. Direct AIM, Copper Polyamide Selective Layer Sintering (SLS), Direct Metal Laser Sintering, high-speed CNC aluminum tooling, and PolySteel are some of the commercialized technologies. However, they all have some limitations, including a low production rate, limited size, and low production volume. Direct AIM makes molds using the stereolithography (SLA) process. The types of materials that can be used to produce parts are limited to low melt temperature thermoplastics, and the part must be less than 2” in any direction. The major limitation of Direct AIM is that the mold material is not very hard, thus limiting its use to small production runs. The PolySteel process produces mold inserts from a semi-solid polymer/steel compound that is formed directly over a stereolithography part. A mold made with this process does not have good thermal conductivity. Therefore the cycle time is long and the production rate is very slow. Some rapid tooling methods, such as Direct Metal Laser Sintering and aluminum tooling, result in molds that are both soft and weak. Repeated high pressure material flow in the mold cavity causes mold wear, so molds made by these processes do not last very long and are not applicable to parts that require a high production quantity. WirePATH TECHNOLOGY OVERVIEW Our patented wirePATH is capable of producing molds that can accommodate a wide range of applications from sand casting and investment casting to high production rate injection molding. WirePATH technology’s core components are CAD, geometric modeling and wire EDM. First, a mold is designed in commercial CAD software. Then the 3D CAD mold model is