Application of rapid prototyping technology in mold industry

Rapid Prototyping Technology (hereinafter referred to as RP) is an emerging technology integrating computer-aided design, precision machinery, CNC laser technology and materials science. It uses the principle of discrete stacking to transform the CAD model of the designed object into a physical sample. Because RP technology adopts the principle of transforming a three-dimensional body into a two-dimensional plane layered manufacturing, it is not sensitive to the complexity of the composition of the object, so the more complex the object, the more it can reflect its superiority.

Rapid mold manufacturing method based on RPM

Molds are an indispensable method for manufacturing, among which casting molds, injection molds, stamping dies and forging dies are the most used. The traditional method of making molds is: turning, milling, planing, drilling, grinding, electro-erosion and other processing on wood or metal blanks to obtain the shape and size of the required mold. This method is time-consuming and expensive, especially for some large molds required for automobiles, motorcycles and home appliances, which often cost more than hundreds of thousands of yuan, and the production cycle can last for several months or even a year. However, RT based on RPM technology directly or indirectly makes molds, which greatly shortens the mold manufacturing time and greatly reduces the cost.

1. Use the rapid prototyping machine to make the mold directly. Because the workpiece made by some rapid prototyping machines has better mechanical strength and stability, the rapid prototyping parts can be directly used as molds. For example, the PPSF parts of Stratasys’ TITAN rapid prototyping machine are as hard as hardwood and can withstand a high temperature of 300°C. After surface treatment (such as spraying varnish, polymer materials or metal), they can be used as sand casting wood molds and low melting point alloy casting molds. , Trial production of injection molds and pressure molds for investment casting. When used as a wooden mold for sand casting, it can be used to repeatedly make 50 to 100 sand molds. When used as a wax mold, it can be used to repeatedly inject more than 100 wax molds. The ABS workpiece of the FDM rapid prototyping machine can selectively fuse the metal powder wrapped with the thermoplastic binder to form the semi-finished product of the mold. The metal powder is sintered and the second metal (aluminum) is infiltrated in the pores to make the metal mold.

2. Use rapid prototyping parts as master molds, copy soft molds (Softtooling) Use rapid prototyping parts as master molds, which can be poured into soft materials such as wax, silicone rubber, epoxy resin, and polyurethane to form a soft mold, or The silicone rubber and epoxy resin molds (that is, the compression molding of the wax mold) are poured first, and then the wax mold is poured. Among them, wax molds can be used for investment casting, while silicone rubber molds, epoxy resin molds, etc. can be used as injection molds for trial production or low melting point alloy casting molds.

3. Use rapid prototyping parts as master molds, copying hard molds (Irontooling) Using rapid prototyping parts as master molds, or soft molds copied from them, can be poured (or coated) gypsum, ceramics, metal-based synthetic materials , Metal, forming hard molds (such as various casting molds, injection molds, wax molds, compression molds, stretch molds), so as to mass produce plastic or metal parts. This kind of mold has good machining performance and can be partly cut to obtain higher precision, or inserted into inserts, cooling systems, pouring systems, etc. The mold life of the wax mold made of metal-based synthetic material can reach 1,000 to 10,000 pieces.

RT (Rapid Tooling), supported by RP technology, was developed to shorten the development cycle of new products and to introduce marketable, multi-variety, small-volume products customized according to customer intentions to the market as soon as possible. New manufacturing technology. Due to the advancement of product development and manufacturing technology, as well as the continuous pursuit of novel, peculiar and changeable market consumption orientation, it is an indisputable fact that the life cycle of products (especially consumer goods) is getting shorter and shorter. For example, products such as automobiles, home appliances, and computers are molded using rapid mold manufacturing technology. The production cycle is 1/3 to 1/10 of that of traditional mold manufacturing, and the production cost is only 1/3 to 1/5. Therefore, industrially developed countries have taken RP/RT as one of the important research topics and core manufacturing technologies to shorten the product development time and mold production cycle. my country has also begun the research, development and application of rapid manufacturing.