The traditional mold manufacturing methods are mainly divided into two types: one is to generate the mold CAD geometric modeling for the geometric modeling system, then NC program all the molding surfaces of the mold to obtain their CAM data, process the mold blank on the CNC machine tool, and then finish the EDM to obtain the precision mold; Another method is to generate a conjugate electrode CAD model with the same geometric shape as the mold forming surface from the part model, and then program the electrode surface NC to generate its CAM data. Then, the electrode assembly is processed on a CNC machine tool, and assembled into a whole electrode for precision mold processing. This method of using CNC machining not only requires time-consuming manual programming, but also has a longer processing time and higher cost.
Precision casting molds based on rapid prototyping technology have many advantages, such as high cavity accuracy, smooth surface, and can be machined without or with a small amount. For molds with complex shapes (complex cavities of binary curved surfaces) such as automotive body stamping molds, it can save a lot of material and processing costs (about
1/2~1/3) can greatly shorten the entire mold making cycle, reduce production costs, and have significant economic benefits. Foreign precision casting has been used in the production of injection molds, extrusion molds, stamping molds, forging molds, and other molds.
The precision casting mold process based on rapid prototyping technology is to first complete the three-dimensional design of the mold, and then use rapid prototyping equipment to quickly manufacture the prototype of the mold within a few or dozens of hours. Then, combined with investment casting, gypsum casting, ceramic casting, lost foam casting, thermosetting resin sand casting, transfer coating and other casting processes, precise mold blanks are quickly manufactured. The process route is shown in Figure 1.