Rapid Lost wax casting molding process trend
The rapid development of precision casting is achieved […]
The rapid development of precision casting is achieved by technological development and progress. There are many new materials, new processes and new technologies that have a great influence on the development of investment casting, such as water-soluble core, ceramic core, metal material improvement, large casting casting. Technology, titanium alloy casting, directional solidification and single crystal casting, filtration purification, hot isostatic pressing, rapid prototyping, computer application in investment casting, mechanized automation, etc. With the development of technology, investment casting has been able to produce ever-large, thinner, thinner and stronger products.
At present, precision casting is the most accurate one of all casting methods, and it has good repeatability, and the casting requires only a small amount of processing. Precision casting first requires the design and fabrication of wax molds or other molds for molds that can be lost, the complexity and size of the castings. It usually takes a few weeks to a few months. It takes a week to get the casting after the mold is obtained. These weeks are mainly used to make wax molds and shells, and the cost of molds is expensive in small batch production.
The application of rapid prototyping technology in precision casting can be divided into three cases. One is forming a wax mold or a lost mold, that is, a prototype for precision casting, which is used for small batch production of complex castings. Product development or trial production. The second is the direct shell method for small-scale production. The third is the rapid prototyping wax mold, the master mold, for mass production. These methods solve the bottleneck problem of the wax mold manufacturing of the conventional method.
The laser rapid prototyping (SLS method) used in wax molds is a paraffin powder. The process is to first lay a layer of powder on the workbench and selectively sinter it with a laser beam under computer control (the hollow part of the part). Without sintering, still a powder material), the sintered portions solidify together to form a solid portion of the part. After the first layer is completed, proceed to the next layer. The new layer is firmly sintered with its upper layer. After all the sintering is completed, the excess powder is removed. A sintered wax pattern is obtained. The process is characterized by a wide range of materials, and a cast wax mold can be produced by casting wax. A ceramic mold can be used to make a ceramic shell, and a metal powder can be used to form a metal mold for pressing a wax mold.