The importance of precision mold in china
2008-07-30

With China's economic development, in the recent years the annual output value keeps growing with a high speed. Meanwhile China production technology of high precision die and mould has been greatly improved. So that China has a great die and mould market. However, high precision die and mould having high technology content are far from meeting the needs of domestic market. At present, the Chinese government and related industries have attached great importance to the development of precision molds. The aim of High precision mold& die technology conference forum and modern mold &die reader anniversary party are to promote the communications between the machine tool, cutting tool and CAD/CAM suppliers and mold makers from Domestics and Oversea to discuss how to improve the technologies, decrease the costs and adopt new materials and new techniques so as to enhance mold making industry competitiveness both in china and global market. In 2008, China mold industry will have a rapid growth, and the country still focuses on developing moulds having high technology contents. All these facts stimulated needs for the machining technology equipment with best quality in China. We have many ways to produce products. Such us Expendable mold casting, Waste molding of plaster, Sand casting, Plaster casting (of metals), Casting of plaster, concrete, or plastic resin, Shell molding, Investment casting, Non-expendable mold casting, Permanent mold casting, Die casting, Centrifugal casting, Continuous casting, Cooling rate, Shrinkage, Solidification shrinkage and Patternmaker's shrink (thermal contraction) are all good methods. Some of these production requirements are very sophisticated. For example, Investment casting derives its name from the fact that the pattern is invested, or surrounded, with a refractory material. The wax patterns require extreme care for they are not strong enough to withstand forces encountered during the mold making. One advantage of investment casting is that the wax can be reused. The process is suitable for repeatable production of net shape components, from a variety of different metals and high performance alloys. Centrifugal casting is both gravity- and pressure-independent since it creates its own force feed using a temporary sand mold held in a spinning chamber at up to 900 N (90 g). Lead time varies with the application. Semi- and true-centrifugal processing permit 30-50 pieces/hr-mold to be produced, with a practical limit for batch processing of approximately 9000 kg total mass with a typical per-item limit of 2.3-4.5 kg. Industrially, the centrifugal casting of railway wheels was an early application of the method developed by German industrial company Krupp and this capability enabled the rapid growth of the enterprise. Small art pieces such as jewelry are often cast by this method using the lost wax process, as the forces enable the rather viscous liquid metals to flow through very small passages and into fine details such as leaves and petals. This effect is similar to the benefits from vacuum casting, also applied to jewelry casting. The mould design for the manufacturing of high-precision glass parts remains a challenging task. This motivates the present study which proposes some optimization techniques to identify the mould design that yields the desired glass piece profile at the end of the compression mould process with the accuracy of the order of 1 μm. The intuitive, yet very efficient method consists in computing at each optimization loop the mismatch between the deformed and desired glass piece geometries and using this information to update the mould design. The accuracy of mold will affect the production. The key factors affecting the die and mold precision were listed on the aspects of design and manufacture of dies and moulds and enterprise management. It was put forward that the die & mould enterprises can make continuous development and progress provided that their staff has established strong precision concept and quality ideation. We can know that precision molds in China's future will be very bright.