Method for precinct laser sintering fast manufacture metal die

Abstract

The invention relates to a method for quickly producing metal mould with laser sintering, which comprises: first, using at least two kinds of different metal powders with different diameters, to be mixed with different mass percentages; using physical or chemical modification to treat the surface of metal powder; then mixing the modified metal powders, the adhesive formed by organic resin and inorganic with different fusion points, and the lubricant uniformly to obtain the metal molding powder; then designing the three-dimension CAD mode of mould, to slice the mode, and laser sintering the metal molding powder; the laser sintered element is baked at 300-800Deg. C; using vacuum pressure penetration to penetrate the metal, to obtain the high-accuracy metal mould.

Description

technical field [0001] The invention relates to rapid manufacturing of metal molds, in particular to a method for rapid manufacturing of metal molds by selective laser sintering (Selective laser sintering, SLS). Background technique: [0002] With the globalization of the market and the intensification of competition, the speed of product replacement is accelerating. The development, research, production cycle of new products, small batches, and fast updates have become one of the main trends in the development of manufacturing technology. Small batches will become an important production mode in the manufacturing industry. In this case, the manufacturing industry puts forward higher requirements for the rapid manufacturing of product prototypes and rapid manufacturing technology of molds, and proposes high-efficiency, high-precision, and high-life three-high molds. The goal of metal mold rapid manufacturing technology is to directly manufacture high-precision durable metal...

AI Technical Summary

Problems solved by technology

[0003] There are three main methods for rapid manufacturing of metal molds by SLS. One is high-power laser sintering of single metal powder. The metal powder is scanned and sintered by high-power laser (above 1000W), and the metal powder is superimposed and formed layer by layer. The molded parts are subjected to surface post-treatment ( grinding, finishing) to complete the mold making; the second is the mixed metal powder laser sintering molding, the molding powder is a mixture of two or more metal powders, one of which has a lower melting point and acts as a binder. The shrinkage of various metals with different melting points is inconsistent, and their volume changes can be compensated for each other, so that the total shrinkage of the workpiece is small, and it must be treated after infiltration; but the metal powder of the above two methods needs to be melted under the action of the laser, and due The characteristics of SLS "rapid melting and rapid cooling" sintering, there are spheroidization and sintering shrinkage phenomena in the process of metal powder melting and sintering, the resulting thermal stress makes the sintered parts prone to warping, and the sintered parts may have some obvious sintering defects. The density is not high, and the laser power required by the laser sintering molding machine is relatively large, the powder is easily oxidized during the sintering process, and inert gas protection is required, and the equipment is expensive

The third is the laser sintering of coated metal powder or metal and resin mixed powder. The metal bonded entity is obtained by low-power laser sintering. After degreasing, high-temperature sintering, and infiltration of low-melting point metals, the metal mold is directly formed; but this type of powder The strength of laser sintered parts is not high, the density is low, and the sintered parts are prone to cracking, deformation and infiltration hole defects after metal infiltration. Especially for metals with poor mutual wettability, it is difficult to infiltrate metals, which still exists in metal molds. There are many technical difficulties, the mechanical properties of the manufacturing mold are not high, the precision is low, and the surface quality is poor. It is difficult to use it directly as the final mold. Generally, it can only be used as a sample or a mold master.

In particular, the current rapid manufacturing technology of iron-based metal dies is immature, and there are problems in dimensional accuracy, surface quality, and comprehensive mechanical properties, and there is still a considerable distance from practicality.