Study On Processes Of Rapid Manufacturing Metal Part And Mould Based On Laser Sintering With Small Power

Selective Laser Sintering(SLS) is a kind of mature Rapid prototyping(RP). At present it is hot issue and difficult problem that SLS is applied to manufacture metal part and mould rapidly. The rapid manufacture of metal part and mould has wide application in mechanical industry. A coated metal powder has been used to fabricate metal part and applied to mould industry successfully through indirect SLS in the foreign country. But the technology and material are kept secret to our country. The purpose of this paper is focus on indirect selective laser sintering metal part and mould. The main research contents and results are as follows: Epoxy resin and metal powder are averagely mixed as SLS material which is very easy to produce with low cost and good forming property. Three kinds of Epoxy resin , E-20,E-12,E-03, are investigated as binder according to combination with metal and metal of 316L, steel45, iron are selected as structure material. The proportion of the binder is also determined. The principle of laser sintering for SLS material has been discussed. The effect of sintering parameters on strength and accuracy of green part is analysed theoretically. Sintering parameters which include laser power, scanning speed, scanning space and layer thickness are optimized as follows: P=14w, v=2000mm/s, d=0.1mm, h=0.1mm. Post-processing of green part has been investigated too. Debinding temperature, keeping time and protection atmosphere are analysed for removal of binder. High temperature sintering study focus on mechanism and process of sintering, effect of sintering parameter on property of sinter, sum of shrinkage during sintering. The ways to reducing and compensation of shrinkage are also discussed. Three kinds of infiltration materials which are copper, bronze and epoxy resin are presented for infiltration for porous parts and their processing parameters are investigated accordingly. Tensile strength of sintering parts are compared with those are infiltrated with epoxy resin and copper. Based on study of indirect selective laser sintering metal parts and moulds, metal parts with complex structure and moulds with conformal cooling channels have been manufactured successfully.