Precoated sand used for laser sintering and nano 3D printing technology and preparation method thereof

Abstract

The invention relates to precoated sand and a preparation method thereof and in particular to the precoated sand used for a laser sintering and nano 3D printing technology and the preparation method thereof. The precoated sand used for the laser sintering and nano 3D printing technology comprises the following raw material components, in part by weight, 80-90 parts of silica sand, 30-45 parts of high-temperature alloy fiber, 6-8 parts of urotropin, 30-35 parts of resin, 30-35 parts of refractory clay, 30-50 parts of nano negative ion powders, 12-18parts of nano carbon powders and 5-8 parts ofoxalate. The toughness and the tensile strength of the precoated sand are improved by adding the high-temperature alloy fiber; the amount of pin holes and nitrogen holes, which are generated by a highgas evolution of the precoated sand, of a precoated sand casting to be printed can be reduced by using the high-strength and low-gas-volution resin; and the amount of free phenol in the precoated sand is reduced by adding the oxalate, so that the environment can be protected and the gas hole disadvantage of the casting can be reduced, and therefore the accuracy of 3D printing can be improved andthe surface quality of the casting can be guaranteed.

Description

technical field [0001] The invention relates to a coated sand and a preparation method thereof, in particular to a coated sand used in laser sintering and nano-3D printing technology and a preparation method thereof. Background technique [0002] Coated sand is the molding sand or core sand whose surface is covered with a layer of cured resin film before molding. There are two kinds of coating processes: cold method and hot method: the cold method uses a solvent (such as alcohol) to dissolve the resin, and in the process of sand mixing, the resin is coated on the surface of the sand grains; the hot method preheats the sand to a certain temperature and adds The resin is mixed so that the resin coats the surface of the sand grains. The new 3D printing technology is a process of superimposing the coated sand layer by layer through laser firing to solidify and shape it, which saves the process of mold opening and core making, and greatly shortens the development cycle of new pr...

AI Technical Summary

Problems solved by technology

The new 3D printing technology is a process of superimposing the coated sand layer by layer through laser firing to solidify and shape it, which saves the process of mold opening and core making, and greatly shortens the development cycle of new products. However, 3D Printing technology has extremely high requirements for coated sand. The formula of coated sand used in the market is usually only suitable for one 3D printing technology, and the amount of pinholes and nitrogen pores in printed coated sand castings is relatively high. Long life, high cost