Coated sand for selective laser sintering (SLS) and preparation method thereof

A technology of laser sintering and coated sand, which is applied in casting molding equipment, manufacturing tools, metal processing equipment, etc. It can solve the problems of easy damage, poor bonding between phenolic resin and sand interface, and no curing crosslinking, so as to increase the absorption rate Effect

Inactive Publication Date: 2010-09-08
武汉华科三维科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, the existing phenolic resin coated sand and its preparation process are all developed for traditional forming methods, not for SLS forming technology
The existing problems are: the strength of the existing SLS molded parts (before post-curing) of phenolic resin coated sand is low, and some fine structures are easily damaged in post-treatment processes such as powder cleaning and transfer, and large-sized molded parts are more likely to break
The main reasons for the low strength of SLS formed parts of phenolic resin coated sand are: different from

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) Cool bisphenol A epoxy resin E-06 to -150°C in a cryogenic freezer, and pulverize it with a high-speed impact mill;

[0025] (2) The powder obtained in step (1) is sieved by air flow to obtain epoxy resin powder with a particle size distribution of 10-50 μm.

[0026] (3) Prepare phenolic resin-coated sand by thermal coating process, in which the original sand is 5000g, and the phenolic resin is 75g (the mass ratio of the original sand to the composite adhesive is 2:100, and the mass ratio of the phenolic resin in the composite adhesive is Percentage is 75%), curing agent urotropine is 10g (the mass ratio of curing agent and composite adhesive is 10: 100), lubricant zinc stearate 7g (the mass ratio of lubricant and composite adhesive is 7:100).

[0027] (4) carbon black (the mass ratio of carbon black and composite binder is 0.5: 100) and step (3) obtained by the epoxy resin powder of 25g that step (2) obtains, 0.5g mean particle diameter is 50nm Add the phenolic r...

Embodiment 2

[0029] (1) Cool the bisphenol A type epoxy resin E-12 to -150°C in a cryogenic freezer, and use a high-speed impact mill to pulverize it;

[0030] (2) The powder obtained in step (1) is sieved by air flow to obtain epoxy resin powder with a particle size distribution of 10-50 μm.

[0031] (3) The phenolic resin coated sand is prepared by thermal coating process, wherein the original sand is 5000g, and the phenolic resin is 75g (the mass ratio of the original sand to the composite adhesive is 3:100, and the mass ratio of the phenolic resin in the composite adhesive is Percentage is 50%), curing agent urotropine is 22.5g (the mass ratio of curing agent and composite adhesive is 15: 100), lubricant lithium stearate 4.5g (the mass ratio of lubricant and composite adhesive The ratio is 3:100).

[0032] (4) the epoxy resin powder of 75g that step (2) obtains, 1.5g mean particle diameter is the carbon black (mass ratio of carbon black and composite binder is 1: 100) and step (3) obt...

Embodiment 3

[0034] (1) Cool bisphenol A epoxy resin E-06 to -150°C in a cryogenic freezer, and pulverize it with a high-speed impact mill;

[0035] (2) The powder obtained in step (1) is sieved by air flow to obtain epoxy resin powder with a particle size distribution of 10-50 μm.

[0036] (3) The phenolic resin coated sand was prepared by the cold method coating process, wherein the original sand was 5000g, and the phenolic resin was 75g (the mass ratio of the original sand to the composite adhesive was 2.4:100, and the mass ratio of the phenolic resin in the composite adhesive was Percentage is 62.5%), curing agent urotropine is 15g (the mass ratio of curing agent and composite adhesive is 12.5: 100), lubricant calcium stearate 6g (the mass ratio of lubricant and composite adhesive is 5:100).

[0037] (4) carbon black (the mass ratio of carbon black and composite binder is 0.75: 100) and step (3) obtained by the epoxy resin powder of 45g that step (2) obtains, 0.9g mean particle diamet...

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Abstract

The invention discloses coated sand for selective laser sintering and a preparation method thereof. The coated sand comprises crude sand, a compound binder, a curing agent, a lubricating agent and a light absorber, wherein the compound binder comprises phenolic resin and epoxy resin; the curing agent is formamine; the lubricating agent is zinc stearate, calcium stearate or lithium stearate; and the light absorber is carbon black. The preparation method comprises the following steps: firstly, carrying out freeze grinding on the epoxy resin; then selecting epoxy resin powder with suitable particle size distribution by a sieving method; and finally, evenly mixing a certain ratio of epoxy resin powder, the carbon black and phenolic resin coated sand prepared by the existing process. Due to the fact that the strength of the SLS formed part of the coated sand is higher, the coated sand can be used for SLS of casting sand moulds (cores) with large-size and complicated structures.

Description

technical field [0001] The invention belongs to the field of new materials, in particular to a coated sand used for selective laser sintering (SLS) forming and a preparation method thereof. technical background [0002] SLS technology is a rapid prototyping technology (rapid prototyping, RP) that uses laser as a heat source to sinter powder materials. , the solid powder material is directly formed into a three-dimensional solid part, which is not affected by the complexity of the formed part. [0003] SLS technology can directly prepare sand molds (cores) for casting, from part drawings to process design of molds (cores), and three-dimensional solid modeling of molds (cores), etc. are all completed by computers. Especially for some curved surfaces or runners in space, it is very difficult to form them by traditional methods. If SLS technology is used, this process will become very simple, because it is not limited by the complexity of the parts. When preparing large-size s...

Claims

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Application Information

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IPC IPC(8): B22C1/00B22C1/02B22C1/22
Inventor 史玉升闫春泽沈其文杨劲松张升文世峰蔡道生
Owner 武汉华科三维科技有限公司
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