| CPC B29C 64/165 (2017.08) [B22C 1/224 (2013.01); B22C 1/2253 (2013.01); B22C 9/02 (2013.01); B29K 2105/251 (2013.01); B29K 2459/00 (2013.01); B29K 2909/14 (2013.01); B33Y 10/00 (2014.12); B33Y 70/10 (2020.01)] | 11 Claims |
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1. A method for additive manufacturing, comprising the following steps:
stirring 1350-1650 parts by weight of furfuryl alcohol, 2-5 parts by weight of an acid catalyst, 120-180 parts by weight of a phenolic compound, and 60-90 parts by weight of polyoxymethylene to form a mixture of a binder, heating up to 120-150° C. and reacting for 1-2 h, then dehydrating at 85° C. or below, cooling down to 45° C. or below, and adding 5-10 parts by weight of a coupling agent, to obtain the binder;
mixing p-toluenesulfonic acid with pure water in a ratio of 70-80 parts by weight to 20-30 parts by weight to form a mixture of the p-toluenesulfonic acid and the pure water, mixing phosphoric acid with the mixture of the p-toluenesulfonic acid and the pure water in a ratio of 90-100 parts by weight to 3-7 parts by weight, heating the obtained mixture of the phosphoric acid and the mixture of the p-toluenesulfonic acid and the pure water to 60-80° C., and stirring for 1-3 h, to obtain a hardener;
mixing the hardener with a sand material in a mass ratio of 0.1-1.0% of the hardener to the sand material, heating at a high temperature of 100-110° C. for mixing, and drying, thereby coating the hardener evenly on a surface of the sand material, and then spraying the binder through a nozzle, with a mass ratio of the binder to the sand material being 0.5-2.5%;
reacting the binder sprayed through the nozzle with the surface of the sand material evenly coated with the hardener to harden a sand mold.
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