选择性激光烧结覆膜砂芯成形工艺的研究

Study of Forming Technology of Selective Laser Sintered Resin Coated Sand Cores

选择性激光烧结覆膜砂芯的成形过程分烧结和后固化两步。通过测量烧结件的弯曲强度可以得出:最适合烧结的覆膜砂的固化剂用量为15%、树脂用量为3.5%,由PF-1350型树脂所构成;激光功率为40W时为最佳烧结功率。将弯曲试样经过后固化,测其弯曲强度的极大值确定最佳固化温度为180℃,最佳固化时间为10min。并且通过试验得出砂件经过后固化后,强度提高了10倍左右。

The forming process of selective laser sintered resin coated sand cores includes two steps which are selective laser sintering and post-curing. Through testing the bend strength of the sintered sample we can get that when the cured agent content is 15%, resin content is 3.5% and the kind of resin is PF-1350, the resin coated sand is the best one. We also can get that 40 W is the best laser power for sintering. Through testing bend strength of the sample after post-curing we can get that the best post-curing temperature is 160℃ and the best post-curing time is 10 min. We find that the strength of the sample after post-curing has been raised about ten times.