3．SLS烧结聚苯乙烯粉末浸蜡模样 

SLS 最初是用激光将特制的蜡粉烧结成蜡模，很适合熔模铸造的工艺特点，早在 1990年底，美国已有超过50家铸造厂，生产多达约 3000个蜡模，并成功铸出多种金属铸件。然而，蜡粉并不是最理想的制模材料，由它制成蜡模的强度不足，气温高时易软化变形，气温低时又容易碎断。因此，1990 年代初期，美国一些 SLA 用户就尝试采用聚苯乙烯(PS)或聚碳酸酯(PC)等热塑性塑料粉末代替蜡粉。此类材料制成模样疏松多孔(孔隙率达25%以上)，减轻了脱模时胀裂型壳的危险，型壳焙烧后灰分少，但模样表面粗糙。因此，模样制成后需要浸蜡和手工打磨精整，使其表面光滑致密。目前这种方法已在国内外普遍应用。图12-8 所示为北京隆源自动成型系统有限公司用 SLS 法烧制成的聚苯乙烯粉末浸蜡模的部分典型实例。

参 考 文 献

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2.  Robert N. Integration of Reverse Engineering Solidification Modeling and Rapid Prototyping Technologies for The Production of Net-Shape Investment Cast Tooling. Proceedings Of The 43th Annual Technical Meeting on Investment Casting., USA. 1995, 21:1~9   

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4.  Tony  Riek.  Comparing  Rapid  Prototyping  Patterns  For  Investment  Casting  - An  Australian  Investigation. Proceedings Of The 9thWorld Conference On Investment Casting. San Francisco, USA. 1996, 20:1~20:11

5.  Curtis Wahleren, Suresh  Jayanth, Tom Mueller. Dimensional  Issues With  Investment Casting Patterns Made By Stereolithography. Proceedings Of The 48th Annual Technical Meeting On Investment Casting., USA. 2000, 3:1~3:9

6.  Charles  Kaufmann.  Investment  Casting  Trial  Studies  Examine  Significant  New  Developments  In Stereolithography Resins. INCAST 2002(11): 12~15

7.  Tom Mueller. Rapid Prototyping Technology ——The Changing The Economics of Low-Volume Investment Casting. INCAST 2004(10): 11~15 

资料来源：精铸分会