研究了快速、精确制造金属模具的方法, 提出利用激光选区烧结(SLS)技术来快速制造高精度陶瓷型精密铸造用母模。首先, 采用正交试验法研究了激光选区烧结工艺参数对制件精度的影响, 确定了最佳激光烧结工艺。在此基础上利用浸水起模法替代传统的起模喷烧工艺对陶瓷型精密铸造工艺进行改进。结果表明, 选定激光烧结工艺参数为激光功率25 W, 扫描速度2.0 m/s, 扫描间距0.19 mm, 分层厚度0.25 mm时, 试样尺寸收缩率最低可达2%。采用陶瓷型浸水起模法起模容易, 起模后陶瓷型表面光洁, 在200 ℃焙烧温度下抗弯强度较高, 为0.361 MPa。这些结果表明, 利用SLS技术能够快速、准确地制造出陶瓷型精密铸造所需母模。

Rapid prototyping technology for producing quickly and precisely metal molds is explored, and the Selective Laser Sintering (SLS) is used to produce a high precision ceramic mold for precision manufacturing. On the basis of orthogonal test and range analysis , the effects of process parameters of SLS, including laser power, scan speed, scan spacing and layer thickness, on the dimensional accuracy of machining work-pieces are discussed and then the optimum parameters are determined. The founder technique is used to replace the traditional removal of organic binders and to improve the precision manufacturing for the ceramic mold. The results show that the shrinkage of the work-piece size is 2% under the conditions of the laser power of 25 W, scan speed of 2.0 m/s with a scan spacing of 0.19 mm and the layer thickness of 0.25 mm. As the ceramic molding founder technique strips easily and the ceramics after stripping has a smooth surface, its tensile strength has been 0.361 MPa in 200℃ roast. These data indicate that the combination of ceramic molding and precision casting has the potential to produce rapid and precise castings.