激光烧结铸造型壳强度试验分析

利用激光烧结快速成型技术可以烧结覆膜陶瓷材料，形成然造用型腔壳体并直接应用于铸造，制作金属零件，由于在快速原型制造领域所使用的激光器功率普遍较低，因此，无法实现真正意义上材料的直接烧结，目前所能实现的是覆膜陶瓷的间接烧结，即利用激光融凝陶瓷表面涂覆的有机物薄膜，使陶资粉末粘结成一个原型壳体。由此形成的壳体原强度较低，不能直接用于铸造。因此，二次烧结作为一种后处理工艺用于提高壳体强度，与烧结工艺参数对原型壳体强度的影响同等重要。通过试验分析，在烧结工艺参数中，扫描间隔和扫描速度是影响原型壳体强度的主要因素，其直接影响烧结原型第一强度的变化。二次烧结后处理可以大幅度提高壳体的二次强度，满足铸造对壳体的强度要求，最后以整体叶轮的快速制造为例，验证了上述结论。

Strength Analysis of Mold Shell Manufactured with Selective Laser Sintering Technology

Polymer coated ceramic powder can be used to manufacture mold shell with selective laser sintering technology, and the mold shell is usually used to cast and produce metal part. Usually, the laser energy used in rapid prototyping manufacturing is not beyond 100 W. It is not enough to sinter ceramic powder directly. So indirect-sintering is adopted. But, the wear intensity of mold shell, which is determined by some sintering parameters, is a fatal reason to cast unsuccessfully. Generally, post- processing, such as high temperature sintering, is unavoidable for those wear intensity shell. This paper presents some results which show the effect of scan speed and scan space on shell intensity, describes the post-processing, and discusses its application to SLS mold shell. Results gained from this process show that it is obvious to improve the intensity of mold shell. An example is used to validate these results above.