Selective laser sintering (melting) of stainless and tool steel powders: experiments and modelling
Selective laser sintering (melting) of stainless and tool steel powders: experiments and modelling
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DOI：
10.1243/095440505x8109
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发表时间：
2005-04-01
期刊：
影响因子：
2.6
通讯作者：
Badrossamay, M
中科院分区：
文献类型：
--
作者：
Childs, THC;Hauser, C;Badrossamay, M
当激光束在金属粉末床的表面上扫描一次时，所产生的轨迹可以是连续的，具有新月形或椭圆形横截面，不规则地断裂，成球或仅部分熔化。本文报道了什么样的激光功率和扫描速度导致什么样的轨道，为CO2激光束聚焦到0.55毫米和1。1 mm直径，扫描由M2和H13工具钢和314 S-HC不锈钢粉末制成的床。床的粒径范围为300 μ m至150 μ m、150 μ m至75 μ m、75 μ m至38 μ m以及小于38 μ m。测量床的物理特性，用于在有限元模型中预测熔池的尺寸和温度也有报道。不同的轨道形成的区域之间的边界解释的熔体表面温度梯度，熔池长径比不稳定性，从部分到完全熔化的过渡。被认为是建筑金属零件在粉末床没有支持的影响。该模型被简单地扩展到多轨道和多层处理，得出的结论是，通过层之间的重熔粘合，同时仍然保持对熔体流动的控制，对最大允许层厚度的严格限制。
When a laser beam scans once across the surface of a metallic powder bed, the resulting track may be continuous with a crescent or an elliptic cross-section, irregularly broken, balled or only partially melted. This paper reports what laser powers and scan speeds lead to what types of track, for a CO2 laser beam focused to 0.55 mm and 1. 1 mm diameters, scanning over beds made from M2 and H13 tool steel and 314S-HC stainless steel powders. Beds have been made with particle size ranges from 300 mu m to 150 mu m, from 150 mu m to 75 mu m, from 75 mu m to 38 mu m, and less than 38 mu m. Measurements are also reported of bed physical properties that are used in a finite element model to predict melt pool dimensions and temperatures. Boundaries between regions of different track formation are explained in terms of melt surface temperature gradients, melt pool length-diameter ratio instabilities, and transitions from partial to complete melting. Implications for building metal parts in powder beds without supports are considered. The modelling is briefly extended to multi-track and multi-layer processing, to conclude that bonding by remelting between layers, while still maintaining control of the melt flow, places severe constraints on the maximum allowable layer thickness.