Laser direct metal deposition process of thin-walled parts using variable spot by inside-beam powder feeding
Laser direct metal deposition process of thin-walled parts using variable spot by inside-beam powder feeding
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DOI：
10.1108/rpj-01-2016-0010
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发表时间：
2017-11
影响因子：
3.9
通讯作者：
Lifang Wang;G. Zhu;Tuo Shi;Jizhuo Wu;B. Lu;G. Fu;Yunxia Ye
中科院分区：
文献类型：
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作者：
Lifang Wang;G. Zhu;Tuo Shi;Jizhuo Wu;B. Lu;G. Fu;Yunxia Ye
目的为了提高激光直接金属沉积技术制造不等宽零件的成形效率和成形质量，设计了一些实验。设计/方法/方法采用改变激光光斑的新方法，用一次扫描的方法制备不等宽的单道，而不是光束内送粉的多道重叠，并逐层制造薄壁零件。建立了z轴层厚与单轨高度、单轨断面曲线顺序之间的理论模型。发现在−2.5~−5 mm和0.5~2.5 mm的激光离焦范围内，薄壁零件的顶面不平度可以自动补偿。大宽高比的生长速度大于小宽高比的生长速度，而单道的设定高度比较均匀。基于步进式单迹方法可以解决生长速度不均匀的问题。通过拼接激光离焦范围，逐层加工出宽度在1~3 mm范围内连续变化的光滑顶面的薄壁零件。实际意义在实际应用中，待加工零件的形状会影响可变激光光斑的加工。例如，在具有孔特征的零件上应用可变激光光斑加工将是困难的。为基于内束送粉的激光直接金属沉积成形不等宽零件提供了指导。
Purpose The purpose of this paper is to improve the forming efficiency and quality of unequal-width parts fabricated by laser direct metal deposition technology, some experiments were designed. Design/methodology/approach A new method by varying laser spot was adopted to fabricate unequal-width single track using one scanning rather than multi-track overlapping in the way of the inside-beam powder feeding, and the thin-walled parts were fabricated layer by layer. The theoretical model among layer thickness of z-axis, height of single track and the section curve order of single track was established. Findings The top surface unevenness of the thin-walled parts could be compensated automatically within the laser defocusing ranges from −2.5 to −5 mm and from 0.5 to 2.5 mm. The growth rate with the large width/height ratio was more than the small ratio, while the set height of the single track was uniform. The problem of non-uniform growth rate could be solved based on a stepped single-track method. The thin-walled parts with the smooth top surface was fabricated layer by layer which had a continuously variable width from 1 to 3 mm by splicing the laser defocusing range. Practical implications The shapes of the to-be-fabricated parts affect variable laser spot process in practical applications. For example, it will be difficult to apply variable laser spot process on the parts with the hole features. Originality/value This paper provided a guidance for forming unequal-width parts by laser direct metal deposition based on the inside-beam powder feeding.