Feedforward control of thermal history in laser powder bed fusion: Toward physics-based optimization of processing parameters
Feedforward control of thermal history in laser powder bed fusion: Toward physics-based optimization of processing parameters
复制标题
激光粉末床熔合热历史的前馈控制：基于物理的加工参数优化
DOI：
10.1016/j.matdes.2022.111351
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发表时间：
2022
影响因子：
8.4
通讯作者：
Rao, Prahalada
中科院分区：
文献类型：
--
作者：
Riensche, Alex;Bevans, Benjamin D.;Smoqi, Ziyad;Yavari, Reza;Krishnan, Ajay;Gilligan, Josie;Piercy, Nicholas;Cole, Kevin;Rao, Prahalada
我们开发和应用了一种模型驱动前馈控制方法来减少激光粉床熔化(LPBF)添加剂制造过程中热致缺陷的形成。其关键思想是通过基于物理的热模拟模型的见解逐层调整工艺参数，以避免LPBF部件在打印前积累热量。其动机是用物理指导的策略取代繁琐的经验构建和测试参数优化。该方法包括三个步骤：预测、分析和修正。首先，利用基于图论的计算热模型快速预测零件的温度分布。其次，分析了模型派生的热趋势，以隔离潜在的热积聚层。第三，通过调整通过迭代模拟优化的工艺参数，在印刷前校正受影响层的积热。该方法的有效性在两个独立的构建板上进行了实验验证。在第一次试制中，在恒定的工艺条件下，生产了10种不同的镍合金718零件。在第二个相同的印版上，称为受控处理，在打印前根据热模拟调整每个部分的激光功率和停留时间，以避免热量积累。为了验证热模型的预测，用校准的红外热像仪跟踪了每个部件的表面温度。用无损和破坏性材料表征技术对零件进行了后处理。与固定加工相比，控制加工生产的零件具有更高的几何精度和分辨率、更细的晶粒度、更高的显微硬度和更低的表面粗糙度。
We developed and applied a model-driven feedforward control approach to mitigate thermal-induced flaw formation in laser powder bed fusion (LPBF) additive manufacturing process. The key idea was to avert heat buildup in a LPBF part before it is printed by adapting process parameters layer-by-layer based on insights from a physics-based thermal simulation model. The motivation being to replace cumbersome empirical build-and-test parameter optimization with a physics-guided strategy. The approach consisted of three steps: prediction, analysis, and correction. First, the temperature distribution of a part was predicted rapidly using a graph theory-based computational thermal model. Second, the model-derived thermal trends were analyzed to isolate layers of potential heat buildup. Third, heat buildup in affected layers was corrected before printing by adjusting process parameters optimized through iterative simulations. The effectiveness of the approach was demonstrated experimentally on two separate build plates. In the first build plate, termedfixed processing, ten different nickel alloy 718 parts were produced under constant processing conditions. On a second identical build plate, calledcontrolled processing,the laser power and dwell time for each part was adjusted before printing based on thermal simulations to avoid heat buildup. To validate the thermal model predictions, the surface temperature of each part was tracked with a calibrated infrared thermal camera. Post-process the parts were examined with non-destructive and destructive materials characterization techniques. Compared to fixed processing, parts produced under controlled processing showed superior geometric accuracy and resolution, finer grain size, increased microhardness, and reduced surface roughness.