High Throughput Laser Array Based Additive Manufacturing

添加剂制造(AM)技术的早期前景承诺提供更大的设计自由，提高生产率水平，最大限度地减少材料使用，压缩供应链，并通过提供增强的产品能力使生产商获得更高水平的竞争力。基于金属的LPBF AM系统在过去20年中稳步发展，现在代表着数十亿英镑的全球机器、材料和软件市场。它们在许多工业部门找到了小众的小批量应用，在航空航天和生物医学部门得到了更广泛的应用。然而，与传统的制造路线相比，LPBF AM工艺仍然很慢，而且相当复杂。它们需要在大型粉末床层上精确聚焦和操纵高能激光束，以便通过激光熔化将金属粉末固化成三维固体。熔化策略对零件质量起着至关重要的作用。所有商用系统中使用的单激光光束熔化策略都存在熔化不稳定、熔化效率低以及达到高密度所需的复杂扫描策略等问题。它们需要高度的劳动密集型、特定于零件的构建参数细化和耗时的后处理操作。尽管这种生产路线具有明显的吸引力，但在制造速度、工艺稳定性、部件精度、可重复性和部件成本方面仍存在一些挑战。在这个项目中，我们建议调查几种解决这些根本问题的技术解决方案。为了提高构建速度，我们将通过重新配置激光粉末相互作用过程来建立一种新的LPBF AM能力，从目前的单一激光相互作用转变为大规模激光阵列。这种方法在多千瓦领域提供了更高的熔化效率和真正的功率可扩展性。由于激光阵列易于扩展，一个20千瓦的系统可以在24小时内提供153公斤的构建速度。这比目前的系统快约20倍。我们的方法可以为LPBF AM系统提供世界领先的性能数据。激光阵列的使用使得有问题的锁孔区域可以被传导受限区域所取代，从而导致工艺稳定性和部件密度的显著提高，通常达到99.99%。更稳定的熔化区域，降低了温度梯度，降低了残余应力，减少了零件变形，最终提高了零件精度。在过程中，将应用计量技术来检测建造层中的错误，并实现纠正步骤，从而提高过程的重复性，并提供正确的第一时间生产过程。结合上述创新，我们估计，与传统的LPBF AM系统相比，可以实现高达80%的部件成本节约。

The early prospects of Additive Manufacturing (AM) technologies promised to provide greater design freedoms, raise productivity levels, minimise material usage, compress supply chains, and enable the producer to attain greater levels of competitiveness by delivering enhanced product capabilities. Metal based LPBF AM systems have developed steadily over the past 20 years and now represent a multibillion-pound global market in machines, materials, and software. They find niche low volume applications in many industrial sectors and somewhat wider applications in aerospace and biomedical sectors. However LPBF AM processes are still slow compared to traditional manufacturing routes and are quite complex. They require precise focusing and manipulation of high energy laser beams over large powder beds in order to consolidate metal powder into a 3-dimensional solid through laser melting. Melting strategies play a significant role in part quality. Single laser beam melting strategies employed in all commercial systems suffer from melt instabilities, low melting efficiencies, and complex scanning strategies to reach high densities. They require a high level of labour-intensive part-specific build parameter refinement and time-consuming post processing operations. Despite the clear attractiveness of this production route, there remain several challenges in terms of build rates, process stability, part accuracy, repeatability, and part cost.In this project we propose to investigate several technology solutions that address these fundamental problems. To improve build rate we will establish a new class of LPBF AM capability by re-configuring the laser powder interaction process away from the current single laser interaction to large scale laser arrays. This approach offers increased melting efficiencies and true power scalability in the multi-kW domain. Since laser arrays are readily scalable, a 20kW system could deliver build rates of 153 kg in 24 hours. This is some 20 times faster than current systems. Our approach could offer world leading performance figures for LPBF AM systems. The use of laser arrays enables the problematic keyholing regime to be replaced with conduction limited regime leading to dramatic increases in process stability and part densities routinely reaching 99.99%. More stable melting regimes with reduced thermal gradients and reduce residual stress, reduce part distortion, and ultimately increase part accuracy. In process metrology will be applied to detect errors in the build layers and enable corrective steps thereby increasing process repeatability and deliver a right-first-time production process. With the combined innovations cited above we estimate that part costs savings up to 80% could be achieved compared to conventional LPBF AM systems.