Device for laserbased powder bed fusion for additive manufacturing

功能磁性材料的添加剂制造仍处于起步阶段。原因有三个：(A)功能取决于界面、结构、缺陷和对块体或印刷部件中纳米尺度的化学控制，从内在磁性到外部特性，(B)是否有足够的粉末前体和(C)为加工功能材料提供必要条件的AM系统。在这里，我们申请了一种带有自适应建腔系统的激光粉末床融合(L-PBF)设备，该系统包括最低氧分数(&lt；25ppm)的气氛控制、使用数百克粉末的建筑体积缩小以及温度高达1200°C的加热阶段，通过这些，我们将获得对金属粉末激光加工功能和完全致密的磁性材料，如高性能永磁体的基本见解。目标是特定化学成分的完全致密的印刷部件，这些部件允许对所使用的功能材料的物理属性进行几何设计，如磁杂散磁场或电导率和热导率。所要求的系统提供使用实验室规模生产的金属粉末的功能材料，用于标准测试和鉴定程序。我们成功地开发了一种鉴定程序，即使是粒度分布相当广泛的非球形颗粒，也可以对大约100克的少量粉末进行鉴定，从而以合理的成本进行科学的材料筛选。为了增加筛粉机会，需要一种灵活的快速换粉系统。此外，在L-PBF过程中，需要一个筛分系统将细颗粒从粉末中分离出来。外部设备，便于接触和清洁，是处理不同粉末的首选。过程监控选项非常重要(熔池管理)，必须直接包含在递归材料设计过程中。具体地说，监测热波动(使用高温计)和熔体行为(cmos高速摄像机)是必要的，以评估打印。功率输入可以通过激光参数来调节，这与粉床温度相结合，通过减少脆性金属间化合物中的裂纹形成，为通常难以打印的材料开辟了一个新的参数空间。总而言之，所描述的装置提供了利用所提供的监测可能性来监测和评估功能材料的复杂熔化行为的可能性。快速和广泛地调整激光参数和体积以适应新型材料粉末，对于对资源至关重要的材料的系统研究是不可或缺的，并将加强材料科学和机械工程领域的研究伙伴之间的合作。

The additive manufacturing (AM) of functional magnetic materials is still in its infancy. The reasons are threefold: (a) functionality depends on interface, structure, defect and chemistry control on the nanoscale in the bulk or printed parts, from intrinsic magnetic to extrinsic properties, (b) the availability of adequate powder precursors and (c) AM systems which provide the necessary conditions for processing functional materials. Here we apply for a laser powder bed fusion (L-PBF) device with an adaptive building chamber system including atmosphere control with lowest oxygen fractions (< 25 ppm), a building volume reduction for the use of several 100 grams of powder and a heating stage reaching temperatures up to 1200°C. With this, we will gain fundamental insights into the metal powder laser processing of functional and fully dense magnetic materials like high performance permanent magnets. Targeted are fully dense printed parts of specific chemical composition that allow the geometrical design of physical properties such as magnetic stray fields or electrical and thermal conductivity of the functional material used. The requested system offers the use of lab scale produced metal powders of functional materials for standard testing and qualification procedures. We managed to develop a qualification procedure for small powder amounts of roughly 100 grams even with non-spherical particle shape in a rather broad size distribution, which allows a scientific material screening at reasonable costs. To increase the powder screening opportunity, a flexible system for quick powder change is required. Furthermore, a sieving system is necessary to separate the fine particle fraction from the powder used during the L‑PBF process. An external device, which allows easy accessibility and cleaning, is preferable for processing different powders. The process monitoring options are of high importance (melt pool management) which have to be directly included into the recursive material design process. Specifically, the monitoring of thermal fluctuations (using a pyrometer) and the melt behaviour (CMOS high speed camera) are necessary to evaluate the print. The power input can be regulated by the laser parameters, which in combination with the powder bed temperature opens a new parameter space for the usually difficult to print materials by reducing crack formation in the mostly brittle intermetallic compounds. In summary, the described device offers the possibility to monitor and evaluate the complex melting behaviour of functional materials with the presented monitoring possibilities. The rapid and wide-ranging adaptation of laser parameters and build volumes to novel material powders is indispensable for systematic research on resource critical materials and will enhance the collaboration between the research partners in the fields of materials science and mechanical engineering.