Metal binder jetting system for the entire additive process chain

激光粉床熔化(LPBF)等直接熔炼金属基添加剂制造(AM)工艺使得能够以高的元件密度和几何尺寸精度生产几何复杂的元件，例如拓扑优化的栅格结构。然而，低积累率和相关的高组件成本阻碍了广泛的工业应用，特别是在汽车行业等成本驱动型工业领域。AM生产率的必要提高可以通过进一步开发间接粉末床AM工艺来解决，例如具有显著更高积累率的金属粘结剂喷射(MBJ)。在工艺序列方面，1990年代开发的MBJ的逐层印刷概念与LPBF工艺相当。然而，MBJ不是聚焦的激光光束，而是使用多喷嘴打印头选择性地将粘结剂微滴施加到粉床上。在使用粘结剂后，将粉床在安装空间中降低一层，并应用另一层。重复施加粉末、施加粘结剂、降低粉床的步骤，直到组件完全组装完毕。在打印过程之后，粉床被固化，从而粘结剂的液体成分蒸发。固化的粘结剂-聚合物和金属粉末形成固体绿色部分，允许去除未渗透的粉末。然后将坯体在熔化温度附近的炉子中烧结。在这个过程中，粘结剂以热的方式溶解。除了速度优势，MBJ烧结还具有比直接AM工艺更多的优势，例如在难以焊接的硬质合金或合金的加工方面。由于最近惠普等新成立的工业公司进入MBJ领域，与以前的MBJ相比，MBJ有了明显的发展。然而，印刷和后处理方法的发展、部件设计和材料开发以及由此产生的部件性能仍然是一项挑战。这正是申请资金的工作组发挥作用的地方。在新系统技术的基础上，通过开发新的粉末材料，对整个生产链的协调进行基础研究，随后的材料/部件表征，以及通过开发预测载荷和故障模型，并在此基础上制定包括收缩现象在内的适当设计规则，将显著扩大MBJ的应用领域。申请机构在AM、材料开发和资格认证、粉末冶金和数字部件/工艺设计方面在主题上相互补充，以便能够全面解决上述MBJ的基础科学问题。

Direct-melting metal-based additive manufacturing (AM) processes such as laser powder bed fusion (LPBF) make it possible to produce geometrically complex components, such as topology-optimized grid structures, with high component density and geometric dimensional accuracy. However, low build-up rates and the associated high component costs prevent the broad industrial application, especially in cost-driven industrial areas such as the automotive sector. The necessary increase in productivity of AM can be addressed by the further development of indirect powder bed AM processes such as Metal Binder Jetting (MBJ) with significantly higher build-up rates.The layer-by-layer printing concept of the MBJ developed in the 1990s is comparable to the LPBF process in terms of process sequence. However, instead of a focused laser beam, the MBJ uses a multi-nozzle print head to selectively apply Binder micro-droplets to the powder bed. After the binder application, the powder bed is lowered one layer in the installation space and another layer is applied. The steps powder application, binder application, powder bed lowering are repeated until the component is completely assembled. After the printing process, the powder bed is cured, whereby the liquid components of the binder evaporate. The cured binder-polymer and metal powder form a solid green part, which allows the removal of the uninfiltrated powder. The green body is then sintered in a furnace near the melting temperature. During this process, the binder dissolves thermally. In addition to speed advantages, MBJ sintering offers further advantages over direct AM processes, e.g. in the processing of hard metals or alloys that are difficult to weld.Due to the recent entry of new, established industrial companies such as Hewlett Packard into the MBJ field, there is a clear development compared to the previous possibilities of the MBJ. However, the development of printing and post-processing methods, component design and material development as well as the resulting component performance remain a challenge. This is precisely where the working group applying for funding comes in. On the basis of the new system technology, a significant expansion of the application areas of the MBJ is to be achieved by developing new powder materials, fundamental research into the coordination of the entire production chain, subsequent material/component characterization, as well as by developing predictive load and failure models and, based on this, by working out adapted design rules including shrinkage phenomena. The applicant institutions complement each other thematically in AM, materials development and qualification, powder metallurgy and digital component/process design, in order to be able to comprehensively work on the aforementioned fundamental scientific questions of the MBJ.