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Powder bed additive manufacturing (AM) processes, including binder jetting (BJAM) and powder bed fusion (PBF), can manufacture complex three-dimensional components from a variety of materials. A fundamental understanding of the spreading of thin powder layers is essential to develop robust process parameters for powder bed AM and to assess the influence of powder feedstock characteristics on the subsequent process outcomes. Toward meeting these needs, this work presents the design, fabrication, and qualification of a testbed for modular, mechanized, multi-layer powder spreading. The testbed is designed to replicate the operating conditions of commercial AM equipment, yet features full control over motion parameters including the translation and rotation of a roller spreading tool and precision motion of a feed piston and the build platform. The powder spreading mechanism is interchangeable and therefore can be customized, including the capability for dispensing of fine, cohesive powders using a vibrating hopper. Validation of the resolution and accuracy of the machine and its subsystems, as well as the spreading of exemplary layers from a range of powder sizes typical of BJAM and PBF processes, are described. The precision engineered testbed can therefore enable the optimization of powder spreading parameters for AM and correlation to build process parameters in future work, as well as exploration of spreading of specialized powders for AM and other techniques.

Binder jet additive manufacturing (BJAM) is capable of fabricating complex three-dimensional components from a variety of material classes. Understanding the fundamentals of BJAM, including spreading of thin layers of powder, powder-binder interactions, and post-processing is critical to develop robust process parameters for BJAM. Toward meeting these needs, this work presents the design, fabrication, and qualification of a testbed for modular, mechanized, BJAM. The testbed seeks replicate the operating conditions of commercial AM equipment and features fully programmable motion control including powder spreading using a precision roller mechanism, powder supply via a vibrating hopper, and gantry positioning of an inkjet printhead. The inkjet deposition system allows for the use of variable nozzle diameters, the exploration of novel binder compositions, and full control of jetting parameters. Validation of the accuracy and repeatability of the machine and its subsystems, as well as the fabrication of exemplary stainless steel components, are described. The precision engineered testbed can therefore enable the study of the BJAM process, exploration of novel binder compositions, and processing of custom powders to further scientific research and industrial applicability of BJAM.

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