Electrostatic Powder Dispenser for Additive Manufacturing Processes
Eric Elton | 21-FS-033
Powder bed additive manufacturing techniques such as selective laser melting or binder jet printing are used to additively manufacture, or 3D print, a wide variety of materials including metals, ceramics, and polymers. These techniques rely on laying a uniform layer of powder, which is then fused either using energy (such as a laser) or a binder into the desired shape. The process is repeated to build up the final part layer by layer. In these processes, powder is typically deposited in front of a spreader bar and pushed across the powder bed. While this is a straightforward process, a variety of problems can result in unsuitable powder beds and failed parts. For example, not all powders flow well and may spread unevenly across the bed, or deviations in the powder bed from parts being built may cause damage to the spreader bar and subsequently defects in the powder bed.
This project examined the feasibility of using an electrostatic powder spreader (ESPS) to deposit metal powder onto a powder bed. The electrostatic powder spreader uses an electric field formed between a slanted electrode and a grounded powder container to move powder particles from the container to the powder bed, and, since it has no spreader bar, avoids common problems that can occur from conventional spreading techniques. We experimentally optimized the powder deposition rate and found that the powder can be deposited at a rate comparable to state of the art spreading techniques. We also found the powder bed thickness can be controlled through adjusting the applied voltage, spreader speed, and electrode position. Finally, we observed that simulated metal build parts inside of a powder bed do not affect future powder layers. All of this suggests that the powder beds depositing using electrostatic powder spreading are sufficient for use in powder bed additive manufacturing processes including laser powder bed fusion.
This project developed and demonstrated cutting-edge capabilities aligned with Lawrence Livermore National Laboratory's core competency in advanced materials and manufacturing. By demonstrating the feasibility of using ESPS for additive manufacturing, this work enables future research and development into novel additive manufacturing techniques, such as multi-material metal additive manufacturing. In addition, it supports the metal additive manufacturing needs within Lawrence Livermore National Laboratory, and specifically within the Weapons and Complex Integration and Global Security programs. Finally, this work addresses the broader DOE and NNSA mission by helping to develop science and technology tools and capabilities to meet future programmatic and national security challenges.