Hybrid ultrasonic and mini motor vibration induced irregularly shaped powder delivery for multiple materials additive manufacturing
Abstract Locally dispensing fine and irregular dry powders with a stable and continuous flow rate for additive manufacturing purposes is challenging. Ultrasonic vibration is an effective tool to deposit spherical powders. However, the existing single ultrasonic vibration actuated powder dispenser could cause powder jamming and blockage when dispensing irregularly shaped ceramic particles. In this study, we demonstrate a hybrid ultrasonic and motor vibration integrated dispensing method to successfully deposit irregularly shaped silicon carbide (SiC) powder and SiC and metal powder mixtures. Flow rate experiments on mixed SiC 316 L powders with SiC volume fractions of 25 vol% 40 vol% and 50 vol% indicated that the powder flow rate was determined by powder packing density after pre mixing and before deposition. A lower packing density resulted in a higher powder flow rate. Both the SiC particle size and SiC volume fraction affected the final mixed powder packing density. The SiC 316 L mixture with 40 vol% of 320 grit SiC powder had the highest powder flow rate (37.53 mL/s) Finally, the new powder deposition approach was successfully used for laser powder bed fusion manufacturing of a double helix structure made of a 316 L stainless steel and a SiC 316 L mixture. Such a powder dispensing technology has the potential to be applied in powder materials involved in additive manufacturing and pharmacy industries.