Effects of Auto-Stirring on Powder Dispensing Rate Consistency in Hopper-Based Binder Jetting 3D Printing with Cohesive Powder

In hopper-based binder jetting 3D printing, a consistent powder dispensing rate from the hopper to the powder bed is essential for reliable printing. This study investigates the effects of adding a custom-built auto-stirrer to the hopper system on the consistency of powder dispensing rate for the ExOne Innovent+ binder jetting 3D printer (Desktop Metal, Burlington, MA, USA). The auto-stirrer incorporates rotating augers that actively agitate the powder in the hopper. Working together with the ultrasonic vibrator, the auto-stirrer facilitates consistent dispensing of powder through the hopper outlet. Experiments with algae powder demonstrated that adding the auto stirrer reduced fluctuations in dispensing rate by over 30% compared with the standard hopper. Statistical analysis confirmed that these improvements were significant (at a significance level of 0.05). These results indicate that integrating active mechanical agitation into hopper-based powder dispensing systems could help to achieve more consistent powder dispensing rates in hopper-based binder jetting 3D printing that uses cohesive powder feedstocks.