Effects of Compaction Rotation Speed and Compaction Thickness in Roller-Compaction-Assisted Binder Jetting Additive Manufacturing

Powder bed compaction can be used to control powder bed density in binder jetting additive manufacturing. Applying a forward-rotating roller to the powder bed is one of the methods for powder bed compaction. Both the compaction rotation speed and compaction thickness are critical parameters affecting the powder packing density and resultant printed sample integrity. However, their joint effects have not been investigated for roller-compaction-assisted binder jetting. This paper reports an experimental study to investigate the effects of the compaction rotation speed and the compaction thickness on powder bed density and the printed sample quality (in terms of distortion and cracks). The experimental results showed that powder bed density was not affected by changing compaction rotation speed but was enhanced by increasing compaction thickness. Small compaction thickness did not cause any observable distortions or cracks in the printed samples at any compaction rotation speed. Large compaction thickness caused printed samples to distort and crack under specific conditions. At large compaction thickness, compaction rotation speed significantly affected both the direction and extent of the printed sample distortion. Samples with improved density and integrity were achieved in the center of the build platform at large compaction thickness and at a compaction circumferential speed larger than the compaction traverse speed. These results can help optimize binder jetting additive manufacturing for printed sample quality.