The Impact of the Printed Part Geometry on the Shrinkage and Relative Density in Binder Jetting Additive Manufacturing of Ceramics Powder

Abstract Additive manufacturing has been used extensively for the last decade in making different parts of different complexities. One of the additive manufacturing methods discussed in this work is binder jetting additive manufacturing (BJAM) process where a liquid-based binder is deposited on the powder bed to make the part layer by layer. In this work, ceramics particles are used to investigate the effect of the part geometry on the density and shrinkage of the part made. Three different shapes (spheres, cylinders, and rectangular blocks) of the same size are printed at 100%, 75% core saturation limit at zero second and 10-seconds delay using a binder jetting 3D printer at 0.2 mm layer thickness. The green parts are de-powdered and dried for 6–8 hours using a drying heater at 35° C then de-bound and sintered to improve the strength and the density of the part made. We use ceramics powder of particle size range 50–200 μm to print the parts. It is found that the apparent density of the rectangular block is the highest in all cases except at 100% saturation with 10-seconds delay. The apparent densities of the sphere and the cylinder are very close to each other. Also, the shrinkage percentage for the sphere is the highest then cylinder comes next, and the rectangular block comes last in all cases except when the core saturation is 100% and delay is 0 second where the cylinder shrinkage is higher than that of the sphere. The reason behind this is maybe the difference in the surface area of each part printed. It is noticed also that the relative density obtained is in the range of about 79% to about 85% and the shrinkage percentage is in the range of 36% to 55%.