During the Binder-Jet printing process, fine metal powders are spread in thin layers inside a build box. The layer thickness can be 0.03~0.07 mm (0.0012”~0.0027”). The layer thickness directly influences the resolution of the printed part. A system of print heads deposit binder material over the powder layer. This process is repeated thousands of times until the full image of the part is printed within the build box. The printed component is called the ‘green component’. The number of parts within the build box per print cycle depends on the size of the components printed.
The build box is moved to a curing oven where the binder material is allowed to cross-link so that the stronger polymer chains hold the metal particles stronger. After the curing process, the build box is moved to a de-powdering station where the loose powder particles that are not touched by the binder are removed through vacuum suction. This process releases the printed green parts for further processing.
The green parts go through de-binding where part of the binder material holding the shape together is allowed to evaporate. At this stage the components are referred to as brown components.
The brown components are sintered in vacuum sintering furnaces. The sintering process is very similar to the process used for producing metal injection molded (MIM) components. Post-sintering, the material properties are very similar to the MIM material with 98% density. Material properties and density can be further improved through HIPing process. The sintered components can be finish machined, heat-treated or plated using conventional process steps.