Multijet 3D Printing (MJP)
Similar to Powder Bed Fusion
What is Multijet 3D Printing?
Multijet printing functions similar to powder bed fusion 3D printing. A powder bed containing a polymer, usually nylon is heated to its glass transition temperature where it becomes soft but doesn't quite melt. A Multijet nozzle similar to that of a typical 2D inkjet nozzle is then used to deposit a substance that allows the polymer to absorb more heat from a set of heat lamps that cover the entire print area. This allows the temperature of the affected powder to increase enough to successfully melt the powder homogenously.
A second jet is also used to define the outside of the part to make sure all the edges are sharp and consistent.
Since the powder is completely melted layer by layer the final parts produced have excellent layer adhesion and a low porosity resulting in stronger parts.
When to use Multijet Printing
Multijet 3D printing provides a low cost alternative to injection moulding, the parts are strong without requiring difficult post processing and unused material can be reused easily. At low volume it should be seriously considered as the final parts have a reasonable surface finish and there is no need to produce tooling.
However, high volume production runs will still be slower and more expensive than traditional injection moulding.
The materials available for Multijet 3D printing are extremely limited. Typically Nylon PA12 is used as it produces consistent final parts.
If you are looking for other materials please view fused deposition modelling (FDM) or injection moulding which lend themselves to a wide variety of plastics.