MJF technology

Multi Jet Fusion (MJF) technology infrared lamp as the heat source for melting of polymer powder, which is, as it is the case with the SLS technology, based on the polyamide PA 12 as the primary component. The lamp exposes to radiation the whole surface of the powder bed, and the selective heating and melting is provided by selective absorption of the radiation due to previous selective deposition of both heat-absorbing and heat-deflecting (called “fusion and “detailing”) agents over the selected areas of top surface of the powder bed.

Apart from the other properties of PBF technologies for polymer materials, the MJF technology has also the following properties:

• The product anisotropy of products of MJF technology is smaller than the products of the SLS technology because of smaller temperature gradients;
• The accuracy of the parts manufactured by MJF technology is usually better than of the parts manufactured by the SLS technology because resolution of the deposition of the fusion agent by the MJF printheads enables definition of spots smaller than the laser spots of typical lasers used for SLS technology; the application of the detailing agent also contributes to better accuracy of small features and sharp edges.
• The MJF technology, in general, is not much faster than the SLS technology although a product layer is fused much faster; the reason is that the layer thickness and duration of a recoating step, which are similar for both technologies, also play important roles in determining of the building time.
• The refreshment rate (the required ratio between the virgin powder and total mass of production powder mixture) is around 20%, which is much lower (and better) than in it is the case with MJF technology; despite this, the material costs of the MJF technology are higher than those of SLS technology, because of relatively high costs of fusion and detailing agents.
• The products manufactured by MJF technology have a light grey appearance with non-uniform surface color after blasting because the fusing agent used in MJF technology is black;