Instead of PBF-LB/M, in PBF-LB/P (also called SLS) we use polymers.
Polymers do not handle a sudden increase of temperature very well. For this reason, the powder bed gets heated up to a few degrees below the melting point of the plastic. The scanning laser then only has to introduce small amounts of energy to the powder to melt it. During the process of adding new layers of powder and melting the powder with a laser, the already molten plastic will stay molten. At the end of the process the whole build box with the powder needs to be cooled down. It is important to do that slowly, since otherwise the parts will deform through stresses introduced by temperature gradients.
Since we don't introduce as much heat into the system as we do with metals, we do not need a heat dissipation system and therefore no support structures. This has the advantage, that the whole build box can be filled with parts, which makes it as efficient as BJT or MJF regarding amount of parts per build.
PBF-LB/P prints accurate and strong parts, that need no or only a low amount of post processing.