Qualified Rapid Products

QRP offers consulting and design services specific to Powder Bed Fusion (or DMLS). This manufacturing process has strengths and weaknesses just like any other process. We believe that the market will expand as more people learn how it works and how to design for it. Consequently, we will be posting a Metal Additive Manufacturing series to teach bite-sized principles of how the process works. We will introduce terms and principles and how where things can go wrong. We'll talk about support structure and tolerance control and share some design examples. We will eventually post it as a compiled set on our webpage as well. Let's start with some basic terms. The part is build in a "build chamber" that consists of a metal build tray made from the same material as the material being used. The tray will drop for each layer and the distance it drops will determine the layer thickness. When it drops, a "coater blade" coats the previous layer (or the raw build plate at first) with a thin layer of metal powder. A laser welds the powder over certain areas at the "exposure plane" to melt it onto the solid material beneath it. The figure above shows a cross section of a part in the build chamber mid-way through the process. You can see a build-up of loose powder that has not been welded and the solid part that has been grown layer by layer. The part is attached to the build tray by "support structure". This structure is fabricated layer by layer with the same method but is made to break-away from the printed part. After fabrication, when the loose powder is brushed away, the part will be cut away from the build tray via a band saw or wire EDM that cuts through the support structure on the bottom and frees the part from the plate. In our next entry we'll zero in on what is going on at the focus point of the laser.