This is the first of three posts that should help you navigate some of the material considerations for Additive Manufacturing (AM) and 3D printing, or more specifically, for Fused Deposition Modeling (FDM) and Selective Laser Sintering (SLS) of polymers. In Part 1, these two manufacturing processes are explained and two representative printers are introduced. Part 2 looks critically at tensile properties of test specimens printed with these systems. Part 3 compares the tensile properties of AM fabricated specimens to injection molded specimens. The series is concluded with some considerations for the AM design process for 3D Printing with plastic.
In this particular series, I’ve been summarizing the work accomplished by M. Sc. Matthias Fischer and M. Sc. Stefan Josupeit from the Direct Manufacturing Research Center. Their goal was to compare the Stratasys Fortus 400mc FDM system (loaded with a high performance polymer called Ultem 9085) and the EOSINT P395 (loaded with polyamide PA12 (part of the PA 2000 series) which is a type of nylon.)
Fused Deposition Modeling
FDM, arguably the most democratized addititive manufacturing method, is the technique used by popular desktop 3D printers like MakerBot and Ultimaker to fabricate parts.
Powdered polymer build material, typically nylon, is transferred from containers holding fresh powder onto the build stage in the process chamber with a recoating tool. A laser then selectively scans the thin layer of powder, sintering together powder particles in the shape of the cross-section of the first layer of the 3D part. The build platform then descends one layer depth and the recoater transfers more fresh powder from the hopper to the surface of the first layer. Just like the first layer, the second cross-section of the 3D model is scanned and sintered. The laser scanning process simultaneously generates the current layer and adjoins it to the previous layer, making a solid part. There is no necessity to generate support material in polymer powder bed processes as the packing of the un-sintered powder supports the structure as its being b
