Thus, different fabrication parameters including nozzle temperature, environmental temperature, print speed, nozzle width, extrusion width, layer height and others will have an effect on the resulting mechanical properties of a printed object.
The adhesion between printed layers is achieved through thermally-driven diffusion welding. In other words, 3D printed parts are often much weaker in the Z-direction than in the X- and Y- direction. As a result, the bond strength between layers of extruded material is often cited as being the weakest and most critical parameter affecting the mechanical properties of FDM parts. The materials are split into three different classes commodity, engineering and high temperature, with some materials overlapping the commodity and engineering class.įigure 2: Diagrammatic view of layer by layer process in FDM printingĭue to the layer upon layer nature of FDM parts (figure 2) tend to have voids or empty spaces between the layers which are detrimental to the mechanical properties of the final part. Figure 1 below shows the common material classes available for 3D printing. As a result, thermoplastic materials can be repeatedly softened from a solid to a viscous fluid on application of heat.Ĭurrently most of the thermoplastic material types available for injection moulding are also available for 3D printing, with more materials being adapted for FDM AM each day. The mechanical and chemical properties of a polymer are affected not only by the chemical make-up of the repeat unit but also the molecular arrangement of the repeat units in the polymer chains, and, the interactions between these polymer chains. In thermoplastic materials, the polymer chains are held together with weak intermolecular forces. Polymers are made of large molecules with a repeating chemical structure, otherwise known as a monomer. This article is an opinion piece from our Magigoo wizard where he discusses the use of common 3D printing materials, their strengths and weaknesses! Thermoplastic materials – an introduction
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