3D printing processes

Although Stereolithography (SLA) is not an Inkjet 3D printing process, this method is briefly described here in order to give a better perspective on the state-of-the-art SFF technologies. 

Despite the fact that Selective Laser Sintering (SLS) is not an Inkjet 3D printing process, due to its industrial importance, a brief description of this method is included here. 

A number of reports show how each parameter in the FDM process contributes to the quality (less distortion) and functionality of printed parts. The complexity of the 3D printing process arises from the number of variables which are used to define the operation of the 3D printer machine and the material. Bearing in mind the possibility of producing solid or shell objects, the correct selection of the manufacturing parameters contributes to the improvement of the properties, such as density, porosity, layer thickness, and material properties (ViUalpando et al. 2014). The intrinsic layer parameters such as printing and feed roller speeds and, extrusion temperature should not be ignored in any optimisation process (Fig. 7.3). 

It is generally understood that thinner layers lead to smoother surfaces and more dimensionally accurate parts. The thickness of each layer is defined in the third step (slicing) of 3D printing process when the construction paths are established. Therefore, the slice thickness determines the Z-axis displacement relative to the subsequent layer during production. The definition of this parameter is considered one of the most important parameters that determines surface quality (Fig. 7.4). 

D printing process can process aii materiais, which are avaiiabie as powders. They aiiow the production of internai cavities. The components do not require support structures. The metai processes are multistage processes and run at room temperature. They require a subsequent oven process and an infiltration with bronze. The relatively rough surface is a disadvantage of the process. Rework will be very complex especially for metal components and also affects the accuracy. 

Components made from plastic, metal, and ceramics can be manufactured with 3D printing processes. The standards are gypsum-ceramic and starch powders for illustrative models and lost molds for investment casting. 

Direct Tooling Mold inserts, which may also contain internal cooling channels, are made with 3D printing processes. The bronze infiltration leads to a higher thermal conductivity, which may be advantageous if the tendency to worse mechanical-technological properties is accepted. 

Although the term 3D printing is often used synonymously with additive manufacturing, there are many different 3D printing processes and material technologies that provide varying characteristics... 

Bak D. Rapid prototyping or rapid production 3D printing processes move industry towards the latter. Assembly Autom 2003 23 340-5. 

Dinwiddle RB, Kune V, Lindal JM, Post B, Smith RJ, Love L., et al. Infrared imaging of the polymer 3D-printing process. Proceedings of SPIE—The International Society for Optical Engineering, SPIE Sensing Technology and Applications, vol. 9105. 12 p. 2014. 

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