Metrological Research of the Dimensional Accuracy of Fused Deposition Modelling Technology in the Context of Prototyping Small-Size Casting Patterns

A paper presents research results on the possibility of applying selected additive technologies to produce casting patterns. A special research model was designed, the geometry of which reflects the features of typical casting patterns, i.e. rounding, casting tilts, and cylindrical shapes. During the production of castings, these types of geometric features can cause significant problems. The Fused Deposition Modelling Technology has been used to produce the research model, considering two variables of printing parameters: printing direction (Pd) and thicknesses of a single material layer (Lt). The next step was a comprehensive assessment of the dimensional accuracy of the research models made using the CMM. Next, the casting patterns have been used to produce casting molds using bituminous molding sand. Each model was used for molding 100 times. After forming cycles to conduct comparative research, the parameters describing the dimensional accuracy of the examined casting patterns were assessed again. Additionally, a visual assessment of the defects and damage to the samples resulting from the forming process was performed. The study concluded that FDM technology is suitable for building small-sized casting patterns. Research has indicated that the formation process may cause insignificant damage to the surface of the casting models, which should not impact the final casting. It should be noted that the forming process itself resulted in reductions in the values of linear dimensions of casting patterns, which is a certain guideline for designers of additive manufacturing processes.