Optimization of the printing parameters affecting dimensional accuracy and internal cavity for HIPS material used in fused deposition modeling processes

• Introducing efficient process of wax fabrication by FDM in investment casting process.
• Investigating effect of material parameters on precision and cavity for HIPS in FDM.
• Presenting experimental method for obtaining optimum quantity of material parameters.
• Representing experimental method for minimizing systematic error in FDM process

Fused deposition modeling (FDM) is an alternative process for fabricating wax pattern in investment casting technologies due to its ability to fabricate parts with complex geometries within a reasonable time using HIPS as extruded material. Considering the nature of investment casting, wax pattern must be fabricated accurately without internal cavity. In this paper, the effect of printing parameters (PPs) on precision and internal cavity of the fabricated part is investigated for materials with unknown PP. Hence, experimental method is presented to determine the optimum quantity of each effective PP for HIPS material. These parameters include extruded temperature, and raster width. Finally, in order to minimize systematic errors between the designed and actual dimensions, calibration factors for parts, holes, and thicknesses were calculated by designing proper benchmarks as well as statistical equations. This method can be used for either determining value of PPs for unknown materials or optimizing PPs for existing materials such as ABS, or PLA where an increase in dimensional accuracy or a reduction in internal cavity is desired.