In the Master's thesis titled "Comprehensive Management of Investment Casting Using Permanent Inserts", a methodology for investment casting is presented, ranging from process planning in the virtual world, to the creation of the expendable model, the construction of the ceramic shell, and finally the casting process itself. The technical issues surrounding the use of machined permanent inserts are addressed. These inserts serve as a core that is placed in the cavity of a wax or 3D-printed model, which in turn rests on a single core pin. This core pin is then rigidly embedded in the ceramic after sintering. Subsequently, the core is partially enveloped by molten metal in the casting cavity, resulting in a tight shrink-fit due to the alloy’s contraction around the insert after solidification and cooling.
The designed casting was comprehensively examined through both virtually and experimentally. The study presents the methodology and computational techniques focused on directional solidification, the formation of casting defects, the development of internal stresses and deformations, and dimensional accuracy to meet quality requirements through laboratory experimentation. It was found that the calculated individual solidification zones align well with the experimental X-ray radiography (RTG) analysis of the macrostructure. The dimensions of the casting are appropriate, and the internal stresses on the surface of the casting, measured by X-ray diffraction (XRD), range from -3 MPa to 43 MPa, which is close to the calculated values. At the site of the shrink-fit between the insert and the cast AlSi10Mg alloy, a high-quality tight fit is achieved. The technique of coating the mechanically treated thread with a zirconium coating proved to be a good technical solution. It was determined that the positioning of the insert in the shell is accurate when the 3D-printed model has a precise tight fit with the insert before the ceramic shell is constructed. The methodology and planning techniques presented in the study offer a comprehensive quality model for rapid prototyping, which is transferable and relevant for serial production using investment casting as a manufacturing technique.
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