The application of 3D printers significantly improves the process of producing foundry patterns in comparison to traditional methods of their production. It should be noted that the quality of the ...surface texture of the foundry pattern is crucial because it affects the quality of the casting mold and eventually the finished casting. In most studies, the surface texture is examined by analyzing the 2D or 3D roughness parameters. This is a certain limitation because, in the case of 3D printing, the influence of technological parameters is more visible for irregularities of a longer range, such as surface waviness. In the paper, the influence of the 3D printing layer thickness on the formation of waviness of the surface of casting patterns was analyzed. Three 3D printers, differing in terms of printing technology and printing material, were tested: PJM (PolyJet Matrix), FDM (fused deposition modeling) and SLS (selective laser sintering). In addition, the surface waviness of patterns manufactured with traditional methods was analyzed. Surface waviness has been measured using the Form Talysurf PGI 1200 measuring system. Preliminary results of the research showed that the layer thickness significantly influences the values of waviness parameters of the surface in the casting patterns made with FDM, PJM and SLS additive technologies. The research results indicated that the smallest surface waviness as defined by parameters Wa, Wq and Wt was obtained for patterns printed using the PJM technology, while the highest was noted when using the FDM technology.
The material properties and processing of investment casting patterns manufactured using conventional wax injection Molding and those manufactured by vat photopolymerization can be substantially ...different in terms of thermal expansion and mechanical properties, which can generate problems with dimensional accuracy and stability before and during ceramic shelling and shell failures during the burn-out of the 3D printed casting patterns. In this paper and for the first time, the monofunctional Acryloyl morpholine monomer was used for 3D printing of casting patterns, due to its thermoplastic-like behavior, e.g., softening by heat. However, the hydrophilic behavior of this polymer led to an incorporation of up to 60 wt% of Hexanediol diacrylate, to control the water absorption of the network, which to some extent, compromised the softening feature of Acryloyl morpholine. Addition of a powdered wax filler resulted in a delayed thermal decomposition of the polymer network, however, it helped to reduce the thermal expansion of the parts. The dimensional accuracy and stability of the wax-filled formulation indicated an excellent dimensional tolerance of less than ±130 µm. Finally, the 3D printed patterns successfully went through a burn out process with no damages to the ceramic shell.
Selective laser sintering (SLS), as a kind of additive manufacturing technology, which uses a laser beam to scan and heat powder material layer by layer to form parts (models), is widely used in the ...field of casting, mainly for preparing casting coated sand cores, investment casting patterns, etc. The SLS technique facilitates rapid casting and shortens the casting production periods by eliminating mold preparation. In this study, we reached conclusions for the basic principles and characteristics of SLS methods, and focused on the research status, key technology and development trend of SLS in the fields of forming coated sand-casting molds and investment casting patterns.
Conventionally, unfilled wax has been used as a universal pattern material for the investment casting process. With increase in demand for accurate dimensions and complex shapes, various materials ...have been blended with wax to develop more suitable patterns for investment casting in order to overcome performance limitations exhibited by unfilled wax. The present article initially reviews various investigations on the development of investment casting patterns by exploring pattern materials, type of waxes and their limitations, the effect of filler materials and various additives on unfilled wax, wax blends for pattern materials, plastics and polymers for pattern materials and 3D-printed patterns. The superiority of filled and polymer patterns in terms of dimensional accuracy, pattern strength, surface and flow properties over unfilled wax is also discussed. The present use of 3D patterns following their versatility in the manufacturing sector to revolutionize the investment casting process is also emphasized. Various studies on wax characterization such as physical (surface and dimensions), thermal (thermogravimetric analysis and differential scanning calorimetry), mechanical (thermomechanical analysis, tensile stress testing, dynamic mechanical analysis) and rheological (viscosity and shearing properties) are also discussed.
3D printer is a rapid prototyping technology that has developed rapidly in this decade. 3D printers use STL files derived from 3D CAD drawings as input data for the processing. The purpose of this ...study is to determine the effect of the resolution of the STL file used on the quality of the geometry and dimensions of the product produced. This research was conducted by using 2 types of STL file resolution created with Autodesk Inventor. The results of this study are that there is an influence of the resolution of the STL file used on the quality of the geometry and dimensions of the product being made. the quality of the product geometry has different geometric shapes in the radius. Whereas in the aspect of the product dimension obtained a product dimension accuracy of 0.02 sampai 0.8 mm.
The issue investigated in this study is the practical implementation of Rapid Casting for Tooling (RCT) concept using locally available technologies. RCT is a tool making process chain essentially ...consisting in metal casting in sand moulds obtained by rapid prototyping. The production of a sand casting pattern is the case study used to uncover and discuss the complexity and challenges of RCT.
The adhesion of IPS InLine ceramics to a cast dental Ni–Cr (Wiron light) alloy is experimentally studied during the tensile test of flat coated specimens, and the results of a numerical simulation ...and multicriteria optimization using the MADMML software package are presented. Casting patterns were printed on a 3D Rapidshape printer at angles of 0° and 90° by a layer 35 and 50 μm thick. The adhesion strength of the coating is 77.9–79.9 MPa under optimum conditions.
This article outlines a methodology of modeling self-induced vibrations that occur in the course of machining of metal objects, i.e. when shaping casting patterns on CNC machining centers. The ...modeling process presented here is based on an algorithm that makes use of local model fuzzy-neural networks. The algorithm falls back on the advantages of fuzzy systems with Takagi-Sugeno-Kanga (TSK) consequences and neural networks with auxiliary modules that help optimize and shorten the time needed to identify the best possible network structure. The modeling of self-induced vibrations allows analyzing how the vibrations come into being. This in turn makes it possible to develop effective ways of eliminating these vibrations and, ultimately, designing a practical control system that would dispose of the vibrations altogether.
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