Papers by Keyword: Mold

Abstract: Designing and manufacturing a new mold is laborious work and requires well-trained human resources but also considerable material investments. The achizition and implementation the CAD/CAM softwares, three and five-axis machining centers, cutting tools with high performance are necessary to processing a mold. That is why it is frequently used to repair used molds. This repair is done by welding and then manufacturing on machines with numerical control. The present paper presents these stages of corrective maintenance of a mold. Starting from a concrete case, the solutions for remediation of the used mold are presented. The two basic operations in retrofitting, welding and computer-assisted processing on CNC machines are also analyzed.

Abstract: Sand casting is a metal casting process to make a component by pouring molten metal into the sand mold. The casting process, the sand is the fundamental material used for mold making. The sand used is generally silica sand, river sand, mountain sand, and beach sand. The sand for molding must have requirements such as having formability, suitable permeability, good distribution of sand grain size, resistance to high temperatures, suitable binder composition, and sand must be cheap. This study investigated to determine the potential of Krueng Mane river sand in Aceh Indonesia for its possible use for metal casting. The important properties studied are moisture content, total clay content, grain fineness number, and grain shape. Tests are carried out following the standards and procedures defined by the American Foundrymen’s Society (AFS). Results obtained revealed that the river sand has average moisture content of 7.78 %, clay content of 3.20%, and grain fineness number (GFN) of 46. Krueng Mane river sand will be suitable for casting of casting of light steel, heavy grey steel, medium grey iron, and non-ferrous metals, with the addition of binding agent in suitable proportion.

Abstract: This paper presents the results of developing a single-stage method to obtain effective structural and thermal insulation products based on cellular concrete with anisotropic structure and studies their properties. Methods to determine the start and end time of gas generation of the system, determine the emission value, determine the density change of anisotropic materials have been used in this study. The experiments show that ability to adjust the coefficient of variation for cellular concrete depends on the shape fill factor. The degree of variation increases from 2.22-2.86-3.33, increasing the load-carrying capacity of construction products with anisotropic structure than concrete with a one-dimensional cellular structure that consumes materials. In addition, products based on cellular concrete meet all the required criteria for strength, stiffness and frost resistance due to the high density of the surface layer.

Abstract: Currently, mathematical modeling applying numerical methods is widely used in the study of metallurgical processes, including metal casting processes in continuous-casting machines. The authors developed a new technology and device for casting metal into a continuous-casting machine mold and metal mixing using the effect of a rotating closed-bottom submerged nozzle with eccentric holes. The theoretical study of processes of mold filling with molten metal was carried out applying a proven numerical method and a special software package. A calculation program was developed based on the numerical schemes and algorithms. The results of calculating metal casting into a rectangular mold are presented as an example. The calculation results are provided in the form of molten metal flow patterns in various sections of the mold.

Abstract: As the need to ensure thermal comfort in buildings is constantly evolving, new technologies continue to emerge with the aim to develop efficient thermal insulation materials. This study aims to explore a textile technology using Airlaid process to develop non-woven fabrics made of natural fibers extracted from Posidonia Oceanica’s waste for assessing their suitability for insulation products in construction field. This technology offers the feature to develop isotropic non-woven structures by orienting randomly the fibers on the fabric surface. The web composed of a mixture of Posidonia Oceanica fibers and a proportion of thermoplastic fibers is then thermally bonded in an oven followed by cooling in order to ensure the solidification of the bonding areas. The prepared panels are then analyzed for the thermal conductivity. It was found that their thermal conductivity is close to commonly used thermal insulation materials, ranging between 0.03515 W/m.K and 0.03957 W/m.K, which allows the non-woven panels to compete with widely-used insulation materials for building’s field. The second part of this work aims to determinate the Posidonia panel's resistance to five common mold types in buildings (Aspergillus niger, Penicilum funiculosum, Trichoderma viride, Chaetomium globosum, Paecilomyces variotii). In fact, at high moisture content, molds are likely to develop on cellulosic materials affecting indoor air quality and eventually causing a variety of health risks to occupants. However, optic microscope results showed no growth of molds on the Posidonia samples which allows conceiving reliable thermal insulation materials.

Abstract: The article considers the requirements for protective coatings operating in the conditions of injection molding of non-ferrous metal alloys, among which the most important are the provision of crack resistance and wear resistance of the forming surface. It is revealed that single-layer coatings applied by the physical vapour deposition method, regardless of its composition, are not able to fully meet the formulated requirements. It is established that multilayer coatings provide increased performance of structural elements of molds in comparison with single-layer ones.

Abstract: The article presents an overview of possible technological schemes to produce an overhead contact wire for railways. Pilot experiments were carried out on the manufacture of a contact wire made of CuMg0.3, CuMg0.4 and CuMg0.5 alloys and having a nominal cross section of 100 mm². The contact wire was obtained from a continuously cast rod with small section, which was subjected to plastic deformation using the Conform technology and cold drawing of the extruded rod. In the casting process, we encountered the formation of cracks on the cast rod surface and the rods breakage. The inner surface of the graphite bushings of the mold after casting the rod was studied and a thin gray layer was found on the inner surface of the graphite bushings. Areas of the graphite bushing with gray layer were studied by scanning electron microscopy and element-by-element mapping was performed with the selection of a spectrum in the sediment layer area. In order to determine the phase composition of the sediment layer it was analyzed by the method of full-profile analysis of the X-ray diffraction pattern according to Rietveld. X-ray phase analysis showed the CuMg₂ and Cu₂Mg phases presence. This allowed us to assume a possible mechanism for the formation of the sediment layer. Ultimate tensile strength, elongation and electrical resistivity was determined. Analysis showed that the overhead wires made of CuMg0.3, CuMg0.4, CuMg0.5 alloys meets the requirements of GOST R 55647-2018 for wires made of the second conditional group bronze.

Abstract: It is known from theory that coatings on the forming surface increase the service life of injection molding molds. In practice, the most widespread method of nitriding, which has a number of undeniable advantages, while there are other promising coatings. Therefore, the article considered coatings applied by the physical vapour deposition method in comparison with nitriding. The comparison was carried out on the basis of pressure and temperature indicators on the walls of the forming surface of the working inserts of the molds.

Abstract: Additive manufacturing is a technology that is influencing every facet of manufacturing such as casting. 3D printing in particular has the potential to revolutionize castings in terms of precision and time taken in production. Patternless molds increase the efficiency of the casting process for large scale manufactured components. Therefore, ceramic based molds can be utilized for low temperature alloy parts such as mounting brackets. Nowadays, 3D printing technologies allow the direct printing of these molds. This is possible with the aid of CAD modelling of the casting mold which allows instant printing of patternless molds. The aim of this work is to introduce an approach to prepare a 3D design for a casting mold that can be manufactured using 3D printing technology. Mold design was made using Solidworks software according to standardized calculations from which cope and drag components were extracted. Candidates for potential mold material are highlighted along with advantages & limitations of utilizing 3D printing methodology.

Abstract: Among the many different ways to improve the performance of molds for injection molding, there are those that are based on the application of thin multi-layer wear-resistant coatings by cathode-ion bombardment. However, due to the relatively small thickness of the applied coatings, measuring their parameters is a difficult task. Therefore, the article considers methods for determining the main parameters of thin multilayer coatings, such as: microhardness, separation and crack resistance coefficients, Young's modulus. The results of measurements of several coatings of different compositions are presented.