Pattern Casting Research Articles

Effects of Sand Material Type and Vibration Conditions on Appearance Quality of Aluminum Alloy Castings in Expendable Pattern Casting Process

Effects of Sand Material Type and Vibration Conditions on Appearance Quality of Aluminum Alloy Castings in Expendable Pattern Casting Process

Multi-jet ice 3D printing

PurposeMulti-jet deposition of the materials is a matured technology used for graphic printing and 3 D printing for a wide range of materials. The multi-jet technology is fine-tuned for liquids with a specific range of viscosity and surface tension. However, the use of multi-jet for low viscosity fluids like water is not very popular. This paper aims to demonstrate the technique, particularly for the water-ice 3 D printing. 3 D printed ice parts can be used as patterns for investment casting, templates for microfluidic channel fabrication, support material for polymer 3 D printing, etc.Design/methodology/approachMulti-jet ice 3 D printing is a novel technique for producing ice parts by selective deposition and freezing water layers. The paper confers the design, embodiment and integration of various subsystems of multi-jet ice 3 D printer. The outcomes of the machine trials are reported as case studies with elaborate details.FindingsThe prismatic geometries are realized by ice 3 D printing. The accuracy of 0.1 mm is found in the build direction. The part height tends to increase due to volumetric expansion during the phase change.Originality/valueThe present paper gives a novel architecture of the ice 3 D printer that produces the ice parts with good accuracy. The potential applications of the process are deliberated in this paper.

PENGARUH TEMPERATUR TUANG TERHADAP POROSITAS, STUKTUR MIKRO DAN KEKERASAN DARI ALUMUNIUM RONGSOK VELG MENGGUNAKAN PENGECORAN EVAPORATIF

The second largest metal material used after steel is Aluminum and its alloys. Ranging from aircraft bodies, vehicles, engine components, ship components, to buildings and very diverse applications using aluminum alloys. Material for making alloy wheels for components in motors using one of the special aluminum alloy applications with regard to the strength and hardness of high-quality aluminum alloys. Industrial companies that make aluminum doors, including windows and frames, make aluminum shelves, storefronts and other products. Produce waste remnants of used aluminum which can be used as aluminum as the main material destination. To reduce the company's production costs, many of them use aluminium scrap as their main casting material. Casting uses a temperature of 650 ° C, 700 ° C, 750 ° C, 800 ° C including casting type evaporative or casting using Styrofoam. The missing styrofoam casting pattern is a casting that uses a pattern of material that can evaporate when exposed to molten metal heat. The casting temperature results can affect microstructure, hardness, porosity and structure.

Aluminum metal composites primed by fused deposition modeling-assisted investment casting: Hardness, surface, wear, and dimensional properties

Fused deposition modeling -based three-dimensional printing techniques, when merged with the investment casting process, is one of the most innovative techniques for developing functionally graded metal–matrix composites in high-performance industrial applications. In this study, Al–Al2O3 matrix composites have been prepared by the combined route of fused deposition modeling and modified investment casting processes. In the first step, the Al–Al2O3 particles have been reinforced into nylon 6 thermoplastics for the preparation of fused deposition modeling-based feedstock filaments (in two configurations: C1 (60% nylon 6–30% Al–10% Al2O3) and C2 (60% nylon 6–28% Al–12% Al2O3). In the next step, the investment casting patterns of the fused deposition modeling process of nylon 6–Al–Al2O3 composites were prepared. Furthermore, the investment casting has been performed by controlling the proportion of nylon 6–Al–Al2O3, the volume of pattern, the density of pattern, barrel finishing media weight, barrel fining time, and number of mold wall layers considering Taguchi L18-based experimental design. Finally, the functional aluminum matrix composites were subjected to testing to investigate average surface roughness ( Ra), deviation inside the cube, average wear, and average hardness. The study results have suggested that maintaining a higher proportion of Al2O3 in three-dimensional printed parts leads to higher Ra, higher dimensional deviation, and higher hardness of investment cast parts. On the contrary, solid patterns have provided low wear rates and low-density patterns resulting in increased wear rates in final investment casted products. Furthermore, the responses are optimized concurrently with the “technique for order of preference by similarity to ideal solution–Taguchi” technique while considering the analytical hierarchical process and entropy weights of significance.

Application of 3D printing in casting

The article presents the applicability of 3D printing in casting. Even complex models produced by 3D printing can be effectively applied in the field of lost pattern casting. The process was realized using Polycast and Pioneer investment powder (gypsum). Based on the measurement it is clear that the size differences come from the printing technology. The minimum wall thickness cannot be less than 0.8 mm, but there is inaccuracy under 2.1 mm when there is no infill section in the rib. More contour lines can reduce the deformation and the inaccuracy.

Investigation of Investment Casting Pattern Using Fused Deposition Modeling

In today's economic climate, various organizations fight with decreasing sales and increasing costs. However, industries that have implemented the process of investment casting are one of the ways of manufacturing complex metallic parts at a low cost. High tooling costs and long manufacturing time are associated with the metal molds production for producing investment casting wax (sacrificial) patterns. It leads to a problem with cost justification for personalized single casting or production of small lots. The present study evaluates the suitability of the fused deposition modeling (FDM) fabricated pattern for investment casting. For this, a case study on a part was also conducted to collect experimental data regarding the process. A trial component was fabricated in an FDM machine and then cast by the investment method. This research resulted in reduced process time and cost for the small and medium size of the batch.

Rapid casting technology based on selective laser sintering

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.

Effects of build orientation on adaptation of casting patterns for three-unit partial fixed dental prostheses fabricated by using digital light projection

Statement of problemThe lost-wax technique is commonly used for fabricating partial fixed dental prostheses. The casting patterns can be fabricated by using vat photopolymerization (a type of additive manufacturing), but the adaptation of these casting patterns has not been elucidated. PurposeThe purpose of this in vitro study was to evaluate the effect of build orientation on the adaptation of casting patterns fabricated by digital light projection (DLP). Material and methodsA 3-unit partial fixed dental prosthesis with mandibular left second premolar and second molar abutment teeth was scanned and virtually designed with a computer-aided design software program. The cement space was designed to be 30 μm. Specimens were fabricated with 3 build orientations: 0 degrees (with the occlusal surface parallel to the platform), 30 degrees, and 45 degrees (by rotating the file along the long axis). The casting patterns were fabricated by using DLP (Cara Print 4.0) with a photopolymerizable monomer (dima Print Cast Q). Photopolymerization, cleaning, and postpolymerization processes were performed according to the manufacturer’s instructions. The adaptation of the specimens was examined by using a silicone replica method. The vertical marginal discrepancy and axial wall, occlusal, and marginal gaps were measured by using a digital measuring microscope. The effect of build orientation at each cross-sectional area was statistically analyzed by using the Kruskal-Wallis test followed by the pairwise Wilcoxon rank sum test with Bonferroni correction (α=.05). ResultsExcess polymerized resin was observed along the intaglio buccal wall at build orientations of 30 degrees and 45 degrees. Vertical marginal discrepancies in the buccolingual section ranged from −50 to 248 μm, while those in the mesiodistal section ranged from −25 to 182 μm. The gaps in the buccolingual section ranged from 0 to 236 μm, while those in the mesiodistal section ranged from 0 to 177 μm. According to the observation of vertical marginal discrepancies and gaps, the 30-degree specimens inclined during insertion, and the 45-degree specimens were not completely seated. However, the marginal gaps of the 0- and 30-degree specimens were within the clinically acceptable limit of 120 μm. ConclusionsThe limited data indicated that the build orientation influenced the adaptation of casting patterns for 3-unit partial fixed dental prostheses fabricated by using DLP. A build orientation of 0 degrees is recommended for fabricating casting patterns for 3-unit partial fixed dental prostheses because no excess polymerization of the intaglio buccal wall was observed.

Study regarding the influence of material type on economic objectives in MEX fabrication

Material Extrusion has been used extensively as an additive manufacturing technology for a variety of applications like visual models, functional prototypes, tooling components, patterns for castings, and final parts. The current research paper proposes a study on the material type influence on economic objectives in material extrusion fabrication of complex assemblies. Three economic objectives have been analysed, namely, estimated fabrication time, material usage and material cost, whilst two commercial additive manufacturing machines have been considered for the simulation. Cura and ZSuite slicing software were used for the generation of Gcode and project files. Five filaments were selected from the same manufacturer and all components of the selected assembly were included in the analysis. Throughout the study, the additive manufacturing parameters were kept constant, as well as the component layout on the build platform of the two machines. Study results were analysed in correspondence with the manufacturing requirements and the optimum fabrication scenario was selected. Further research includes the analysis of multiple material manufacturers, in order to evaluate the influence of chemical composition on economic outputs.

Effect of Melt Velocity on Density of Aluminum Alloy Castings in Expendable Pattern Casting Process

Effect of Melt Velocity on Density of Aluminum Alloy Castings in Expendable Pattern Casting Process

COMPARISON OF 3D PRINTER AND WOOD CASTING PATTERN

Pola cor merupakan replika dari benda yang digunakan sebagai acuan dalam proses pengecoran. Pembuatan pola cor masih didominasi dengan proses konvensional menggunakan kayu. Penelitian ini bertujuan untuk melakukan perbandingan antara pola cor konvensional kayu dengan pola cor yang dibuat menggunakan 3D printer. Penelitian ini dilakukan dengan melakukan pembuatan produk pola cor menggunakan metode konvensional dan 3D printer. Pembuatan pola konvensional menggunakan proses pengerjaan kayu sedangakan pola 3D printer menggunkan 3D printer sistem stereolithography (SLA). Produk pola cor konvensional dan 3D printer kemudian dibandingkan dari sisi kualitas geometri dan presisian ukuran. Hasil yang diperoleh adalah pola cor hasil pembuatan dengan 3D printer memiliki keunggulan dalam kepresisian ukuran yang lebih baik dibandingkan dengan pola konvensional. Sedangkan untuk kualitas geometri dan kekasaran permukaan kedua metode sama-sama memiliki hasil yang baik. hal ini membuka peluang untuk melakukan tinjauan lebih mendalam mengenai aplikasi 3D printer dalam sektor pengecoran logam

Influence of reinforcement bar on accuracy of removable partial denture framework fabricated by casting with a 3D-printed pattern and selective laser sintering.

The purpose of this study was to investigate the accuracy of removable partial denture frameworks fabricated by 3D-printed pattern casting (AM-Cast) and selective laser sintering (SLS) under different co nditions with a reinforcement bar. A partially edentulous model was scanned with a dental laboratory scanner, and CAD software was used to design the framework. Reinforcement bars (n=0-2) were set on the lingual side of the framework. 3D scanning of the fabricated frameworks by AM-Cast and SLS was performed, and the obtained data were overlapped with the design data. The differences in shape among setting conditions of the bar were statistically compared using the Bonferroni method after the Kruskal-Wallis test. The ranges in differences of the AM-Cast-0, AM-Cast-1, and AM-Cast-2 were -0.167 to 0.128 mm, -0.101 to 0.105 mm, and -0.185 to 0.015 mm, respectively. The ranges of SLS-0, SLS-1, and SLS-2 were -0.166 to 0.035 mm, -0.182 to 0.049 mm, and -0.138 to 0.038 mm, respectively. Large discrepancies were observed at the joining area of the lingual bar on the right side of the AM-Cast. A significant difference was found between the AM-Cast-0 and AM-Cast-1, and between the AM-Cast-0 and AM-Cast-2. The setting conditions of the reinforcement bar affected the accuracy of the lingual bar in the AM-Cast; however, no effect was observed on the displacement of the central area of the lingual bar in SLS. Setting a single reinforcing bar on the retentive latticework contributed to improving the accuracy of the lingual bar in the AM-Cast but not the displacement of the central area of the lingual bar in SLS.

Influence of temperature conditions on the shrinkage of wax patterns for investment casting

The study of free linear shrinkage of unfilled (PS50-50, MBC 3-T, Romocast 105, Romocast 152) and filled (Romocast 252, Romocast 325) model compositions for investment casting depending on the ambient temperature was carried out. It has been shown that unfilled model compositions have the greatest free linear shrinkage, and filled ones have the smallest. Moreover, the processes associated with free linear shrinkage proceeded in the samples for a long time (up to 24 h). This is probably caused by the duration of the polymerization processes and the low thermal conductivity of the model compositions. A change in the ambient temperature in the range from –5 to +35 °C has a significant effect on the linear dimensions of the samples from the studied model compositions. The length of samples from unfilled model compositions varies from +0.3 to –0.4%, and from filled ones from +0.2 to –0.15%. When samples from unfilled compositions cooled to –5 °C and subsequently heated to +20 °C, their initial length decreases on average by 0.2 mm, and at heating to +35 °C and subsequent cooling to +20 °C, it increases on average by 0.2–0.3 mm. At similar changes in ambient temperature, the dimensional change of samples from filled model compositions is not more than 0.1 mm.

Evaluating the growth of candida albicans on removable complete dentures bases manufactured using CAD/CAM designed metal (Co-Cr casted from milled wax patterns) and injection molded resin

Acrylic resin processed by compression molded technique had been used to manufacture the removable complete dentures bases for many years. However there are many disadvantages connected to the use of this material with the ordinary compression molding as a denture base, the reason that made the researches try to find a better alternatives whether by changing the processing technique: like in the case of using acrylic resins processed by injection molded technique which proved to be a better choice in many aspects, on the other hand some researchers preferred to use another material so they used metal bases as replacement for the ordinary acrylic denture base. There are many ways to make patterns for metal bases casting in partial and complete dentures. Recently many researchers and practitioners used CAD-CAM technologies to make patterns for metal casting and facilitate the work, and save time. This study compares the candida albicans colony formation on the two materials mentioned above as an advantage to the material studied.Purpose: The purpose of this study is to compare the growth of candida albicans on removable complete dentures bases manufactured using CAD/CAM designed metal (Co-Cr casted from milled wax patterns) and injection molded acrylic resin. Materials and Methods: Split-palate maxillary complete dentures were fabricated for 10 edentulous patients. one-half of the palate was made in acrylic resin and the other half in Co-Cr metal palate that was casted from CAD-CAM milled patterns for each patient in this study. specimens were collected at 1, 3, and 5 months using a modified imprint culture method. Speciation of Candida albicans was performed using a chromogenic culture medium. Two-sample t-test was employed to determine effects and significant interactions between the acrylic and the metal groups. Results: Significant differences were observed in the candida albicans colony counts between both materials during the first, the third, and the fifth month. The Colony forming unit(CFU)/cm2 means were significantly less on the Co-Cr casted metal denture bases than CFU/cm2 means on the injection molded acrylic resin. Conclusions: The metal base proved to be effective in decreasing the candida albicans growth typically present in complete dentures. Colony counts of Candida albicans were higher in the injection molded acrylic resin part of denture bases of the patients in this study.

Education, Caste and Women’s Work in India

Based on the Periodic Labour Force Survey (2017–2018), this paper explores women’s labour market participation and employment patterns mediated by education and caste, with a focus on highly educated women. We find that women’s workforce participation follows a clear caste pattern, with the upper castes having the lowest work participation rates and this increases as we go down the caste hierarchy. These differences narrow down among highly educated women (graduate and above), particularly in urban areas. Considering the workforce participation rate (WPR) by education, female WPR by education class follows a U-shape and this holds across castes. Caste patterns persist in work status; in the female labour force in urban areas, general-caste women are more likely to be in regular employment characterised by employment stability than the other social groups. Among regular workers, Scheduled Caste (SC) and Scheduled Tribe (ST) women are more likely to work in the public sector—a likely result of affirmative action policies of the state. However, while the policy of reservations may have worked in favour of SC/ST communities in terms of accessing public employment, it has not translated to access to good-quality jobs as caste patterns permeate into industry and occupation. Regression results show that caste and education emerge as important variables that explain women’s workforce participation, and the interaction effect of caste and education is critical in understanding women’s work participation. That accessing education even at the highest levels does not level the gap between social groups in terms of WPR implying that policies aimed towards increasing female employment therefore need to be nuanced to take into account the hetegeneous nature of the women workers, even for the highly educated segment.

Zastosowanie druku 3D w odlewnictwie artystycznym

The paper presents one of the roles of additive manufacturing used for preparing an art casting. Based on the virtual model (CAD), a casting pattern was 3D printed, based on which the wax pattern was made and in the final step an art casting was made.

Effects of build conditions and angle acuteness on edge reproducibility of casting patterns fabricated using digital light projection.

The aim of the present study was to evaluate the effects of build conditions and angle acuteness on edge reproducibility of the casting patterns fabricated using a digital light process. The prism-shaped patterns with various vertex angles were fabricated in three build orientations. The height from the base to the vertex angle point of the fabricated pattern was measured and the incomplete height was calculated as the discrepancy between the original and measured heights. Two-way ANOVA revealed that the vertex angle and build orientation and their interaction were significant (p<0.05). The incomplete height significantly decreased with an increase of the vertex angle. When the vertex angle was 20° and the build-up direction was parallel to the edge of vertex angle and perpendicular to the triangular base, the incomplete height was the smallest. Therefore, build orientation and angle acuteness influenced the edge reproducibility of the casting patterns fabricated using a digital light process.

Influence of Vapour Smoothing Process Parameters on Fused Deposition Modelling Parts Surface Roughness at Different Build Orientation

Additive Manufacturing is becoming increasingly important to the manufacturing industry with the gradual rise in the complexity of products and technology. In this paper, influence of finishing method i.e vapour smoothing process parameters on fused deposition modelling surface finish is studied. Process parameters considered for investigation in this study are build orientation, volume of chemical solution used for finishing and vapour smoothing process time. The test specimen is fabricated in polylactic acid thermoplastic using CubePro FDM machine and THF (Tetra Hydro Flouride) solution is used for vapour smoothing. From experimentation, it is observed that finishing method has significant influence and among the process parameters notable impact is observed in build orientation. Minimum surface roughness is observed at 90°orientation, 10ml volume of THF and VS process time of 5 minutes. Work presented in this study will further enhance the application of FDM parts in patterns for casting, and consumer goods which required high surface finish

A Comparative Study of Dimensional Tolerancing Capabilities and Microstructure Formation between Binder Jet Additively Manufactured Sand Molds and Olivine Green Sand Molds for Metalcasting of A356.0

The development of additive manufacturing in the 1980s led to a revolution in various metalcasting processes as early as the 1990s, including the use of polymer 3D printing for the manufacture of sand casting patterns. While additive manufacturing has entered many metalcasting processes, including both expendable and permanent mold processes, this paper specifically examines the sand casting process. ExOne’s development of binder jetting technology over the last 20 years has allowed designers in the sand casting field to directly 3D print sand molds for metalcasting. Use of binder jet additively manufactured sand molds allows for quicker turnaround time for testing prototypes, new gating designs, and for producing one-off parts. Additive manufacturing of sand molds for metalcasting may implement any of the same foundry sands as green sand processes, but uses a furan binder instead of the traditional mixture of bentonite clay and water. The use of a chemical binder had led to questions about the resulting dimensional capabilities and mechanical properties of the castings produced by the mold. This study investigated the dimensional tolerancing capabilities, surface finish, mechanical properties, microstructure, and defects present in identical castings made from both a traditional olivine green sand molding process and a binder jet additively manufactured silica sand molding process. It was concluded that binder jet additively manufactured sand molds are capable of either equal or better dimensional accuracy and tolerance capabilities than traditional olivine green sand molds. The olivine green sand parts had an average of approximately 1 μm better surface finish than the binder jet sand molds; however, it is likely that both the addition of sea coal to the green sand and the difference in final part color significantly affected this result. The mean hardness of the binder jet parts was 58.9 HBW with a standard deviation of 5.6 HBW, compared to the mean of the green sand parts of 47.7 HBW with a standard deviation of 7.2 HBW. The hardness findings were confirmed by the presence of a finer microstructure in the binder jet parts than the green sand parts. While both types of molds produced parts with defects, a greater variety of defects was evident in the olivine green sand molds. Porosity tended to move toward the surface of the olivine green sand parts, but was relatively evenly spread through the additively manufactured sand mold parts.

Manufacturing technology and application of cooling stave in blast furnace

The service life of blast furnace (BF) is depending on the cooling equipment of furnace body, cooling stave which is an important cooling equipment for BF has attracted more attention. In the current paper, the classification of BF cooling staves in China was introduced, cast iron stave, cast steel stave, copper stave, and copper-steel composite stave were used on different parts of furnace body. The manufacture of cooling staves was studied, evaporative pattern casting (EPC) was favored due to high automation and environmental protection. The strong combination between steel plate and copper plate of copper-steel composite stave could be ensured under high-speed oblique impact through explosive welding. High density and high thermal conductivity of copper stave could be obtained by efficient rolling technology. The performance and application of BF cooling stave were investigated, the advantages and disadvantages of the various cooling staves were analysed, the thermal resistance between the steel water pipe and the cast iron body accounted for about 80% of the total thermal resistance which would affect the cooling effect of cast iron stave. The significant cost advantage of copper-steel composite stave was found compared with copper stave, test results of copper-steel composite stave in a commercial BF showed that the cooling effect is equivalent to that of the copper stave. The suitable cooling stave in BF should be selected according to the characteristics of the various cooling staves, the heat transfer balance and the stability of the skull on the hot face must be ensured to protect the cooling stave.