Metal Casting Research Articles

Stresses in Premolars Restored Using Different Post-and-Core and Crown Materials: An FEA Study.

The aim of the present study was to investigate the influence of three post-and-core systems and two crown materials on stresses in restored premolars using Finite Element Analysis (FEA). A maxillary second premolar 3D model was created in SolidWorks 2014 (Dassault Systémés). Severe loss of tooth structure was simulated with six restorative options: 1) glass-fiber-reinforced composite post and composite core (GFRC)+CAD/CAM leucite-reinforced glass-ceramic crown (LRC); 2) carbon-fiberreinforced composite post and composite core (CFRC)+LRC; 3) metal cast post-and-core (MPC)+LRC 4) GFRC+CAD/CAM composite resin crown (CC); 5) CFRC+CC; 6) MPC+CC. Three-point occlusal loading (150N) was simulated and von Misses and maximum principal stresses calculated. Although maximum von Mises stresses in the crown and dentin were similar across groups (137.9-139.2MPa crown; 17.2-19.6 dentin), there were important differences in stress distribution in dentin. Only in MPC+CC group the maximum stresses were on the bottom of the post preparation cavity. Stress values within the posts were: CFRC(4.8MPa)>GFRC(6.7MPa)>MPC(10.3MPa). CC-restored models presented higher von Mises stresses within the post-and-core compared to the LRC groups. Maximum principal stresses were lower compared to von Mises stresses, following the same trend, and were distributed similarly in all the groups. Both GFRC and CFRC showed favourable stresses distribution in the dentin and restorative materials, while MPC increased stresses in core, post and post cement. The more rigid crown material seems to transmit less stresses to the underlying core and crown cement compared to CC.

Synergistic impacts of radiative flow of Maxwell fluid past a rotating disk with reactive conditions: An Arrhenius model analysis

This study presents an analysis of the hydromagnetic radiative flow of a Maxwell fluid past a rotating disk around its own axis with an angular velocity Ω0 which has enormous applications in metal casting (help to optimize the solidification and cooling of molten metals), plastic molding and aerospace engineering (cooling system of aircraft engines). The flow is constrained by boundaries that induce convection and chemical reactions described by the Arrhenius model. By applying similarity transformations, the non-linear partial differential equations, which describe the flow phenomenon, are metamorphosed into the non-dimensional system of ordinary differential equations (ODEs). The obtained ODEs are then solved numerically using ‘Keller box method’, an efficient computational technique, by implementing the finite-difference approach. The influence of different parameters, namely magnetic field strength, radiation parameter, reaction rate constant, and convective heat transfer coefficient, on the flow and heat/mass transfer characteristics are investigated. The findings suggest that the higher activation energy leads to a slower rate of reaction. As the reaction rate decreases, the consumption of reactant molecules and the reduction in their concentration also slow down. The influence of the convective heat transfer coefficient is also examined in terms of its effect on the thermal and concentration boundary layers. As the stretching parameter increases, the Maxwell fluid undergoes greater deformation, leading to greater strain and a consequent slowing of the fluid's radial velocity. Heat transfer is enhanced by thermal radiation and convective condition at the surface of rotating disk. The findings of this study provide valuable insights into the industries dealing with Maxwell fluids, enabling them to enhance process efficiency, optimize resource utilization, and develop sustainable and environmentally friendly solutions.

Measuring thermal profiles in high explosives using neural networks

We present a new method for calculating the temperature profile of high explosive (HE) material using a Convolutional Neural Network (CNN). To train/test the CNN, we have developed a hybrid experiment/simulation method for collecting acoustic and temperature data. We experimentally heat cylindrical containers of HE material until detonation/deflagration, where we continuously measure the acoustic bursts through the HE using multiple acoustic transducers lined around the exterior container circumference. However, measuring the temperature profile in the HE in an experiment would require inserting a large number of thermal probes, which would disrupt the heating process. Thus, we use two thermal probes, one at the HE center and one at the wall. We then use numerical simulation of the heating process to calculate the temperature distribution and correct the simulated temperatures based on the experimental center and wall temperatures. We calculate temperature errors on the order of 15 °C, which is ∼12% of the range of temperatures in the experiment. We also investigate how the algorithm’s accuracy is affected by the number of acoustic receivers used to collect each measurement and the resolution of the temperature prediction. This work provides a means of assessing the safety status of HE material, which cannot be achieved using existing temperature measurement methods. In addition, it has implications for a range of other applications where internal temperature profile measurements would provide critical information. These applications include detecting chemical reactions, observing thermodynamic processes such as combustion, monitoring metal or plastic casting, determining the energy density in thermal storage capsules, and identifying abnormal battery operations.

PENGARUH PENAMBAHAN PROSES INOKULASI TERHADAP STRUKTUR MIKRO DAN KEKERASAN PRODUK COR DENGAN MATERIAL FC 250

The inoculation process in metal casting is needed to make grey cast iron or nodular cast iron. Inoculation aims to increase the number of freezing nuclei and promotes the formation of a homogeneous microstructure. This research aims to determine the effect of the inoculation addition process on the microstructure and hardness of PP products with FC-250 material. The changes made include changes to the inoculation process and changes to the chemical composition of the induction furnace. Changes in the inoculation process include changing the inoculation process which was initially only carried out on ladles with an inoculation material weight of 0.5 kg to 2 processes, namely on ladles with an additional weight of 0.8 kg of inoculation material and an inoculation process on crucible (kowi) with an additional material weight of 0.4 kg. The results of the metallography test after the additional inoculation process showed that the pearlite and ferrite graphite spread evenly and fell into Type-A graphite. The hardness test results show that the effect of adding inoculation changes the level of hardness so that it complies with ASTM 40 specifications/standards, namely 180 – 302 HB. The hardness value after the addition of the inoculation process was 190 HB.

POTENTIAL HAZARDS AND RISK FACTORS OF THE WORK ENVIRONMENT IN THE FOUNDRY INDUSTRY X

Background: Workers have a risk of work accidents and Occupational Diseases (PAK) caused by the work process, behavior at work, and the work environment. Identification of potential hazards and risk assessment is the first step to find hazards in the workplace and then carry out control measures to create a safe and healthy workplace.
 Objective: Knowing potential hazards, environmental risk values, and physical working conditions in the Metal Casting Industry of X.
 Method: The method used in this study is a descriptive survey. The number of samples in this study were 36 workers. Data collection techniques are carried out through observation activities using sheetsJob Safety Analysis (JSA) and risk assessment sheets, interviews using interview guides, and measurements of physical working conditions usingenvironment meter. The data analysis carried out is descriptive analysis which provides an overview of potential hazards and environmental risk values.
 Results: Overall there are 54 potential hazards in the production process at CV Dwi Jaya Logam which consist of a wet mold making process, there are 12 potential hazards, dry mold making CO method2 there are 10 potential hazards, metal smelting has 20 potential hazards, pouring molten metal into the mold has 6 potential hazards, and disassembling the mold has 6 potential hazards. There are 28 potential hazards in the production process at CV Mulya Jaya consisting of grinding there are 6 potential hazards, cutting iron using a saw machine there are 2 potential hazards, drilling there are 6 potential hazards, turning there are 4 potential hazards, making holes using machinesscrap there are 3 potential hazards, the formation of workpieces using machinesmilling there are 2 potential hazards, welding has 3 potential hazards, and product painting has 2 potential hazards. Overall, the physical working environment conditions in the form of temperature and lighting at CV Dwi Jaya Logam and CV Mulya Jaya did not meet the requirements, while the results of noise measurements at the two locations met the requirements.
 Conclusion: Potential hazards found in the metal casting industry CV Dwi Jaya Logam, namely 54 potential hazards which are divided into 2 levels of risklow, 10 levels of riskmoderate, 30 levels of risk high, and 12 levels of riskextreme. CV Mulya Jaya Metal casting industry identified 28 potential hazards divided into 4 risk levelslow, 4 levels of riskmoderate, 12 levels of risk high, and 8 levels of riskextreme. These potential hazards come from the physical work environment (temperature, lighting, and noise) and the production process at each work step. The results of measurements of the physical working environment in the form of temperature do not meet the requirements according to the Regulation of the Minister of Manpower of the Republic of Indonesia No. 5 of 2018, the average lighting measurement results are also . do not meet the requirements according to Regulation of the Minister of Health No. 70 of 2016, and the average noise measurement results meet the requirements according to the Indonesian Minister of Manpower Regulation No. 5 of 2018.

Analysis of gaseous emission and particle number size distributions in metal casting processes with binder jetting moulds

The impact on indoor air quality during metal casting processes using the 3D printing (3DP) binder jetting technique to manufacture moulds is analyzed in this research. This study investigates the particle size distribution and gas concentration during the manufacturing stages of 3DP moulds, with focus on particle deposition in the human respiratory system. The goal is to understand the risks associated with particle and gas emissions in binder jetting 3D printing, and thus improve worker safety. The results indicate that particle emission rates are lowest during printing (0.01 1011particles min−1) but increase during post-processing and melting-pouring phases (3.07 1011 particles min−1). During melting and pouring, the emission of particles was mainly in the range 7.9–71 nm, with values 10 times higher than in the previous phases. The study calculates the deposition of inhaled particles in different parts of the respiratory tract and reveals a 2.39 times higher extrathoracic mass deposition during 3DP mould manufacturing stages compared to melting-pouring stages. Additionally, alveolar mass deposition is higher during melting-pouring stages due to an increase in ultrafine emission rates. The study emphasizes the importance of insulation equipment and workplace ventilation in indoor spaces, particularly during heating processes that generate ultrafine particles through nucleation, so that health risks can be mitigated.

Comparative Evaluation of Different Post and Core Systems in Maxillary Molar Endodontic Treatments: An Original Study.

Maxillary molar endodontic treatments require the right post and core system. This study tested cast metal, glass fiber with composite resin, carbon fiber with composite resin, and zirconia post and core materials. Sixty removed human maxillary teeth were randomly divided into four post and core material groups (n = 15 per group). The teeth acquired their post and core system after normal endodontic treatment. Fracture resistance, cyclic fatigue resistance, and microleakage analyses were statistically assessed. The zirconia post and core material had the highest fracture resistance (mean: 900 N), followed by carbon fiber with composite resin, cast metal, and glass fiber with composite resin. Zirconia had the highest mean cycles to failure (120,000), followed by carbon fiber with composite resin (100,000), cast metal (110,000), and glass fiber with composite resin (90,000). Zirconia had the lowest mean microleakage score (1.8), and glass fiber with composite resin, the highest (3.0). The zirconia post and core material outperformed the others in fracture resistance, cyclic fatigue resistance, and sealing. The cast metal has better fracture and cycle fatigue resistance than glass fiber with composite resin. These findings help doctors choose maxillary molar endodontic post and core materials.

Numerical Analysis on Stagnation Point Flow of Micropolar Nanofluid with Thermal Radiations over an Exponentially Stretching Surface

Several industrial developments such as polymer extrusion in metal spinning and continuous metal casting include energy transmission and flow over a stretchy surface. In this paper, the stagnation point flow of micropolar nanofluid over a slanted surface is presenting also considering the influence of thermal radiations. Buongiorno’s nanoliquid model is deployed to recover the thermophoretic effects. By using similarity transformations, the governing boundary layer equations are transformed into ordinary differential equations. The Keller-box approach is used to solve transformed equations numerically. The numerical outcomes are presented in tabular and graphical form. A comparison of the outcomes attained with previously published results is done after providing the entire formulation of the Keller-Box approach for the flow problem under consideration. It has been found that the reduced sherwood number grows for increasing values of radiation parameter while, reduced Nusselt number and skin friction coefficient decreases. Furthermore, the skin-friction coefficient increases as the inclination factor increases, but Nusselt and Sherwood's numbers decline.

Restoring an Extremely Destructed Tooth with Flared Root Canal Walls: A Case Report.

Reconstructing severely damaged teeth has always presented a challenge when the remaining crown structure is limited, often requiring retention from the root canal using intracanal posts. However, the real challenge is when the root canal walls are also weak, and there is a high risk of vertical root fracture due to the wedging forces of a rigid post. This case report presents a tooth with extremely flared (0.3mm) root canal walls, successfully restored with a newly introduced polymer made of polyether ether ketone (PEEK), with one-year follow-up. Due to its close elastic modulus to dentin, capacity to bond effectively to tooth structure, shock-absorbing properties, and thereby facilitating favorable stress distribution, utilizing this material for an intracanal post has the potential to mitigate the risk of fractures often associated with cast metal posts. It combines the good fitness of cast posts with the low modulus of elasticity and optical properties of prefabricated fiber posts.

Preliminary Study on the Potential of Krueng Mane River Sand for Metal Casting Use

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.

Multimodal Golden DNA Superstructures (GDSs) for Highly Efficient Photothermal Immunotherapy.

DNA-templated metallization has emerged as an efficient strategy for creating nanoscale-metal DNA hybrid structures with a desirable conformation and function. Despite the potential of DNA-metal hybrids, their use as combinatory therapeutic agents has rarely been examined. Herein, we present a simple approach for fabricating a multipurpose DNA superstructure that serves as an efficient photoimmunotherapy agent. Specifically, we adsorb and locally concentrate Au ions onto DNA superstructures through induced local reduction, resulting in the formation of Au nanoclusters. The mechanical and optical properties of these metallic nanoclusters can be rationally controlled by their conformations and metal ions. The resulting golden DNA superstructures (GDSs) exhibit significant photothermal effects that induce cancer cell apoptosis. When sequence-specific immunostimulatory effects of DNA are combined, GDSs provide a synergistic effect to eradicate cancer and inhibit metastasis, demonstrating potential as a combinatory therapeutic agent for tumor treatment. Altogether, the DNA superstructure-templated metal casting system offers promising materials for future biomedical applications.

Teaching Materials Science to High School Students at the ASM Eisenman Camp

Abstract The hands-on experience provided during an Eisenman Materials Camp for students is a compelling way to excite young people to consider a STEM career. The volunteer-lead curriculum pairs a weeklong failure analysis project with many hands-on heat treating, metal casting, and materials characterization experiments. This article provides background about the Eisenman camp as well as the other student camps organized by the ASM Materials Education Foundation and discusses their benefits and long-term impact.

INSIGHT INTO THE IMPACT OF MELTING HEAT TRANSFER AND MHD ON STAGNATION POINT FLOW OF TANGENT HYPERBOLIC FLUID OVER A POROUS ROTATING DISK

Melting heat transfer plays a crucial role in many industrial devices, including heat exchangers, air conditioning, and metal casting. Considering these uses the heat transmission in three-dimensional tangent hyperbolic fluid flow is evaluated. The effects of magnetohydrodynamics (MHD), Ohmic heating, porous medium and melting heat transfer at the boundary are applied to the stretching rotating disk. The governing equations are transformed into a nondimensional form after applying a similarity transformation. The simplified ordinary differential equations contain various dimensionless terms, and the results of these variables are obtained by the bvp4c method. The graphical and tabular results for existing parameters are displayed. For the validation of our results, a comparison is done. From the outcomes, it is noticed that velocity and temperature profiles are enhanced with melting heat transfer at the boundary. The porosity parameter reduces the velocity of the tangent hyperbolic fluid. Moreover, the Eckert number demonstrates the dual nature of temperature profiles.

Imprinting Bone Surface Topography on Cast Metal

Chemical and physical features including stiffness and roughness texture of the biomaterials are important factors for in-vitro and in-vivo cell behaviour. Bone mimetic topography of the biomaterials can enhance the cell adhesion, cell proliferation and differentiation, leading to promoted bone tissue regeneration. In this study, a new technique for transferring the topography of the decellularized cortical bone to the cast metal was described. Imprinting efficiency and accuracy were high, as shown with light microscopy and atomic force microscopy. This method will pave the way for the development of new materials for bone tissue engineering.

Investigation of Fracture Strength of Current Post Materials (Peek, Fiber, Cast Metal) in Different Ferrule Conditions

Investigation of Fracture Strength of Current Post Materials (Peek, Fiber, Cast Metal) in Different Ferrule Conditions

A review of electromagnetic stirring on solidification characteristics of molten metal in continuous casting

The solidification of molten metal represents a pivotal phase in the preparation and shaping of metallic materials. Continuous casting, as a crucial juncture in the solidification of molten metal, occupies a position of paramount significance. Nevertheless, during the process of continuous casting, challenges emerge, including uneven temperature field distribution, non-uniform solidification microstructures, and the presence of impurities, leading to defects such as segregation and shrinkage in the castings. Researchers have devoted decades to addressing these issues, culminating in the discovery that the application of electromagnetic stirring during continuous casting can expedite the flow of molten metal, enhance solute diffusion, thereby achieving uniform temperature and flow field distributions, refining solidification microstructures, and ameliorating macrosegregation, among other benefits. This article provides an overview of the recent research achievements and advancements in the utilization of electromagnetic stirring during the continuous casting process. It primarily elucidates various stirring devices commonly employed in continuous casting and expounds upon the influence of electromagnetic stirring on solidification characteristics. And the current problems and future development trends in the application of electromagnetic stirring were discussed.

Sustainability and livelihood of small-scale handicraft producers in India: A SWOT analysis of Dhokra artisans

Dhokra art, a unique non-ferrous metal casting technique integral to the lost wax process, is not just an art form but a treasure that embodies India's rich cultural heritage. This small-scale handicraft sector holds immense economic, social and cultural potential despite the challenges. This study was conducted in a community dominated by Dhokra artisans in Kondagaon district, Bastar division of Chhattisgarh, India. The study was conducted through structured interviews and focus group discussions involving (N = 60) male and female artisans for their insights and experiences through SWOT analysis. The findings signify several strengths of the Dhokra sector, like natural resources availability, skilled artisans, and relatively low investment, all of which contribute to the sector's resilience. Nonetheless, significant weaknesses persist, such as inadequate infrastructure, outdated techniques, and a waning interest among the younger generation. On the other hand, opportunities arise from the increasing demand for natural and handmade products, supportive government policies, and the growing trend of eco-tourism. However, these opportunities are countered by threats like rising costs of raw materials, the influence of mediators that cut into artisans' profits, seasonal demand fluctuations, and competition from cheaper industrial alternatives. This research offers a comprehensive overview of the current state of Dhokra art and strategic recommendations for policymakers. It underscores the urgent need for the proposed Sustainability Framework and an immediate implementation of the framework for sustainable craft practices and succession.

Influence of partial replacement of calcined red clay by gypsum-bonded casting investment waste on geopolymerization reaction of red clay-based geopolymer

The main objective of this research is to study the influence of partial replacement of calcined red clay by gypsum-bonded casting investment waste (GCIW) from precious metal casting process on geopolymerization reaction of a red clay-based geopolymer. Calcined red clay was partially replaced by GCIW powder with different contents before mixing with sodium-based alkali activator solution to produce the geopolymers. The results indicate that the GCIW significantly impacted the reaction of flesh geopolymers detected by Differential scanning calorimetry (DSC). The reaction products (hydration products and others) of 28-day geopolymers detected by Fourier transform Infrared spectroscopy (FTIR) and X-ray diffractometry (XRD) were employed to support the reaction results. Moreover, the relation between reaction products and compressive strength was discussed. This work concluded that the calcium sulfate compounds contained in GCIW play an important role on geopolymerization reaction, reaction products, and mechanical properties of geopolymer. Furthermore, the results could be employed to propose a reaction mechanism that occurred in geopolymers. The potential use of GCIW as an additive for red clay-based geopolymer bricks preparation was confirmed in this research.

A Comparative Review of Cast Metal vs Composite Inlays: Which One Should I Prefer?

A Comparative Review of Cast Metal vs Composite Inlays: Which One Should I Prefer?

Порівняльний аналіз стану опорних тканин при використанні різних ортопедичних конструкцій для негайного навантаження на дентальних імплантатах при втраті зубів на одній із щелеп

Abstract. The use of fixed prosthetic structures supported by implants in case of partial or complete tooth loss remains relevant. Thanks to the use of intraoral welding of temporary prosthesis elements, the method of manufacturing temporary prosthetic structures has been integrated into the practice of prosthetic dentistry, which allows them to be fixed during dental implantation surgery. The aim of the study is to compare the condition of supporting tissues when using different orthopedic structures for immediate loading on dental implants in case of partial or complete loss of teeth in one of the jaws. For the comparative evaluation of different orthopedic structures on implants for immediate loading, temporary structures made of polymethyl methacrylate, composite structures reinforced with metal beams using intraoral welding, acrylic structures with dentures reinforced with a cast beam were selected. Computed tomography and orthopantomography were used to assess the condition of the bone tissue before implantation, 3 days and 1, 6, months after implantation. The study resulted in the following conclusions. Restoration of complete tooth loss in one of the jaws with fixed orthopedic composite structures reinforced with metal beams using intraoral welding is a promising method that allows to reduce the time of patient rehabilitation, the number of surgical stages and the trauma of the surgical stage of treatment. In this regard, soft and bone tissue trophism is less disturbed, which affects the subsequent osseointegration and functioning of implants. At the same time, the risks of bone resorption are minimized. Clinical evaluation of the tissues around the implants and X-ray analysis of the bone in patients with acrylic structures with set teeth reinforced with cast metal beams showed almost similar results. However, the technique involves additional surgical intervention, which negatively affects the trophism and healing of soft and bone tissues, increases the risk of complications, and extends the rehabilitation period. The use of temporary structures made of polymethyl methacrylate is less appropriate due to their less stable fixation, which can lead to inflammation of the soft tissues surrounding the implants and bone resorption. Key words: fixed structures, occlusal relations of the jaws, digital technologies, dental implantation.