Cast Parts Research Articles

Optimizing the Material Extrusion Process for Investment Casting Mould Production

This study investigates the optimization of the Material Extrusion (MEX) process for producing polylactic acid (PLA) patterns used in investment casting moulds, specifically targeting the casting of non-ferrous alloys such as brass. Key MEX process parameters—layer thickness, wall thickness, infill density, and post-processing with dichloromethane vapour for surface enhancement—were systematically analyzed for their impact on mould quality. Results indicate that an optimized combination of MEX parameters yields moulds with high dimensional accuracy, low surface roughness, and minimal pattern residue within the mould cavity. These optimized moulds were subsequently used in brass casting, with the final cast parts evaluated for dimensional precision and surface finish. The study concludes that PLA patterns manufactured via optimized MEX parameters provide a precise, cost-effective, and easy-to-implement solution for industry applications. Additionally, this process is environmentally friendly and presents clear advantages over other pattern-making methods, offering a sustainable alternative for producing complex metal parts with reduced environmental impact. The findings underscore the significant role of post-processing in enhancing mould quality and, consequently, the quality of the cast parts.

Integration of confocal chromatic spectroscopy into a test bench concept for safety inspection practices, with focus on stress detection

Evaluating casting’s mechanical stress is of significant interest from a safety inspection’s point of view. Residual stress, in particular, leads to an early or even immediate failure of some parts. Therefore, several methods exist to determine casting’s external and internal strain leading to stress. By determining the state of stress and residual stress, it is possible to design casting parts that are much safer. The present concept of a test bench shows a new way of inspecting parts for safety reasons using an optical fiber confocal chromatic sensor to measure strain. The method is based on the deep-drilling method, where a minimal invasive hole is placed at an area of interest in the first step. In a second step, this hole is then precisely measured to be able to map the borehole. From this information, conclusions can be drawn of any forces acting on the inspected part. In this case, the concept of the test bench uses gun drills to place boreholes measuring 6.0 mm in diameter with up to 500.0 mm in depth, and for the inspection, a confocal sensor with a precision of ± 100.0 nm in dissolving distances is used. This work focuses on evaluating the test bench’s precision in conducting such measurements and on how an external thermal load and mechanical load influence the results when conducting differential measurements. The experiments are performed on typical cast alloys such as iron cast and Zamac.

Effect of Films on In‐Mold Decoration and Microcellular Foaming Injection Molding Parts: Cell Structure, Surface, Warpage, and Mechanical Properties

ABSTRACTThe in‐mold decoration and microcellular foaming injection molding (IMD‐MIM) process was proposed to solve the apparent quality problem of polypropylene in microcellular foaming injection molding. Based on physical experiments and finite element simulation, stainless steel (ST) and polyethylene glycol terephthalate (PET) decorative films were selected for analysis, and the influence of the type and thickness of the decorative films on the cell structure, surface morphology, warpage deformation, and mechanical properties was revealed. The results show that the surface quality of the samples coated is significantly improved, and the asymmetric temperature field caused by the films changes the structure and distribution of the cells. The cell density on the coated side is higher than that on the non‐coated side, and the average cell diameter is smaller, and the foam core layer is shifted to the coated side. The warpage caused by ST film is larger, up to 2.836 mm. With the intervention of ST film and PET film, the impact properties of the samples have little change, but the tensile and flexural properties of the foamed samples have been effectively improved. The tensile strength increased by 28.6% and 25.9%, while the flexural strength increased by 28.6% and 28.1%, respectively. This study provides new insights into the comprehensive optimization of the structure and performance of polypropylene microcellular foaming materials and provides support for the development and application of lightweight materials in the future.

Facilitating the Production of 3D-Printed Spare Parts in the Design of Plastic Parts: A Design Requirement Review

Using additive manufacturing for spare part production can ensure that spare parts are available for a long time. However, spare parts are currently not designed for additive manufacturing. This study aimed to find how the production of 3D-printed spare parts can be facilitated in the design of plastic parts. We used a literature review and illustrative case to find how the design requirements for standard injection moulded plastic parts relate to the manufacturing capabilities of additive manufacturing for spare parts. The design requirements were defined by assigning corresponding structural and material properties. These requirements were then used to construct and evaluate the capabilities of additive manufacturing compared to injection moulding. It was found that additive manufacturing is especially suitable for requirements like Accuracy, Heat resistance, and Chemical resistance. However, to fully enable 3D-printed spare parts, certain design challenges still need to be tackled. Designers should pay careful attention to the synergies and trade-offs between design requirements and the challenges that might arise from the combination of certain requirements. Also, designers should ensure products are easily reparable before considering 3D-printed spare parts. If we target these challenges in the design phase, we can facilitate 3D-printed spare parts that enable product repairability.

Time reduction in changing of plastic injection mold part bottom cover injection machine size 380 ton

This study focuses on enhancing efficiency by reducing the time required to adjust plastic injection molds on a 380-ton machine. The setup time for mold change was 61 minutes, exceeding the company's target of 30 minutes. The research employed a quasi-experimental approach, capturing pre-improvement data, measuring the time for each mold change, and documenting sub-work steps using a Flow Process Chart and a Man-Machine Chart. The main activities identified were mold change and Jig robot adjustment using the Quick changeover technique, involving internal and external activities. The study revealed that some mold-changing steps could be prepared in advance, and applying SMED (Single Minute Exchange of Die) and ECRS (Eliminate, Combine, Rearrange, Simplify) principles led to the identification of seven external adjustment steps. Assigning another employee to assist in these steps significantly reduced the average mold adjustment time to 28 minutes, representing a 54.09% improvement.

An artifactual fibre overlap removal algorithm for micro-computed tomography image post-processing and 3D microstructure generation with graphics processing unit acceleration

A novel algorithm based on radial basis functions is proposed for the removal of artifactual fibre overlap within fibre structures extracted from micro-computed tomography (micro-CT) images of fibre reinforced polymer matrix composites. The proposed algorithm is highly efficient and excels in preserving the original fibre structures extracted from the micro-CT images. Besides, graphics processing unit (GPU) acceleration is applied to further enhance the efficiency of the fibre overlap removal process. Furthermore, the proposed algorithm is also modified for the generation of periodic 3D microstructures. For practical application, the proposed algorithm is implemented for both the artifactual fibre overlap removal within micro-CT images from an injection moulded part and the microstructure generation for 3D printed samples. The unidirectional elastic modulus of the resultant microstructures is computed via numerical simulations and shows a close match to the experimental measurements with relative errors less than 2%. Overall, the proposed algorithm significantly facilitates the reconstruction of micro-CT image-based numerical models and can also be easily repurposed to generate complex microstructures, which is of great value for the development of data-driven models for characterization and design of composite materials that demands large amounts of data on material microstructures.

Effect of cast part size on the microstructure and mechanical properties of a bainitic High-Carbon and High-Silicon Cast Steel

This study aims at assessing the impact of casting size on the bainitic transformation, resulting microstructures, and tensile properties of a high-carbon, high-silicon steel austempered at different temperatures. The casting size was analyzed by using Y blocks of two different thicknesses. The microsegregation, a common occurrence in cast parts, leads to different bainitic transformation rates at the microscopic scale. Specifically, interdendritic areas with higher alloying contents exhibit a slower transformation, resulting in a lower degree of transformation and a higher amount of blocky austenite. Despite differences in solidification structure and distribution of alloying elements, samples obtained from the thinner and thicker Y blocks yield comparable transformation times and mechanical properties, leading to enhanced uniformity in the mechanical behavior of the entire component. However, it is essential to ensure that the bainitic transformation is completed to minimize the detrimental effects of microsegregation in these cast steel components. The presence of very fine microstructures results in ultra-high strength with low ductility cast steel.

On the reliability of steel frame joints in earthquake zones exposed to low temperatures

The paper analyzes the existing construction solutions of steel frames with a box-section column and an I-beam crossbar in order to use them in earthquake zones, including areas with low temperatures. Such solutions will allow the structure to accept the seismic inertial forces, while maintaining its bearing capacity throughout the entire period of operation. In order to solve this problem, the study proposes to use steel frame joints, which can be used both for the entire frame of the building and on individual floors, thereby creating a “flexible story” effect. The authors studied articles, books and patents issued in Russia, the United States, Japan, China and Iran, analyzed the factors that reduce the reliability and performance characteristics of the joints. The main factor consists in a welded joint, which is used to attach the crossbars to the columns, transverse ribs in the column body, and to form the box section of the column from sheets, angles or channels. The reliability of the welded joint is reduced even more under conditions of seismic zones with low temperatures in Russia. However, units without welded joints require special cast parts or structures, thereby reducing their availability. In this regard, the task consists in developing new original construction solutions for joints that meet the requirements of reliability and availability.

Strain-Based Heating of Polymers under Ultrasonic Excitation

Ultrasonic welding is the most common type of polymer joining used in industry today. It is critical that the energy transfer and heating mechanisms be well understood to enable the use of this process for more challenging applications. This work seeks to provide new tools to predict the heating rate in a molded polymer part excited by ultrasonic energy. Current assumptions for the mechanics of energy transfer are explored, and new equations for attenuation and strain-based heating are proposed.

Studies on the Influence of Methane Gas Bubbling of Metal Alloys on the Casting Properties

Abstract The purpose of using bubbling in the case of metal alloys was to increase the mechanical resistance, to improve the casting properties as well as to observe the changes brought by gases on the structure. During bubbling, especially hydrogen and oxygen are removed, which obviously leads to the improvement of metal alloys. The influence of bubbling on the casting properties is explained by the structural changes that occur in the cast alloys. Therefore, bubbling with methane gas is a safe means of improving the quality of cast parts, ensuring at the same time the increase of casting properties of alloys.

Experimental study of shielding gas concentration on mechanical properties of stainless steel alloy parts using wire and arc additive manufacturing

Wire Arc Additive Manufacturing (WAAM) is an emerging three-dimensional fabrication technology that enables higher deposition rate, material savings, and near net-shape. In this study, various shielding gas concentration (SGC) of argon (Ar) and carbon-di-oxide (CO2) was employed to fabricate 316L using Cold Metal Transfer (CMT) WAAM process. Microstructure characteristics and mechanical properties of thick-walled parts were studied. Microstructure studies show a combination of columnar and equiaxed grains in various regions. Microhardness results exhibit the uneven distribution of hardness value from bottom to top region along the building direction and the values are ranging between185 and 240 HV. Tensile studies indicates the both horizontal and vertical direction samples secures the higher ultimate tensile strength (UTS), yield strength (YS) and elongation (EL) values and confirmed the isotropic properties. Fractography studies prove ductile fracture with the evidence of dimples and enough plastic deformation. From the experimental results, the SGC-2 possesses finer solidification structure and higher mechanical properties than the other samples. The as-fabricated WAAM parts possess higher mechanical properties than the 316L parts fabricated via casting and wrought parts.

Wear properties of a new Al80Mg10Si5Cu5 multicomponent alloy

The present study investigates the tribological properties of a newly developed multicomponent aluminium weight-light multicomponent alloy for wear based on the Al80Mg10Si5Cu5 system for lightweight automotive applications, especially back drum discs. The samples were manufactured by High-Pressure Die Casting (HPDC) employing cast alloy returns and secondary aluminium ingots and were tested at room temperature (RT) and 200 °C. It has been observed that the Al80Mg10Si5Cu5 alloy offers a higher hardness and wear resistance at RT and especially at 200 °C compared with the AlSi9Cu3 reference alloy (x10 times reduction in wear rate). The impact of maintaining the external surface layer (skin) of HPDC cast parts has been studied for the ball-on disc test, showing improved tribological properties and the possibility of avoiding the machining of contact surfaces. The as-cast Al80Mg10Si5Cu alloy with the surface layer showed a wear rate coefficient of 5 × 10−4 mm3/N.m2 at RT, a 50 % lower than that of the sample without skin. Solution heat-treated samples (72 h at 440 °C, water quenching at 75 °C, and natural aging) with the surface layer showed a wear rate coefficient of 11 × 10−4 mm3/N.m2, approximately 20 % lower than the sample without a surface layer. The wear rate of AlSi9Cu3 alloy decreased by more than 50 % in the samples without skin at RT. At 200 °C, wear rate coefficients were lower in the samples with the surface layer.

FOUNDRY TRIBOTECHNICAL BRONZE BrO3A3 CORROSION RESISTANCE INVESTIGATION

Problem statement. Bronzes have been and remain the main material for friction bearings, anti-friction and corrosion-resistant parts manufacturing that work under high loads, chemically active aggression influence at low and elevated temperatures, in cavitation, erosion, etc. conditions. That is, technology continuous development requires from anti-friction bronzes constant their corrosion resistance increasing, as a factor that will allow to significantly expand their application scope and increase cast products from them durability and reliability. The purpose of the articles. Based on relationship between corrosion damages and chemical composition analysis, compare BrO3A3 bronze corrosion resistance with BrA5, BrA9Zh3L and BrO5Tz5C5 bronzes corrosion resistance as the materials most often used in industry for parts manufacturing that work in friction nodes and chemically active environments. Methodology. Alloys for samples production have been prepared by technical purity primary charge materials fusing. Melting has been carried out in induction crucible furnace using a graphite crucible and charcoal as a coating material. Cast bronze samples corrosion resistance studies have been carried out in accordance with ISO 7384:2001, ISO 11845:1995 and GOST 9.308-85 requirements. Studied samples corrosion resistance has been evaluated based on the results of their relative weight loss during exposure for 90 days in climate chamber at relative humidity of 93 ± 3 % and temperature of 40 ± 2 °С, in sea and fresh water with temperature of 20...22 °С. Conclusions. BrO3A3 bronze, among the studied foundry bronzes, is characterized by the best level of anti-corrosion properties in all environments used in this research. In this regard, it is a reason to recommend the studied bronze for tribotechnical purpose cast parts manufacturing, which work in air, fresh or sea water.

Effect of varying part geometry and mold constraints on dimensional deviations of sand cast parts

Effect of varying part geometry and mold constraints on dimensional deviations of sand cast parts

Progress in the Study of Quality and Mechanical Properties of Selective Laser Melting Molded Parts

Abstract: Selective laser melting (SLM) is considered to be a widely promising additive manufacturing technology with the advantages of high machining precision, high manufacturing freedom, and short cycle time, which is widely used in aerospace, the integration of medicine, and industry, chemical, and other fields. The research progress on the temperature field, stress field, forming quality, and mechanical properties during the SLM manufacturing process is reviewed. The study aims to systematically analyze how SLM process parameters affect the temperature field, stress field, forming quality, and mechanical properties, and to discuss the importance of the selection of process parameters and performance regulation to achieve high-quality, highperformance metal parts. The effects of SLM process parameters on temperature field, stress field, surface roughness, densification, hardness, strength, and fatigue properties are analyzed and summarized. The importance of process parameters in the SLM forming procedure in the quality of formed components is emphasized, and conducting an in-depth study on the optimization and performance regulation of the process parameters is of great significance in achieving the high quality and performance of metal parts. With the rapid advancement of technology, the potential of SLM technology in terms of molding quality and mechanical performance has become increasingly significant, heralding significant breakthroughs. These potential breakthroughs will greatly promote the widespread application of SLM technology in various industries, thus more efficiently meeting the growing needs and expectations of industries such as petrochemicals, transportation, aerospace, nuclear energy, as well as food and medical sectors.

Supplementary treatment of FDM printed parts. Review

The application of additive technologies to the manufacture of polymer and composite products is now actively expanding. The FDM printing process is popular because of its ability to adapt to specific tasks and to bring products with complex geometries into production quickly and at minimal cost, and is seen as a technology that can compete with injection molding. However, due to the nature of the process, FDM printed parts are significantly inferior in quality to injection molded parts. Much attention is now being paid to research into supplementary treatment methods to improve the properties of FDM printing parts. However, there is no complete and clear description of such methods, nor are there any recommendations on the choice of treatment methods aimed at improving the specific parts properties. The aim of this review is to analyse the research in the field of post-treatment of parts in order to systematise their advantages and limitations, which will allow a more reasoned choice of a post-treatment method to improve specific properties of FDM printing parts. <br> The bibliography includes 120 references.

Design of Steel-Cu composites for enhancing thermal properties of plastic processing tools by using a numerical model of the microstructure

Limitationsof conventional materials used for plastic processing tools, particularly related to thermal conductivity, significantly influence production efficiency, with the cooling time of moulded parts appearing as one of the key factors. Therefore, this study focuses on designing Steel-Cu composites with the aid of a numerical model of the composite's microstructure for enhancing their overall thermal properties. We present a novel procedure for designing such composites, which facilitates the identification of the optimal shape for the phases to improve overall thermal conductivity. We have developed a data-driven homogenization model to aid the optimization process and ensure time-efficient solutions. The data has been generated through numerical homogenization based on the finite element method. The proposed shape optimization procedure has been applied to determine the optimal shape of the Cu phase across various volume fractions. We found out that the optimal shape of the Cu phase is not constant but depends on its volume fraction. Emphasizing the practical utility of the proposed procedure, it is noteworthy that once the data-driven model is established, it enables a time-efficient optimization of the Cu phase shape for arbitrary volume fractions of phases. Consequently, this may expedite the decision-making process for material manufacturers.

Non-isothermal crystallization kinetics of biocomposites based on PLA/PHBV and spent coffee grounds

AbstractThis study deals with the modification of a predominantly amorphous poly(lactic acid) (PLA) by blending it with a semi-crystalline biopolymer, polyhydroxybutyrate-co-valerate (PHBV), which has a high crystallinity. The blends with different concentrations of PLA and PHBV were compounded with spent coffee grounds (SCGs) and processed by injection moulding. The structural, thermal and mechanical properties of the produced samples were investigated. Particular attention was paid to the effect of the presence of SCG and the concentration of PHBV in the blend on the crystallization kinetics and the heat deflection temperature (HDT). For equimolar blends, only a slight increase in HDT (about 5 °C) was observed, but the addition of PHBV suppressed the cold crystallization of PLA, which otherwise negatively affects the dimensional stability of injection moulded parts. A similar effect, but to a lesser extent, was achieved by adding SCG to the PLA matrix. Thus, it is clear that the material structures of PLA/PHBV blends and composites help to minimize additional shrinkage of the parts and increase their dimensional stability. Due to the co-continuous structure of the symmetric PLA/PHBV blends and the increase in the degree of crystallinity from 36 to 47% by annealing the produced samples, the heat deflection temperature increased from 65 up to 90 °C.

Nature-Inspired Dual-Sensor Thread for Independent Measurement of Internal Temperature and Strain in Cast Parts or Fabrics

Nature-Inspired Dual-Sensor Thread for Independent Measurement of Internal Temperature and Strain in Cast Parts or Fabrics

Thermal Properties of 3D-Printed Molds for Light Metal Casting

AbstractBinder Jetting technology is well established for the production of sand molds and cores for foundry use, owing to its flexibility and expansive design capabilities. A wide array of sand, aggregate, and binder combinations is commercially available. Utilizing these types of refractory materials in the casting process presents both technical and economic benefits and drawbacks. For intricate cast components, foundry technologists must assess the thermophysical properties of the mold material systems. With this knowledge, specialized high-performance material combinations may be employed in specific areas of the mold, while more economically viable systems are used for shaping the external mold support. This study primarily focuses on determining the heat capacity and thermal diffusivity and consequently the thermal conductivity using a specially developed analytical method. It investigates three different fundamental aggregates: silica, cerabeads®, and chromite. The result’s range provides an overview of relevant characteristics for the selected material systems. Given that the properties of sand affect heat flow during casting and solidification, these newly determined values can be utilized in future simulations. Consequently, these findings aid in maintaining and enhancing the quality of critically stressed cast parts.