Cast Parts Research Articles

Deep learning-based detection of internal defect types and their grades in high-pressure aluminum castings

With the increasing use of light alloy castings in automobiles, ensuring quality control is essential for safety. X-ray imaging offers a practical approach to detecting internal defects in cast components. This study proposes a method to automatically and in real-time identify the location, type, and size of internal defects in aluminum parts produced via high-pressure casting. The proposed two-stage method can detect, segment, and grade defects without expensive hardware in less than a second. Using the YOLOv5 algorithm for defect detection in the first stage, a mean Average Precision (mAP) of 0.971 was achieved. In the second stage, defect grading is performed through segmentation, enabling classification in accordance with international standards without requiring additional training. The methodology provides real-time and highly accurate internal defect quality control and can be applied to different metals and standards. The dataset used in this study contains over 5,000 labelled X-ray images of aluminum cast parts, and it is made available as open access to support the NDT community and researchers.

Research on injection molded parts defect detection algorithm based on multiplicative feature fusion and improved attention mechanism

Injection molded parts are increasingly utilized across various industries due to their cost-effectiveness, lightweight nature, and durability. However, traditional defect detection methods for these parts often rely on manual visual inspection, which is inefficient, expensive, and prone to errors. To enhance the accuracy of defect detection in injection molded parts, a new method called MRB-YOLO, based on the YOLOv8 model, has been proposed. This method introduces several key improvements: (1) the MAFHead, a four-detection head based on multiplicative feature fusion, which replaces the original detection head to enhance feature representation; (2) the RepGFPN-SE module, a re-parameterized generalized feature pyramid network that improves detection of small objects by replacing the original C2f. module; (3) and the BiNorma module, employing a bi-level routing attention mechanism to optimize the training process by reducing input distribution changes across layers. The effectiveness of the MRB-YOLO model was validated through ablation and contrast experiments using a specially constructed dataset of injection molded parts defects. The results demonstrated an accuracy of 88.8%, a recall rate of 86.8%, and a mean average precision (mAP) of 91.5%. Compared to the YOLOv8n model, the MRB-YOLO model shows an increase in accuracy by 8.2%, in recall rate by 17.2%, and in mAP by 11.8%. These findings confirm that the MRB-YOLO model meets the requirements for accurate detection of defects in injection molded parts.

Research on the Wear Suppression of Diamond Grain Enabled by Hexagonal Boron Nitride in Grinding Cast Steel.

Diamond grinding wheels have been widely used to remove the residual features of cast parts, such as parting lines and pouring risers. However, diamond grains are prone to chemical wear as a result of their strong interaction with ferrous metals. To mitigate this wear, this study proposes the use of a novel water-based hexagonal boron nitride (hBN) as a minimum quantity lubrication (MQL) during the grinding of cast steel and conducted the grinding experiment and molecular dynamics simulation. The experiment demonstrated that compared to dry grinding, the water-based hBN nanofluid can effectively reduce the maximum temperature of a workpiece at contact zone from 408 K to 335 K and change the serious abrasion wear of diamond grain to slightly micro-broken. The molecular dynamics simulation indicates that the flake of hBN can weaken the catalytic effect of iron on the diamond, prevent the diffusion of carbon atom to cast steel, and suppress the graphitization of diamond grain. Additionally, the flake of hBN improves the contact state between the diamond grain and cast steel and reduces the cutting heat and friction coefficient from about 0.5 to 0.25. Thus, the water-based hBN nanofluid as a new MQL was proven to be suitable for the wear inhibition of diamond grain when grinding cast steel.

Performance evaluation of developing electrical discharge machining tools through 3D-printed mould using selective laser sintering and expanding its applications in developing free-form tools

In the current study, an attempt has been made to find the optimum parameters for electroplating three-dimensional (3D) casted low melting point alloys. The electroplated profile is used as a tool in an electric discharge machining setup. A selective laser sintering process is used for 3D printing the mould in two halves. The mould parts are 3D scanned to find out the dimensional deviation. The low melting point alloy (LMPA) is cast in the mould. The surface roughness of the mould and the pattern are measured. Electroplating the casted LMPA sample is carried out in three stages in search of optimum parameters for getting stable copper deposits. The thickness of copper deposits under varying conditions is measured. The microstructures of cast alloys and copper deposits are analysed using a scanning electron microscope. The casted alloy and copper composition is verified through energy dispersive spectroscopy mapping and X-ray diffraction technique. The developed electric discharge machining electrode successfully performs the machining on the workpiece, and its performance is compared with that of a solid copper tool. The information gained is transferred to prepare the free-form tool using the developed path and is tested on the implant-shaped workpiece.

Prediction of the Stability of the Casting Process by the HPDC Method on the Basis of Knowledge Obtained by Data Mining Techniques.

High-pressure die casting (HPDC) of aluminum alloys is one of the most efficient manufacturing methods, offering high repeatability and the ability to produce highly complex castings. The cast parts are characterized by good surface quality, high dimensional accuracy, and high tensile strength. Continuous technological advancements are driving the increase in part complexity and quality requirements. Numerous parameters impact the quality of a casting in the HPDC process. The most commonly controlled parameters include plunger velocity in the first and second phases, switching point, and intensification pressure. However, a key question arises: is there a parameter that can predict casting quality? This article presents an exploratory analysis of data recorded in a modern HPDC casting machine, focusing on the thickness of the biscuit. The biscuit is the first component of the casting runner system, with a diameter equivalent to that of the injection chamber and a height linked to various processes and mold characteristics. While its diameter is fixed, the thickness varies. The nominal thickness value and tolerances are defined by the process designer based on calculations. Although the thickness of the biscuit does not affect the casting geometry, it influences porosity and cold-shot formation. This study aimed to determine the relationship between biscuit thickness and casting quality parameters, such as porosity. For this purpose, a series of injections was produced using automated gating, and biscuit thicknesses were examined. This article presents quality assessment tools and statistical analyses demonstrating a strong correlation between biscuit thickness and casting quality. The knowledge gained from the methodology and analyses developed in this study can be applied in support systems for the quality diagnostics of HPDC castings.

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.

Performance Analysis of Surface Defect Detection Algorithm of Aerospace Parts via Confusion Matrix Approach

This paper examines the development of surface defect detection algorithm of a real plastic injection moulding parts from an aerospace part supplier company. Plastic injection moulding has evolved into one of the most essential and commonly utilized polymer processing activities in the plastics industry today. The work being done attempts to accomplish three goals: identify the frequency of defective injection moulded parts produced, develop an algorithm to detect defective parts using image processing techniques, and evaluate the effectiveness of image processing techniques for quality inspection in terms of accuracy and processing time. According to the protocol, there are five phases to this project: fault frequency detection, technique selection for image processing, MATLAB coding development, MATLAB coding debugging, and automatic inspection analysis. In this project, the algorithm and Graphical User Interface (GUI) are generated using the MATLAB Simulink program. A total of 100 parts samples were inspected, and the accuracy attained was 96% while processing time was reduced by 8.81 seconds.

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