Mold Material Research Articles

Improved of Process Production Disc Car Whell Type PSD3K (City Car Type)

This research accelerates the production process with the aim of increasing productivity from Manufacturers engaged in the manufacture of automotive parts currently experiencing an increase in sales orders on the other hand facing problems in productivity due to cracked side dies in rim production to 1400 pcs. The cracking of the side die is due to thermal shock that occurs to accelerate the production process, as a result of which cracks occur in the side die. With the concept of conducting research in the field of direct production then analyzing the characteristics of mold materials, die characteristics, process characteristics, characteristics of finished products before and after changes by testing the results of the laboratory of measuring instruments and conducting trials of variations in machine setting parameters, variations in the production process and products produced. The experiment involved changing the standard temperature from 520 °C–545 °C to 532 °C–538 °C and reducing the immersion time from a minimum of 270–540 seconds to 332 seconds. It reduces the soaking time from 69 seconds to 46 seconds and the aging time from 190 seconds to 180 seconds, increasing the casting productivity from 194,870 Pcs/28 days to 213,311 Pcs/28 days from seven machines, thus meeting the customer's requirement of 200,000 Pcs/28 days without cracking side die. Durability testing on five product samples in accordance with TSD5605G standards confirms that the quality meets customer specifications. The results of this study prove that SKD6 matrial is much stronger than FCD550 against thermal shock. Keywords: thermal shock, die disc car wheel, manufacturing, automotive parts, casting productivity

Fabrication of slanted gratings with high refractive index starting from master nanoimprint mold

Recently, nanoimprinting has attracted a new round of attention in the industry due to the boom in demand for augmented reality/virtual reality (AR/VR), metalens and microlens, and even semiconductors. Slanted gratings have great application prospects in AR/VR displays because of their high efficiency in light coupling. UV-Nanoimprint lithography (UV-NIL) has been identified as one of the most feasible routes for mass manufacture of high refractive index (RI) slanted gratings. This paper presents a fabrication of high RI slanted gratings based on UV-NIL. A comprehensive study on the optical principles of slanted gratings is conducted, followed by simulation-based optimization of the grating parameters. The key element for applying nanoimprint to fabricate slanted gratings is the master mold, which is acquired by a tilted angle etching of metal gratings as an etching mask on silicon wafers with F-based plasma. The influence of experimental parameters, such as the etching power and etching mask thickness on the morphology of the slanted gratings on the master mold are investigated. The working mold was simply duplicated from the master mold by UV-NIL with a low surface energy working mold material. The high RI slanted gratings were achieved by imprinting a UV-curable resin with high RI. Finally, experimental verification was performed to assess the optical performance of the slanted gratings.

Determining method of optimal process parameters using Taguchi method and technique for order preference by similarity to ideal solution in plastic injection molding

Many plastic injection molding (PIM) process optimization problems are multi-objective optimization problems that optimize multiple mechanical properties. This paper proposed a determining method of optimal process parameters and their effect ranks using Taguchi method and TOPSIS in the PIM. TOPSIS was used to convert multiple mechanical properties into single comprehensive response. It was selected as a reasonable multi-attribute decision-making (MADM) method from among some well-known MADM methods based on mean rank correlation coefficient and mean absolute rank deviation. Taguchi method was used to design experiment and find the optimal process parameters. The proposed method was applied to determine the optimal values of the process parameters: melt temperature (MT), packing pressure (PP), cooling time (CT), and injection pressure (IP) for improving tensile strength, elasticity module, flexural modulus, and impact strength in the PIM with Acrylonitrile-Butadiene-Styrene compound as plastic materials and AISI 1020 as mold materials. The optimal values of the process parameters were MT of 280°C, PP of 28 MPa, CT of 22 s, and IP of 50 MPa, and their effect ranking was IP (51.941%), PP (32.280%), CT (9.045%), and MT (6.734%). The method could be widely applied to not only the PIM process optimization but also various manufacturing process optimization problems.

Effect of Machining Parameters on the Surface Roughness of Hot Die Steel

H13 tool steel is frequently used in hot work dies, hot forging, hot extrusion, and mold materials for casting ferrous and nonferrous materials. Surface roughness is of key importance in case of dies and moulds, as it insures the finish of the final product. After studying the work done by the researchers in field of machining and its impact over surface roughness, it was found that machining behaviour of H13 steel at the annealed state is not being studied. The surface finish obtained during turning of H13 steel are not studied on a greater scale, so the present study includes the analysis of finish (surface roughness) generated. Turning operation is carried out on the CNC machine at dry condition with an aim to find systematically the effect on surface roughness by distinct machining variables like feed rate, depth of cut and speed. RSM model using Box Behnken design is used to predict the roughness developed during turning of annealed H13 steel using carbide tool. It was found that feed rate and the depth of cut have a direct relation with the surface finish and the value of surface roughness increases with increase in these parameters. On the other side, cutting speed has a less impact over the surface roughness & is inversely related.

Multimodal Non-Destructive In Situ Observation of Crystallinity Changes in High-Density Polyethylene Samples with Relation to Optical Parameters during Tensile Deformation

Abstract: Many non-destructive optical testing methods are currently used for material research, providing various information about material parameters. At RECENDT, a multimodal experimental setup has been designed that combines terahertz (THz) spectroscopy, optical coherence tomography (OCT), infrared (IR), and Raman spectroscopy with a tensile test stage. This setup aims to gather material information such as crystallinity and optical parameters of high-density polyethylene (HDPE) during a tensile test. The setup compares common IR and Raman spectroscopy and the less common optical methods THz and OCT. Complementarity is achieved through different frequency ranges and measurement approaches, resulting in different measured optical material parameters and depths. During tensile testing, HDPE samples with varying crystallinity were analysed, and the determined optical parameters such as refractive index, birefringence, scattering coefficient of decay, and penetration depth can be correlated with the change in crystallinity. These findings demonstrate that the optical methods and their outcomes can be interconnected. With further optimization of the experimental setup, it would be possible to observe the alignment of fibres in fibre composite panels and the stress distribution of polymers effectively. This opens interesting possibilities for polymer characterization in the future, including quality control during moulding processes and material testing.

On tailored microstructure in AA 2024 alloy during in-situ microwave casting

In the present study, application of microwave energy was explored for tailoring the microstructure in AA 2024 alloy through directional solidification route. Microwave transparent (alumina) and absorbing (graphite) mould materials were utilized to investigate the effect of microwave interaction (electric and magnetic field components) with AA 2024 alloy on microstructure evolution in terms of dendrite size distribution and formation of eutectic phase. Results showed more pronounced eutectic phase gradient was developed using alumina mould. On the other hand, a more uniform distribution of the eutectic phase and grain size was observed with graphite mould. The development of the eutectic phase gradient is attributed to the effective microwave interaction with the AA 2024 alloy melt during solidification. This is primarily associated with the formation of an additional flux at the solid-liquid (S/L) interface of the alloy under the effect of magnetic field and an enhancement in diffusion flux due to mass transport caused by electric field component of microwave. Formation of AlCu, Al2Cu, and Al2CuMg intermetallic phases in both alumina and graphite mould casts was confirmed. Significantly higher hardness was observed at the higher eutectic phase sites within the alumina mould cast, whereas graphite mould casts exhibited better tensile properties.

Procedimentos para modelagem BIM de lajes nervuradas de concreto armado em edificações

It is impossible not to admit that commercial computational tools for structural analysis and detailing have become indispensable in the various applications of Structural Engineering nowadays. The importance of these tools equipped with graphical interfaces based on the BIM (Building Information Modeling) environment is mainly due to the flexibility and ease in making common corrections and changes during the elaboration stage, as well as the proposition of different structural conceptions, not always innovative, but almost always bold, as in the case of reinforced concrete ribbed slabs. The use of ribbed slabs in reinforced concrete is an old practice in Structural Engineering, which has encouraged the adaptation of commercial computational tools, both in the development of structurally consistent mathematical formulations, as well as in the development of specific databases, equipped with information from mold manufacturers and materials intended for the execution of this type of slabs. It is highly efficient in building structures in which there are numerous problems of interference of structural elements with elements of installations, such as large-diameter pipes for wastewater, sewage, gas, fire, and even air conditioning ducts, exhaust and architectural elements. This efficiency is mainly due to the fact that large beams are not considered in their supports, making the lower face of the slab practically without obstacles to the building pipes, and is also due to the low average thickness of concrete used in the pavement compared to conventional rectangular supported slabs and flat mushroom slabs. However, it is not always possible to obtain an optimal final result, even with all the adaptations previously described, mainly due to executive and computational modeling problems. This work intends to present a possible structural modeling methodology, which provides results within the limits of the feasibility of the slab, both in the construction aspect of the computational structural model, as well as the possibility of using materials from manufacturers and labor, using a commercial computational tool for structural analysis and detailing.

Development of New Hard Material for High Thermal Expansion Glass Molds

Development of New Hard Material for High Thermal Expansion Glass Molds

Design of Mold Flipper in an Effort to Improve The Efficiency of Mold Maintenance Process

Molding is a production process by forming raw materials using a rigid frame or model used in the manufacturing industry to mold materials called a mold. Injection molding is a technique in the manufacturing industry for molding thermoplastic materials. Thermoplasctic materials commonly molded with Injection Molding techniques are Polystyrene, Acrylonitrile Butadiene Styrene (ABS), PMMA (Polymethyl Methacrylatic) and others. The purpose of this research is to design and build a flipper molding tool for an easier and more efficient mold maintenance process. This research uses descriptive methods. Data is taken through direct observation and through reference books both from companies and websites and journals related to the report material. The data obtained was analyzed using descriptive analysis. it is found that the material used in the work is Carbon Steel (S45C). The process of making Flipper Clamps Mold has several stages, namely the Design Making Process, Material Selection Process, Cutting Process, Milling Process, Grinding Process, Drilling Process, Welding Process, and Assembly Process. With this Flipper Clamping tool, it is hoped that it can make it easier for operators to maintain and repair molds, because the previous mechanism requires two operators to flip molds that weigh more than 200 kg, now they only need to flip by turning the lever of this tool.

Advances in elastomeric mount concepts for quasi-zero stiffness isolation

Quasi-zero stiffness (QZS) mounts can exploit geometric nonlinearity to minimize stiffness about an operating point, which isolates vibrations from a supported source or receiver. Previous research on elastomeric QZS mounts featured 3D-printed prototypes but did not consider unique material properties and fabrication artifacts that may impact the static and dynamic behavior of the mounts. Additionally, multi-axis properties and their influence on common box-like systems supported by several mounts lack detailed study. To overcome these limitations and improve the practicality of elastomeric QZS mechanisms, this article discusses nonlinear stiffness, hysteresis, and fabrication issues with elastomeric materials in this context. Multimaterial mount designs that improve strength and stability are considered, and their effectiveness for QZS isolation is experimentally evaluated. System-level dynamics are presented for a box-like load supported by QZS mounts. Comparisons between additive and cast materials in the fabrication of QZS mounts are discussed, and the mounts' dynamic stiffness amplification effect is examined for additive and molded materials.

Structural behaviour and construction of a monumental ice structure

This paper investigates the use of ice-based materials combined with Fiber-Reinforced Polymer (FRP) to enhance the bending capacity of ice sculptures. Through three-point bending tests and ABAQUS simulations, the study analyses the mechanical behaviour of GFRP and cellulose ice, both separately and together. The results show that FRP improves tensile resistance while cellulose ice adds mass and ductility. An ABAQUS simulation with a layered shell partially captures the mechanical behaviour but has limitations in modelling beyond the elastic phase due to assumptions of perfect connection and material failure. Applied to a monumental sculpture by artist KAWS, incorporating a steel framework, GFRP mould, and ice-based material, the study confirms the potential of combining FRP and cellulose ice to achieve improved structural performance in ice-based sculptures.

Study on process optimization of electroless Ni-P plating on binderless WC

Abstract In the field of Precision Glass Molding (PGM), binderless tungsten carbide (WC) is a pivotal material for molds, despite its high processing costs and complexities. Nickel-phosphorus (Ni-P) alloys also exhibit superior performance at elevated temperatures. The innovation of Ni-P/WC composite molds addresses the issue of the poor machinability of WC. This research delves into the influence of the activating solution’s concentration on the surface activation energy of WC, the quality of plating, and the deposition rate during the electroless Ni-P plating process. Additionally, the study scrutinizes how the pH level of the plating solution impacts the quality of Ni-P, the rate of deposition, and the phosphorus content. These investigations have led to the realization of an efficient and high-quality Ni-P plating process for WC.

Stress-strain state of ceramic shell mold during formation of spherical steel casting in it. Part 2

The paper presents the results of numerical calculations of the solution to the problem of modeling the process of possible cracking in a spherical shell mold when pouring liquid steel into it and cooling the solidifying casting. The numerical scheme of the axisymmetric problem and the algorithm for its solution were given in Part 1. The crack resistance is estimated by magnitude of the normal stresses in the ceramic shell during its co-cooling with a solidifying casting. The results detailed analysis considered: fields of displacement, stresses, and temperatures both on spherical surface and in growing crust of solidified metal. The solution took into account the change in the shear modulus of the mold material from temperature, and an assessment of this refinement was given. The problem was solved in two ways. The first – with a constant shift modulus of the shell mold; the second – with its temperature-dependent shift modulus. There is a significant difference between these variants in terms of magnitude of the normal stresses arising in the shell mold. The authors analyzed resistance of the shell mold spherical geometry to external influences from its support filler and filling funnel. The problem of determining the contact and free surfaces at the boundary of the shell mold and support filler was solved. The results are presented graphically in the form of diagrams of stresses and temperatures over the studied area in its different sections and time intervals for cooling of the growing metal crust. The role of compressive normal stresses σ22 , σ33 on the surface of contact of the shell mold with liquid metal at the initial moment of cooling on probability of cracking in a spherical mold is shown. The level of strain-stress state in a spherical shell mold when cooling a steel casting in it is significantly determined by dependence of shift modulus of the shell mold on temperature.

A preparation method for microstructure of flexible pressure sensors based on origami craft

With the development of flexible pressure sensors, an increasing number of microstructures and their preparation methods have been developed. However, how to reduce the cost and complexity of microstructure preparation while ensuring sensors’ performance and microstructure diversity remains a significant challenge. This paper explores the feasibility and diversity of origami craft in the microstructure preparation. Based on origami craft, various different microstructures, such as linear, cross, wrinkle and wave, could be prepared using low-cost silicone paper as mold material and simple steps. Due to the diversity of origami craft in microstructure preparation, our sensors with different microstructures also have their own advantage interval of pressure detection (0–4.4 kPa: the sensitivities of piezoresistive sensors with linear and cross microstructures are So = -0.31 kPa−1, St = -0.34 kPa−1; 4.4–13.3 kPa: the sensitivity of the piezoresistive sensor with wave microstructure is Swa = -0.028 kPa−1), some of the sensors have rapid response times, excellent response characteristics, repeatability, and hysteresis. Sensors designed for low-pressure applications can detect pressures as low as 22 Pa. Additionally, it was observed that they possess significant potential in human motion environments, office environments, and equipment testing environments. This indicates that origami craft offers excellent diversity and feasibility in the preparation of sensor microstructures.

Reaction of a Molten Cr-Si-Base Alloy with Ceramics and a High Entropy Oxide

Due to their higher thermal and chemical stability than other high-temperature materials, chromium-silicon-base (Cr-Si-base) alloys are promising materials for future gas turbines and other high-temperature applications operating under harsh conditions. To enable near-net-shape casting of Cr-Si-base alloys, a compatibility of the alloy melt with the ceramic crucibles and molds is necessary. Additionally, a metal-ceramic contact exists at the interface between thermal barrier coating (TBC) and alloy, where metallic may melts play a role in the case of coating failure and overheating. In this study, molten Cr92Si8 (in at. %) alloy is brought into contact with powders of ceramics commonly used for casting molds or crucibles (e.g. ZrSiO4, Al2O3, 3YSZ), to investigate liquid metal corrosion, interdiffusion, and stabilities. Additionally, the high entropy oxide (Sm0.2Gd0.2Dy0.2Er0.2Yb0.2)2Zr2O7 (HEO), a potential future TBC material, is investigated. Before melting using an electric arc furnace, the powders of the investigated ceramics were mixed with pulverized Cr92Si8 and pressed into alloy-ceramic pairs, to maximize the contact area between molten metal and ceramic. For microstructural investigations and phase analysis, the materials were assessed using scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The widely used mold material ZrSiO4 and the coating BN were found to decompose, while reaction products of SiO2 and CoAl2O4 with the melt were detected. Al2O3, 3YSZ, and the HEO did not show decomposition or corrosion by the melt. Al2O3, 3YSZ, and the HEO are therefore considered as promising crucible, mold, and TBC materials for Cr-Si-base alloys.

Non-conformance aspects of moulded composite materials and “corresponding” simulation models with 3D textile reinforcement

Composite materials with 3-dimensional (3D) reinforcement were manufactured and corresponding simulation models were created in parallel. The used simulation approach has earlier been shown to produce close to authentic geometrical representation of the yarn architecture in 3D reinforcement. It is shown that although the as-woven reinforcement pattern can be modelled quite reliably, significant distortion from the nominal fibre arrangement might take place later in manufacturing, primarily related to compression during moulding. Such effects have earlier received significant attention for composites with 2-dimensional reinforcement but not as much for their 3D counterparts. The yarns in the real and the simulated materials are studied and compared, and some of the discrepancies and the mechanisms behind are discussed. The distortions are partly attributed to the relatively sparse weave that allows yarns oriented in the through-thickness direction, in particular, to deviate from their original positions.

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.

Comparative Evaluation of the Marginal Fit and Internal Adaptation of Polymethyl Methacrylate Interim Crowns Fabricated using two different techniques- “Conventional” and “CAD-CAM Milling”: An In Vitro Study

Introduction Interim crowns provide valuable functional and esthetic information of the final outcome during the evaluation period and act as the blueprint for the design of definitive prostheses. The fabrication technique and material used are the key factors involved in the success of the prosthesis. However, marginal fit and internal adaptation of Polymethyl Methacrylate (PMMA) interim crowns fabricated using conventional and computer aided designing-computer aided machining (CAD-CAM) PMMA milling have not been well investigated. The inter-group statistical comparison of means of normally distributed continuous variables is done using independent sample t test. Material and Methods Typodont (Nissin, Japan) of the maxillary central incisor was scanned (Ceramill Map 600+, Amann Girrbach AG) and 3D printed (Form 4, Formlabs) to create the master die used in the study, while a Typodont of a prepared maxillary central incisor was scanned using a digital scanner (Ceramill Map 600+, Amann Girrbach AG) and a .STL file obtained was modified using Exocad software for designing the study models. Three equidistant points A, B and C passing from the center of the incisal edge to the root of the typodont were indented labially and A` B` and C` were indented palatally in the same plane using Exocad software for symmetrical sectioning while checking for marginal fit and internal adaptation. 50 3D printed (Form 4, Formlabs India) models of the prepared tooth were printed and 25 interim crowns were fabricated using Polymethyl Methacrylate (DPI Tooth moulding material, DPI India) by conventional and 25 interim crowns were fabricated using CAD-CAM PMMA (Ceramill a-temp, Amann Girrbach AG). They were then luted (Han Temp Cement eugenol free, NE Korea) to respective models and viewed under a stereomicroscope (Ziess) for marginal fit at 2 specific points and internal adaptation at 4 specific points. Results The mean SD of marginal fit measurements at buccal and site in Group A (conventional technique) and Group B (CAD-CAM milling) was 95.32 ± 7.78 µm and 66.92 ± 14.59 µm respectively. At lingual site in Group A and Group B was 94.84 ± 7.97 µm and 66.80 ± 10.93 µm respectively. The mean marginal fit measurement at lingual site is significantly higher in Group A compared to Group B (P-value%3C0.05). The mean SD of internal fit measurements at upper 1 site in Group A and Group B was 335.19 ± 94.70 µm and 226.76 ± 89.68 µm respectively. At upper 2 site in Group A and Group B was 368.88 ± 120.25 µm and 240.85 ± 93.72 µm respectively. At lower 1 site in Group A and Group B was 313.52 ± 99.92 µm and 262.49 ± 94.33 µm respectively. At lower 2 site in Group A and Group B was 367.93 ± 107.36 µm and 264.52 ± 86.97 µm respectively. The mean internal fit measurement is significantly higher in Group A compared to Group B (P-value%3C0.05). Conclusion The interim crowns fabricated using the conventional technique displayed a less favourable marginal fit and internal adaptation when compared to CAD-CAM fabricated interim crowns. Key Words CAD-CAM, Interim crowns, Marginal fit and internal adaptation

Advances in elastomeric mount concepts for quasi-zero stiffness isolation

Quasi-zero stiffness (QZS) mounts can exploit geometric nonlinearity to minimize stiffness about an operating point which isolates vibrations from a supported source or receiver. Previous research on elastomeric QZS mounts featured 3D printed prototypes but did not consider unique material properties and fabrication artifacts that may impact the static and dynamic behavior of the mounts. Additionally, multi-axis properties and their influence on common, box-like systems supported by several mounts lacks detailed study. To overcome these limitations and improve the practicality of elastomeric QZS mechanisms, this paper discusses nonlinear stiffness, hysteresis, and fabrication issues with elastomeric materials in this context. Multi-material mount designs that improve strength and stability are considered, and their effectiveness for QZS isolation is experimentally evaluated. System-level dynamics are presented for a box-like load supported by QZS mounts. Comparisons between additive and cast materials in the fabrication of QZS mounts are discussed, and the mounts' dynamic stiffness amplification effect is examined for additive and molded materials.

Thermal and rheological properties and processability of thermoplastic lignocellulose

AbstractFossil‐free biobased materials like thermoplastic lignocellulose are gaining attention because of climate issues. However, there is a challenge to make these as thermoplastic as commonly used thermoplastics. Arboform® is one of today's commercially available thermoplastic lignocellulose materials. In this work, the processability of this material was studied in detail and the effects of plasticizers on its processability, rheological, and mechanical properties were determined. Thermal/calorimetry analysis indicated that the processing temperature window was shifted to lower temperature with the use of tributyl citrate (TBC) and poly(ethylene glycol) (PEG 400) plasticizers, thus enabling extrusion at lower temperature. TBC and PEG 400 decreased both the glass transition temperature and melting point of the polylactide component. Surprisingly, they also affected the lignin component, as observed by the decreasing lignin decomposition temperature. It is observed that TBC and PEG400 lowered the stiffness of the compression molded material in the temperature range investigated (−30–180°C), and tensile tests in the presence of TBC revealed a decrease in ductility. Notable is that, in contrast to most thermoplastics, the Arboform® melt increases in viscosity and elastic moduli when the processing temperature was increased (from 180 to 200°C) or when processing time was increased.