Mold Temperature Research Articles

Three‐dimensional numerical simulation on fiber orientation of short‐glass‐fiber‐reinforced polypropylene composite thin‐wall injection‐molded parts simultaneously accounting for wall slip effect and pressure dependence of viscosity

AbstractOn account of the inherent features of the thin‐wall injection molding process, a three‐dimensional numerical model, which accounts for wall slip effect and pressure dependence of viscosity (PDoV), was proposed for a more accurate simulation of the fiber orientation in thin‐wall injection‐molded parts of short‐glass‐fiber‐reinforced polymer composites (SGFRPC). First, the fiber orientation was simulated using the three‐dimensional and mid‐plane models, respectively. The comparison between the simulated and experimental results verifies that the three‐dimensional numerical results were in better agreement with the experimental measurements. Secondly, the influences of wall slip effect and PDoV on fiber orientation in thin‐wall injection‐molded parts of SGFRPC were analyzed based on the three‐dimensional numerical model. The results show that the three‐dimensional numerical simulation simultaneously accounting for wall slip effect and PDoV can better predict the fiber orientation in thin‐wall injection‐molded parts of SGFRPC, suggesting the validation of the proposed model. Finally, five main processing parameters, that is, injection rate, melt temperature, mold temperature, packing pressure, and packing time, were also studied in terms of their influences on the fiber orientation in thin‐wall injection‐molded parts of SGFRPC.

Eş Kanallı Açısal Presleme (EKAP) ile Deforme Edilen ETP Bakırın Mikroyapı ve Mekanik Özelliklerinin İncelenmesi

Severe plastic deformation (SPD), the plastic deformation of materials under high pressure, is used to improve the mechanical and structural properties of materials. Equal Channel Angular Pressing (ECAP) is one of these methods used to produce materials microstructure with submicron or nano-sized grains by applying high pressure to the sample passing through two angular intersecting channels with the same diameters. In recent years, studies on the production of nano-grained metallic materials have increased. The aim of this study is to examine the gradual change of the microstructure and mechanical properties of the material under high pressure and to determine the effect of ECAP on the improvement of these properties. This process is directly related to the internal structure and texture of the material. With the applied method, it is aimed to obtain a more durable material structure. Electrolytic Tough Pitch (ETP) copper material, which is one of the copper types commonly used in electrical applications, was chosen in the study. 12 mm diameter and 35 mm long ETP copper samples, which were not subjected to any heat treatment, processed on 2 mm/s pressing speed, 200°C mold temperature and Bc ECAP route using a 120 ton capacity hydraulic press, a precision machined mold which has 120° (Φ=120°, ψ=20°) channel angle. The changes in the crystal structure, microstructure and mechanical properties of the ECAP applied samples were investigated. According to the data obtained, it was observed that the 4 passes of ECAP application resulted in having finer grains in microstructure and improvement in mechanical properties.

Efficacy of various structural forms of disentangled polyethylene laminates against low velocity impact

Filament-based unidirectional laminates of para-aramid and ultra-high molecular weight polyethylene exhibit excellent impact resistance performance. This research explored the possibility of using disentangled polyethylene (DPE) tape, instead of filaments, as an alternative impact resistant material. The effects of laminate structure, binding resin content and processing temperature on the tensile and impact properties of cross-ply laminates prepared from DPE tape was investigated. Three types of cross-ply laminates prepared from tape, woven fabric of untwisted tape and woven fabric of twisted tape were explored. Tensile properties and low velocity impact resistance of laminates were evaluated. Laminate made from woven untwisted tape showed much lower impact energy absorption than cross-ply laminate, while the woven twisted tape based laminate performed the worst. Cross-ply laminates made with low resin content showed better tensile and impact resistance performances. Cross-ply laminates prepared at higher moulding temperature showed significantly enhanced impact energy absorption than its counterpart prepared at a lower temperature. Therefore, cross-ply laminate of DPE tape with low resin content is ideal for impact resistance applications.

Press-forming molded pulp from repulped liquid packaging board: Role of heat input, pressing force, and defect formation

Laboratory sheets were prepared from repulped liquid packaging board (LPB) for press-forming experiments and tensile tests to study convertibility and mechanical properties of molded pulp material developed from the repulped LPB. Maximum forming depth was utilized as a convertibility indicator, and defect formation in press-formed molded pulp samples was observed with a visual analysis. Female mold temperature and pressing force were altered among press-forming parameters. The results showed that the laboratory sheets had a limited convertibility. The fragile structure of the laboratory sheets was connected to negative effects from the presence of plastic particles in the material. Increased heat input and decreased pressing force improved the convertibility, and the defect formation during the press-forming was aggravated by flattening of the material in flange and bottom regions of the samples. The use of repulped LPB as the raw material in the manufacturing of molded pulp by press-forming was found viable, and the presented solution offers an ecological alternative to conventional recycling of LPB.

Novel Method for Failure Modes Detection in UV-Cured Clear Coated Polymer for Automotive Interior Mechatronic Devices.

Plastic parts used in automotive interior are difficult to coat, due to their low surface energies as well as their sensitivity to temperature and solvents, rendering the development of coating systems for such substrates challenging. Automotive customer requirements are explicit and clear, mainly focused on functional and surface defects. A new failure modes detection methodology of UV clear coated polymers for automotive interior, obtained by a multi-step manufacturing process, is proposed. The polymer complex parts analyzed in this paper are manufactured in various steps as follows: two components plastic injection molding, primer coating, laser engraving, and UV-cured clear coating. The failure modes detection methodology of the parts within each process step is investigated using different tests and analyses as follows: surface tension test, painting adhesion test, optical 3D measuring, energy dispersive X-ray analysis (EDX), and microscopy. A design of the experiments (DoE) based on the Taguchi technique with the aim to detect the influence of the main factors that lead to surface defects was performed. The proposed methodology is validated by a case study. The results showed that the mold temperature and the laser engraving current have a significant influence on the surface defect occurrence. Additionally, a possible contamination of the molding tool can generate the defects. A solution to reduce the occurrence of the failures was proposed, reducing the defect rate from 50% to 0.9%.

Difference in mechanical properties between plastic and metal molds for injection molding a talc reinforced rubber modified polypropylene

AbstractTooling for injection molding is costly, and delivery time is a concern, especially for companies that are on a tight production schedule. The introduction of additive manufacturing tooling for injection molding is an attractive rapid tooling for cutting cost and time not only for prototype parts but also for low volume production, that is, less than 100 parts. In this work, digital acrylonitrile butadiene styrene (ABS) mold insert was 3D printed on a Stratasys PolyJet printer, and then installed on the mold frame for injection molding investigation. The mechanical properties of talc reinforced rubber modified polypropylene (PP) parts molded by 3D printed ABS mold and conventional steel mold are compared. When the 3D printed ABS mold was used, a significantly higher mold temperature was observed during the molding cycles compared to the steel mold because of the lower thermal conductivity of ABS. The ductility of PP parts molded by the ABS mold is much lower compared to the metal mold, while other mechanical properties, such as tensile strength, Young's modulus, and flexural strength are not significantly different.

Research on the Injection Mold Design and Molding Process Parameter Optimization of a Car Door Inner Panel

Numerical simulation of the injection molding of the inner panel of the car door and the optimization of its process parameters were completed. The inner panel and its injection mold were designed by UG software and simulated by the filling and cooling module of the Moldflow software. Different gate schemes were selected to compare quality indicators such as filling time, air pockets, and weld lines to obtain the optimal number of gates. We established the objective function model with gate position as the independent variable, and used a multi-population genetic algorithm to solve the optimal position of the function model to get the best gate position. The mold temperature, melt temperature, cooling time, holding pressure, and holding time were selected as the influencing factors, and volume shrinkage and warpage deformation were selected as the evaluation indicators to design and complete the orthogonal test. The test data were simulated by Moldflow, and the optimal combination of process parameters was determined by range and variance analysis. The BP neural network model related to the molding process parameters, volume shrinkage, and warpage deformation was built, and the trained network model was optimized with the ant colony algorithm. The optimal parameter combination was: mold temperature 76 ° C , melt temperature 205 ° C , cooling time 23.8s, holding pressure 54.7Mpa, and holding time 22.1s. The simulation results showed that volume shrinkage was 13.32% and warpage deformation was 4.315 mm. The design of an injection mold for the car door inner panel was completed and its molding process parameters were optimized.

ANALISIS PENGARUH TEMPERATUR MOLD DAN TEMPERATUR MELT TERHADAP FILL TIME DAN QUALITY PREDICTION PRODUK PLASTIK DALAM PROSES INJECTION MOLDING MENGGUNAKAN SOFTWARE AUTODESK MOLDFLOW ADVISER

This study aims to determine the effect of mold temperature and melt temperature on fill time and quality prediction of tablespoon products. This product is made of plastic with Polystyrene (PS) product material and is produced by the injection molding method. This research was conducted using Autodesk Moldflow Advisor software. From the results of this study, it is known that the best parameter setting among the twelve data obtained is at a mold temperature of 55°C and melt temperature of 220°C with a fill time of 0.2169 s and a high quality prediction of 13.80%, a medium value of 86, 20%, and a low value of 0.00%, because the quality of the resulting product is better and the production time is smaller. So that it can make the production process more effective and efficient

Production of low wear friction lining material from agro-industrial wastes

This research aims at producing and characterizing a low-wear friction lining material using a hybrid mixture of burnt vehicle tyres, pulverized palm kernel shell (PKS), pulverized coconut shell (CS), iron and brass filings obtained from the machine shop floor. The Taguchi method was used to determine the optimum parameter settings to obtain a friction lining with a low wear rate by exploring the signal-to-noise ratios (S/N) of the smaller-the-better. The developed friction lining was subjected to the scanning electron microscopy-energy dispersive spectroscopy (SEM-EDX) and X-ray fluorescence (XRF) to ascertain the functional groups present in the friction lining, their elemental composition and finally the morphology. The control factors used in the Taguchi analysis are the moulding temperature, cure time and heat treatment. The optimum parameter settings for a low wear rate were obtained as follows: moulding temperature of 175 °C, cure time of 8 min and heat treatment time of 3 h. The XRF spectroscopy indicated that the developed friction lining materials contained the following compounds in large proportions: CaO, SiO2, Al2O3 and Fe2O3. The SEM-EDX results for the two image scans reported show that carbon and oxygen were the predominant elements observed in the micrograph.

Industry 4.0 In-Line AI Quality Control of Plastic Injection Molded Parts.

Automatic in-line process quality control plays a crucial role to enhance production efficiency in the injection molding industry. Industry 4.0 is leading the productivity and efficiency of companies to minimize scrap rates and strive for zero-defect production, especially in the injection molding industry. In this study, a fully automated closed-loop injection molding (IM) setup with a communication platform via OPC UA was built in compliance with Industry 4.0. The setup included fully automated inline measurements, in-line data analysis, and an AI control system to set the new machine parameters via the OPC UA communication protocol. The surface quality of the injection molded parts was rated using the ResNet-18 convolutional neural network, which was trained on data gathered by a heuristic approach. Further, eight different machine learning models for predicting the part quality (weight, surface quality, and dimensional properties) and for predicting sensor data were trained using data from a variety of production information sources, including in-mold sensors, injection molding machine (IMM) sensors, ambient sensors, and inline product quality measurements. These models are the backbone of the AI control system, which is a heuristic model predictive control (MPC) method. This method was applied to find new sets of machine parameters during production to control the specified part quality feature. The control system and predictive models were successfully tested for two groups of quality features: Geometry control and surface quality control. Control parameters were limited to injection speed and holding pressure. Moreover, the geometry control was repeated with mold temperature as an additional control parameter.

Морфологія і топографія карбідної фази при легуванні сплава ЖС3ДК-ВІ гафнієм і танталом

This study describes the results of studying the effect of modification/micro alloying with hafnium and alloying with tantalum on the morphology and distribution of the carbide phase in the ZhS3DK-VI alloy microstructure. The carbide phase is an integral structural component of the microstructure of nickel heat-resistant alloys, has a tremendous impact on the strength characteristics of the material. In this regard, the shape, size, and distribution of particles of this phase in the microstructure are of great importance. The formation of the morphology of carbide particles largely depends on the technological factors of casting such as temperature of the ceramic mold, crystallization rate, melt temperature, etc. The higher the temperature parameters and the lower the crystallization rate during casting, the coarser the morphology and topography of carbide particles formed during solidification and, accordingly, the lower the strength characteristics of the material. However, technological parameters also affect the geometry of the casting and it is not always possible to change the technology; so the only possibility is the use of modification or alloying of the alloy upon receipt of the work piece. Such carbide-forming elements as hafnium and tantalum, due to their chemical activity, react with carbon at the stage of crystallization and form thermally stable primary MC-type carbides. The use of hafnium in nickel alloys is limited to a concentration of 0.1 % since at a higher concentration, this element and nickel form a eutectic phase, the melting temperature of which is much lower than the homogenization temperature of the alloys. It is studied the possibility of doping the ZhS3DK-VI alloy with tantalum to form a favorable morphology of the carbide phase. The dispersed carbide particles are taken in the microstructure of the ZhS3DK-VI alloy after experimental work. The chemical composition of the particles is dominated by tantalum, and there is some hafnium.

Study on the Effect of Processing Parameters on Residual Stresses of Injection Molded Micro-Pillar Array.

As one of the main methods for fabricating microstructured surfaces, micro-injection molding has the advantages of short cycle time, high production efficiency, and the potential for batch manufacturing. However, non-negligible residual stresses inside the molded part could affect the replication quality, dimensions, and physical properties of the microstructure. Therefore, studying the effects of processing parameters on residual stresses is a necessary prerequisite to ensure the successful fabrication of microstructured parts. In this paper, an injection molding simulation model of micro-pillar arrays was developed using molecular dynamics software, and a series of injection molding experiments were conducted. It was found that increasing the mold temperature and melt temperature can reduce the thermal residual stresses and molecular orientation stresses, and effectively improve the uniformity of residual stress distribution. The increase in the packing pressure can make the shear field of flow more intense and increase the molecular orientation stresses, thus making the residual stresses more severe.

Comparing the Replication Fidelity of Solid Microneedles Using Injection Compression Moulding and Conventional Injection Moulding.

Polymer surfaces are increasingly being functionalized with micro- and nano- surface features using mass replication methods such as injection moulding. An example of these are microneedle arrays, which contain needle-like microscopic structures, which facilitate drug or vaccine delivery in a minimally invasive way. In this study, the replication fidelity of two types of solid polycarbonate microneedles was investigated using injection compression moulding and conventional injection moulding. Using a full factorial design of experiments for the injection moulding process, it was found that the volumetric injection rate had the largest positive effect on the replication fidelity. The mould temperature and holding pressure were also found to have a positive effect, while the effect of the melt temperature was found to be insignificant for the considered temperature range. For the injection compression moulding process, it was found that a larger compression stroke resulted in a better replication fidelity. A comparison between the replication fidelity for the injection moulding and injection compression moulding indicated that the injection compression moulding process resulted in a higher and more uniform replication fidelity. Using finite element flow simulations, a higher and more evenly distributed cavity pressure was observed compared to the conventional injection moulding process.

A novel process for manufacturing spur gear with uniform microstructure and excellent strength-ductility synergy by warm mold continuous casting

Continuous casting spur gear with uniform microstructure and excellent performance remains challenging due to the intensive radial heat flux and nonuniform circumferential cooling in the traditional cooling mold. In this paper, a novel process for manufacturing spur gear with uniform microstructure and excellent strength-ductility synergy by warm mold continuous casting was proposed. The effects of the warm mold continuous casting process on the microstructure and mechanical properties of the QAl9–4 aluminum bronze spur gear billets were systematically studied by simulations and experiments to evaluate the effectiveness of the process. The induction heated mold reduces the radial temperature gradient while improving the vertical temperature gradient. The cooling rate was uniform at the transvers section of the spur gear and increased with increasing casting speed and mold temperature. Spur gear billets with good surface quality, dimensional precision and uniform microstructures were successfully prepared by warm mold continuous casting, and had excellent tensile stress and elongation of 692 MPa and 41%. The synchronously improved strength and ductility of the continuously cast QAl9–4 aluminum bronze spur gear billets results from a higher volume fraction of micron-sized fine α grains and numerous submicron-sized as well as nanosized coherent Fe-rich κ precipitates. The present process could be beneficial for manufacturing high-quality spur gear more efficiently and may also introduce a promising method in integrated control of shape, microstructure and performance of metallic products by continuous casting.

Microinjection molding of polyoxymethylene stepped‐parts: Morphology, crystallinity, shrinkage, and thermal characterization

AbstractThis paper addresses an experimental investigation of the microinjection molding process through three increasing sections of polyoxymethylene (POM) stepped parts. High and low levels of mold temperature and injection velocity were defined to evaluate the relationship between machine settings, melting and crystallization properties, morphology formation, and shrinkage. The internal morphology of parts showed a mix of structures, from the mold surface towards the core region of each section. Differential scanning calorimetry (DSC) tests highlighted the difficulty of concluding the relationship between the melting temperatures, the processing conditions, and the position of the samples within the mold. The skin‐layer crystallinity declines with increasing part‐step thickness, while the crystallinity degrees of intermediate and core layers are sensitive to the thermal gradients. It was also observed that crystallinity rises along with increasing thickness, benefiting from further polymer chain relaxation and perfection. The unsymmetrical mold cavity results in substantial differences in shrinkage. High shrinkage occurs across the thickness direction due to fast material solidification. The experimental results were supported by the calculated shear rates and temperature fields at the end of the mold‐filling phase. This work yields new insights into comprehending the intricate flow and thermal properties of stepped micropart geometries, which are widely encountered in the plastics manufacturing industry.

Comparison of Conventional and Conformal Cooling Channels in the Production of a Commercial Injection-Moulded Component

Cooling channels are critical in injection mould tooling as cooling performance influences component quality, cycle time, and overall process efficiency. Additively Manufactured moulds allow the incorporation of cooling channels conforming to the shape of the cavity and core to improve heat removal. These conformal channels can reduce the cycle time, reduce mould temperature, and enhance the temperature uniformity on the mould's surface, leading to improved quality of the moulded components and reduced wastage in the production. The design of such channels is more challenging than conventional channels; thus, Computer-Aided Engineering (CAE) has a significant role within the design process. In this paper, a novel design for conformal cooling channels for the production of a commercial component from an industrial partner is investigated. This component had issues of high cycle time and a high defect rate due to residual stresses, resulting in component shrinkage. First, the existing conventional drilled cooling channels in the mould were simulated in Autodesk Moldflow Insight to evaluate temperature distribution and cycle time. Based on the temperature distribution, conformal cooling channels were designed in Solidworks, addressing the problem areas. Next, a simulation of fluid flow in the conformal channels was conducted in ANSYS-Fluent to ensure equal flow distribution in the entire circuit, iteratively arriving at an optimal configuration. Finally, the results of the new conformal channels, including mould temperature and cycle time, were compared with conventional cooling channels in simulation. The results showed a significant reduction in cycle time and improvement in the temperature distribution, thereby minimising residual stresses and shrinkage.

Effect on Compression Molding Parameters in Mechanical Properties of MWCNT/Glass Fiber/Epoxy Composites

Reinforcing fibers, nanofillers, matrix materials, and manufacturing techniques all have a role in the mechanical characteristics of hybrid composites. MWCNTs-reinforced E-glass/Kevlar/epoxy composites are appropriate fillers for structural applications. The impact of different concentrations of MWCNT fillers (0.4%, 0.8%, and 1.2% wt) on the mechanical characteristics of hybrid composites has been studied. Tensile and bending strength, as well as hardness, were measured in compression-molded composites. The effects of compression pressure, mold temperature, and applied pressure on hybrid (0.8% MWCNT) were investigated. When it came to composite tensile and bending strength, compression pressure was the most important factor, closely succeeded by mold temperature and pressure period. Compression molding were optimized, resulting in a tensile strength of 183 MPa, a bending strength of 158.3 MPa, and a hardness value of 23.8 HV.

Influence of Lanthanum-Doped Tungsten Wire Drawing Process on Microstructure and Properties.

A reasonable preparation processing of Lanthanum-doped tungsten wire plays a decisive role in the final properties of the wire. This paper gives the optimum drawing process parameters of lanthanum-doped tungsten wire with φ1.00 mm–φ0.50 mm and explains the phenomenon of coarsening of fiber-like grains in the preparation processing of tungsten wire. The final optimum process parameters of lanthanum-doped tungsten wire are given: the temperature is 950 °C (the first pass temperature is 950 °C, and the temperature decreases by about 20 °C for each pass), the compression ratio is 15%, mold temperature is 550 °C, because of the limitation of equipment conditions, the wire drawing speed is fixed at 0.19 m/s. It is found that the fiber-like grains of the tungsten wire coarsen when the temperature is too high, and it is prone to breakage when the temperature is too low during the drawing process. When the compression ratio is too high (for example, 22%), there is a negative impact on the surface quality and the straightness of the tungsten wire. When the compression ratio is too low, the processing die time is increased, and the production cost is increased.

Non-Dominant Genetic Algorithm for Multi-Objective Optimization Design of Unmanned Aerial Vehicle Shell Process.

This paper uses Pareto-optimized frames and injection molding process parameters to optimize the quality of UAV housing parts with multi-objective optimization. Process parameters, such as melt temperature, filling time, pressure, and pressure time, were studied as model variables. The quality of a plastic part is determined by two defect parameters, warpage value and mold index, which require minimal defect parameters. This paper proposes a three-stage optimization system. In the first stage, the main node position of the electronic chip in the module is collected by the unified sampling method, and the chip calculation index of these node positions is analyzed by the mold flow analysis software. In the second stage, the kriging function predicts the mathematical relationship between the mold index and warpage value and the process parameters, such as melt temperature, filling time, packing pressure, and packing time. In the third stage, using LHD sampling and non-dominant rank genetic algorithm II, a convergence curve of warp value is found near the Pareto optimal frontier. In the fourth stage, the fitting degree of Pareto optimal leading edge curve points was verified by analytical experiments. According to experimental verification, it can be seen that the injection molding factors are pressure and pressure time, because the injection molding time and pressure time are completely positively correlated with the mold indicators, the correlation is the strongest, the mold temperature and glue temperature are not the main influencing factors, and the mold temperature shows a certain degree of negative correlation. In this experiment, the die index is mainly improved by injection time and pressure, optimal injection parameter factor combination and minimum injection index, the optimization rate of the die index is up to 96.2% through genetic algorithm optimization nodes and experimental verification, the average optimization rate of the four main optimization nodes is 91.2%, and the error rate with the actual situation is only 8.48%, which is in line with the needs of actual production, and the improvement of the UAV IME membrane is realized.

Research on Lightweight Injection Molding (CAE) and Numerical Simulation Calculate of New Energy Vehicle

Abstract In this paper, the new energy automobile front-end frame of a factory is taken as the research object, the polypropylene plastic is used to replace the traditional sheet metal material, and the hyper mesh is used to load the front-end frame’s six loading loads, which are the locking limit tension and the cushion impact force, respectively, pedestrian impact strength, condenser support strength, radiator support strength, oil cooler support strength, ensure to achieve certain mechanical properties before production. The maximum warpage deformation is 1.023 mm by mold flow analysis with Moldflow. It does not meet the needs of manufacturers, so it is necessary to optimize the process parameters. We use the mold temperature, melt temperature, holding pressure, injection time, and holding time as test factors, and take the amount of warpage as the optimization goal. Then this paper uses the orthogonal test method to design the test plan and establishes 25 groups of 5-level 5-factor orthogonal tests. Moreover, the effect of the deformation on the warpage is analyzed. These are all to obtain the minimum warpage deformation and find the optimal combination of process parameters. Verification by numerical simulation shows that the warpage is reduced to 0.632 mm. By analyzing the range and variance, the combination of process parameters is optimized, and the warpage is effectively reduced. In the premise of satisfying mechanical properties, plastic instead of steel, to achieve a lightweight design. It provides correct theoretical guidance for setting the actual injection molding process parameters.