Mold Design Research Articles

Stability Analysis of the Rapid Heating Multilayer Structure Mold by the Contact Error and Thickness of Layers

Rapid heating of the mold surface is necessary for the high-gloss, high-productivity injection molding process. A rapid heating mold system that uses a carbon nanotube (CNT) as a heating element was investigated because of its structure. For CNT web film to be utilized in the injection molding process, heating must be applied inside the mold. That can cause poor contact at the contact area between the mold and the CNT heating element, leading to local temperature deviation and resistance changes that reduce the heating stability of the CNT surface element. Additionally, the multilayer structure of the CNT web film can cause heat-transfer performance variations due to the different layer thicknesses. To address these issues, an adjustable flush was constructed at the contact area between the electrode inside the mold and the insulator to analyze the heating behavior of the CNT heating element as a function of dimensional deviation. The thermal durability of the CNT web film was also evaluated by analyzing the Raman spectra and measuring resistance changes caused by local overheating. The film can withstand high temperatures, with a flush limit value of 0.3 mm. An optimization analysis was conducted to determine the ideal thicknesses of the multilayer CNT web film, insulator, and electrical insulator. Optimal layer thicknesses were found to be 10 μm, 5 mm, and 0.5 mm, respectively. The main variables of the rapid heating mold required for application to the injection process were identified and reflected in the mold design to suggest directions for commercialization.

Identify Product Defects In The Injection Molding Process

Injection molding is a method of processing thermoplastic polymer seeds that are inserted into a hopper intoa barrel then the material is pushed by a screw to enter the mold (mold). However, products produced by injectionmolding machines are sometimes still found defects in the product. Common defects include: Short shot, Flash, Sinkmark, Flow mark, Black spot, Warpage and Colour streaks. And the most causative factors are materials that do notcomply with production procedures, lack of checking on the control panel, mold design errors (mold).Keywords - Injection molding; defects; mold

Global Sensitivity Analysis of Factors Influencing the Surface Temperature of Mold during Autoclave Processing.

During the process of forming carbon fiber reinforced plastics (CFRP) in an autoclave, deeply understanding the global sensitivity of factors influencing mold surface temperature is of paramount importance for optimizing large frame-type mold thermally and enhancing curing quality. In this study, the convective heat transfer coefficient (CHTC), the thickness of composite laminates (TCL), the thickness of mold facesheet (TMF), the mold material type (MMT), and the thickness of the auxiliary materials layer (TAL) have been quantitatively assessed for the effects on the mold surface temperature. This assessment was conducted by building the thermal-chemical curing model of composite laminates and utilizing the Sobol global sensitivity analysis (GSA) method. Additionally, the interactions among these factors were investigated to gain a comprehensive understanding of their combined effects. The results show that the sensitivity order of these factors is as follows: CHTC > MMT > TMF > TCL > TAL. Moreover, CHTC, MMT, and TMF are the main factors influencing mold surface temperature, as the sum of their first-order sensitivity indices accounts for over 97.3%. The influence of a single factor is more significant than that of the interaction between factors since the sum of the first-order sensitivity indices of the factors is more than 78.1%. This study will support the development of science-based guidelines for the thermal design of molds and associated heating equipment design.

A seamless CAD/CAM integration approach for venting system generation in injection mold design

A seamless CAD/CAM integration approach for venting system generation in injection mold design

Comparison of Linear and Nonlinear Twist Extrusion Processes with Crystal Plasticity Finite Element Analysis.

The mechanical characteristics of polycrystalline metallic materials are influenced significantly by various microstructural parameters, one of which is the grain size. Specifically, the strength and the toughness of polycrystalline metals exhibit enhancement as the grain size is reduced. Applying severe plastic deformations (SPDs) has a noticeable result in obtaining metallic materials with ultrafine-grained (UFG) microstructure. SPD, executed through conventional shaping methods like extrusion, plays a pivotal role in the evolution of the texture, which is closely related to the plastic behavior and ductility. A number of SPD processes have been developed to generate ultrafine-grained materials, each having a different shear deformation mechanism. Among these methods, linear twist extrusion (LTE) presents a non-uniform and non-monotonic form of severe plastic deformation, leading to significant shifts in the microstructure. Prior research demonstrates the capability of the LTE process to yield consistent, weak textures in pre-textured copper. However, limitations in production efficiency and the uneven distribution of grain refinement have curbed the widespread use of LTE in industrial settings. This has facilitated the development of an improved novel method, that surpasses the traditional approach, known as the nonlinear twist extrusion procedure (NLTE). The NLTE method innovatively adjusts the channel design of the mold within the twist section to mitigate strain reversal and the rotational movement of the workpiece, both of which have been identified as shortcomings of twist extrusion. Accurate anticipation of texture changes in SPD processes is essential for mold design and process parameter optimization. The performance of the proposed extrusion technique should still be studied. In this context, here, a single crystal (SC) of copper in billet form, passing through both LTE and NLTE, is analyzed, employing a rate-dependent crystal plasticity finite element (CPFE) framework. CPFE simulations were performed for both LTE and NLTE of SC copper specimens having <100> or <111> directions parallel to the extrusion direction initially. The texture evolution as well as the cross-sectional distribution of the stress and strain is studied in detail, and the performance of both processes is compared.

Investigation into the Three-Stage Formation of Micro-Channels with Ultra-Thin Titanium Sheets Used for Proton-Exchange Membrane Fuel Cell Bipolar Plates.

Titanium has a low density and high corrosion resistance. In order to achieve the goal of a lightweight material, and to extend the normal working hour of proton-exchange membrane fuel cells (PEMFCs), ultra-thin titanium plates were chosen to manufacture the key components-bipolar plates (BPs). For the purpose of overcoming the challenges of manufacturing with a large depth to width ratio, a multi-stage formation process was established with characteristics such as high efficiency and a lower price. In this study, the process parameters were examined through an experimental approach. The outcomes show that the channel formed by multistage forming is deeper than that formed by single-stage forming under the same displacement conditions. To achieve greater flow depths, it is recommended to increase the displacements as much as possible during both the first- and second-stage forming processes. The implementation of three-stage forming can effectively reduce the maximum thinning rates within flow channels while improving the overall deformation uniformity. This method deviates from traditional one-stage loading processes by adopting multi-stage loading instead. By employing appropriate mold designs, material deformation and flow can be enhanced throughout gradual loading processes, thereby preventing strain concentration and enhancing the ultimate formation height accuracy within micro-flow channels. Consequently, the proposed three-stage forming process proves highly appropriate for the mass production of BPs utilizing titanium plates.

Analysis of variation of iron coating rubber for upper punch moulds

This study investigates the evolution of ceramic mold design and manufacturing processes, focusing on the role of punches in shaping ceramics through injection molding techniques. Key findings reveal diverse punch types—isostatic, pressure rubber, and exhaust punches—tailored to meet varying market demands. By employing ASTM 1045 high-performance 45 steel, we explore the impact of these punches on product quality and efficiency. Qualitative research methods, comprising literature review, observations, and interviews, were utilized to analyze the production process, formulation of ceramic bodies, and variations within ceramic molding tools and procedures. Our work contributes valuable insights into the advancements of injection molding technology, particularly in the context of rapid growth in polymeric materials' usage and their potential for mass production via fast cycle times and high quantities.&#x0D; Highlight :&#x0D; &#x0D; Diverse punch types tailored to meet market demands, including isostatic, pressure rubber, and exhaust punches&#x0D; Utilization of ASTM 1045 high-performance 45 steel for improved product quality and efficiency&#x0D; Employment of qualitative research methods, such as literature reviews, observations, and interviews, to examine the production process, ceramic body formation, and tool variations&#x0D; &#x0D; Keywords: ceramic mold, punches, injection molding, ASTM 1045 steel, diversified punches, qualitative analysis

Optimization of forward pulsed currents for combining the precision shaping and polishing of nickel micro mould tools to reduce demoulding defects

Precise tooling is vital for defect-free production of micro injection moulded (μ-IM) or hot-embossed products. The demoulding stage of such moulding and forming processes poses a serious challenge to the integrity of thin miniature features because of friction, adhesion, and thermal stresses. Typically, micro moulds involve geometrically textured patterns or features such as linear ridges, pillars, channels, and holes, the characteristic dimensions of which range from 10 to 300 μm. Realistically complex mould designs, containing precision micro features (enhanced fillet radius and positive draft angle) and high surface quality, are presented in this work. Electropolishing based on forward pulse currents (PC) has been used to shape and polish Ni micro moulds that contain sets of micron-scaled linear ridges and star patterns in order to ease the separation of moulded polymeric parts from the metallic mould during ejection and demoulding. The use of forward pulsed currents improved the mould design by increasing the fillet radii and draft angle while keeping the surface roughness low and maintaining a good surface shine. An optimization study of forward PC using a green solution of nickel sulfamate varied EP times (0–70 min) and duty cycles (40, 50, 60, and 70%) at a process conditions of 2.8 V, 50 °C, and 250 rpm. The best topographical and morphological changes were observed for a typical microfluidic channel (w × h, 100 × 110 μm) with an EP time of 70 min and 50% duty cycle: fillet radius increased by 3.8 μm, draft angle by 3.3°, and the channel width reduced by 11.4% while surface roughness changed by 8.6% and surface shine improved by 48.9%. Experimental validation was performed using hot embossing wherein the electropolished Ni mould replicated the micro channels and star patterns in PMMA chips with notably fewer burrs, material pile up, and no feature distortion. Moreover, there was a reduction in the side wall roughness of micro channels in PDMS casting with electropolished Ni mould by 16%. Hence, this work presents a significant scientific contribution to improving the efficiency of micro mould tools and reduces the defects caused by friction and adhesion in replicated polymeric parts.

Experimental Characterization of Screw-Extruded Carbon Fibre-Reinforced Polyamide: Design for Aeronautical Mould Preforms with Multiphysics Computational Guidance

In this research work, the suitability of short carbon fibre-reinforced polyamide 6 in pellet form for printing an aeronautical mould preform with specific thermomechanical requirements is investigated. This research study is based on an extensive experimental characterization campaign, in which the principal mechanical properties of the printed material are determined. Furthermore, the temperature dependency of the material properties is characterized by testing samples at different temperatures for bead printing and stacking directions. Additionally, the thermal properties of the material are characterized, including the coefficient of thermal expansion. Moreover, the influence of printing machine parameters is evaluated by comparing the obtained tensile moduli and strengths of several manufactured samples at room temperature. The results show that the moduli and strengths can vary from 78% to 112% and from 55% to 87%, respectively. Based on a real case study of its aeronautical use and on the experimental data from the characterization stage, a new mould design is iteratively developed with multiphysics computational guidance, considering 3D printing features and limitations. Specific design drivers are identified from the observed material’s thermomechanical performance. The designed mould, whose mass is reduced around 90% in comparison to that of the original invar design, is numerically proven to fulfil thermal and mechanical requirements with a high performance.

A Leap Into The Future

Plyable’s automated mould design offers and alternative to the limitations of traditional manufacturing mould design and can even reduce lead times

Analysis of Plastic Injection Mold Design and Cooling System

Plastik malzeme, otomotivden beyaz eşyaya, kırtasiye malzemelerinden oyuncaklara, mutfak eşyalarından ofis malzemelerine kadar her sektörde yerini almıştır. Plastik enjeksiyon yöntemi, plastik parça üretiminde en çok kullanılan imalat yöntemidir. Üretimi talep edilen plastik malzemeler için, plastik enjeksiyon kalıpları tasarlanmaktadır. Bu kalıplar tasarlanırken, ilk aşamada ürün tasarımı göz önüne alınır. Üretime uygun, kısa sürede ve kaliteli bir imalat yapmak için en önemli faktör tasarlanan ürünün, üretilebilir olmasıdır.&#x0D; Bu çalışmada plastik bir kırtasiye-oyuncak sektörü diyebileceğimiz bir sulu boya paletinin ürün tasarımı ve kalıp tasarımı aşama aşama incelenecektir. Ürün, kalıplamaya uygun hale getirilip, kalıp tasarımı gerçekleştirilmiştir. Tasarımı biten ürün, daha üretimi yapılmadan yolluk ve soğutma sistemlerinde karşımıza çıkabilecek olası hataları gözlemlenmiştir. Yapılan analize göre yolluk giriş yerinin en iyi ürün merkezinden olacağı ama maliyeti arttırdığı tespit edilip soğuk yolluk sistemi kullanılarak bir tasarım gerçekleştirilmiştir. Hava birikecek yerler tespit edilmiştir, bu bölgelere hava çıkışını sağlayacak cepler kullanılması önerilmiştir. Soğutma kalitesiyle ilgili yapılan analiz ile ürünün et kalınlığının homojen olduğu ve erken donma ihtimalinin düşük olduğu tespit edilmiştir. Bu yüzden et kalınlığına müdahale edilmesine gerek görülmemiştir.

Numerical investigation of pull in control of rectangular AA1050 rolling ingot through the design of convex mould during direct chill casting process

The pull in effect/concavity on the lateral faces of the ingot is formed during the solidification of the ingot due to the thermal stresses induced in the ingot. A part of rolling ingots with pull in effect are cut by a conventional cutting process which affects the recovery and increases wastage and cost of production. In the present work, an elemental death and birth technique was used to develop a numerical model to study mechanical and thermal behavior during the solidification of AA1050 rolling ingot. The results of the model are validated with the results of the Williams model available in the literature. Furthermore, different mould designs provided with convexity on lateral surfaces with a convexity radius of 16 mm to 26 mm were numerically analyzed. A series of numerical simulations were conducted with varying mould convexity with an increment value of one. The results revealed that, providing convexity to the mould is an effective method to control the pull in effect during the direct chill casting process. The convexity radius of 26 mm is enough to completely eliminate the pull in radius of 23.34 mm for the rectangular AA1050 ingot.

ANALISA PENGARUH CACAT PRODUK AIR TRAPS PADA SIMULASI INJECTION MOLDING

Injection molding, is a manufacturing process for making plastic components. The plastic material is melted, pressed into a mold, then cooled to become the finished product. Injection molding has the potential for air problems or trapped air affecting the quality of the final product. Test data is obtained from software analysis. The bucket cast test results showed defects in the form of holes or unwanted mold marks due to air trapped in the injection molding process. Injection pressure affects air traps defects. At a pressure of 170 Mpa, 180 Mpa, 190 Mpa at a temperature of 200 °C, there is no significant change in the pressure difference and there are still bubble defects in the product, but it is still within the allowable tolerance limits. Optimizing injection pressure is important to reduce bubble defects in the injection molding process. To overcome the air problem in the injection molding process, several ways that can be done include choosing the right plastic raw materials, optimizing injection pressure, adjusting injection speed, and paying attention to good product design or mold design.

IMPLEMENTASI SISTEM KONTROL PENGGERAK MOTOR STEPPER PADA PROSES MOLDING MICROPLASTIC BERBASIS PID MENGGUNAKAN PLC DAN ARDUINO

The current industry has entered an era where every production process incorporates automation and data exchange in its manufacturing. This era is known as Industry 4.0. Industry 4.0 has had a significant impact on various industrial sectors, particularly in the production of plastic goods using techniques such as injection molding. This process is capable of producing more precise products. In the injection molding process, a well-controlled system is needed to guide plastic pellets according to the intended mold design, utilizing actuators like stepper motors. This research aims to apply the PID (Proportional-Integral-Derivative) method to control stepper motors in microplastic molding processes. The proposed system has been successfully implemented and can produce products according to the planned specifications. The most suitable PID parameter values for controlling the stepper motor are Kp = 14, Ki = 0.007, and Kd = 7000. Changing the setpoint value from 2500 to 2700 has an impact on the molding results, with the best results achieved at a setpoint value of 2700. A setpoint value of 2700 ensures that the mold and nozzle are in the correct, tight position, allowing the molding process to proceed smoothly in line with the provided design.

Uticaj položaja hranitelja na temperaturnu raspodelu predgrevanja pri simulaciji aluminotermijskog zavarivanja šina

One of the most used techniques for making a continuous rail track is aluminothermic welding. This technique has its advantages in its simplicity, portability, and it does not require external energy when repairing or connecting tracks. One of the crucial parts when implementing this process is the mold design that influences the solidification of the casting. In this study three models were investigated that have varying positions of the feeders: asymmetrical mold, centered mold, and symmetrical mold. The focus of the paper is to determine how the position of the feeder effects the preheating of the side rails that would be welded together. This was carried out using NovaFlow &amp; Solid CV and utilizing its sensor function. The rail was modeled after the 49E1 standard rail, and the preheating was carried out by simulating a burner at 1000 oC for 900 seconds. The asymmetrical model had a negligible increase in temperature, while the symmetrical and centered model were similar. One side rail was more heated than the other, which can be attributed to the positioning and shape of the burner source area.

Adaptations to a triaxial equipment for testing of mine tailings

Mine tailings are usually materials with particle sizes in the range of silts, frequently exhibiting very low consistency. This low-consistency condition poses challenges when trying to reconstitute specimens for triaxial testing. The first part of this work presents a description of the main geotechnical properties of mine tailings used in the tests and the difficulties associated with triaxial testing. Next, some developments, in terms of equipment and testing procedure, are presented: the design of a compaction mould, the specimen preparation using moist tamping and the lubricated end platens. Finally, the process of dismantling the specimen using freezing is presented and discussed. The final part of the paper presents some results and summarizes the challenges associated with adapting the equipment and implementing the testing procedures.

Effects of hollow sand mold on the microstructure and mechanical properties of a low pressure aluminum alloy casting

The hollow mold revolutionizes conventional dense mold design as it can optimize the solidification and cooling processes of casting and offer potential to improve performance of castings. In this paper, the effect of hollow mold structures on the microstructure and mechanical properties of a low pressure thin-walled aluminum alloy conical cabin casting was investigated. A hollow mold combined by four sectors with different shell thicknesses was tactfully designed. The hollow mold structures delayed the cooling and solidification of casting. They significantly reduced the pore defect from 0.4 % to 0.03 % at the lower, from 0.68 % to 0.04 % at the middle and from 0.3 % to 0.03 % at the top, compared to dense mold. In the lower and middle areas of casting, improvements of 1.0 % and 1.1 % in mechanical properties were respectively achieved when applying 50 mm-thick-shell hollow sand molds compared with using dense sand mold, while an improvement of 1.1 % was achieved in the upper area of casting with 70 mm-thick-shell. This allows designers to create hollow molds with different shell thicknesses depending on the position in the casting to meet specific needs. For example, thin shell for the bottom to achieve high fluid flow and feeding while thick shell for the top for improved cooling. For castings with wall thickness of 10 mm–20 mm, the most effective shell thickness for the hollow mold is 50 mm–70 mm. The hollow mold provides the feasibility to differentiated semi-quantitatively control the solidification and cooling processes of castings, which can be applied in production of high-end castings in the future.

Modelling smart machining process towards intelligent manufacturing - a case study

According to the concept of Industry 4.0 (even Industry 5.0) managers strive to improve production by applying information technologies and next integrating them into operational technologies, that’s enabled to transform the traditional into Intelligent Manufacturing (IM). Introduction of these changes is particularly important to improve the machining process, which is complex and dynamic. In this article the smart machining process is modelled and demonstrated for a real-world case, namely manufacturing of the die casting mould in order to increase life of the die casting mould. Therefore, firstly, the data was acquired based on the applied within a company information system and additionally on the IoT sensors from the diecasting machines, the moulds themselves and the process parameters which are used during the manufacturing process of the diecasting parts from such mould. Next, a model for predicting the life of the die-casting mould using regression analysis, based on acquired data was applied. The results of mould design and mould manufacturing process are ultimately visible on the die casting machines. Such gathered data is used to model the prediction of the possibilities for increasing life of the die casting was elaborated.

ANALISIS RANCANGAN PERBAIKAN DESIGN MOLD DENGAN MENGGUNAKAN METODE TAGUCHI DI PT X

PT X Indonesia is one of the Korean Foreign Manufacturing Companies (PMA) that produce injection molding. December 2022 PT X Indonesia received customer complaints from PT. Y because of defects in products such as: gas burn, white spot, weld line, bending, short shoot, bubbles, flashing, silver, wrong color, and contamination. Flashing is a type of defect that the largest number of ratios reaches 10% while the defect restriction of the customer is 2% so the company and the authors choose the theme of improvement in 2018 is the improvement of molding design to reduce flashing defects in plastic products. The method used in the proposed improvement of molding design is the taguchi method by making 4 point suggestion that is the level 1 slot dimension: Hight 70mm taper 15 °, level 2: Hight 70mm taper 10 °, level 3: High 70mm taper 5 °; insert level 1 dimension: 70mm taper insert 1 °, level 2: 70mm taper deepness insert 2 °, level 3: 70mm taper deepth insert 3 °; clamping tolerance force level 1: + 5%, level 2: + 8%, level 3: + 10% and parting line line length 1: 10mm, level 2: 20mm, level 3: 30mm. The proposed best molding design improvements are in Slast dimensions: Hight 70 mm taper 15 °, Insert: 70mm taper deepness 2 °, clamping force tolerance + 10%, Parting Line Length: 30mm. The smallest flashing flaw was found to be 0.1% in confirmatory experimental conditions, much smaller than the specified target defects of 2%. Cost reduction cost obtained by PT ART Mold Indonesia with the proposed repair on Molding design that is Rp 115.600.000,00 per 1 molding. The cost savings incurred by customers of PT ART Mold Indonesia is worth Rp 784.080.000,00 per year

Modeling Electrical Conductivity of Injection-Molded Polymer Composite Bipolar Plates

Bipolar plates can be responsible for up to 40% of the total stack cost and 80% of the weight of a polymer electrolyte membrane fuel cell [1]. To reduce these cost and weight limitations, this work explores injection molding of polymer composites. Injection molding is well-suited for mass production and polymeric materials can significantly reduce the weight of traditional metallic bipolar plates. While polymers lack electrical conductivity, fillers can be added to fabricate conductive polymer composites. The main objective of this research is to model and injection mold polymer composites that will meet the United States Department of Energy technical target for bipolar plate electrical conductivity (> 100 S/cm).A fiber contact model was developed to predict electrical conductivity based upon direction in the material, fiber alignment, fiber length and diameter, fiber concentration, and fiber conductivity [2]. Fiber alignment was measured experimentally by imaging cross sections of injection-molded nylon/carbon fiber composites. Imaging was performed on samples with different weight percentages of carbon fiber and from different mold designs to compare how fiber angles change based on mold geometry. To reduce the significant time required to measure fiber angles experimentally, computer recognition and processing of fiber alignment was developed. Nylon composites were injection molded with carbon fiber loadings ranging from 10 to 40 wt%. Modeling predictions show good correlation within 20% of experimental conductivity measurements. Samples with at least 20 wt% carbon fiber exceeded the US DOE technical target for bipolar plate conductivity, reaching 250 S/cm. In addition to modeling electrical conductivity, the Halpin-Tsai equations are used to model the elastic modulus and ultimate strain of the polymer composite. Tensile testing showed that the modulus of elasticity increases with carbon fiber loadings up to 30 wt%, reaching 7.3 GPa. At loadings above 30 wt%, the higher filler content can create voids which decrease the modulus of elasticity. De Las Heras, A.; Vivas, F. J.; Segura, F.; Andujar, J. M., From the cell to the stack. A chronological walk through the techniques to manufacture the PEFCs core. Renewable & Sustainable Energy Reviews 2018, 96, 29-45.Weber, M.; Kamal, M. R., Estimation of the volume resistivity of electrically conductive composites. Polymer Composites 1997, 18 (6), 711-725. Figure 1