Mold Manufacturing Research Articles

High-Resolution Nanotransfer Printing of Porous Crossbar Array Using Patterned Metal Molds by Extreme-Pressure Imprint Lithography.

High-resolution nanotransfer printing (nTP) technologies have attracted a tremendous amount of attention due to their excellent patternability, high productivity, and cost-effectiveness. However, there is still a need to develop low-cost mold manufacturing methods, because most nTP techniques generally require the use of patterned molds fabricated by high-cost lithography technology. Here, we introduce a novel nTP strategy that uses imprinted metal molds to serve as an alternative to a Si stamp in the transfer printing process. We present a method by which to fabricate rigid surface-patterned metallic molds (Zn, Al, and Ni) based on the process of direct extreme-pressure imprint lithography (EPIL). We also demonstrate the nanoscale pattern formation of functional materials, in this case Au, TiO2, and GST, onto diverse surfaces of SiO2/Si, polished metal, and slippery glass by the versatile nTP method using the imprinted metallic molds with nanopatterns. Furthermore, we show the patterning results of nanoporous crossbar arrays on colorless polyimide (CPI) by a repeated nTP process. We expect that this combined nanopatterning method of EPIL and nTP processes will be extendable to the fabrication of various nanodevices with complex circuits based on micro/nanostructures.

A study of the workers’ working conditions in areas of the manufacture castings from copper alloys

The results of the study of workers working conditions at the areas of the manufacture of castings from copper alloys are presented. It is noted that the main production factors of working conditions are noise, vibration, dustiness, gas contamination, temperature, intensity of infrared (thermal) radiation, severity and labor process intensity. The results have shown that at all workplaces there are exceedances of permissible values for noise and local vibration, the content of dust and harmful substances in the air of the working environment, the intensity of infrared (thermal) radiation and temperature. It is noted that the work performed due to the severity and labor process intensity can negatively affect the workers’ health.

Mastering the technology for production of high-strength cast iron with nodular graphite for manufacture of castings in the conditions of JSC Ural Steel

Mastering the technology for production of high-strength cast iron with nodular graphite for manufacture of castings in the conditions of JSC Ural Steel

Effect of Cavitation Phenomenon on the Quality of High-Pressure Aluminium Alloy Castings

This article presents an analysis of the effect of cavitation on the erosion of pressure moulds intended for the HPDC casting mould manufacturing process. Changes in the surface area of the eroded areas were investigated via photographs of castings at the beginning of the mould life as well as at 30%. The individual process variables were described and their influence verified via the cavitation potential module of the Flow3D simulation programme. The results are presented graphically with a description of the relationships and observations. The summary provides an explanation of the results and the dependencies that occurred.

Manufacturing of Composite Castings by the Method of Fused Models Reinforced with Carbon Fibers Based on the Aluminum Matrix

Manufacturing of Composite Castings by the Method of Fused Models Reinforced with Carbon Fibers Based on the Aluminum Matrix

Environmental impact of process constrained topology optimization design on automotive component’ life

The components’ lightweighting has been pursued, especially in the transport industry, for greenhouse gas reduction. Topology optimization, being able to allocate the material within a provided design space, is a mathematical method that can support the design of lightweight components, preserving, at the same time, their mechanical performances. In this paper, a standard shape of a component, specifically an automotive bracket, was topology optimized by estimating the impacts of the new designs from an eco-friendly point of view. A subtractive, an additive and a casting manufacturing process were considered as possible manufacturing routes achieving an optimized geometry of the component for each of them. The topology optimizations were performed considering each processes’ peculiarities, introduced as constraints. Same strength for a given set of loads and boundary conditions was the target of each analysis. The component’s lightening can be considered environmentally friendly just after assessing the impacts associated with all the stages of the product’ life cycle. Indeed, each phase of the product’ life cycle can be affected, differently, by the performed topology optimization taking into account the peculiarities of the employed manufacturing process. The overall considerations on the most environmentally safe strategies can, therefore, change according to the specificities of the optimized shapes. The topology optimization showed its utmost potentiality, from a sustainable point of view, if applied to additive manufacturing techniques for the advantages arisen by the capability to manufacture complex shapes benefiting also of reduction time process owing to less material to be deposited.

Development of aluminium-tin alloy for high strength application

This study looks into the preparation of an aluminium-tin alloy for high strength applications. The aluminium base metal was melted using a gas-fired lift-out crucible furnace. The basic aluminium (>99% Al) was melted first, and the control sample was cast into one of the prepared moulds at 710 °C. This inquiry was divided into two stages, the first being casting manufacture and the second being experimental testing. In the first stage, a set amount of aluminium and tin ingots were placed within a massive crucible and melted at temperatures of 710 °C, which is somewhat higher than the melting temperature of aluminium (680 °C). The investigation's second phase entails analyzing the microstructure and properties of the product. The investigation's main focus was on the tensile strength, metal composition, and mechanical characteristics of the aluminium-tin alloy. Tensile specimens of ASTM standards were prepared in the longitudinal direction and tested using a Universal Testing Machine to ascertain the tensile strength (UTM). Micro hardness was assessed using a Brinell Hardness Tester. In order to determine how the alloys' metal composition manifested itself in their microstructure, the optical microscope and scanning electron microscope (SEM) observations of the alloys were mostly used.

Framework Development for Patient-Specific Compliant Aortic Dissection Phantom Model Fabrication: Magnetic Resonance Imaging Validation and Deep-Learning Segmentation.

Type B aortic dissection is a life-threatening medical emergency that can result in rupture of the aorta. Due to the complexity of patient-specific characteristics, only limited information on flow patterns in dissected aortas has been reported in the literature. Leveraging the medical imaging data for patient-specific in vitro modeling can complement the hemodynamic understanding of aortic dissections. We propose a new approach toward fully automated patient-specific type B aortic dissection model fabrication. Our framework uses a novel deep-learning-based segmentation for negative mold manufacturing. Deep-learning architectures were trained on a dataset of 15 unique computed tomography scans of dissection subjects and were blind-tested on 4 sets of scans, which were targeted for fabrication. Following segmentation, the three-dimensional models were created and printed using polyvinyl alcohol. These models were then coated with latex to create compliant patient-specific phantom models. The magnetic resonance imaging (MRI) structural images demonstrate the ability of the introduced manufacturing technique for creating intimal septum walls and tears based on patient-specific anatomy. The in vitro experiments show the fabricated phantoms generate physiologically-accurate pressure results. The deep-learning models also show high similarity metrics between manual segmentation and autosegmentation where Dice metric is as high as 0.86. The proposed deep-learning-based negative mold manufacturing method facilitates an inexpensive, reproducible, and physiologically-accurate patient-specific phantom model fabrication suitable for aortic dissection flow modeling.

The effects of cooling rate (mould temperature) on HDPE gears produced through injection moulding

The effects of mould temperature (cooling temperature) on molten HDPE (Hostalen GC 7260) during manufacture, is evaluated in this paper. HDPE gears were produced at varying mould temperatures using Injection Moulding. Optimised injection values for melt temperature, injection volume, hold pressure, and hold time were obtained, and then held constant while the mould temperature was altered.Analysis on how the mould temperature affected peak melting points and crystallinity were then carried out using differential scanning calorimetry (DSC). These revealed that crystallinity improved as the mould temperature was increased from 22 °C to 65 °C. Gears produced at similar cooling temperatures were then meshed on a gear test rig and run at 1000 rpm, using different torque loadings. Their wear rates, and modes of failure were then analysed, and comparisons were made to ascertain how the differing mould temperatures employed during the injection moulding manufacturing process affected their wear characteristics. Topographical analysis of worn gear teeth was performed using scanning electron microscopy (SEM). It was noted that gear tooth wear and failure was dependent on the mould temperature employed during the manufacturing process. Gears produced at 65 °C showed improved tooth surface wear resistance at lower loads (0.5 Nm and 1 Nm) compared to those produced at 22 °C, but were more likely to fail through tooth fracture at the pitch line due to excessive material removal. Gears produced at lower mould temperatures, on the other hand, exhibited better wear resistance for higher loads (3 Nm and 4 Nm), compared to those produced at higher mould temperatures, and were more likely to fail due to material flow. The results show a correlation between mould temperature, crystallinity, and gear performance. Based on wear rate responses of gears produced at differing mould temperatures to the application of varying torque loadings, a Mould Temperature to Torque Reference Chart for HDPE is presented.

Effect of Current and Pulse-on Time on Material Removal Rate and Surface Roughness of Tungsten Carbide in Electric Discharge Machine Die-sinking

The focus of manufacturing for tungsten carbide applications often demands a smooth surface quality as the result of the Electric Discharge Machine (EDM) die-sinking process, especially in the manufacture of die and mold with tungsten carbide material processed using a die-sinking EDM machine. The purpose of this study is to analyze the effect of electric current and pulse-on time on the Material Removal Rate (MRR) and surface roughness of tungsten carbide. Through the experimental method, the parameters varied, namely electric current 17 A, 20 A, 23 A, and pulse-on time 30 µs, 55 µs, and 80 µs. MRR was calculated through weight loss. Surface roughness was obtained from a surface roughness tester and a Scanning Electron Microscope for surface morphology. The results showed that the highest material removal rate was 1.509 mm3/min at 23 A and 30 µs, and the lowest material removal rate was 0.262 mm3/min at 17 A and 80 µs. The highest surface roughness value was 4.278 µm at 23 A and 80 µs. The lowest surface roughness value was 2.166 µm at 17 A and 30 µs. The tungsten carbide surface topography results are crater, globule, crack, and porous. The greater the current used, the higher the MRR value and surface roughness. Meanwhile, the greater the pulse-on time used, the MRR value decreases, and the surface roughness increases.

Application of CAE for mold flow analysis in plastic molding mold design

Abstract In this paper, injection molding is used as a method of plastic molding, which is a method in which plastic in the molten state is injected into a closed mold cavity by compression, and the molten material fills the cavity and is then cured by cooling to maintain the shape in the mold. The basic structural form and parameters of the mold’s parting surface, winding injection system, and cooling system are determined by mold flow analysis. CAE analysis is used to move the mold filling analysis to the computer, and the mold casting and cooling system’s design scheme can be evaluated and optimized according to the analysis results. After Moldflow software analysis of warpage deformation, the total warpage deformation of the molded part was obtained, the maximum deformation reached 0.931mm, the maximum deformation from uneven cooling was 0.192mm, the maximum deformation from uneven shrinkage was up to 0.942mm, the deformation from shrinkage was even larger than the integrated deformation, which had a greater impact on the final deformation of the molded part. It has a relatively large impact on the final deformation of the plastic part. Therefore, using CAE can improve the efficiency of mold design, optimize the structural design of the mold, effectively improve the quality of the mold and reduce the mold manufacturing cost. The promotion of its application is in line with the development of the times and promotes the rapid development of the injection mold field.

Three-Dimensional Printing of Large Ceramic Products and Process Simulation.

Ceramic 3D printing is a promising technology that overcomes the limitations of traditional ceramic molding. It offers advantages such as refined models, reduced mold manufacturing costs, simplified processes, and automatic operation, which have attracted a growing number of researchers. However, current research tends to focus more on the molding process and print molding quality rather than exploring printing parameters in detail. In this study, we successfully prepared a large-size ceramic blank using screw extrusion stacking printing technology. Subsequent glazing and sintering processes were used to create complex ceramic handicrafts. Additionally, we used modeling and simulation technology to explore the fluid model printed by the printing nozzle at different flow rates. We adjusted two core parameters that affect the printing speed separately: three feed rates were set to be 0.001 m/s, 0.005 m/s, and 0.010 m/s, and three screw speeds were set to be 0.5 r/s, 1.5 r/s, and 2.5 r/s. Through a comparative analysis, we were able to simulate the printing exit speed, which ranged from 0.0751 m/s to 0.6828 m/s. It is evident that these two parameters have a significant impact on the printing exit speed. Our findings show that the extrusion velocity of clay is approximately 700 times faster than the inlet velocity at an inlet velocity of 0.001-0.010 m/s. Furthermore, the screw speed is influenced by the inlet velocity. Overall, our study sheds light on the importance of exploring printing parameters in ceramic 3D printing. By gaining a deeper understanding of the printing process, we can optimize printing parameters and further improve the quality of ceramic 3D printing.

Effects of Heat Input on Weld Microstructure and Properties in Keyhole TIG Welding of Invar 36 Alloy.

The Invar alloy is widely used for aircraft wing mould manufacturing. In this work, keyhole-tungsten inert gas (K-TIG) butt welding was used to join 10 mm thick Invar 36 alloy plates. The effect of heat input on the microstructure, morphology and mechanical properties was studied by using scanning electron microscopy, high energy synchrotron X-ray diffraction, microhardness mapping, tensile and impact testing. It was shown that regardless of the selected heat input, the material was solely composed of austenite, although the grain size changed significantly. The change in heat input also led to texture changes in the fusion zone, as qualitatively determined with synchrotron radiation. With increases in heat input, the impact properties of the welded joints decreased. The coefficient of thermal expansion of the joints was measured, which demonstrated that the current process is suitable for aerospace applications.

Rapid recycling of waste salt core materials in foundry industry using fractional crystallization

The water-soluble composite salt core materials have attracted increasing interest in the manufacture of hollow castings with complex structures due to their high strength and excellent water solubility, while the treatment of waste brine generated from the salt core represents a major pain point for its large-scale application. To change the above situation, the recycling technology of the waste brine from composite salt core materials was developed using cooling crystallization combined with solvent-driven crystallization. The influences of dissolution temperature and solvent content on the recovery rate of the composite salt core materials, including inorganic salt and fortifier, were investigated. In addition, the mechanical properties and microstructures of the composite salt core with multiple cycles were compared and analyzed. The results show that the fortifier material of corundum powder exhibits excellent chemical and thermal stability with a 100% recovery rate, and the recovery rate of inorganic salt material can reach 79.31% with a 40 °C dissolution temperature and a 1.0 mass ratio of methanol to brine. The microstructures, phase compositions and mechanical properties of the multi-recycled composite salt core have not changed, demonstrating that the recycling of the water-soluble composite salt core is feasible, and favoring the green development of the foundry industry.

Custom Silicone Distal Cup Designed and Fabricated Using 3D Optical Scanning and Additive Manufacturing to Improve Socket Fit of an Individual with Tranfemoral Amputation with Irregular Distal Residual Limb Morphology

ABSTRACT Introduction The study presents the design and manufacturing of a custom silicone distal cup, with a high spatial resolution, to fit inside the prosthetic liner for the treatment of irregular morphology at the distal residual limb of a patient with lower-limb amputation. This distal cup for the inside of the prosthetic liner has intricate interior features matching the shape of the distal residual limb to prevent localized high-pressure regions. Methods High-resolution 3D optical scanning, computer-aided design (CAD), and material extrusion (MEX) process for additive manufacturing of molds are three key techniques for designing and manufacturing this custom distal cup. A three-part mold for molding the distal cup with matching features was designed by CAD and fabricated by MEX. The subject evaluated the distal cup by walking using the distal cup before wearing the prosthetic liner in the lower-limb prosthesis. Results A custom silicone distal cup was fabricated using a 3D-printed mold and evaluated using a Prosthetic User’s Survey. Based on the survey, the insert has an acceptable comfort, suspension requirement, and ease of use. Conclusions The scan by high spatial resolution Space Spider optical scanner could capture detailed features of the distal residual limb. The resulting distal cup had the protrusion that functioned to separate the invaginations. The subject was satisfied with the distal cup based on the Prosthetic User’s Survey. Clinical Relevance The approach to fabricate the custom silicone distal cup using a high-resolution 3D optical scanner and a 3D-printed mold can be applied to fabricate the distal cup with intricate features for a patient with irregular morphology at the distal residual limbs.

Integrated property predictions during casting and heat treatment of Al-Si-Cu-Mg alloys by precipitation simulation

The production and manufacture of aluminium castings typically involves multiple heat treatment process steps. Simulation tools are very useful to help predict the evolution of mechanical properties, to improve process parameters and as a guideline for casting design. In this study, a kinetic model, based on Nucleation and Growth Theory (CNGT), was developed and implemented for modelling heat treatment in a casting process simulation tool. Starting from information generated from the simulation of solidification and cooling of the casting, simulation was carried out to predict further precipitation behaviour of multiple Cu or Mg-Si -containing phases during solution treatment, quenching, and artificial ageing processes in heat treatment of Al alloys. Model validation was carried out within the research cluster “Advance Metals and Processes” in Aachen, Germany. Heat treatments were performed on two different Al-Si-Cu-Mg alloys with different quench methods and at different ageing temperatures. Experimental investigations including atom probe, wavelength dispersive X-ray spectroscopy, and tensile tests were conducted to calibrate and validate the model. The simulations showed good agreement for the studied conditions and a promising modelling approach for integrated simulation of casting and heat treatment for industrial applications.

ECOLOGIZATION OF PRINTING PLATE PROCESSES PRODUCTION

The article analyzes the technological process of manufacturing photopolymer flexographic plates, determines the danger from the point of view of ecological impact that certain technological processes can cause, and proposes measures that minimize their dangerous impact on the environment. A comparison of the properties of solvents and their advantages and at the same time harmfulness was carried out with the establishment of the reasons for the subsequent development of alternative organic solvents and the operation of washout flexographic photopolymer printing plates with water or waters solutions. General strategic directions for solving the problem of using volatile organic solvents have been established. The following classification of ways to solve this problem is proposed: use of less toxic solvents or water; elimination of the washing operation from the technological process of manufacturing flexographic photopolymer plates; development of new technological processes for the production of flexographic plates. Based on the results of a comparative analysis of mold manufacturing technologies, a change in the anthropogenic factor was established as a result of improving processes and their environmentalization. It is shown that by introducing information and laser technologies into the technological processes of manufacturing printing forms due to the reduction of the influence of the anthropogenic factor, a significant improvement in the environmental safety of production is achieved, although the introduction of such technology requires large capital investments. According to the results of a comparative analysis of printing plate manufacturing technologies, the so-called ecological factor is shown as a result of improving processes and their ecologization. If we talk about spent photopolymer plates, then the problem of their disposal is still open. Taking into account the current negative effects on the economy of Ukraine, the use of more environmentally friendly technologies and materials in the flexographic sector of printing depends to a greater extent on the economic situation at specific enterprises, and not on the purposeful environmental policy of the state.

Optimization design of cooling system for injection molding mold of non-pneumatic tire

Non-pneumatic tire has the advantage of puncture resistance and low-energy consumption, which is the development target of new type tire. Injection molding is a vital molding method of non-pneumatic tires, in which the cooling system of mold plays a central role. Whether its design is reasonable will directly affect the processing quality and service lifetime of the tire. Therefore, in this paper, a new idea of conformal cooling layout for non-pneumatic tires forming molds was proposed, and a three-dimensional model for optimizing the molding mold cooling system of the non-pneumatic tire was established. Based on the actual process simulation calculation and Taguchi method experiment design, the influence law of the cooling system on the molding process and quality was obtained, and a semi-annular conformal cooling channel scheme with the best cooling effect and its optimal parameters combination were found. Compared with the traditional direct cooling channel, the semi-annular conformal cooling channel layout reduced the cooling loop pressure loss by 77%, shortened the cycle time and cooling time by 9.6%, reduced the tire volume shrinkage rate by 0.012%. It can shorten the production cycle, raise production efficiency, reduce energy loss, and make the cooling effect more uniform, thus improve tire quality. This would provide a theoretical basis and reference for the optimization design and manufacturing of mold cooling systems similar to non-pneumatic tires.

Analysis of the slurry and ceramic properties for investment casting obtained with domestic colloidal silica binders

The quality of cast parts produced by investment casting is largely determined by the quality of the ceramic molds. Currently, aircraft and engine building enterprises are switching to an environmentally friendly colloidal silica binders for the manufacture of ceramic molds. In this work, the dynamic and relative viscosity of slurries prepared using fused silica powder and colloidal silica binders of the VT13-02U (Vakuumteh LLC), Stavroform VS (Polymet LLC), UltraCast One + and UltraCast Prime (both Technopark LLC) manufacturers were determined. It is shown that the slurries prepared on the considered binders have similar viscosity values, and in their rheological properties they are close to Newtonian liquids. The values of dynamic and relative viscosity at a binder content of 400 mL per 1 kg of fused silica powder were ~732 mPa·s and ~380 s, respectively. With an increase in the binder content to 600 mL per 1 kg of fused silica powder, the dynamic and relative viscosity decreased to ~70 mPa·s and ~16 s, respectively. An equation was also found that relates the dynamic viscosity determined using a rotational viscometer and the relative viscosity determined using the VZ-4 viscosimeter. The mechanical properties were determined during three-point bending tests on ceramic samples obtained using slurries on the above-mentioned colloidal silica binders and fused silica stucco. Samples obtained on binders VT13-02U, Stavroform VS and UltraCast One+ showed very similar bending strength values, namely 3.5–4.3 MPa after drying and 5.8–6.1 MPa after firing. Due to the presence of a polymer addition in the binder, the ceramic samples obtained on the UltraCast Prime binder had higher values of bending strength after drying and after firing – 6.4 and 7.2 MPa, respectively. It was also shown that with an increase in the viscosity of the slurry and a decrease in the fraction of fused silica stucco, the strength of the samples increases. The lowest surface roughness was observed for samples obtained with UltraCast grade binders.

Design and Fabrication of Composite Monocoque Chassis for Formula Student Racing Car

This study uses a combination of analytical, simulation, and experimental methods in the design process of a sandwich-structured composite monocoque chassis. The analytical method, which determines the stiffness value of the composite, depends on the number of layers and the orientation of the fiber angle. The simulation method, which is based on the finite-element method, is used to validate the stiffness value. The experimental method involves a 3-point bending test used to verify the effectiveness of the design produced by analytical and simulation methods. After all model designs were validated through simulation and experimental methods, the next stage is fabrication. The stiffness and strength are achieved with variations, which have combined layup orientation angles of 0° and 45°. This can be applied to all panels, regardless of the number of layers. Based on the design results, the processes involved in fabricating the monocoque chassis begin with the manufacture of molds and the lay-up of carbon fiber. The process is continued by inserting the prototype into the oven, after which the final product then undergoes finishing to prepare it for use. The fabricated monocoque chassis has been used in 2 events in Japan’s annual Formula SAE student racing car competition.