Mold Press Research Articles

Solar interfacial evaporation for efficient treatment of sewage containing volatile organic compounds and toxic heavy metal ions: A sequential process of adsorption, coagulation, and evaporation

Solar interfacial evaporation (SIE) is an eco-friendly and sustainable technology for addressing water pollution and freshwater scarcity. However, treating wastewater containing volatile organic compounds and heavy metal ions with a single SIE method is inefficient. The combination of adsorption, coagulation, and evaporation process provides an alternative solution for treating this type of wastewater. In this study, activated carbon powder (C) is introduced as an adsorbent and an integral part of photothermal conversion material, which is coagulated with polyvinyl alcohol (PVA) and polyethylene glycol (PEG) through a mold press process to fabricate PVA/C/PEG composite hydrogels. The volatile organic compounds and heavy metal ions in the wastewater are adsorbed by the activated carbon powder and the wastewater is then further purified into freshwater through SIE. This stepwise “adsorption first, then coagulation and evaporation” method can not only rapidly remove pollutants from the raw water, but also provides a much higher removal efficiency than the adsorption-evaporation synergetic process. This work demonstrates a successful attempt to utilize the SIE method for treating wastewater containing volatile organic compounds and heavy metal ions.

Compositional and structural study of B2O3–La2O3–Ta2O5–SiO2 glasses for high refractive index optical lenses

High-refractive index glasses are used to produce glass lenses by the precision optical Glass Mold Press (GMP) process and have been extensively studied because of increased demand for their application in telecommunications, optical lenses, and cameras. Borate glasses containing Ta2O5, Nb2O5, La2O3 and Gd2O3 have mainly been used as materials for GMP because of their excellent optical properties and low production cost. This study conducted a systematic investigation of the B2O3–La2O3–Ta2O5–SiO2 quaternary glass system for precision GMP applications. The glass forming range of the quaternary system was studied using (B2O3+SiO2)–La2O3–Ta2O5 and changes in physical and thermal properties such as refractive index, density and glass transition temperature of the obtained glasses were examined. Compositional dependent structural changes were also inspected by Raman spectroscopy and solid state nuclear magnetic resonance (NMR) analyses, to determine the compositions’ effect on thermal and optical properties.

A study of a bio-inspired impact resistant carbon fiber laminate with a sinusoidal helicoidal structure in the mandibles of trap-jaw ants.

The majority of living organisms demonstrate remarkable attributes and have evolved effective mechanisms for synthesizing impact-resistant and damage-tolerant structures. One exemplary instance is the rapid mandible strikes exhibited by trap-jaw ants, which are a highly aggressive species of terrestrial social organisms. An impact-resistant sinusoidal helicoidal architecture is discovered in the mandibles of trap-jaw ants. The bioinspired laminate with a bi-sinusoidal helicoidal structure was manufactured using unidirectional carbon fiber prepreg by mold press forming. This study examines the impact resistance and damage tolerance of a bionic laminate through low velocity impact, computed tomography, and compression after impact tests. The results demonstrate that bionic laminates effectively limit damage propagation within the plane while enhancing energy dissipation capacity. The sinusoidal helicoidal configuration enhances cushioning capability against impact forces, retards penetration under higher loads, hinders crack propagation, and improves residual strength. Bionic laminates provide a valuable solution for damage tolerance through the resistance to through-the-thickness loads. STATEMENT OF SIGNIFICANCE: Helicoidal and sinusoidal helicoidal microstructures have been identified in the cross-section of the jaws of trap-jaw ants. The multiple waviness ratio parameters are designed for fabricating a sinusoidal helicoidal structure laminate using unidirectional carbon fiber prepreg through the mold press forming technique. This results in a damage-tolerant mechanism characterized by reduced delamination damage, which leads to a stiffer mechanical response. Meanwhile, it enhances resistance to crack propagation, leading to the formation of discontinuous delamination areas and the accumulation of sub-critical failures. Additionally, the sinusoidal helicoidal structure laminate combines the cushioning performance of bi-sinusoidal arrangements with the enhanced impact resistance of helical arrangements. This design delays penetration at higher loads, resulting in increased residual strength.

An investigation into the impact resistance of bio‐inspired laminates with interlayer hybrid unidirectional/woven carbon fibers

AbstractThis study investigates the rapid mandible strike behavior of trap‐jaw ants (Odontomachus monticola), a highly aggressive species of terrestrial social organisms. An impact‐resistant gradient waviness structure is discovered in the mandibles of trap‐jaw ants. The gradient waviness structure is incorporated into the fiber laminates to enhance their impact resistance and damage tolerance. Bioinspired interlayer hybrid laminates with both unidirectional and woven arrangements were fabricated using the mold press forming technique. The impact resistance and damage tolerance of the bionic laminates are investigated through low‐velocity impact, ultrasonic C‐scanning, and compression after impact tests. The results indicate that hybrid laminates play a key role in limiting damage propagation and improving energy dissipation capacity. The hybrid configuration effectively mitigates crack propagation, enhances load‐bearing capacity, and improves residual compressive strength. Bionic laminates offer an efficient solution for enhancing damage tolerance against through‐the‐thickness loads.Highlights An impact‐resistant gradient waviness structure is discovered in trap‐jaw ants. Bioinspired interlayer hybrid laminate is fabricated by mold pressing. The hybrid laminate restrict damage propagation and improve residual strength. Bionic laminate offer an efficient solution for enhancing damage tolerance.

Analysis of three-layer gasket performance affected by flange surface

Gaskets are components that play a very important role in piping connections to prevent leakage. Several factors affect the performance of the gasket, one of which is the contact surface of the flange. The quality of the contact surfaces in the connection also influences the leakage rate of each connection, therefore the gasket sealing performance is assessed by the rate of leakage that occurs. As a result, the surface roughness of the flange has an effect on sealing. This study examines the capability of a three-layer corrugated metal gasket to prevent leakage when the outside layer thickness and flange roughness are adjusted. The feature of three-layer corrugated metal gasket was elucidated using the finite element analysis (FEA) and experimental method. The leak rate was tested using a helium leak quantity test experimentally. The gasket was constructed with oxygen-free copper (C1020) as the outside layer and SUS304 as the base layer, and it was structured in a three-layer pattern with no bonding. A mold press was used to make the gasket. The simulation method applies finite element analysis software to investigate the correlation between contact stress, contact width, surface thickness and surface roughness. The projected results matched the experiment results fairly well. A three-layer corrugated metal gasket shows improvement capability to prevent leakage than a single gasket (standard). The gasket three-layer shows sealing performance improvement that leakage did not occur in low axial force 40 kN for all surface roughness test. In terms of sealing, a three-layer gasket with a low thickness ratio works well. Surface roughness of the flange has no influence on the three-layer gasket

Design of mold press for the manufacturing of silica sand pellet form

Currently, the ceramic industries is utilizing many natural mineral resources. The purpose of this study is to design and manufacture the tool; a mold press pellet or silica sand mold and to obtain the results of silica sand pellets that are affected by varying pressure. The materials used for the tools were STM A276, Type 410 steel. ST60 martensite. SS400 steel was used to made the round plate at a mold position. This study produced mold with dimensions of 25.45 mm of diameter, height of 89 mm, volume at 45.07 cm³ with a mold circle area of 5.06 cm² and punch cross-sectional area of 452.16 mm². The maximum pressing force on the mold was 49050 N, the normal stress result was 108.47 MPa, the strain value was 3.8 mm / mm, the modulus of elasticity value was 28.54 MPa, the mold material had a maximum limit of 812,871 MPa, indicating that the mold material used was v ery good. This silica sand pellet mold produced can be utilized for the development of fuel cell and composite materials.

The Effects of Nanosilica and Nanoclay Particles Inclusions on Mode II Delamination, Thermal and Water Absorption of Intraply Woven Carbon/Aramid Hybrid Composites

Abstract The effects of nanosilica (NS) and nanoclay (NC) particle inclusions on mode II delamination and thermal properties as well as water absorption capability of carbon/aramid fiber reinforced hybrid composites (CAFRE) were experimentally investigated at different nanoparticle contents. NS and NC particles modified CAFRE samples were reinforced with intraply woven and twill weave of carbon and aramid fibers, and were manufactured by using hot mold press assisted with hand-layup method. Various thermal properties such as thermal conductivity, thermal diffusivity, and specific heat capacity were experimentally measured with respect to NS and NC particle weight contents according to ISO-22007 standard. In addition, the water absorption test was performed according to ASTM D570-98 standard. Results from this study showed that addition of NS and NC particles improved mode II delamination toughness of CAFRE composites at 1.5 wt% and 2 wt% of NS and NC particle contents, respectively. Water absorption capacity of the CAFRE samples was increased as increasing NS and NC weigh contents while thermal tests showed that thermal diffusivity values increased, and specific heat decreased with increasing both NC and NS particle weight contents.

Pressing Control Design Based on Analysis of Metal Temperature and Flow in Sand Mold Press Casting

The sand mold press casting method is a novel iron casting process, which has developed by our group in recent years. The proposed method can cast iron into complex shapes with a high yield over 90% and produces high-quality products by filling control of molten metal during pressing motion. However, molten metal inside mold is cooled down by heat transfer to the molds and atmosphere, and often causes solidification before the end of press. Then, the pressing movement of the upper mold is blocked by the solidified metal. Therefore, to avoid the solidification during pressing sand mold, metal temperature must be heated properly to estimate the filling temperature decrease behavior based on analysis results of CFD simulator, FLOW-3D. The necessary condition not to solidify molten metal before the end of press has been found. It was made clear that the mold must be heated up to the necessary temperature beforehand in the pressing process. Furthermore, optimum velocity reference with specified pressure constraints has been designed to prevent casting defect such as penetration and also to minimize the temperature decrease. In this paper, optimum velocity control of servo cylinder considering the both of allowable pressure of molten metal and starting time of solidification is proposed by using a theoretical approach of Model Predictive Control: MPC method. The effectiveness of the proposed control system has been demonstrated by computer simulation and experiments using a laboratory scale machine with molten metal of casting iron.

A study of the mechanical properties of pre-oxidized fiber felt/epoxy resin composite material

In this article, the pre-oxidized fiber felt composite material was firstly prepared by a mold press process, and the pre-oxidized fiber and resin were used as the reinforcing material and substrate of composite material, respectively. The pretreatment method of the pre-oxidized fiber felt and the impact of the amount of curing agent and the curing pressure on the mechanical properties of the composite material were studied, and the tensile and flexural properties were assessed to optimize the preparation process of composite material. Results show that when the curing agent accounts for 60% of the epoxy resin and the curing pressure is 3 MPa, the best tensile and flexural properties of the prepared composite material are achieved. The mechanical properties for the pretreated composite sheet prepared from pre-oxidized fiber were superior to those for the untreated sheet.

Natural Fiber Reinforced Composites: A Review on Potential for Corrugated Core of Sandwich Structures

Natural fibers, characterized by sustainability, have gained a considerable attention in recent years, due to their advantages of environmental acceptability and commercial viability. In this paper, the characterization of natural fibers including the mechanical properties and alkalization of fibers is presented. Most recent study had gone through the mercerization process to improve the toughness of natural fibers; which is a well-known hydrophilic material. Traditional reinforcement method was commonly used to fabricate a natural fiber composite such as hand lay-up and mold press due to its convenience in terms of time and cost. Also, different kind of matrix material used in different kind of natural fibers gave high impact on the tensile and flexural test result. By selecting appropriate chemical treatment, matrix material and fabrication method, the tensile and flexural test gives different results and findings. As most researchers tend to use metals to create corrugated cores for sandwich structure, it is possible to develop this structure using natural fibers such as kenaf, wood dust, and other natural fibers.

Evaluation of Demolding Force by Parallel Mold Press for Glass Imprint

Measurement method of compressive or tensile forces during glass imptrint was developed by improving a lens mold press machine. Deformation and demolding behaviors could be quantified under the pressing using a glassy carbon and a tungsten carbide mold. After the pressing of a glass at slightly above the deformation temperature followed by the cooling of the glass and mold under applying a small tensile force, an abrupt demolding was observed below the glass transition temperature, which was affected by the pressing temperature and the glass compositions. This measurement method should be useful for the characterization of deformation and demolding behaviors of wide variety of glasses not only for optical lens but also for nanostructured optical components.

Molten Metal Pressure Control for Defect Prevention with Generalized Predictive Control in Rapid Press Casting

This paper presents a technique for controlling the pressure of molten metal when using a new type of the iron production method called greensand mold press casting to realize high productivity and obtain high-quality castings. In this method, molten metal is poured into a lower mold first, and the after upper mold is moved down toward the lower mold, then both molds are matched. Casting defects such as metal penetration are often caused by the high pressure in the high-velocity pressing process. Therefore, we proposed a pressure control method with a mathematical model of molten metal pressure, and with it we achieved confirmation simulation of the successful pressing production at the different pressing condition such as mold shape. Results show that the proposed pressing production considering the generalized predictive control: GPC can realize sound, penetration-free casting production under the pressure constraint for defect prevention. Here a simple simulation of model predictive pressing control and water pressing experiment using feed-forward motion input calculated by off-line GPC are presented. Discussions of the theoretical control design for the process as well as its practical confirmation result of water pressure behavior in pressing experiment are concluded.

렌즈 성형용 유리탄소 금형의 초정밀연삭

In this study, glassy carbon was ground for lens core of glass mold press. Ultraprecision grinding process was applied for machining of core surfaces. During the process, brittle crack occurred because of hard-brittleness of glassy carbon. Author investigated optimized grinding conditions from the viewpoint of ductile mode grinding. Geometrical undeformed chip thickness was adopted for critical chip thickness that enables crack free surface. Machined cores are utilized for biaspheric glass lens fabrication and surfaces of lens were compared for verification of ground surface.

1A1-F04 プレスキャスティングにおける上昇流動液体の飛跳ね挙動のモデリングと空気巻き込み抑制を考慮したプレス速度設計(生産システム・生産機器メカトロニクス)

This paper presents modeling of liquid upward flow and design of pressing velocity considering air entrainment suppression in press casting process. In this study, the problem of air entrainment is focused on an innovative casting method called "Same Mold Press Casting". This method has two molds which are an upper mold and a lower mold, molten metal is directly poured into the lower mold without a runner, and then pressed to fill the cavity by the upper mold being lowered down. Thus, fluid of molten metal which was turbulent by moving upper mold has air entrainment. Then, air entrainment are suppressed by modeling of liquid upward flow has been clarified.

Optimum Pressure Control of Molten Metals for Casting Production Using a Novel Greensand Mold Press Casting Method

This paper presents a novel method of sand mold press casting. In this process, molten metal is poured into a drag mold, and then the cope mold is placed on top of the drag mold, and the two molds are matched. The mold design for casting, the pouring control and the velocity control of the press have been previously clarified as key factors in the manufacture of sound products. This paper presents methods for modeling and control of the molten metal’s pressure for novel sand press casting technique. Substituting detailed information for the complex mold shape, the poured volume and initial temperature into a developed control input generator, an optimum pressing velocity design and a robust design for defect-free production are proposed by the sequential control algorithm based on the construction of an inverse system comprised of a sequential switching from higher to lower speed. The effectiveness of adaptive press casting is demonstrated by using CFD model simulations.

Development of a Sand Mold Press Casting Process: “Post-Filled Formed Casting Process”

This paper presents the development of a sand mold press casting process called the “Post-Filled Formed Casting Process.” In this process, molten metal is directly poured into the lower mold; the upper mold then falls down on the lower mold, and both molds are then matched. This method does not use a sprue cup and runner. Therefore, both the quantity of scrap and energy consumption are enormously reduced. This means that the sand mold press casting process is an eco-friendly casting process resulting in a large reduction of CO2 gas. During the last few years, the author's group has been devoted to developing this method as a national project. Mold design for casting, pouring control, and velocity control of the press have been identified as key factors in manufacturing sound products. In this paper, we provide an overview of this novel casting method and present the fundamental results obtained.

PREPARATION OF PANEL AND CHARGED PARTICLES FOR ELECTROPHORETIC DISPLAY

Studies on the formulation of photosensitive paste for transparent soft mold press (TSMP) method have been performed. With the optimum formulation of the photosensitive paste the box-type barrier rib with good flexibility and high solvent resistance was fabricated, suitable for the panel material of the electrophoretic display. Cationically-charged white particles were prepared by using TiO2 nanoparticles, silane coupling agent with amino groups, dispersant and acetic acid. The cationically charged TiO2 particles exhibited 74.09 mV of zeta potential and 3.11 × 10-5 cm2/Vs of mobility. Electrophoretic display fabricated with the charged TiO2 particles exhibited 10 V of low driving voltage and maximum contrast ratio (5.3/1) at 30 V.

A new tabu search method for continuous parameter optimization: application to design problems in electromagnetic

AbstractSpecificities of optimal design problem in electromagnetic are emphasized. To overcome the revolting difficulties met with the classical stochastic methods, a new tabu search algorithm for global optimization of multimodal functions with continuous variables is presented and used for solving some of this kind of electromagnetic optimization problems such as Bruhless DC motor, SMES optimization, and die mold press. It is compared favorably with Hu's tabu search and universal tabu search methods. Copyright © 2005 John Wiley & Sons, Ltd.

Fabrication of Electrophoretic Display Panel Using Prepatterned Barrier Rib

Fabrication process of electrophoretic display panels was investigated by utilizing transparent soft mold press, which enables to guide uniform packing of charged TiO2particles and colored particles for color e-Paper display. For this process, transparent soft mold was prepared by reacting silicone solution(silicone prepolymer/curing agent = 10/1 wt./wt.)into the base mold. While pressed with the transparent soft mold under 1.5 ∼ 3.0 Kgf/cm2of pressure at 60 ∼ 90°C, the photosensitive film was exposed to UV light at 365 nm in the range of 800 ∼ 2,000 mJ/cm2. The transparent soft mold was demolded by rolling up to give electrophoretic display panels with precise geometry. The process of obtaining colored electrophoretic display was also discussed.

Evaluation of Pressure Uniformity Using a Pressure-Sensitive Film and Calculation of Wafer Distortions Caused by Mold Press in Imprint Lithography

In order to simply evaluate the uniformity of imprint pressure across a large imprint area instead of measuring critical dimension and/or height of imprinted patterns, we propose a new method using a pressure-sensitive film that changes color according to the intensity of pressure. Degradation factors of pressure uniformity will be investigated by measuring color density at multiple points on the pressed film and their mitigating factors will be discussed. Simulation using a finite element method will also clarify that wafer distortions caused by imprint pressure applied to a limited area of a wafer should not be negligible for uniform press and accurate pattern placement.