Journal articles on the topic 'Compression molds for molding soles'
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1
Nagato, Keisuke. "Injection Compression Molding of Replica Molds for Nanoimprint Lithography." Polymers 6, no. 3 (March 5, 2014): 604–12. http://dx.doi.org/10.3390/polym6030604.
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Castro, J. M., and C. C. Lee. "Thermal and cure analysis in sheet molding compound compression molds." Polymer Engineering and Science 27, no. 3 (February 1987): 218–24. http://dx.doi.org/10.1002/pen.760270307.
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Wang, Youmin, Xiangli Li, and He Sui. "Numerical Investigation and Mold Optimization of the Automobile Coat Rack Compression Molding." Advances in Materials Science and Engineering 2021 (April 30, 2021): 1–19. http://dx.doi.org/10.1155/2021/6665753.
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In order to have more accurate control over the compression molding of automobile coat rack, improve the quality of molding products, and achieve the goal of lightweight design, a novel mechanical model for the main two-layer composite structure of the coat rack is proposed. In this regard, the main factors affecting the mechanical properties of the composite structure are obtained. The hot air convection is selected for the sheet preheating. During the experiment, the hot air temperature, preheating time, molding pressure, and pressing holding time are set to 250°C, 110 s, 13 MPa, and 80 s, respectively. Moreover, the error compensation method is applied to compensate for the shrinkage of the product during solidification and cooling. The LS-DYNA finite element software is used to simulate the molding process of the main body of the coat rack, and the node force information with large deformation is obtained accordingly. The load mapping is used as the boundary condition of mold topology optimization, and the compression molding of the main body of the coat rack is optimized. A lightweight design process and method for the compression molding of automotive interior parts and a mathematical model for the optimization of the solid isotropic material penalty (SIMP) (power law) material interpolation of the concave and convex molds are established. Based on the variable density method, OptiStruct is used for the lightweight design of the convex and concave molds of the main body of the coat rack, which reduces the mold weight by 15.6% and meets the requirements of production quality and lightweight.
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Tedde, Giovanni Matteo, Denise Bellisario, Loredana Santo, and Fabrizio Quadrini. "Microsculpturing of Polymeric Surfaces by Compression Molding." Key Engineering Materials 699 (July 2016): 49–56. http://dx.doi.org/10.4028/www.scientific.net/kem.699.49.
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Surface micropatterning of polymers is an important process in a large number of applications ranging from microelectronics, sensors design and material science, to tissue engineering and cell biology. In this study a simple and versatile method for manufacturing micro-scale polymer surface patterns has been developed. Micropatterned surfaces of acrylonitrile-butadiene–styrene (ABS) were engineered by compression molding. Two different micropatterned surfaces were fabricated using diverse molds. The first micropatterning was achieved on a brass mold by the intersection of instrumented microindentation traces. The second microsculptured surface was realized through a bronze sintered mold. The morphological aspects and the surface wettability after microsculpturing were investigated. The microsculptured ABS surface produced by the sintered mold shows a higher contact angle compared with those of flat ABS surfaces. From the experimental results, it was found that the intrinsic hydrophobicity of the material is enhanced simply through increasing surface roughness of the solid surface. The method presented is an economical process to fabricate hydrophobic microsculptured surfaces and it is suitable for many kinds of materials.
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Chval, Zdenek, Karel Raz, and Frantisek Sedlacek. "Design of Injection Mold from Plastic Material." Key Engineering Materials 847 (June 2020): 75–80. http://dx.doi.org/10.4028/www.scientific.net/kem.847.75.
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This paper deals with the use of plastics for making injection molds. Mold production times reduced by 90% and costs cut by up to 75% are some of the benefits of prototype molds from plastic materials. Today, materials with melt temperatures above 300 °C are used for plastic molds. They include ABS, PE, PP and PA. In this study, testing of high-temperature resin from Formlabs was performed. Compression and tensile test data are compared with the datasheet values and with virtual simulations. The tests were carried out at different temperatures. Based on their results, one can identify a suitable molding process with molds from this material.
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Jeong, Jin-Ho, Ki-Taek Kim, and Yong-Taek Im. "Plane-strain compression molding analysis of sheet molding compounds in flat and cross-sectional T-shape molds." Journal of Materials Processing Technology 57, no. 3-4 (February 1996): 320–31. http://dx.doi.org/10.1016/0924-0136(95)02077-2.
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Hanulikova, Barbora, Dana Shejbalova, and Zdenek Dvorak. "INFRARED ANALYSIS OF FOULING DURING EPDM CURING STUDIED ON MOLDS MADE OF STEEL AND ALUMINIUM ALLOYS." Rubber Chemistry and Technology 91, no. 2 (April 1, 2018): 390–400. http://dx.doi.org/10.5254/rct.18.81662.
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ABSTRACT Mold fouling during the crosslinking process of EPDM rubber compounds results in defects in compression-molded products and deterioration of process conditions. Moreover, subsequent cleaning of molds is expensive and causes a loss at production. The fouling of several types of steel and aluminum alloys, which represent molds with variously machined surfaces, was analyzed during 0–70 cycles of EPDM molding. Fourier transform infrared microscopy was used for investigation of fouling and paraffin oil (softener) and/or EPDM fragments were detected in vibrational spectra of fouling as the most probable components of it. Metal specimens with a grinded surface were found to be more resistant to EPDM residue deposition.
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Zyukov, E. A., M. A. Bulatov, and V. G. Duvidzon. "Calculation of thermal regimes and forecasting of the molds for plastic injection molding." Izvestiya MGTU MAMI 8, no. 2-3 (May 20, 2014): 106–16. http://dx.doi.org/10.17816/2074-0530-67599.
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In this paper the mathematical model of the formation of precipitation in the cooling channels of molds are presented, experimentally determined parameters of the cooling system and developed a software module for the calculation of the heat transfer coefficient. The technique for calculating the cooling system, introduced evaluation of the effectiveness of cooling, which allows to predict the performance of the mold. On the example of pressing parts of polypropylene defined cycle time compression and turnaround hot runner mold.
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Synyuk, Oleg, Janusz Musiał, Borys Zlotenko, and Tetiana Kulik. "Development of Equipment for Injection Molding of Polymer Products Filled with Recycled Polymer Waste." Polymers 12, no. 11 (November 17, 2020): 2725. http://dx.doi.org/10.3390/polym12112725.
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Polymer waste of light industry and other industries is processed by chemical recycling and mechanical grinding. Modern equipment for polymer waste processing has the following drawbacks: significant energy consumption and reduced performance properties of recycled polymer. New technological processes and equipment for polymer waste recycling have been developed for the manufacture of light industry polymer products with increased performance characteristics. The manufacturing of such products was made possible by the development of the mathematical model, which describes the movement of a mixture of main polymer material and particles of recycled polymer waste in the process of filling a mold cavity. The model, in contrast to the existing models, allows observing the formation of the polymer product structure containing recycled waste particles. Improvement in the performance characteristics of shoe soles made by the injection molding of a mixture of polyvinylchloride and particles of recycled polyvinylchloride was confirmed by experimental tests of breaking strength and fatigue life. The results of these tests can be used in the design of processing equipment to obtain waste particles of the required shape and size and in the design of molds to provide the required concentration and orientation of waste particles in light industry polymer products.
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Sommer, J. G. "Molding of Rubber for High Performance Applications." Rubber Chemistry and Technology 58, no. 3 (July 1, 1985): 662–83. http://dx.doi.org/10.5254/1.3536084.
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Abstract This paper broadly considers rubbers (elastomers), molding methods, and some problems associated with molding for high-performance (HP) applications. Molding procedures are then reviewed for several products used in HP applications. The elastomers mainly discussed are NR, SBR, CR, NBR, chloro-sulfonylpolyethylene rubber, silicone rubber, hydrofluoroelastomer and perfluorelastomer. NR is used in HP applications because it possesses desirable properties such as excellent fatigue resistance and high strength. Other rubbers or elastomers, such as silicone or perfluoroelastomer, are used in HP applications because they resist high temperatures and aggressive fluids. When molding these elastomers by compression, transfer, and injection, special procedures are sometimes necessary. These are discussed along with factors that affect molding behavior and the quality of molded products. These factors include: rheology, rubber shrinkage, inserts in moldings, mold fouling, mold materials, and design factors for molds. A special design is used for a compression mold for O-rings made from perfluoroelastomer. These are used to seal against aggressive fluids like dinitrogen tetroxide. In other HP sealing applications, NBR lip seals are used; molding factors are discussed which significantly affect their sealing capability. Also discussed are laminates, where NR is bonded to metal. These are used as bridge bearings and the steel plates in them cause nonuniform shrinkage. A nozzle bearing for the space shuttle is another HP application for an NR laminate; over 100 thermocouples were used to monitor temperature during molding. This paper concludes with a brief discussion of molding silicone rubber for spark plug boots and electrical connectors.
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Wang, Jian Wei, Yan Shan Sun, Zi Ren Jin, Zhi Yuan Feng, and Fu Gui Dong. "Effect of Densification Conditions on Physical Quality of Densified Sorghum Straw Briquette Fuel." Applied Mechanics and Materials 339 (July 2013): 651–56. http://dx.doi.org/10.4028/www.scientific.net/amm.339.651.
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An experiment was conducted on densification processing of sorghum straw stalks with self-made steel molds on a hydraulic universal test platform. The influences of different densification conditions on physical quality of briquette fuel are investigated, including pressures, temperatures, moisture contents and straw preheating method. Moreover, the relationship between molding temperature and inner stress decreasing rate of straw briquette at holding pressure stage is also analyzed. The result shows that the suitable value of moisture content, temperature and molding pressure for straw compression process is 20%, 90°C and at least 50MPa, respectively. The phenomenon of uneven temperature distribution in straw briquette keeps in existence even in the case of microwave preheating. However, in contrast with the very low central temperature in straw briquette when preheating by electric heater wire, the phenomenon of local overheating caused by microwave preheating may be helpful to straw molding process.
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Bellisario, Denise, Fabrizio Quadrini, Gustavo Santolim, Giovanni Matteo Tedde, Valerio Caputo, Paola Spitalieri, Federica Sangiuolo, and Loredana Santo. "Effects of Micro-Textured Polystyrene Substrates by Compression Molding on Cell Adhesion and Proliferation." Materiale Plastice 55, no. 4 (December 30, 2018): 502–6. http://dx.doi.org/10.37358/mp.18.4.5062.
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Surface chemistry and micro-nanoscale topography of biomaterials can significantly influence tissue engineering and cell biology. In this study, polystyrene (PS) Petri dishes were subjected to microtexturing by compression molding process, which resulted in three-dimensional (3D) microscale surface topographies. Three different micropatterned surfaces were fabricated using bronze sintered molds with different mean pore pitch sizes. The surface changes and the morphological aspects were analyzed by 3D surface analyzer. The dishes were then used to investigate the cell behavior of Mouse Embryonic Fibroblasts (MEF) P4 cells. The surface micropatterning have affected in different ways the MEF cell adhesion and proliferation, related to the morphological changes in comparison with unmodified PS. At the increasing of the sintered particle dimensions of the mold, the cavities dimensions on the molded Petri increase and also the cells adhesion in the cavities seems to increase independently from the roughness inside them.
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Korotchenko, A. Yu, D. E. Khilkov, M. V. Tverskoy, and A. A. Khilkova. "Development of Ultra-Fluid Compositions of Feedstock for Metal Injection Molding." Materials Science Forum 992 (May 2020): 529–33. http://dx.doi.org/10.4028/www.scientific.net/msf.992.529.
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In this paper, to reduce the cost of production of parts by injection molding technology of metal powder mixtures (MIM technology), it is proposed to use metal powder mixtures (feedstock) with high fluidity for the manufacture of green parts. High fluidity is achieved by increasing the proportion of paraffin wax in the binder. This can significantly reduce the pressing pressure when pressing the feedstock into the mold cavity to values less than 1 bar, and eliminate the use of expensive injection molding machines with high compression pressure. High fluidity also allows the use of powders with large particle sizes, which significantly reduces the cost of feedstock. The absence of high pressure on the mold walls during the pressing of the feedstock allows the use of molds made of cheaper materials such as silicone, plastic, gypsum and others.
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Chizhikov, Andrey, Alexander Konstantinov, Pavel Bazhin, and Alexander Stolin. "Features of Molding and Structure of Composite Materials Based on TiB/Ti, Obtained by Free SHS Compression Method." Materials Science Forum 1009 (August 2020): 37–42. http://dx.doi.org/10.4028/www.scientific.net/msf.1009.37.
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The work presents the thermodynamic calculations of the adiabatic combustion temperature and the fraction of the liquid titanium phase during the chemical reaction of the initial titanium and boron powders with the initial titanium content from 5 to 80 wt. % during the synthesis of materials based on TiB-Ti. It is shown that with an increase in the preheating temperature of the initial samples to 500 °C, the combustion temperature of the selected composition increases from 3200 to 3600 K, and the fraction of the liquid phase increases from 40 to 80 %. The peculiarity of molding composite materials based on TiB-Ti under conditions combining self-propagating high-temperature synthesis (SHS) and high-temperature shear deformation is studied. These conditions are realized in the method of free SHS compression, which allows synthesizing, molding and obtaining compact material in tens of seconds without using special molds. It was found that the maximum degree of deformation of the synthesized material corresponds to 20-40 wt. % free titanium. For the selected compositions, compact composite materials were obtained by free SHS compression method, the structural features were studied, and the density and porosity of the central and regional parts of the samples were measured.
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Udupa, Ganesha, Pramod Sreedharan, P. Sai Dinesh, and Doik Kim. "Asymmetric Bellow Flexible Pneumatic Actuator for Miniature Robotic Soft Gripper." Journal of Robotics 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/902625.
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The necessity of the soft gripping devices is increasing day-by-day in medical robotics especially when safe, gentle motions and soft touch are necessary. In this paper, a novel asymmetric bellow flexible pneumatic actuator (AFPA) has been designed and fabricated to construct a miniaturised soft gripper that could be used to grip small objects. The model of AFPA is designed using solid works and its bending motion is simulated in Abaqus software for optimisation and compared with experimental results. The actuator is fabricated using compression molding process that includes micromachining of the molds. Experiments conducted show the bending characteristics of the actuator at different pressures. The actuator shows excellent bending performance and the eccentricity in its design supports increased bending or curling motion up to a certain extent compared to normal bellows without eccentricity. The effects of profile shape and eccentricity on the actuator performance are analysed and the results are presented.
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Ul Hassan, Noor, Bahadir Tunaboylu, and Ali Soydan. "A Competitive Design and Material Consideration for Fabrication of Polymer Electrolyte Membrane Fuel Cell Bipolar Plates." Designs 3, no. 1 (February 8, 2019): 13. http://dx.doi.org/10.3390/designs3010013.
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The bipolar plate is one of the most significant components of a polymer electrolyte membrane (PEM) fuel cell, and contributes substantially to the cost structure and the weight of the stacks. A number of graphite polymer composites with different fabrication techniques have been reported in the literature. Graphite composites show excellent electromechanical properties and chemical stability in acidic environments. Compression and injection molding are the most common manufacturing methods being used for mass production. In this study, a competitive bipolar plate design and fabrication technique is adopted in order to develop a low-cost and light-weight expanded graphite (EG) polymer composite bipolar plate for an air-breathing PEM fuel cell. Cutting molds are designed to cut fuel flow channels on thin expanded graphite (EG) sheets (0.6 mm thickness). Three separate sheets, with the flow channel textures removed, are glued to each other by a commercial conductive epoxy to build a single bipolar plate. The final product has a density of 1.79 g/cm3. A bipolar plate with a 20 cm2 active area weighs only 11.38 g. The manufacturing cost is estimated to be 7.77 $/kWe, and a total manufacturing time of 2 minutes/plate is achieved with lab-scale fabrication. A flexural strength value of 29 MPa is obtained with the three-point bending method. A total resistance of 22.3 milliohms.cm2 is measured for the three-layer bipolar plate. We presume that the suggested design and fabrication process can be a competitive alternate for the small-scale, as well as mass production of bipolar plates.
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Narbonne, Guy M., and Robert W. Dalrymple. "Taphonomy and ecology of deep-water Ediacaran organisms from northwestern Canada." Paleontological Society Special Publications 6 (1992): 219. http://dx.doi.org/10.1017/s2475262200007796.
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Although most occurrences of Ediacaran fossils are from shallow-shelf deposits, taxonomically-similar assemblages have recently been described from a 2.5 km-thick succession of dark mudstones and turbiditic sandstones in the Windermere Supergroup of the Mackenzie Mountains, northwestern Canada. The paleogeographic position (20-40 km seaward of the shelf edge), abundant evidence of mass flow, and the complete absence of in situ shallow-water features imply that deposition took place on a slope considerably below storm wave-base. Ediacaran fossils were not observed in axial trough deposits (lower parts of the Twitya and Sheepbed formations), but megafossils occur sporadically in lower to middle slope deposits higher in the same formations. Megafossils and trace fossils are present in upper slope settings (Blueflower Formation) at the top of the Ediacaran succession. The megafossil assemblage varies stratigraphically, but in all formations is dominated by discoid forms (e.g. Cyclomedusa, Ediacaria, Nimbia); frondose forms and vendomiids are very rare.Megafossils are preserved mainly as positive features on the soles of thin turbidite beds. Most fossiliferous beds begin with the rippled layer of the turbidite (Tc), but a few begin with the graded (Ta) or parallel-laminated (Tb) layer. Consistent orientation and high relief of individuals, evidence of mutual deformation during growth of adjacent organisms, and other taphonomic features imply that virtually all of the taxa represent benthic polypoid and frond-like organisms (not jellyfish). Slump structures occur commonly in the sandstone fill of fossils, suggesting that many of the organisms were buried alive by the turbidite and later decomposed. Other individuals, even on the same bedding plane, exhibit graded to laminated fill identical to that of the overlying turbidite bed, indicating that the depressions on the sea bottom produced by these individuals were empty at the time of turbidite deposition. Escape structures are absent, suggesting that the Ediacaran organisms were not capable of burrowing up through even thin layers of sand.Ediacaran megafossils are invariably preserved on black, wrinkled surfaces similar to those elsewhere interpreted as microbial mats. Molding of delicate features (including tentacles), preservation of open molds as negative epireliefs, and sedimentological evidence of considerable cohesion of these surfaces relative to the underlying turbiditic muds (Td,e) supports this interpretation, and suggests that microbial mats were as important in the preservation of these deep-water Ediacara faunas as they were in their shallow-water equivalents. The presence of the wrinkled mats and their associated Ediacaran fossils almost exclusively in the pyritic intervals of the succession suggests that both may have lived under exaerobic conditions in this deep-water setting.
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Lee, Sahng Hoon, Sang Cheol Seong, Jin Ho Lee, Il Kyu Han, Se Heang Oh, Kwang Joon Cho, Hyuk Soo Han, and Myung Chul Lee. "Porous Polymer Prosthesis for Meniscal Regeneration." Key Engineering Materials 342-343 (July 2007): 33–36. http://dx.doi.org/10.4028/www.scientific.net/kem.342-343.33.
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Meniscus is the most commonly injured structure in the knee joint. Resection of the meniscus as well as the torn menisci is known to induce the degeneration of the articular cartilage. Replacement of the resected meniscus by allograft is limited by its availability and potential disease transmission. Artificial prostheses are being tried in an attempt to regenerate the meniscal tissue and we developed the biodegradable porous polycaprolactone(PCL) scaffold, which acts as a temporary scaffold to enable the regeneration of a new tissue in time. We report the results of rabbit implantation model. Biodegradable PCL scaffold coated with type I collagen with pores sized 100~150 +m and with compression modulus 400 kpa were fabricated by melt-molding particulate- leaching method. The molds were made using the native meniscus of the rabbit. Medial meniscus of right knee was partially removed through arthrotomy, leaving anterior 1/5 of the meniscus, after sectioning medial collateral ligament. The implant was attached to the peripheral capsule and remnant anterior meniscus with sutures. The medial meniscus of the left knee was removed and served as a control without replacement. The regenerated meniscus was harvested at 4 & 12wks after implantation. In addition to the routine histology of the tissue regenerated and remnant scaffold, junction between the normal meniscus and the regenerated tissue, and cartilage surface degeneration was observed. After 4 and 12 weeks the scaffolds, although considerable amount of the materials remained, were largely filled and covered with fibrous tissue which was assumed to be derived from synovial tissue of peripheral capsule. The tissue grossly resembling the native meniscus was maintained and spindle shaped cells with extracellular matrices were observed histologically. Neither cells with chondrocytic phenotype nor distinct cartilage matrices were observed until 12 weeks. The bonding between the regenerated tissue and the peripheral synovial capsule was firm and solid in all cases. The tissue bridges between the native meniscus and the regenerated tissue were found in 9/10 operated knees. Articular surface degeneration was not different between experimental and control groups except one case. More or less, the extrusion of the meniscus was found in almost all knees. This study revealed that meniscal replacement with PCL polymer prosthesis was feasible and led to adequate tissue formation. Long term studies on adaptive remodeling will be required.
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Kerst, Capella F., and Mark R. Cutkosky. "Compression Molding and Nickel Molds for Directional Gecko-Inspired Adhesives." Journal of Micro and Nano-Manufacturing 9, no. 2 (June 1, 2021). http://dx.doi.org/10.1115/1.4051139.
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Abstract In the fabrication of directional gecko-inspired adhesives, a new capability made possible by the availability of metal molds is hot compression molding. This molding process allows the use of elastomers with much higher toughness than those cast at ambient temperature and pressure, as has been the common case in fabricating adhesives. In addition, it permits fast cycle times (minutes instead of hours), which is useful for volume manufacturing. We present the results of hot compression molding of elastomers in metal molds created with overhanging and tapered microscopic surface features, which give rise to anisotropic adhesion. We show that the adhesive performance so obtained is equivalent to that obtained earlier with polydimethylsiloxane (PDMS).
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Wang, Fei, Yang Chen, Fritz Klocke, Guido Pongs, and Allen Y. Yi. "Numerical Simulation Assisted Curve Compensation in Compression Molding of High Precision Aspherical Glass Lenses." Journal of Manufacturing Science and Engineering 131, no. 1 (January 23, 2009). http://dx.doi.org/10.1115/1.3063652.
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Compression molding is an effective high volume and net-shape fabrication method for aspherical lenses and precision glass optical components in general. Geometrical deviation (or curve change as often referred to in industry) incurred during heating, molding, and cooling processes is a critically important manufacturing quality parameter. In the compression glass molding process, there are many factors that could lead to curve change in final products, such as thermal expansion, stress and structural relaxation, and inhomogeneous temperature distribution inside the molding machine. In this research, an integrated numerical simulation scheme was developed to predict curve change in molded glass aspherical lenses. The geometrical deviation in the final lens shape was analyzed using both an experimental approach and a numerical simulation with a finite element method program. Specifically, numerical simulation was compared with experimental results to validate the proposed manufacturing approach. The measurements showed that the difference between numerical simulation and experimental results was less than 2 μm. Based on the comparison, the mold curve was revised using numerical simulation in order to produce more accurate lens shapes. The glass lenses molded using the compensated molds showed a much better agreement with the design value than the lenses molded without compensation. It has been demonstrated in this research that numerical simulation can be used to predict the final geometrical shape of compression molded precision glass components. This research provided an opportunity for optical manufacturers to achieve a lower production cost and a shorter cycle time.
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Farioli, Daniele, Matteo Strano, Francesco Briatico Vangosa, Veronica Geraldine Zaragoza, and Andrea Aicardi. "Rapid tooling for injection molding inserts." ESAFORM 2021, April 1, 2021. http://dx.doi.org/10.25518/esaform21.4186.
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Injection molding is a widespread manufacturing technology for mass production of polymeric parts. Conventionally, fused polymers are injected at high pressure in a metallic mold. This tool is typically characterized by high manufacturing costs and times, making the injection molding process not affordable for small batches or prototypal applications. Additive Manufacturing represents a practical solution to cut down tooling costs and times of molds and inserts. In this work, FDM (Fused Deposition Technology) has been considered as candidate technology to produce polymeric inserts for injection molding. Considering the commercially available filaments for FDM, a PEI (Polyetherimide) grade has been selected as tooling material for the injection of a part made of Polypropylene. The PEI grade represents a good compromise between manufacturing costs and thermo-mechanical properties required for the application. The PEI grade has been characterized with DSC (Differential Scanning Calorimetry), DMA (Dynamical Mechanical Analysis) and compression tests. The data gathered were used to set up 2D simplified thermo-mechanical finite element analyses, simulating the response of the PEI inserts subjected to repeated injection molding cycles. The simulations confirmed that the PEI grade is a good candidate tooling material but the progressive tool heating could lead to prolonged cooling time of the Polypropylene part. Finally, some PEI inserts were 3D printed with FDM and tested in a real injection molding machine injecting POM. In total, 20 POM parts have been injected correctly without relevant damaging of the PEI inserts.
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Gómez-Beltrán, Guillermina, and Diana Vanessa Sierra-Salgado. "Elaboración de bloques de construcción a partir de residuos de arena sílica proveniente del proceso de fundición aluminio en una empresa automotriz." Revista de Ingeniería Civil, December 31, 2019, 19–26. http://dx.doi.org/10.35429/jce.2019.10.3.19.26.
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The objective of the project was to develop a procedure for the construction of building blocks with silica sand residues, from an aluminum smelting process of an automotive spinning company. The blocks obtained were evaluated in accordance with NMX-C-404-1997-ONNCCE standards for the design and formulations of the block, and NMX-C-036-ONNCCE for tests and compression calculations. Initially these arenas are used for the elaboration of the molds of the mechanical parts that are manufactured in the company, however, once the utility of these arenas for molding is fulfilled, they are sent to final disposal sites. For the elaboration of the blocks, the physical characteristics and chemical properties of the silica sand were initially determined (grain size, pH, structure, grain shape, humidity, specific gravity, bulk and bulk density). The mold was then designed and two formulations based on the residues of silica sand, cement, water and lime were tested. The product quality assessment included tests for drying, moisture absorption, design resistance to compression. Finally, the manufacturing costs were compared with the costs of existing commercial blocks in the market.
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Zhou, Jian, Mujun Li, Yang Hu, Tianyi Shi, Yueliang Ji, and Lianguan Shen. "Numerical Evaluation on the Curve Deviation of the Molded Glass Lens." Journal of Manufacturing Science and Engineering 136, no. 5 (August 6, 2014). http://dx.doi.org/10.1115/1.4027342.
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The compression molding of precision glass lens is a near net-shape forming process for optical components fabrication. The final profile curve accuracy is one of the most crucial criterions for evaluating the quality of the molded lens. In this research, our purpose was focused on the evaluation of the molded lens curve deviation. By incorporating stress relaxation and structural relaxation model of glass, numerical simulations of the whole molding process for fabricating a planoconvex lens were conducted by utilizing the commercial software msc Marc. The relationship of the three variables, i.e., the lens curve deviation, the mold curve deviation, the gap between the lens and the lower mold, was discussed and the evolution plots with time of the three variables were obtained. Details of the thermal boundary conditions were discussed by considering the contact heat transfer behavior. Then the essentiality of a small gap between the molds and the molded lens after releasing the upper mold was demonstrated. In details, the sensitivity analysis of the processing parameters was conducted, such as the releasing temperature, the cooling rate in the annealing and fast cooling stage, respectively, and the magnitude of the hold-up force. The results showed that the glass lens curve deviation was not sensitive to the choices of the releasing temperature and the cooling rate. What's more, the results indicated that the curve deviation decreased with the hold-up force increasing. Finally, with all the details considered, the final simulation results were presented accurately with good reason.
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Nam, Ki-Woo, and Seo-Hyun Yun. "Failure analysis and countermeasures of the SCM435 high-tension bolt of three-step injection mold." International Journal of Structural Integrity ahead-of-print, ahead-of-print (October 9, 2020). http://dx.doi.org/10.1108/ijsi-07-2020-0064.
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PurposeThe objective of this study was to perform damage analysis of SCM435 high-tension bolts connecting upper and lower parts of a three-stage injection molding machine.Design/methodology/approachDamage material used in this study was a SCM435 high-strength bolt connecting upper and lower molds of a three-stage injection mold. Causes of damage were determined by macroscopic observation. Microstructure observation was done using a metallic microscope, scanning electron microscope (SEM, S-2400, HiTachi, Japan), energy dispersive X-ray spectroscopy (EDS, Kevex Ltd., Sigma) and Vickers hardness tester (HV-114, Mitutoyo). Fatigue limit of the damaged material was evaluated using equivalent crack length.FindingsBolts were fractured by cyclic bending stress in the observation of ratchet marks and beach marks. The damaged specimen showed an acicular microstructure. Impurity was observed. Chromium carbide was observed near the crack origin. Both shape parameters of the Vickers hardness were similar. However, the scale parameter of the damaged specimen was about smaller than that of the as-received specimen. Much degradation occurred in the damaged specimen. Bolts should undergo accurate heat treatment to prevent the formation of chromium carbide. They must prevent the action of dynamic stresses. Bolts need accurate tightening and accuracy of heat treatment. Screws require compression residual stress due to peening.Originality/valueThis study conducted failure analysis of damaged SCM435 bolts connecting upper and lower parts of the three-stage injection mold. Fatigue limit of the damaged material was evaluated using equivalent crack length. In order to control this fracture, accurate tightening of bolts, accuracy of heat treatment and screws are required for compression residual stress due to peening.
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Jones, Wanda, Bedanga Sapkota, Brian Simpson, Tarig A. Hassan, Shaik Jeelani, and Vijaya Rangari. "Fabrication and characterization of carbon nanofibers coated expandable thermoplastic microspheres-based polymer composites." Current Applied Polymer Science 05 (January 14, 2022). http://dx.doi.org/10.2174/2452271605666220114113214.
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Background: Thermoplastic expandable microspheres (TEMs) are spherical particles that consist of polymer shell encapsulating a low boiling point liquid hydrocarbon that acts as the blowing agent. When TEMs are heated at 80-190 C, the polymer shell softens and the hydrocarbon gasifies, causing the microspheres expand leading to increase in volume and decrease in density. TEMs are used in food packaging, elastomeric cool roof coatings, shoe soles, fiber and paper board, and various applications in the automotive industry. It is noted that TEMs are known by its brand name ‘Expancel’ which is also used to refer TEMs in this paper. Objective: The objective of this work was to develop and characterize forms prepared from TEMs with/without carbon nanofibers (CNFs) coatings to study the effect of CNFs on structural, thermal, and mechanical properties. Method: Sonochemical method was used to coat TEMs with various weight percentage (1, 2, and 3 %) of CNF. Neat foam (without CNF) and composite foams (TEMs coated with various wt.% of CNF) were prepared by compression molding the TEMs and TEMs-CNF composites powders. Thermal and mechanical properties of the neat and composite foams were investigated. Result: The mechanical properties of the composite foam were notably improved, which is exhibited by a 54% increase in flexural modulus and a 6% decrease in failure strain with the TEMs-(2 wt.% CNF) composite foam as compared to the neat foam. Improvement in thermal properties of composite foam was demonstrated by a 38% increase in thermal stability at 800 ºC with the TEMs-(1 wt.% CNF) composite foam as compared to the neat foam. However, no change in glass transition of TEMs was observed with the CNF coating. SEM-based analysis revealed that CNFs were well dispersed throughout the volume of the TEMs matrix forming a strong interface. Conclusions: Straightforward sonochemical method successfully triggered efficient coating of TEMs with CNFs resulting to strong adhesion interface. The mechanical properties of composite foams increased up to 2% of CNFs coating and then decreased with the higher coating presumably due to interwoven bundles and aggregation of CNFs, which might have acted as critical flaws to initiate and propagate cracking. Thermal properties of foams increased with the CNFs coating while no change in glass transition temperature was observed due to coating.