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Micro-surface texturing of elastomeric seals is a validated method to improve the friction and wear characteristics of the seals. In this study, the injection process of high-viscosity elastomeric materials in moulds with wall microprotusions is evaluated. To this end, a novel CFD methodology is developed and implemented in OpenFOAM to address rubb...
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... selected rubber is a fluorocarbon elastomer whose hardness is 80 Shore A, denominated FKM80A, whose characterization is performed experimentally [30] and consists of: (i) Rubber-Capillary-Rheometer (RCR) experiments at 80, 100 and 120 • C from 10 s −1 up to 750 s −1 shear rate, the resulting data are used to fit the parameters of the "Reactive Viscosity Model" (Equation (20) (160, 170, 180 and 190 • C) to estimate the value of the cure reaction-kinetics parameters (Equation (24) reported in Table 2). RCR and MDR raw data are attached as Supplementary materials. ...Similar publications
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... Since cavity pressure variations have a high impact on the final part quality and the process control, mould sensor integration enables the user to obtain information about the filling behaviour and the volumetric filling point, contrary to the hydraulic pressure or nozzle pressure which does not supply information from the cavity [6,7]. Simultaneously, injection moulding process simulation is broadly used to predict the polymer melt behaviour in the mould [8], to support the manufacturing tool design [9,10], and to diminish the experimental trial-and-error techniques on process optimization [9]. Thus, numerical simulation is a powerful tool in reducing energy consumption and costs [11], helping to prevent or determine the origin of injection part defects such as jetting [12], welding lines [13] or hesitation [14], venting problems [15], and birefringence [16], and later eliminate them. ...
... Since cavity pressure variations have a high impact on the final part quality and the process control, mould sensor integration enables the user to obtain information about the filling behaviour and the volumetric filling point, contrary to the hydraulic pressure or nozzle pressure which does not supply information from the cavity [6,7]. Simultaneously, injection moulding process simulation is broadly used to predict the polymer melt behaviour in the mould [8], to support the manufacturing tool design [9,10], and to diminish the experimental trial-and-error techniques on process optimization [9]. Thus, numerical simulation is a powerful tool in reducing energy consumption and costs [11], helping to prevent or determine the origin of injection part defects such as jetting [12], welding lines [13] or hesitation [14], venting problems [15], and birefringence [16], and later eliminate them. ...
The pressure profile analysis for monitoring and diagnosis processing failures during an injection moulding process, such as burn marks and short shots, is a useful instrument for process and part quality control and production with zero defects and greater efficiency. Therefore, this work aims to demonstrate the in-cavity pressure monitoring feasibility for failure diagnosis and injection moulding process optimization. The methodology used to analyse the obtained pressure variation is presented. The results were correlated to the typical cavity pressure profile, which enables the acquisition of information about the process and the moulding tool. This way, it was possible to determine the origin of the defects present in the injected parts, focusing not only on the velocity to pressure switchover but also on the initial part of the curve, related to the filling phase. Moreover, the obtained results and the studied processing conditions were correlated with the injection moulding process simulation.
... Globally, the used capacity of plastic first became greater than steel after the 1980s [1,2]. Injection molding was the most frequently applied manufacturing procedure and one of the most important techniques for global fabricating plastic parts [3,4]. However, it was a technologically complicated procedure and very hard to consider all the transformations occurring during the procedure. ...
This paper adopted transient CFD (Computational Fluid Dynamics) simulation analysis with an experimental method for designing and surveying the quick and uniform rise in the temperature of the plastics into the insert mold cavity. Plastic injection molding utilizing VCRHCS (Vapor Chamber for Rapid Heating and Cooling System) favorably decreased the defects of crystalline plastic goods’ welding lines, enhancing the tensile intensity and lowering the weakness of welding lines of a plastic matter. The vapor chamber (VC) possessed a rapid uniform temperature identity, which was embedded between the heating unit and the mold cavity. The results show that the tensile strength of the plastic specimen increased above 8%, and the depths of the welding line (V-gap) decreased by 24 times (from 12 μm to 0.5 μm). The VCRHCS plastic injection molding procedure can constructively diminish the development time for novel related products, as described in this paper.
... There are two main ways to achieve texture on polymers: by applying the texture on previously manufactured components, or by transferring from the mould during the component manufacturing, through either injection moulding [18][19][20] , injection compression moulding, compression moulding 21 , hot embossing, among others. While the first approach is limited, especially for the production of high-volume components, the second approach is postulated as an encouraging technique for mass production 3 . ...
Background: Micro-texturing is an increasingly used technique that aims at improving the functional behaviour of components during their useful life, and it is applied in different industrial manufacturing processes for different purposes, such as reducing friction on dynamic rubber seals for pneumatic equipment, among others. Micro-texturing is produced on polymer components by transfer from the mould and might critically increase the adhesion and friction between the moulded rubber part with the mould, provoking issues during demoulding, both on the mould itself and on the rubber part. The mould design, the coating release agent applied to the mould surface, and the operational parameters of the moulding/demoulding process, are fundamental aspects to avoid problems and guarantee a correct texture transfer during the demoulding process.
Methods: In this work, the lack of knowledge about demoulding processes was addressed with an in-house test rig and a robust experimental procedure to measure demoulding forces (DFs) as well as the final quality of the moulded part, between thermoset polymers and moulds. After the characterization of several Sol-Gel coating formulations (inorganic; hybrid) the influence of several parameters was analysed experimentally, i.e.: Sol-Gel efficiency, texture effects, pattern geometry, roughness and material compound.
Results: The results obtained from the experimental studies revealed that texture depth is the most critical geometrical parameter, showing high scatter among the selected compounds. Finally, the experimental results were used to compute a model through reduced order modelling (ROM) technique for the prediction of DFs.
Conclusions: The characterization of DFs in a laboratory, with a specific device operated by a universal testing machine (UTM), provided valuable information that allows a fast and optimized introduction of texturing in rubber components. Selection of a novel Sol-Gel coating and the use of the ROM technique contributed to speed up implementation for mass production.
Chromatic confocal surface profilometry has been a widespread technique in industrial applications for many years. Beside excellent resolution and speed, the contactless measuring capability make it ideal in applications where no physical contact is possible, (e.g. measurement of fluid levels), or where physical contact could damage the part to be inspected (e.g. high precision lenses or coatings). Since these systems rely on the spectral analysis of the reflected light, if the reflectance of the examined specimen is low, the measurement speed and accuracy can substantially degrade. In this paper, we present a high-intensity chromatic confocal surface profiling system based on an infrared superluminescent diode and custom designed optics. Due to its very small etendue, the superluminescent source allows orders of magnitude higher illumination intensity than conventional LED sources. We mounted the designed optics on a 5-axis precision positioning stage, which allows topography measurements along 5° of freedom on complex shaped samples, with a wide focus range (>350 μm) and a high scanning speed (>10 kHz). The paper presents the design procedure and the figures of merit of the device, and measurement results of microstructured elastomer samples are also shown.
Background: Micro-texturing is an increasingly used technique that aims at improving the functional behaviour of components during their useful life, and it is applied in different industrial manufacturing processes for different purposes, such as reducing friction on dynamic rubber seals for pneumatic equipment, among others. Micro-texturing is produced on polymer components by transfer from the mould and might critically increase the adhesion and friction between the moulded rubber part with the mould, provoking issues during demoulding, both on the mould itself and on the rubber part. The mould design, the coating release agent applied to the mould surface, and the operational parameters of the moulding/demoulding process, are fundamental aspects to avoid problems and guarantee a correct texture transfer during the demoulding process.
Methods: In this work, the lack of knowledge about demoulding processes was addressed with an in-house test rig and a robust experimental procedure to measure demoulding forces (DFs) as well as the final quality of the moulded part, between thermoset polymers and moulds. After the characterization of several Sol-Gel coating formulations (inorganic; hybrid) the influence of several parameters was analysed experimentally, i.e.: Sol-Gel efficiency, texture effects, pattern geometry, roughness and material compound.
Results: The results obtained from the experimental studies revealed that texture depth is the most critical geometrical parameter, showing high scatter among the selected compounds. Finally, the experimental results were used to compute a model through reduced order modelling (ROM) technique for the prediction of DFs.
Conclusions: The characterization of DFs in a laboratory, with a specific device operated by a universal testing machine (UTM), provided valuable information that allows a fast and optimized introduction of texturing in rubber components. Selection of a novel Sol-Gel coating and the use of the ROM technique contributed to speed up implementation for mass production.
