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Plastics
Published in Sherif D. El Wakil, Processes and Design for Manufacturing, 2019
Transfer molding is a modified version of the compression molding process, and it is aimed at increasing the productivity by accelerating the production rate. As can be seen in Figure 8.10, the process involves placing the charge in an open, separate “pot,” where the thermosetting polymer is heated and forced through sprues and runners to fill several closed cavities. The surfaces of the sprues, runners, and cavities are kept at a temperature of 280°F to 300°F (140°C to 200°C) to promote curing of the polymer. Next, the entire shot (i.e., sprues, runners, product, and the excess polymer in the pot) is ejected.
Fabrication Processes
Published in Manas Chanda, Plastics Technology Handbook, 2017
Transfer molding has an advantage over compression molding in that the molding powder is fluid when it enters the mold cavity. The process therefore enables production of intricate parts and molding around thin pins and metal inserts (such as an electrical lug). Thus, by transfer molding, metal inserts can be molded into the component in predetermined positions held by thin pins, which would, however, bend or break under compression-molding conditions. Typical articles made by the transfer molding process are terminal-bloc insulators with many metal inserts and intricate shapes, such as cups and caps for cosmetic bottles.
Polymer Processing Operations
Published in Nicholas P. Cheremisinoff, An Introduction to Polymer Rheology and Processing, 1993
Transfer molding is a variation of compression molding. In transfer molding, a plunger compresses a rubber preform in a pot, as shown in Figure 35. The rubber is heated by contact with the plunger face and pot. When sufficient force is applied to a mold by a press, rubber flows through the spur and into the mold cavity, as illustrated in Figure 36.
Experimental and numerical investigation of the behavior of three-dimensional orthogonal woven composite plates under high-velocity impact
Published in Mechanics of Advanced Materials and Structures, 2023
Hao Su, Xuena Si, Yan Liu, Ming-ming Xu, Guang-yan Huang, Jiacong Pan
The specimens used in the impact experiment are made of carbon fibers T300 and epoxy resin TDE-86. The cross section of the fiber is assumed elliptical. The schematic diagram of internal structure of 3DOWC specimens is shown in Figure 1, where represent the sizes of cross sections of warp yarn, weft yarn, and binder yarn, respectively. The parameters of the 3DOWC specimen are listed in Table 1. All of the section sizes of yarns are measured from CT images. Vacuum-assisted resin transfer molding (VARTM) technique was used in the molding process of the specimens. The volume fraction of fiber in the specimens is about 47%. The in-plane size of specimens is 80 × 80 mm2, and the thickness is 10.8 mm. Spherical projectiles of the diameters Dp = 6 or 8 mm are made of tungsten alloy.
The effect of molding process on thermomechanical properties of feather nonwoven reinforced polyester composites
Published in The Journal of The Textile Institute, 2022
Ouahiba Mrajji, Mohamed El Wazna, Abdeslam El Bouari, Omar Cherkaoui
The properties of composite materials with natural fibers depend on several factors such as: manufacturing technique, nature and quantity of the constituents, morphology, orientation and state of dispersion in the matrix, porosity and fiber-matrix interface (El Habib, 2013). Sreekumar et al. (2007) studied the tensile properties of sisal/polyester composites at different fiber length using resin transfer molding and compression molding. The results show that the composites fabricated by RTM have maximum tensile strength and Young’s modulus for fiber having 30 mm length and fiber loading of 43 vol%. RTM composites had better performances under loads compared to the compression molded samples. The authors concluded that this was due to lower void content and better wettability (fiber–matrix interaction) of the composites prepared with RTM.
Impregnation and resin flow analysis during compression process for thermoplastic composite production
Published in Advanced Composite Materials, 2021
Osuke Ishida, Junichi Kitada, Katsuhiko Nunotani, Kiyoshi Uzawa
Resin impregnation process during compression molding has been studied by many researchers [19–24]. In these studies, the resin flow through fiber network has been modelled based on Darcy’s law. For example, Gutowski et al. [19] evaluated the transverse permeability of fiber bundles based on fiber elastic deformation model. Michaud et al. [20] developed the impregnation model of glass mat thermoplastic (GMT) based on local resin flow in compressible porous media. Kobayashi et al. [21] studied the impregnation behavior of Micro-Braided-Yarn based on the ellipsoidal model of fiber yarn and evaluated the effects of the yarn conditions. For the compression resin transfer molding (CRTM) process, Merrote et al. [22] modelled the resin in-plane flow in fiber preform during compression process. Their works have successfully explained the resin flow behavior through fiber reinforcements. However, these analyses cannot describe the combined process of the fiber bundle impregnation and resin in-plane flow of film stacking material. The aim of our study is to clarify this combined impregnation and in-plane flow behavior.