A. Jabarirad, D. Akbari, M. Golzar,
Volume 6, Issue 2 (Journal OF Welding Science and Technology 2020)
Abstract
In this paper, ultrasonic welding of glass fiber reinforced thermoses, co-cured whit a thermoplastic has been studied. Co-curing process forms a connection between the thermoset and the thermoplastic while curing the composite. Considering that the calculated stress should not be related to the dimensions of the sample, a horn with a tip dimension smaller than the standard overlap was used. The results show that the actual weld dimensions are bigger than the intended weld dimensions. This has happened due to the movement of the melted thermoplastic to the sideways during the welding. The design of experiment has been done using response surface central composite, and a quadratic equation based on the lap shear strength of the welds containing three principle parameters time, force and amplitude was suggested, as well as predicting the optimum values. The equation shows that the force is an insignificant factor. In the samples with a higher time value the thermosetting resin started to degrade. The dominant failure mode of the specimens is segregation between the thermoset and fibers. The results show that the optimum parameters can result in a lap shear strength of 28.2 MPa, which is a very decent value compared to other methods of joining.
Hamed Tirband, Davood Akbari, Mohammad Golzar,
Volume 7, Issue 1 (Journal OF Welding Science and Technology 2021)
Abstract
In this research, tensile strength of ultrasonic welded parts made of thermoset polymer-reinforced glass fiber with surface preparation has been investiagted. In order to elevate the adhesion of two surfaces laser grooving method has been applied. Two type of thermoplastic materials including Plymethyl methacrylate (PMMA) and polypropylene (PP) have been used as interlayers. Influences of main welding parameters were investigated. The results show that the force and compression parameters in these joints have been ineffective parameters and in higher weld welds, the thermosetting resin has started thermal degradation. The pressure considered constant and set at 2 bar, welding time set at 1.6 seconds and holding time considered 3 seconds. The results showed that the minimum tensile strength of welded samples with laser surface preparation method is 1286 N, which is much more than maximum tensile strength of welded samples without any surface preapration. This indicates that laser beam surface preparation is an effective method in improving of the adhesion strength of thermoset polymeric parts.
B. Zamzami, M. Safari, M. Golzar,
Volume 12, Issue 1 (Journal OF Welding Science and Technology 2026)
Abstract
Copper coils are essential components of induction hardening machines. The traditional manufacturing process of these coils utilizes extruded copper profiles. In this study, the production of copper profiles using metal 3D printing was experimentally investigated. Two copper samples with hollow square cross-sections, produced by extrusion and metal 3D printing, were evalated for the purpose of manufacturing induction hardening coils. Density, electrical conductivity, hardness, and surface roughness tests were performed in accordance with the relevant standards. The quantitative results for the extruded and 3D-printed samples were, respectively: density of 99% and 93% of the theoretical density of copper; electrical conductivity of 100.8% and 99.1% relative to the annealed copper standard; Brinell hardness of 50 and 59 HB; and surface roughness (Ra) of 0.324-0.533 and 11.949-13.194. The results indicated that the extruded sample possessed higher density, superior electrical conductivity, and a smoother surface, whereas the 3D-printed sample exhibited higher hardness, lower density, and greater surface roughness. These findings demonstrate that metal 3D printing can be utilized for the manufacturing of induction hardening coils.
