The objective of this work is using a hot press technique to join a hybrid structure of aluminum alloy AA6061-T6 sheet of 1mm thickness together with polyamide PA sheet of 2mm thickness. The aluminum alloy specimen was pre-holed with two holes of 5mm diameter. The joining process was carried out with a lap joint configuration. Three different process parameters of the joining process were used: temperature (164, 172 and180°C), pressure (4, 7 and 10 bar) and time (1, 2.5 and 4 min.). The joints were tested by a shear test, macrostructure and scanning electron microscope (SEM) inspection. The design of the experiments (DOE) method was used to analysis the effect of the process parameters on the joint shear force. The DOE optimized the shear force of the joint with a maximum value of 1565 N at 177.5°C 4bar and 3.5min. The SEM examination indicated that the joining mechanism occurred by re-solidified the PA through the internal surface of the aluminum hole.

Resistance spot welding (RSW) is a complicated process, which involves the interaction of electrical, thermal, mechanical, and metallurgical phenomena. In this research we used two types of material (UNS G10050 carbon steel and UNS C10010 copper) and welded them in similar and dissimilar condition with four variables welding current, pressure, squeeze time and welding time. The results of the tensile-shear force were analyzed statistically by the Design of experiments (DOE) utilizing Taguchi method. Tensile-shear test used for counting the strength of the joint, maximum strength was found in similar joining condition for carbon steel, also it is interesting to note that the strength of dissimilar joint is stronger than copper joining in similar condition.

Hot press bounding technique was used to join a polyethylene sheet of 4mm thickness to stainless steel AISI 304L of 1mm thickness. Three different process parameters were used during the joining process: pressure of 4, 6, 8 and 10 bar, processing time of 1.5, 2, 2.5 and 3 min. and temperature of 115, 120, 125 and 130°C. The steel surface was treated with two methods: mechanical (scratch) and electrochemical (electro-polishing) treatment. A shear tensile, microstructure, scanning electron microscope and energy dispersive spectrometry tests were used to examine the joint specimens. The effect of process parameters on the joint properties was analyzed by the Minitab program. The scratched and electro-polished joint specimens exhibited a maximum shear force of 1112 and 1022N respectively. The tested joints were failed by an interfacial shear and necking in the polymer side with a ductile fracture. The joining process was occurred by a mechanical interlocking between the molten polymer and pores of the treated surface of steel specimen. The average thickness of the joining line for the scratched and electro-polished specimens was 5 and 4μm.

A hot press process was used as a technique to pound a polyamide type of polymer of a thickness (2mm) to stainless steel AISI 316L of the thickness (1mm). A hybrid joint of dissimilar material was accomplished by a hot press bonding process.  During the joining process, three different parameters of process were used:  processing temperature of 175, 170 and 165°C, processing pressure of 3, 6 and 9 bar and time of 1.5, 3 and 4.5 min. The surface of stainless steel was prepared and treated by a mechanical treatment (surface grinding) to improve the wettability to increase the shear strength. A shear tensile, scanning electron microscope (SEM) and energy dispersive spectrometry (EDS) tests were used to investigate and examine the joint (bounding) specimens. The Minitab program was used to analyze the effect of the parameters of the joining process on the joint properties. The maximum and minimum values of shear force are exhibited at a processing temperature of 165°C, applied pressure of 6 bars and processing time of 1.5 minutes; the minimum shear force was found to be 675 N, while the maximum shear force was 2182 N at a processing temperature of 175°C, applied pressure of 6 bars and processing time of 3 minutes.  The tested joints failed by an interfacial shear and necking in the polymer side with a ductile fracture. The joining process occurred through a mechanical interlocking between the molten polymer and the treated surface of the steel specimen. The average thickness of the joining line for the tested specimens was 8µm.