Influence of welding parameters and surface preparation on thin copper–copper sheets welded by ultrasonic welding process

Abstract

Ultrasonic welding is increasingly used in industry. In this paper, the influence of ultrasonic welding parameters (USW) on the joint strength and quality was analysed. The properties of the USW joints depend on many factors. The work focuses on the influence of the technological parameters and the surface properties of welded EN Cu-ETP copper sheets with a thickness of 1 mm. The impact of the process parameters, such as welding time, pressure, vibration amplitude and the surface roughness on the lap shear strength and the metallographic weld properties was analysed. The welding energy for each variant was also determined. The research was conducted on the basis of a full factorial design of experiments. The optimal process parameters were determined to obtain high-quality joints in terms of strength and weld quality. Based on the presented experimental study, it was demonstrated that the ultrasonic vibration amplitude has the greatest impact on the joint strength. A surface preparation with acetone resulted in the highest tensile strength and welding energy and, making any additional surface treatment prior to welding unnecessary.

Factors affecting evolutions of contact area formation and bonding strength in pure Cu/Cu joints produced by ultrasonic spot welding

“…That is, bonding strength increased with increases in bonded fraction, as shown in the cross-sectional observation. A previous study [21] reports that higher roughness could facilitate a higher degree of plastic deformation to enhance joint strength by mechanical interlocking. With a higher bonding fraction, strength could increase correspondingly (measurement of bonding fraction can refer to Figure S3 in supplementary material, where examples are shown in Figure S3a).…”

“…Regarding the welding parameters affecting the formation of bonding areas between Cu sheets, it has been reported that rougher surface combinations yielded better joint strength because rough peaks allowed a higher degree of plastic flow at the contact points [21]. On the other hand, a recent study reports that a smoother surface combination yields a higher strength than a rougher one, which can be attributed to the difference in contact fraction between these two cases [22].…”

Determination of proper parameters for ultrasonic welding of copper plate with copper wire strands

“…Minitab can create Contour plots with the response variable on the 𝑧-axis and the two control variables on the 𝑥and 𝑦-axes, used to identify optimal values of the predictor variables for a given response variable [15].…”