Process And Mechanism Of Joining Of ABS Polymer And Metal By Resistance Welding

Recent years,with the depletion of petrochemical resources and further deterioration of people's living environment,lightweight manufacture have gradually become an effective way to realize energy saving and environment protecting,especially the increasing utilize of light metal Al,Mg,Ti and polymer,carbon fiber and composite in automobile and aerospace industry promotes deve lopment of lightweight manufacture.Consequently,joining of metal and nonmetal materials plays an important role in the lightweight manufacture.In this paper,thermoplastic polymer and metal joining by resistance welding was explored.After welding process optimization,joints with excellent comprehensive properties were obtained,which provided technical support for the development of lightweight manufacture.Using experimental material ABS polymer,aluminum and Q235 steel,set self-made multi electrode multi-function Resistance welding machine as experimental platform.Unilateral electricity obtained through coordination of three electrodes and secondary coil.Resistance hot was transferred to ABS polymer from metal as welding heat source,and two materials joining was achieved in the process of polymer melting and spreading with temperature and pressure.The following experiment research on joint formation,mechanical properties and joining mechanism were carried out:Based on Lab VIEW data acquisition system,electric signal in the welding process were collected.By analyzing and comparing the deformation behavior of joint,welding process parameters were optimized.Research influence of welding parameters vary on joining quality and optimize process parameters;With the increase of welding current or time in reasonable parameter range,joint connection area and strength increased and testing results had smaller discreteness.While the larger heat input parameters made the melted polymer extrusion sharply at interface,and brought large stress concentration in welding joints.While the electrode pressure changes,joining strength had no stable variable trend with large strength concentration.Developed joint strength tests and results shown that joints failure had three different modes,Interface peeling out,polymer tearing at interface and polymer matrix fracture.Failure loads of interface peeling was quite small,and tensile curve reached the peak at the end of linear phase.Tensile failure l oads of polymer at interface or matrix fracture reached up to strength of polymer matrix and tensile curves had obvious yield stage.The matrix failure modes had the longest yield stage and absorbed highest energy during tensile testing.In order to improve quality of joint,ultrasonic assistance system was added in welding process.Formation and mechanical properties of joints after the application of assistance system were analyzed by contrast with the conventional process.With the same welding parameters,ultrasonic assistance made an obvious improvement on joint quality.The area of effective joining zone got larger and strength increased about 10% and has smaller discreteness under ultrasonic assistance.Mechanical interlocking,diffusion and coordination bonds multiple mechanisms contributed into joining of polymer and metals together.With the observation of the cross-section of the joint and the plastic interface,the analysis of the interface element energy spectrum,the infrared spectrum analysis and X ray photoelectron spectroscopy technology.