| With the rapid development of science and technology,lightweight plastic integrated components have been widely used in automotive manufacturing,aerospace and artificial intelligence industries.However,mechanical and adhesive bonding methods are difficult to meet the high efficiency of rigid bonding of plastic composite components.With the high reliability requirement,it is urgent to develop a new technology of fastening plastic composite components.Ultrasonic plastic welding is a kind of bonding method by which the energy of the welded joint is focused on the weldment by ultrasonic vibration,and the contact surface molecules are rapidly fused under the thermal-mechanical coupling action.At present,the research of ultrasonic plastic welding technology mainly focuses on the bonding of micro-devices,the discussion on the properties of composite joints and the analysis of interface microstructure,etc.In this paper,the welding process of the motor gear unit(nylon material)plastic composite component in the electronic parking brake system is used as the research object,and the method of the combination of the finite element numerical simulation analysis and the test is adopted,the thermal mechanism analysis of the ultrasonic welding and the design of the welding processing system are carried out.The optimization of the welding parameters of the orthogonal test is to improve the welding efficiency and reliability index.The parametric model of ultrasonic welding temperature field is established by the thermo-mechanical coupling module of ANSYS finite element analysis software.The thermodynamic analysis and temperature field simulation are carried out by using the coupling function of multiple physical fields,and the welding pressure 400N and welding time 0.5s are discussed.When the ultrasonic amplitudes are 10 ?m,20 ?m,30 ?m and 40 ?m respectively,the temperature of the welding zone can reach,the reasonable amplitude of the nylon plastic composite component is 30 ?m,and the temperature of the welding zone can reach 319 ?.The results of this study can be used to select the parameters of welding test and application.The rotating ultrasonic effect is analyzed,and friction assisted ultrasonic welding is put forward.The heat-forming mechanism and temperature of the friction and ultrasonic wave are analyzed and discussed in this paper.On the basis of the research results of the mechanism of ultrasonic welding,based on the ultrasonic welding technology of plastic composite components of motor gear unit,the sandwich piezoelectric ultrasonic transducer,amplitude augmentation rod,welding tool head,and so on,are designed.Using ANSYS software modal analysis,harmonic response analysis module to the ultrasonic vibration system parametric modeling,characteristics analysis,and ultrasonic welding vibration system optimization design,the ultrasonic amplitude of welded joints can be stable 0 ?m-33 ? m continuous adjustable.The pneumatic transmission system,the pressure measuring device and the clamping device are designed,and the high efficiency and reliable ultrasonic welding system is constructed.The laser micro-position is used to construct the whole system of ultrasonic welding.Taking pull-off force as the evaluation standard for ultrasonic plastic welding,selecting trigger pressure,welding pressure and welding depth to carry out three-level three-factor orthogonal test of welding parameters,the optimized process parameters combination is obtained as follows:trigger pressure 560N,The welding pressure is 800N,the welding depth is 0.75 mm,and the corresponding pull-off force is 1254N.It is proved that the ultrasonic welding method of plastic composite components has good machining effect and fastening reliability.The friction-assisted ultrasonic welding test of nylon materials and plastics was carried out,and the good welding effect was obtained.The new technology of friction-assisted ultrasonic welding was further analyzed and improved,and the effective improvement measures were put forward. |
PDF Full Text Request