| Wool top is installed on doors and windows to enhance the sealing,sound insulation,waterproof and other functions between door frames and leaves.It is widely used in construction,environmental protection,home and other fields.At present,ultrasonic welding technology is mainly used in top production,and then the welding quality is tested by top tension.The process parameters used in the traditional ultrasonic welding process mainly rely on workers' experience,and there is a lack of systematic research on the influencing factors of top welding quality,which seriously affects the production efficiency of top and the welding quality of formed top.Therefore,this paper mainly studies the following aspects.Firstly,the technological process of ultrasonic welding top is analyzed,and the factors affecting the welding quality of welding top in the technological process are analyzed.The orthogonal experiment is designed to deeply explore the relationship between each influencing factor and the welding quality of top,and obtain the influence rules of each influencing factor on the welding quality.It is found that the welding material has the greatest influence on the welding quality.Secondly,the finite element transient thermal analysis module is used to establish the ultrasonic welding simulation model of wool composite components,and the thermodynamic simulation of the welding process is carried out.According to the welding process parameters,the welding pressure is 130 n,the welding speed is4.0m/min,and the welding power is 1200 W.The simulation results show that the welding interface is a high-temperature concentration area,and the maximum temperature of the center of the top weld is 201.34 ?.Along the y-axis direction of the bottom plate,the temperature rise of welding rises sharply to 120 ? in the first 0.15 s,and then the temperature rise increases gently and approximately linearly.Along the z-axis direction of the bottom plate,the temperature at 0.2mm of the navigation bar reaches the melting point and melts.Thirdly,the experimental platform of ultrasonic welding top is built to verify the simulation results.The higher the temperature at the midpoint of the simulation,the more sufficient the local friction is,the more thoroughly the contact area melts,and the better the top quality.Therefore,the temperature value at the midpoint can be transformed into the top tension value under the same parameters,and the top production and tension test can be carried out with the same process parameters as the simulation.The test results show that the top tension and temperature field show the same trend,that is,with the increase of welding speed,the top tension decreases,and the highest temperature corresponds to the maximum test top tension,which verifies the accuracy of the simulation results.Finally,the process parameters of obtaining high-quality top are optimized.Single factor analysis was used to optimize the welding material,energy strip width and welding speed.The experimental results show that the addition of thermoplastic vulcanized rubber(TPV)to polypropylene of base plate materials K8003 and 3015 significantly improves the top quality.The top quality first increases and then decreases with the increase of the amount of thermoplastic vulcanized rubber(TPV),and the top quality is improved most significantly when the amount of TPV is 10%.The simulated temperature field results show that the welding quality of wool top is inversely proportional to the welding speed and energy strip width.Therefore,the optimized welding materials are 60% of K8003 polypropylene and 30% of 3015 polypropylene,10% TPV is added,and the width of energy strip is 0.4mm.After optimization,the welding speed of high-quality wool top is increased to 4.8m/min,compared with the highest welding speed of 3.0m/min before optimization,and the production efficiency is increased by 60%. |
PDF Full Text Request