聚合物双振子超声焊接量子升温优势

Advantage of quantum heating on double-vibrator ultrasonic welding of polymers

针对聚合物超声焊接升温机理,通过量子理论建立超声声场模型.将聚合物升温过程视为超声场能量转化为聚合物内能的能量转换过程.研究了聚合物双振子超声焊接相比单振子超声焊接的优势.通过二次量子化理论分析发现单振子焊接时,只有频率为声场频率整数倍的原子能吸收声子,而双振子焊接时,除了频率为两个声场频率整数倍的原子之外,频率为两个声场频率整数倍组合的原子也可以吸收声子.双振子焊接相比单振子超声焊接对超声场能量的利用率更高.并通过试验验证了这一结果.结果表明:振子功率保持恒定时要实现同样的焊接效果,双振子焊接时间为单振子焊接时间的3/8;焊接时间一定时要实现同样的焊接效果,双振子总功率是单振子功率的12/13.

In ultrasonic welding of polymers,the heating process can be considered as the process that the energy of sound field converts into the internal energy of polymers.According to the theory of second quantization,the energy flow of ultraosnic is equivalent to the phonons flow of a given flux.Phonons can only be absorbed as a complete unit by atoms.Atoms have separate energy levels and will absorb phonons in the transition from a lower level to a higher level.The total energy of these absorbed phonons is equal to the difference in energy of these two levels.According to this theory,in the process of one-vibrator welding,only the atomic vibrators with frequencies of an integer multiple of ultrasonic frequency can effectively absorb phonons.Whereas,in double-vibrator welding,besides the vibrators with the frequencies of integer multiples of these two ultrasonic frequencies,phonons can also be absorbed by the vibrators with the frequencies of the sum of integer multiples of the two ultrasonic freqiencies.Therefore,the absorption capacity of phonons in double-vibrator ultrasonic welding is superior to that of single-vibrator welding,that is,the utilization rate of ultrasonic field energy in double-vibrator welding is much higher.The results of the corresponding experiments indicate that the double-vibrator system spends only 3/8 of the time of the single-vibrator system with half of the power in completing the same welding;and in the same welding time,the double-vibrator system with 12/13 of the power of single-vibrator system can accomplish the same welding.