At present basic theory and welding criterion of UPW are defective, research on welding mechanism and melt behavior of the welding region is not enough for the difficulty in study.

• 由于超声波塑料焊接是涉及多学科的交叉学科，研究难度较大，目前超声波塑料焊接的焊接基础理论和工艺规范还比较欠缺，对超声波塑料焊接机理和熔接行为研究不足。