A Study on Ultrasonic Welding of Metals to Non-Metalic Materials

Abstract

Joining of metals to plastics and to glasses can be performed by the methods of plating and vapor depositing and by use of a proper organic adhesive agent. Diffusion bonding of metals to ceramics and to cermets can also be performed with some proper brazing materials. However, it seems that making of a smaller point joint for the precision components by such joining methods is very difficult. In addition, these joining methods will be attended with many difficulties in operation.
Ultrasonic welding, as known well, possesses many characteristics superior to other conventional welding methods. Consequently, there is good prospect that make a smaller point joint of metals to the above non-metallic materials can be made by this. Since there was little research on such welding, some experiments were carried out in order to make clear the possibility and bonding mechanism of the ultrasonic welding of metals to non-metallic materials.
This report describes the relation between the welding conditions and the weld properties, the output energy loss at the weld interface with the non-metallic materials diformed and softened during the welding and some results of photomicro examination on the weld interface in the ultrasonic welding of low carbon steel to some plastics and to glass.
To obtain good welds of such combinations, it is probably necessary that the non-metallic materials be not greatly deformed and softened during the welding and materials possess some elements such as O, N, Al, Si and others which make an atomic bond to the metals a foil interleaf and are more diffusible into the foil interleaf.
In this work, welding of low carbon steel to glass and to acrylic or polypropylene was performed without any difficulty by use of Al foil interleaf. Welding of steel to polyethylene or fluorinated ethylene was attended with some difficulties, especially, fluorinated ethylene could not be welded to steel. This is probably due to some energy loss at the weld interface on account of softening and deforming of the latter materials during the welding, and also due to the materials possessing no elements which are diffusible into Al foil interleaf.