TWI Industrial Member Report Summary 671/1999
R Hardy and I A Jones
The infrared (IR) lamp and laser welding characteristics of polyethylene (PE) and polyester terephthalate (PET) films have been shown to be dependent on the wavelength of the heat source, as well as supplied power, welding speed and clamping design.
Film welding is widely used for a large number of components spanning many industry sectors. Applications include blood bags, stationery, life jackets, bin bags, car interiors and food packaging. There is an industry drive towards faster processing and more consistent welding quality. New technological developments will also have to deal with sterile applications, environmental concerns and automation. Laser and IR lamp welding offer the opportunity of making high speed, non-contact joints in plastic films, in a fully automated manner with a high degree of quality control. In 1995 work at TWI  examined the possibility of welding thin plastic films in a lap joint configuration using CO2 laser energy. The results of this study showed welding speeds of at least 100 m/min were achieveable with tensile strengths up to 100% of the parent material strength. This study showed the high potential for welding plastic films using CO The areas of industrial interest, as described earlier, use several different types of thermoplastics for the applications. Plastic films were selected to cover a wide range of physical characteristics such as melt temperature and melt viscosity. Driven by the industrial requirements, the objective of this project was to investigate the applications and the potential benefits of lasers and IR lamps for welding plastic films.
- To develop methods for IR lamp and laser welding of plastic films, and to assess the techniques with regard to joining speeds and joint quality for PE and PET.
- To compare the use of IR lamps and laser types for welding of PE and PET plastic films with respect to potential industrial application.