TWI Industrial Member Report Summary 519/1995
I A Jones
Scope
Welding of materials using lasers was first developed in the 1970s when high power CO2 lasers first became available. Since then they have found a number of industrial applications due to the high power densities available from the focused light beam and the capability of precise delivery and control of this energy in a non-contact process. Lasers are now used industrially for cutting of metals, ceramics and plastics and for welding of a wide range of metal products in automotive, electronic and domestic applications. The application to plastic processing with lasers was demonstrated in 1970 for drilling, cutting and certain welding procedures. Full industrial application was probably restricted at that stage by the high cost of lasers. Developments in manufacturing methods and laser design have resulted in large cost reductions and mass production of lasers to such an extent that they may be considered for a wider range of applications.
The potential for welding plastics using lasers has been examined because of the possibilities for high speed processing of a range of materials and a range of joint configurations which are difficult to join using other techniques. For example, ultrasonic sealing is rapid but limited in the size of component which may be joined, and dielectric sealing is limited to joining plastics which contain polar molecules, hence excluding polyethylene and polypropylene. The development of an alternative technique for joining plastics using lasers should allow for new design possibilities, use of different materials or an increase in production rates when applied in relevant applications.
Objectives
- To realise plastics joining techniques using CO2 lasers as a localised heat source to provide continuous high speed processing.
- To investigate the feasibility of using Nd:YAG lasers in the processing of plastics.