For many years, Nd:YAG, CO2 and high-power semiconductor lasers have been successfully cutting, welding and marking on metals, ceramics and other materials. You need look no further than your computer keyboard or the buttons on your automobile radio for evidence that lasers are useful to manufacturers who use plastic. In fact, laser marking of plastics has been an established application for more than a decade, which is why its importance today is remarkable only because of its magnitude. More recently, laser manufacturers have started touting their products' use in welding plastics. Several manufacturing trends are driving significant growth in these applications: • Many application markets are turning away from metals in favor of plastics for business and technical reasons. Tap the body panels of a typical Saturn automobile as an example of an application in which plastic has largely replaced steel. • Improvements in computer interfaces, software and hardware have made laser systems easier to use, more rugged and more robust. • Environmental concerns make manufacturers eager to employ processing technologies that don't use chemicals or produce waste. • Manufacturers are making increasingly complex parts as a deterrent to knock-off products and theft. These factors combine to encourage job shops and production engineers to investigate how lasers can solve problems in plastics manufacturing.