Dr. Rolf Klein was educated as physicist at the University of Darmstadt and received his PhD in mechanical engineering from RWTH, Aachen. He worked at the Fraunhofer ILT, involved in R&D for laser processing polymers. Prior to starting his own business in July 2009, he held senior positions within a number of German laser companies, working for R&D of metal processing, system development as well as polymer welding with laser. For several years he worked for Gentex Corp., an US based company, as technical senior engineer in the field of absorbing additives for laser plastic welding and development of related processes. Rolf Klein has authored several scientific and technical publications with topics of laser material processing and laser system design. He is also a member of VDI and SPE and active in the DVS working group for plastic laser welding.

1. Introduction
2. Material properties of plastics
2.1. Formation and structure
2.2. Types of plastics
2.3. Thermal properties
2.4. Optical properties
2.5. Literature
3. Laser sources for plastic welding
3.1. Properties of laser radiation
3.2. Types of lasers
3.3. Literature
4. Basics of laser plastic welding
4.1. Butt joint welding
4.2. Through transmission welding
4.3. Processes for through transmission welding
4.4. Methods of proces control
4.5. Design of joint geometry
4.6. Material compatibilities
4.7. Adaption of absorption
4.8. Literature
5. Case studies
5.1. Automobile
5.2. Housware goods
5.3. Medical devices
5.4. Literature
6. Summary
7. Appendix
8. Used formulary characters and constants