High-power direct-diode laser successes

Abstract

ABSTRACT Direct diode laser will become much more prevalent in the solar system of manufacturing due to their high efficiency, small portable size, unique beam profiles, and low ownership costs. There has been many novel applications described for high power direct diode laser [HPDDL] systems but few have been implemented in extreme production environments due to diode and diode system reliability. We discuss several novel applications in which the HPDDL have been implemented and proven reliable and cost-effective in production environments. These applications are laser hardening / surface modification, laser wire feed welding and laser paint stripping. Each of these applications uniquely tests the direct diode laser systems capabilities and confirms their reliability in production environments. A comparison of the advantages direct diode laser versus traditional industrial lasers such as CO2 and Nd:YAG and non-laser technologies such a RF induction, and MIG welders for each of these production application is presented. Keywords: Diode Laser, Direct Diode Laser, Hardening, Welding, and Paint Stripping 1. INTRODUCTION This paper will summarize the results of three successful HPDDL system production installations with over 20 months of service. We will share the cost savings and performance improvements for a laser hardening and a laser wire feed welding installations. In the first case the HPDDL replaced a Nd:YAG laser and in the second the HPDDL replaced a conventional MIG welder. When a comparison is made, the return on investment [ROI] is dramatic in each case due to the increased production speed and quality, and the high reliability and low maintenance experienced with the HPDDL systems. In the third production case, the pulsing capability of HPDDL system is used for a relatively new application of laser paint /coating stripping. This application demonstrates that HPDDL, when properly packaged, can have long term pulsing reliability. 2. HPDDL HEAT TREATMENT PRODUCTION INSTALLATIONS 2.1. Overview A 4 kW HPDDL system was installed into Caterpillar’s heavy off road earth moving equipment production line to provide the laser surface hardening for large steel parts. This installation was a complete success by delivering high quality at a cheaper cost. The ROI was made in less than a year because of the low installation, maintenance, operating costs, and high reliability. 2.2. Advantages The production processes had been performed over the past two years by a lamp pumped Nd:YAG laser. However, the Nd:YAG laser was not well suited to this application due to the long continuous on times. The high maintenance and inordinate amount of downtime had become a serious problem for the manufacturer