Small gear hardening with a CO2 laser

Abstract

The CO2 laser is a unique light source whose properties make it a powerful tool for materials processing. The laser’s ability to provide a collimated beam of coherent light allows light energy to be directed over distances without spreading out. In that this energy is in the form of light it propagates through air, no force is exerted on the workpiece, and it can be directed and focused to high power densities by simple optical elements.Laser hardening occurs when the laser energy is directed onto the surface of a hardenable material. The high power density rapidly raises the surface to above a transformation temperature while the bulk of the material provides a rapid quench. The high power density allows the heat treatment to be located with precision and with minimal heat input.These features of laser hardening make it an ideal process for the hardening of small gears.A 16 pitch, 1″ diameter, alloy steel gear was laser hardened. An 0.018″ case was developed over the tooth profile with a hardness of Knoop 870 that was consistent over the transformed area. This hardness was consistent from tooth to tooth as well. The process time was 4 seconds for the 16 teeth.The CO2 laser is a unique light source whose properties make it a powerful tool for materials processing. The laser’s ability to provide a collimated beam of coherent light allows light energy to be directed over distances without spreading out. In that this energy is in the form of light it propagates through air, no force is exerted on the workpiece, and it can be directed and focused to high power densities by simple optical elements.Laser hardening occurs when the laser energy is directed onto the surface of a hardenable material. The high power density rapidly raises the surface to above a transformation temperature while the bulk of the material provides a rapid quench. The high power density allows the heat treatment to be located with precision and with minimal heat input.These features of laser hardening make it an ideal process for the hardening of small gears.A 16 pitch, 1″ diameter, alloy steel gear was laser hardened. An 0.018″ case was developed over the tooth profile with a hardness of Knoo...