Laser channels opening in graphite: parameters and analysis methodologies

Graphite has a large spectrum of applications, being used from automotive industry to the electronics field. Their characteristics lead to their application as a key component on some fuel cells architecture. Being a non-contact processing technique, the laser appears as an interesting replacing tool to open channels on graphite plates. In this work, CO₂ and Nd:YAG lasers were tested in order to obtain channels with 0.5 mm to 1 mm depth, and 1 mm width, on 3.5 mm thickness graphite plates. This study allowed the definition of the relevant parameters and to identify their influence in the results. The use of CO ₂ laser radiation has showed that, in order to accomplish the required depths, the applied laser power leads to the appearance of a zone on the edge of the channel that becomes thermally affected. However, preliminary tests with a Nd:YAG laser have demonstrated that this could fulfil the requirements