Effect of grain size on laser machining of alumina

By: Michael Furlan

Laser machining is filling the niche market created by the increased demand for advanced ceramics and high manufacturing tolerances. The effect of grain size on the laser machinability of alumina (Al2O3) was examined in order to meet the demand of higher tolerances when laser machining advanced ceramics.  Laser lines created in alumina samples fabricated by using progressively increasing sintering times, which results in increased grain size, showed a difference in the amount of damage produced along the edges of the channels that were created, with less damage in smaller-grained samples. The average line width of the samples decreased with increasing grain size. These phenomena can be seen in figure 1. It was hypothesized that these effects are a result of grain boundaries absorbing a higher amount of energy than the bulk. The removal of entire grains due to the cracking mechanism of ablation is not uncommon. If the grain boundaries are absorbing a larger amount of energy relative to the bulk, it is possible that rather than bonds breaking and ablating individual atoms, that the energy absorbed by the boundaries leads to entire grains being ejected from the material.  This improvement with regards to cut quality that smaller grain structured materials have, offers a benefit in many fields ranging from micro-fluidic channels to fine scale micro and nano-machining.

The above brief overview was extracted from its original abstract and paper presented at The International Congress on Applications of Lasers & Electro-Optics (ICALEO) in Orlando, FL. To order a copy of the complete proceedings from this conference click here