Abstract:
In recent times, the use of laser has gained popularity in micro machining applications due to the
unique properties of the laser beam. Laser micromachining is used in the machining of a wide variety of
materials including solar cells. However, this process faces challenges such as microcracking which can be
as a result of incorrect combination of laser process parameters. The cutting process requires an optimal
combination of cutting parameters which lead to excellent cut quality and quality solar cells. Indeed, the
effects of each particular cutting parameter on the output parameters have not been well established for this
process. This research is focused on investigating and optimizing the laser beam and process parameters on cut
quality attributes of solar cells. The variables which were selected as input parameters are: the scan speed (v),
the spot diameter (d), and the laser power (P). The output parameters, quality attributes or responses
investigated were: the kerf depth (K.d), the kerf width (K.w), and the material removal rate (MRR). A Taguchi
orthogonal array based on Minitab17 software was used for the design of the experiments, analys i s , and
opt imi zat ion. The input variables were found to have a significant effect on the quality attributes of the solar
cell. The kerf depth was found to increase with the laser power and decreased with the spot diameter and the
scan speed. The kerf width was found to increase with the laser power and the spot diameter while it decreased
with the scan speed. On the other hand, the material removal rate was found to increase with the laser power
and the spot diameter while the scan speed had the opposite effect.
The optimal conditions obtained for cutting a standard 156mmX156mm solar cell were: the laser power at
126.67W, the spot diameter at 0.4158mm and the scan speed at 3121mm/min. Validation experiments were
conducted, and experimental output values obtained were: the kerf depth at 0.1839mm, the kerf width at
0.5828mm and the material removal rate at 1456mm3/min. These experimental results showed conformity to the
optimal conditions obtained using the software.
