Abstract:
Laser ablation is a technique that is highly embraced in many applications and
especially in Micro-Electro-Mechanical Systems (MEMS) industry. This work focused
on development of a Carbo-dioxide gas (CO2) laser system, a control program to run
the system and determination of the e ect of machining conditions such as machining
time and the number of passes on cut parameters. E ect of compressed air as the
assisting gas on hole pro les and glass cracking were also investigated.
The materials experimented with included wood, perspex, ceramics, glass, mild
steel and aluminium. These materials were rst prepared and the number of passes
and machining time varied. It was observed that due to the low power of the laser,
mild steel could not be machined. A coating was applied on the surface and left to
dry before machining. Cut parameters (kerf widths, inner and outer hole diameters,
heat-a ected-zone (HAZ), taper, depths machined) and microstructural changes were
measured as an indication of the cut quality.
Pro le Projector was used for perspex and glass measurements and a traveling
microscope on wood. Wood and perspex were easily laser cut although wood produced
charred edges. Mild steel was hard to machine due to its high re
ectance to CO2
laser wavelength but visible marks were made after coating. After coating, mild steel
specimens were exposed to the beam for 30-500 s and their microstructural changes
observed. It was observed that there were microstructural changes on all the cases.
Another factor observed was the tapering e ect on the holes and cuts made due to the
Gaussian nature of a laser beam.
