Determination of Optimal Focal Position during CO2 Laser Cutting of MDFB Thick Sheets to Reduce Side Kerf Curvature

Abstract

Wood products such as MDFB (medium density fiberboard) have become extensively used today in the furniture and sign industries among other applications. CO2 laser cutting of MDFB has also been successfully applied due to the fast cut speed response of the process. Nonetheless, laser cutting of MDFB having thickness greater than 8 mm, keeping focal position fixed at the surface of the sheet, render curved side kerfs. This side curvature is more notorious when increasing the board thickness. MDFB cutting using a state of the art industrial laser cutting machine was carried out. MDFB sets having same density and thicknesses of up to 18 mm were laser cut under multiple laser beam velocities and focal positions. It was observed that the side kerf curvature was minimized at a given focal position for each board thickness and process parameters. A plot of focal position against board thickness for minimum side kerf curvature allowed determining optimal cutting conditions when combined with a plot of cutting velocity against board thickness at a certain laser power. This methodology could be made extensive to other materials, specifically those that undergo a chemical reaction or sublime during the laser material interaction.