Abstract:

Objectve: Using solid laser to cut veneer, the aim of this paper was to obtain reasonable cutting process parameters, reduce the kerf width and saw road losses, and to guarantee the cutting veneer edge roughness of incision. Method: The mathematical model of laser cutting veneer is established based on the laser pulse energy in order to get the expression of the relationships between laser cutting speed and output power. Choosing the thickness of 0.3 mm, moisture content of 10% of black walnut veneer as processing object, two sets of laser output power were selected for test verification. The laser output power of each group corresponds to six different cutting speeds, and the theoretical cutting speed is within the range of the six experimental cutting speeds. The width of straight-line slit and the average value after machining and observing the incision width and the flatness of the incision section under a 40×10 light microscope were obtained, then the best test results of the cutting speed were found out, and theoretical cutting speed obtained by calculations were compared. Result: In the test conditions of the first set of laser output power(pulse voltage 400 V, single pulse energy 96.5 mJ, pulse frequency 10 Hz), when the cutting speed is 2.5 mm·s^-1, the incision of the board can be guaranteed to be completely cut through, a continuous and complete kerf is formed, and the width of the kerf is the narrowest. The mean value of the measurement kerf width is 0.54 mm. The saw road loss is minimal, and the edge of the kerf section is relatively flat. Under the test conditions of the second set of laser output power(pulse voltage 500 V, single pulse energy of 198.2 mJ, pulse frequency of 10 Hz), when the cutting speeds are 5.0 mm·s^-1 and 5.5 mm·s^-1, the incision of the board can be guaranteed to be completely cut through, width of the laser cut obtained was the narrowest, the mean value of the measurement kerf width was 0.69 mm and 0.62 mm, respectively, and the incisions obtained under the two cutting speeds are also relatively flat. Through the comparison of the two sets of test data, it can be concluded that when the cutting speed is close to the theoretical cutting speed, the cut of the black walnut cut is continuous and the width of the cut seam is the smallest. When the cutting speed is lower than the theoretical cutting speed, the width of the cut seam will gradually increased, when higher than the theoretical cutting speed, the resulting incision is prone to discontinuous phenomena. Conclusion: When a solid laser is used to cut a veneer, the choice of process parameters has a direct effect on the width of the kerf and the flatness of the edge of the kerf. Reasonable process parameters are crucial to obtain a small kerf width. Each laser output power corresponds to the best cutting speed. During the actual machining process, the cutting speed should be consistent with the theoretical cutting speed or close to the theoretical cutting speed, so that better final cutting effects might be obtained.

Key words: veneer, laser cutting, kerf width, mathematical model, cutting quality