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High speed drilling of aluminium plates
Pilný, Lukáš ; Humár, Anton (oponent) ; Píška, Miroslav (vedoucí práce)
Optimization of the metal drilling process requires creation of minimum amount of burrs and uniform appearance of the drilled holes. The goal was to understand the role of various key factors such as cutting conditions, clamping conditions and drill geometry on burr formation when 2 mm sheets of wrought aluminium alloy Al99.7Mg0.5Cu-H24, using 1.6 and 2 mm diameter drills, so that the burr formation could be minimized and an uniform hole surface obtained for a great number of holes drilled on a single workpiece. This goal was approached by three subsequent investigations. First, an experimental test was performed to investigate the effect of cutting speed and feed per revolution, as the most recognized drilling parameters influencing burr formation, on the resulting burr size and drilled hole uniformity. Second, a vacuum clamping system, used to hold the aluminium sheet and restrict the space for burr formation at the drill exit, was constructed and tested for its influence on burr formation. Third, the effect of different drill geometries on burr formation and the uniformity of hole appearance was evaluated. Results from the first experiment showed that burr height and width is reduced at both the entry and exit sides of a sheet when a higher cutting speed is used. With greater feed rates, it was found that burr height and width increase on both sides, with the exception of the height of burrs on the entry side, which may be minimally decreased. The second experiment showed that a properly designed vacuum clamp fixture can be used to significantly reduce exit-side burr formation. In the third experiment, a three flute drill with a properly constructed vacuum clamp was found to eliminate both entry and exit burrs, the demand on the uniform appearance of drilled holes was fulfilled as well as high productivity achieved. Such optimized process requiring no additional deburring results in a noticeable production cost reduction. Furthermore, recommendations for further research into improvements of the production process are made.
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High speed drilling of aluminium plates
Pilný, Lukáš ; Humár, Anton (oponent) ; Píška, Miroslav (vedoucí práce)
Optimization of the metal drilling process requires creation of minimum amount of burrs and uniform appearance of the drilled holes. The goal was to understand the role of various key factors such as cutting conditions, clamping conditions and drill geometry on burr formation when 2 mm sheets of wrought aluminium alloy Al99.7Mg0.5Cu-H24, using 1.6 and 2 mm diameter drills, so that the burr formation could be minimized and an uniform hole surface obtained for a great number of holes drilled on a single workpiece. This goal was approached by three subsequent investigations. First, an experimental test was performed to investigate the effect of cutting speed and feed per revolution, as the most recognized drilling parameters influencing burr formation, on the resulting burr size and drilled hole uniformity. Second, a vacuum clamping system, used to hold the aluminium sheet and restrict the space for burr formation at the drill exit, was constructed and tested for its influence on burr formation. Third, the effect of different drill geometries on burr formation and the uniformity of hole appearance was evaluated. Results from the first experiment showed that burr height and width is reduced at both the entry and exit sides of a sheet when a higher cutting speed is used. With greater feed rates, it was found that burr height and width increase on both sides, with the exception of the height of burrs on the entry side, which may be minimally decreased. The second experiment showed that a properly designed vacuum clamp fixture can be used to significantly reduce exit-side burr formation. In the third experiment, a three flute drill with a properly constructed vacuum clamp was found to eliminate both entry and exit burrs, the demand on the uniform appearance of drilled holes was fulfilled as well as high productivity achieved. Such optimized process requiring no additional deburring results in a noticeable production cost reduction. Furthermore, recommendations for further research into improvements of the production process are made.
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