A study on new machining method applied to a collaborative robot for drilling

Abstract

In the assembly of aircraft fuselages, manual hole drilling is conducted in some cases instead of applying robotic drilling due to the issues of burr formation and vibration. In manual operation, tool feeding is realized by applying force to the tool. A prototype system was developed in which a load is applied from the upper side of the spindle by a weight to move a spindle in a vertical downward (CLF method). Drilling in aluminum using this system did not lead to crown-shaped burr formation or irregular vibrations which are often problems in robotic machining. The level of the load applied to the tool becomes an important parameter in the CLF method. To minimize the damage generation, it may be important to adjust the load to the minimum level required for cutting and tool feed. Given such a tool feed system, a drilling unit could be composed from general purpose units such as a shaft and bushing combination. Robotic machining with this type of drilling unit is expected to lead to significant labor savings and improved machining accuracy in machining that is currently conducted manually.