摘要:
A numerical control apparatus (1 or 20) judging an overload on the basis of a specified reference value without any affection of a wear and abrasion of a tool, executing a pecking process even in machining wherein a feed rate changes every moment. In the numerical control apparatus (1 or 20) comprising pecking operation controlling means (12) which make a feed drive system (14) retracted when a cutting load detected by cutting load detecting means (7) exceeds a reference value during a drilling process, the cutting load detecting means (7) comprise a bite load detecting section (8) to detect the cutting load at a biting stage wherein a tool bites a work piece, and a stationary load detecting section (10) to detect the cutting load after the biting stage. The numerical control apparatus (1 or 20) comprises pecking judgement means (11) to judge that the feed drive system (14) should be retracted when a fluctuation load exceeds a specified reference value wherein the fluctuation load is obtained by reducing the bite load from the detected stationary load. When it is judged that the feed drive system (14) should be retracted, the pecking operation controlling means (12) make the feed drive system (14) retracted.
摘要:
A control method for an NC machine tool is provided which ensures a high precision of the contouring control, and allows for extension of the drill life, and reduction in machining time. The control method comprises: generating an operation command signal on the basis of the machining program and a time constant; generating a velocity command signal by multiplying a deviation of a present position signal fed back from the feed drive system (106) from the generated operation command signal by a position loop gain; generating an electric current command signal by multiplying a deviation of a present velocity signal fed back from the feed drive system (106) from the generated velocity command signal by a velocity loop gain; and controlling a drive motor of the feed drive system (106) on the basis of the generated electric current command signal for driving thereof, wherein a machining mode is determined from the machining program and, if the machining mode is a drilling mode, at least one of the operation command signal, the velocity command signal and the electric current command signal is modified when the feed drive system (106) is driven to be retracted opposite to a drilling feed direction.