Provided is a numerical control system of a machine tool that can shorten a cycle time. A command unit of a numerical control system of a machine tool includes: an interpolation block waveform drawing unit that performs a simulation of an NC program, calculates an interpolation pulse of a relationship between speed and time indicating an operation of the respective axes from a command value of an axis address of the respective axes, and sequentially outputs an interpolation command of the respective axes for each block to draw a waveform of the relationship between speed and time in a case of operating the machine tool; a different axis block specifying unit that compares two blocks adjacent in time series which are drawn by the interpolation block waveform drawing unit, and specifies the two adjacent blocks calculated from command values of different axis addresses; and an interpolation overlap block waveform creating unit that obtains an overlappable amount of the two adjacent blocks specified by the different axis block specifying unit, and overlaps the two adjacent blocks on a basis of the overlappable amount to create a waveform of the relationship between speed and time in a case of operating the machine tool.

This invention, a feedrate scheduling method for five-axis dual-spline curve interpolation, belongs to multi-axis NC (Numerical Control) machining filed, featured a feedrate scheduling method with constant speed at feedrate-sensitive regions under axial drive constraints for five-axis dual-spline interpolation. This method first discretizes the tool-tip spline with equal arc length, thus getting the relation between the axial motion and the toolpath by computing the first, second, and third order derivatives of the axial positions with respect to the tool-tip motion arc length. After that, determine the feedrate-sensitive regions with the constraints of axial drive limitations and the objective of balanced machining quality and efficiency. Finally, determine the acceleration/deceleration-start-point curve parameters by bi-directional scanning. The invented method can effectively make a balance between the feed motion stability and efficiency in five-axis machining, and possesses a high computational efficiency and a good real-time capability.

A numerical controller analyzes a machining program, generates movement command data for moving a main spindle relative to a workpiece, causes an interpolation unit to perform interpolation processing based on the generated movement command data, and generates and outputs interpolation data for each interpolation cycle. Further, the interpolation unit performs provisional interpolation processing according to command speed F on a non-rotating coordinate system, converts a start point and an end point of provisional interpolation to positions on a rotating coordinate system to obtain speed F on the rotating coordinate system, obtains a ratio r of the speed F to the command speed F, and performs main interpolation processing at speed of F/r.

A numerical controller carries out acceleration/deceleration control over an interpolation pulse produced based on command blocks. This numerical controller exercises acceleration/deceleration control processing over the interpolation pulse based on an acceleration/deceleration setting which corresponds to the command blocks, and outputs a first speed pulse. The numerical controller exercises acceleration/deceleration control processing over the first speed pulse such that command blocks overlap each other, based on an overlapping shared acceleration/deceleration setting which does not depended on the command blocks, and outputs a second speed pulse.

A numerical controller generates movement command data, and performs an interpolation process based on the generated movement command data to generate and output interpolation data. Further, in the case of a state in which a press operation in punch press machining is started from a different position from a position of a preset rising edge, an overlap time is calculated based on a position of a punch head when the press operation is started, and an output timing of interpolation data related to an axis controlling the press operation is controlled based on the calculated overlap time. In this way, even when there is a change in press stroke, a dead time may be prevented from being generated.

A numerical controller includes a division setting unit which sets division information for dividing a machining region into a plurality of areas, an area division unit which divides a machining region into a plurality of areas based on division information, a program division unit which generates divided programs respectively used for machining control in the areas, an area coordinate system setting unit which sets a virtual coordinate system in the plurality of areas, and an operation precision setting unit which sets operation precision, and performs internal operation for controlling an operation of a machine in accordance with the virtual coordinate system and the operation precision to control each axis of the machine.

A numerical control apparatus includes a program command shape determining unit that determines a shape of a command path formed by command points on the basis of information on the command points included in a machining program. There is also an insertion point generating unit that generates insertion points on the basis of a result of determination by the program command shape determining unit and the information on the command points. Further, there is an interpolation unit that generates a tool path by performing interpolation on the basis of the insertion points and causes a motor control unit to control a motor on the basis of the tool path.

A numerical controller that creates a tool path from a plurality of command points includes: a command point sequence acquisition unit that acquires an existing command point sequence; a command point creating unit that creates at least one additional command point, based on the existing command point sequence; and an interpolation processing unit that interpolates the existing command point sequence and the additional command point to create the tool path. The command point creating unit outputs, as the additional command point, an intersection point Q1 between an arc C1 passing through consecutive three command points, P0, P1 and P2, in the existing command point sequence and a perpendicular bisector of a line segment whose end points are P1 and P2.

A numerical controller controls a relative speed between a tool and a workpiece on the basis of a machining program. In a case where a corner part exists between a current block and a next block of the machining program, the next block is prefetched, and an allowable speed at the corner part at an end point of the current block is calculated. At least one of pre-interpolation acceleration of an acceleration part, a pre-interpolation speed of a constant-speed part, and pre-interpolation acceleration of a deceleration part that are relative speeds between the tool and the workpiece is adjusted so that the relative speed between the tool and the workpiece is maintained at a preset allowable speed while the corner part is passed through.

A numerical controller generates movement command data, and performs an interpolation process based on the generated movement command data to generate and output interpolation data. Further, in the case of a state in which a press operation in punch press machining is started from a different position from a position of a preset rising edge, an overlap time is calculated based on a position of a punch head when the press operation is started, and an output timing of interpolation data related to an axis controlling the press operation is controlled based on the calculated overlap time. In this way, even when there is a change in press stroke, a dead time may be prevented from being generated.