In wire-electrical discharge machine and a numerical control apparatus thereof and a numerical control apparatus for controlling a machine tool, optional minute blocks are automatically created in front of and behind a connecting point, i.e., a joint of a block to which an offset command is instructed, and an offset value is exchanged between the minute blocks so that a correct offset value is set in a desired block.

In wire-electrical discharge machine and a numerical control apparatus thereof and a numerical control apparatus for controlling a machine tool, optional minute blocks are automatically created in front of and behind a connecting point, i.e., a joint of a block to which an offset command is instructed, and an offset value is exchanged between the minute blocks so that a correct offset value is set in a desired block.

In a corner portion formed at an intersection of a first block to be machined first and a second block to be machined second, an end point of the first block is extended. Then, after moving from the first block to the extended end point of the first block, a wire electrode of an electrical discharge machine returns to an end point of the original block (an end point of the original first block and a start point of the original second block) therefrom along the same path as before, and machines the second block therefrom.

In a corner portion formed at an intersection of a first block to be machined first and a second block to be machined second, an end point of the first block is extended. Then, after moving from the first block to the extended end point of the first block, a wire electrode of an electrical discharge machine returns to an end point of the original block (an end point of the original first block and a start point of the original second block) therefrom along the same path as before, and machines the second block therefrom.

In a method of welding a cut-out part with a workpiece at a preselected area in a thickness direction of the workpiece in a wire electrical discharge machining to retain temporarily or tentatively the part on the workpiece, a wire electrode 5 tilted in posture cuts the workpiece 6 to form a slant cutting surface 30 at a spark discharge location in a desired contour 21 in the workpiece 6. The wire electrode 5 after kept in an upright posture executes the welding process on the workpiece 6 along the slant cutting surface. A plurality of the welded spots is formed over a preselected length at preselected areas in the thickness direction of the workpiece 6. Even if the cut-out part 26 weighs more or the spark discharge is executed on the workpiece 6 overlapped one on the other, the welding spot 20 is formed in the thickness direction of the workpiece 6 adequately depending on the working situation to tentatively retain the cut-out part 26 on the workpiece 6.

In a method of welding a cut-out part with a workpiece at a preselected area in a thickness direction of the workpiece in a wire electrical discharge machining to retain temporarily or tentatively the part on the workpiece, a wire electrode 5 tilted in posture cuts the workpiece 6 to form a slant cutting surface 30 at a spark discharge location in a desired contour 21 in the workpiece 6. The wire electrode 5 after kept in an upright posture executes the welding process on the workpiece 6 along the slant cutting surface. A plurality of the welded spots is formed over a preselected length at preselected areas in the thickness direction of the workpiece 6. Even if the cut-out part 26 weighs more or the spark discharge is executed on the workpiece 6 overlapped one on the other, the welding spot 20 is formed in the thickness direction of the workpiece 6 adequately depending on the working situation to tentatively retain the cut-out part 26 on the workpiece 6.

When graphic information is selected, program creating unit receives machining shape data from graphic information analysis unit and pivot axis information from rotation center storage unit. Based on the received data, the program creating unit generates a new amount of movement of a wire electrode relative to a workpiece and the amounts of rotation of pivots, used to machine the workpiece with the wire electrode held vertical.

When graphic information is selected, program creating unit receives machining shape data from graphic information analysis unit and pivot axis information from rotation center storage unit. Based on the received data, the program creating unit generates a new amount of movement of a wire electrode relative to a workpiece and the amounts of rotation of pivots, used to machine the workpiece with the wire electrode held vertical.

In a wire electric discharge machine that machines a blade section of a cutting tool, in a state in which a rod-shaped reference jig is fixed to a rotary axis, a position on an outer circumferential surface of the reference jig is measured at each rotation position and stored. A rotational run-out error is calculated based on the stored rotational run-out position information, and a machining program is corrected to cancel the rotational run-out error.

In a wire electric discharge machine that machines a blade section of a cutting tool, in a state in which a rod-shaped reference jig is fixed to a rotary axis, a position on an outer circumferential surface of the reference jig is measured at each rotation position and stored. A rotational run-out error is calculated based on the stored rotational run-out position information, and a machining program is corrected to cancel the rotational run-out error.