Three-dimensional electrical discharge machining method and apparatus utilizing NC control

An electrical discharge machining apparatus which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said apparatus comprising:

• a storage means for storing a correction amount for performing correction of the electrode feed in the Z-axis direction corresponding to a fixed unit moving distance of the electrode in an X-Y plane and a two-dimensional path of the electrode in the X-Y plane, as a NC program for the NC control,
• and a relative position control means for performing a feed of the electrode by the correction amount in the Z-axis direction each time the electrode moves by the fixed unit moving distance in the X-Y plane during machining.

An electrical discharge machining method which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said method comprising the steps of:

• storing a relation between a fixed unit moving distance in an X-Y plane and a corresponding correction amount for performing correction of the electrode feed in the Z-axis direction and a two-dimensional path of the electrode in the X-Y plane, as a NC program for the NC control, and
• performing a feed of the electrode by said correction amount in the Z-axis direction each time the electrode moves by the fixed unit moving distance in the X-Y plane during machining.

An electrical discharge machining apparatus which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said apparatus comprising:

• a storage means for storing a relation between a fixed unit moving distance in an X-Y plane and a corresponding correction amount for performing correction of the electrode feed in the Z-axis direction and a two-dimensional path of the electrode in the X-Y plane, as a NC program for the NC control, and
• a relative position control means for performing a feed of the electrode by the correction amount in the Z-axis direction each time the electrode moves by the fixed unit moving distance in the X-Y plane during machining.

An electrical discharge machining method which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said method comprising the steps of:

• storing a relation between a specific unit moving distance in an X-Y plane and a corresponding correction amount, for performing correction of the electrode feed in the Z-axis direction, as a specific unit moving distance in the X-Y plane and an angle, and a two-dimensional path of the electrode in the X-Y plane, as a NC program for the NC control, and
• performing a feed of the electrode by the correction amount in the Z-axis direction each time the electrode moves by the specific unit moving distance in the X-Y plane during machining.

An electrical discharge machining apparatus which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said apparatus comprising:

• a storage means for storing a relation between a fixed unit moving distance in an X-Y plane and a corresponding correction amount, for performing correction of the electrode feed in the Z-axis direction as a fixed unit moving distance in the X-Y plane and an angle, and a two-dimensional path of the electrode in the X-Y plane, as a NC program for the NC control, and
• a relative position control means for performing a feed of the electrode by the correction amount in the Z-axis direction each time the electrode moves by the fixed unit moving distance in the X-Y plane during machining.

An electrical discharge machining method which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of an electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said method comprising the steps of:

• storing a relation between a fixed unit moving distance in an X-Y plane and a corresponding correction amount for performing correction of the electrode feed in the Z-axis direction, and a relation between a fixed unit moving distance in the Z-axis direction and the corresponding correction amount, for performing correction of the electrode feed in the Z-axis direction, and
• calculating a corrected fixed unit moving distance in the X-Y plane on the basis of the fixed unit moving distance in the X-Y plane and the fixed unit moving distance in the Z-axis direction, and
• performing a feed of the electrode by the correction amount in the Z-axis direction each time the electrode moves by the corrected fixed unit moving distance in the X-Y plane during machining.

An electrical discharge machining apparatus which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said apparatus comprising:

• a storage means for storing a relation between a fixed unit moving distance in an X-Y plane and a corresponding correction amount for performing correction in the Z-axis direction, and a relation between a fixed unit moving distance in the Z-axis direction and the corresponding correction amount for performing correction in the Z-axis direction, and
• a relative position control means for calculating a corrected fixed unit moving distance in the X-Y plane on the basis of the fixed unit moving distance in the X-Y plane and the fixed unit moving distance in the Z-axis direction, and performing a feed of the electrode by the correction amount in the Z-axis direction each time the electrode moves by the corrected fixed unit moving distance in the X-Y plane during machining.

An electrical discharge machining method which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said method comprising the steps of:

• storing a relation between a fixed unit moving distance in an X-Y plane and a corresponding correction amount for performing correction in the Z-axis direction, and a relation between a fixed unit moving distance in the Z-axis direction and the corresponding correction amount for performing correction in the Z-axis direction, and
• performing a feed of the electrode by the correction amount in the Z-axis direction each time the electrode moves by the fixed unit moving distance in the X-Y plane and the electrode moves by the fixed unit moving distance in the Z-axis direction during machining.

An electrical discharge machining apparatus which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said apparatus comprising:

• a storage means for storing a relation between a fixed unit moving distance in an X-Y plane and a corresponding correction amount for performing correction in the Z-axis direction, and a relation between a fixed unit moving distance in the Z-axis direction and the corresponding correction amount for performing correction in the Z-axis direction, and
• a relative position control means for performing a feed of the electrode by the correction amount in the Z-axis direction each time the electrode moves by the fixed unit moving distance in the X-Y plane and the fixed unit moving distance in the Z-axis direction during machining.

An electrical discharge machining method which divides a desired three-dimensional shape into a plurality of layers in a Z-axis direction, which applies voltage between an electrode and a workpiece and which performs machining for each layer while regulating a feed of an electrode in the Z-axis direction, for correcting for a longitudinal wear amount of the electrode, so as to perform three-dimensional NC control, said method comprising the steps of:

• storing X-Y data of a tool path for each layer, a correction unit interval as a standard for performing correction in an X-Y axis direction, and a unit moving distance in the Z-axis direction corresponding to the correction unit interval, and a two-dimensional path of the electrode in the X-Y plane, as a NC program for the NC control;
• controlling the number of times machining on the tool path is performed for each layer based on a machining depth determined by a moving amount in the Z-axis direction and the unit moving distance in the Z-axis direction corresponding to an X-Y moving distance.

An electrical discharge machining apparatus which divides a desired three-dimensional shape into a plurality of layers in a Z-axis direction, which applies voltage between an electrode and a workpiece and which performs machining for each layer while regulating a feed of the electrode in the Z-axis direction, for correcting for a longitudinal wear amount of the electrode, so as to perform three-dimensional NC control, said apparatus comprising:

• a storage means for storing X-Y data of a tool path for each layer, a correction unit interval as a standard for correcting in an X-Y axis direction, and a unit moving distance in the Z-axis direction corresponding to the correction unit interval, and a two-dimensional path of the electrode in the X-Y plane, as a NC program for the NC control, and
• a repetition time control means for controlling the number of times machining on the tool path is for each layer performed based on the unit moving distance in the Z-axis direction, an X-Y moving distance in the X-Y plane corresponding to the unit moving distance in the Z-axis direction and a machining depth determined by a thickness of each layer.

An electrical discharge machining method which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said method comprising the step of:

• performing machining while repeatedly moving an inside machining path for forming an inside shape path in a machining shape and repeatedly moving a profile machining path for forming a profile shape path in the machining shape.

An electrical discharge machining apparatus which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of an electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said apparatus comprising:

• an inside machining path generating means for generating an inside shape path in a machining shape, and
• a profile machining path generating means for generating a profile shape path in the machining shape,
• thereby performing machining while repeatedly moving the inside shape path and the profile shape path.

An electrical discharge machining apparatus which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said apparatus comprising:

• an inside machining path generating means for forming an inside shape path in a machining shape and
• a profile machining path generating means for forming a profile shape path in the machining shape.

An electrical discharge machining apparatus which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said apparatus comprising:

• an electrode holding means for fixing the electrode at a slanting state of a predetermined angle from its electrode rotation axis, and
• a working power source that can vary an electrode wear amount, thereby providing an apparatus which forms a side surface shape having a constant slope by profile machining during the machining of the desired shape and while rotating the electrode at the slanting state of the predetermined angle.

An electrical discharge machining method which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said method comprising the steps of:

• performing machining of an inside corner portion of a radius R by a cylindrical electrode or tubular electrode, and, thereafter, finishing a corner portion which the cylindrical electrode or tubular electrode fails to remove by a quadrangular electrode having one side length L being ##EQU14## 30.

An electrical discharge machining method which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said method comprising the steps of:

• performing machining of an inside corner portion of a radius R using a cylindrical electrode or tubular initial machining electrode, and, thereafter, finishing machining a corner portion which the initial machining electrode fails to remove by a finishing electrode of either cylindrical or tubular shape, said finishing electrode having a radius R' of ##EQU15##

An electrical discharge machining method which applies voltage between an electrode and a workpiece and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said method comprising the steps of:

• performing machining of an inside corner portion of a radius R using a tubular shaped initial machining electrode, and, thereafter,
• finishing a corner portion which the initial machining electrode fails to remove by a finishing electrode of either cylindrical or tubular shape, said finishing electrode further having such a shape as a part of a liquid hole portion covers the corner portion which the finishing electrode fails to remove.

An electrical discharge machining apparatus which applies voltage between an electrode and a workpiece, and which performs three-dimensional NC control while regulating a feed of the electrode in a Z-axis direction, for correcting for a longitudinal wear amount of the electrode, said apparatus comprising:

• an interpole detecting means for detecting when an interpole space is opened due to a decrease of a discharge frequency or an increase of an average machining voltage or the like during machining,
• said interpole detecting means stopping a feed in a Z-axis direction and performing only the X-Y plane feed when the interpole detecting means detects that the interpole space is opened or nearly opened.