Abstract: An acceleration and deceleration method with steps that calculate transferring distance, average transferring speed in the x-direction and y-direction, intermediate destination position at every sampling time and the number of sampling times based on final destination position, initial current position and rectilinearly transferring speed; a step of determining initial position; and steps which calculate position pattern and destination position with linear equations, detect intermediate current position with linear equations, sequentially calculate position deviation and transferring speed per sampling time, so that the next step outputs a driving signal for a servo motor. Therefore, an object is transferred in exponential acceleration and deceleration according to linear equations describing rectilinearly transfer speed, and transferring distance in x-direction and y-direction.

Abstract: A CNC method controls a plurality of paths with a single computerized numerical control apparatus. In the CNC method, an order (6) in which to execute part programs (5) for the respective paths (4) is designated, and the part programs (5) are sequentially executed in the designated order. The contents of the part programs (5) can thus be checked for each of the part programs.

Abstract: In a method of forming an offset configuration for a cutting tool which is used to machine a workpiece under the control of a numerical control device, both in the case where a cutting tool having first and second edges on both sides which have nose Rs, respectively, are used in such a manner that the cutting tool is moved horizontally and vertically with respect to a workpiece rotating, and the first edge is used when a machine configuration increases in vertical coordinate, and the second edge is used when a machining configuration decreases in vertical coordinate, and in the case where a cutting tool having first and second edges on both sides which have nose Rs, respectively, and provide a predetermined inclination angle .theta. is used in such a manner that the tool is moved horizontally and vertically with respect to a workpiece rotating, and the first edge is used when the inclination angle, in a vertical direction, of a machining configuration is smaller than the inclination angle .theta.

Abstract: This invention concerns a control unit for program-controlled machine tools with control circuits for the individual feed motors (20) of the moving machine parts (2) which are connected to the program control unit (34) and also contain at least one switching element (14) for manually switching on feed motors (20). In order to give the operator a feel for the respective operating process in manual operation, each control circuit according to this invention has at least one sensor (26, 42) for detecting a power parameter (I;M) of the respective feed motor (20). Furthermore, a brake gear (30 or 44) that is controlled by the output signals of the sensor (26; 42) is assigned to each switching element that is designed as a manually adjustable control element (14), whereby the braking device is actuated in proportion to the power parameters picked up by the sensors and it makes continued turning of the control element which is designed as a hand crank more difficult.

Abstract: A positioning control apparatus comprises a plurality of servo mechanisms corresponding to respective axes, a sequence operation part for successively outputting start commands for the respective servo mechanisms, a positioning operation part for storing a plurality of programs specified in accordance with the start commands and for processing the program in accordance with specified one of the programs to thereby output a positioning control command, and a servo interface for supplying the positioning control command to one of the servo mechanisms to be actuated to start.

Abstract: The invention relates to a reference-point return method for returning a movable element of a machine to a reference point using solely a linear scale, without relying upon a limit switch. The method includes providing the linear scale (1) with a second scale portion (2) for stipulating a deceleration starting position and a reference-point position, in addition to first scale portion (3, 4) for generating two-phase signals for position detection, generating signals (S.sub.1, S.sub.2) indicative of the deceleration starting position (D) and reference-point position (O) from the second scale portion (2) of the linear scale, slowing a reference point return rapid-traverse velocity (Va) to a reference-point return rapid-traverse velocity (Vb) using the deceleration starting signal (S.sub.1), and effecting return to the reference point by stopping movement in response to the reference-point signal (S.sub.2).

Abstract: A device for correcting mechanical errors in an NC machine, by which an incremental amount of movement of a control shaft is corrected for mechanical errors such as backlash and lost motion and the value thus corrected is transmitted to a servo control section. The incremental amount of movement of the control shaft calculated every sampling is subjected to a speed adjustment. A position command value is calculated by progressively adding a command value of the incremental amount of movement subjected to a speed adjustment. A position command correction value is obtained by adding a predetermined amount of correction for mechanical error to the position command value. A corrected incremental amount of movement is calculated by substracting a previously calculated position command correction value, and is transmitted to the servo control section.

Abstract: A numerical control apparatus according to the present invention is such that when a machine tool using a spindle motor (5) is commanded to perform a reference-point return operation and positional control of a tool or the like is carried out in response to this command, spindle reference-point return is made possible merely by applying the reference-point return command to a spindle amplifier (SPA) which drives the spindle motor (5). In accordance with the invention, a grid-shift quantity (P2) decided by the relationship between the spindle motor (5) and the object controlled thereby is set in advance on the side of the spindle amplifier (SPA) before numerical control unit (CNC) operation of the machine tool. The grid-shift quantity (P2) is added to position data (P3), which corresponds to the distance from a machine reference point to a machining starting point transferred before a fixed-position stopping command.

Abstract: Disclosed is a three dimensional coordinate measuring machine which is used to measure a workpiece. The machine has a probe containing a piezoelectric crystal which is capable of detecting the shockwave generated when the probe stylus contacts the surface of the workpiece, in order to provide a trigger signal. In order to reduce the risk of the piezoelectric crystal not triggering satisfactorily upon receipt of this shockwave, the workpiece is vibrated so that immediately upon contact the vibrations travel up the probe stylus to trigger the piezoelectric crystal. The vibrations are introduced by a vibration transducer which is bolted to the bed of the coordinate measuring machine.

Abstract: The elongated edge of a workpiece is machined to preselected dimensions and tolerances using a numerically controlled machining system by probing the surface of the workpiece along the length of the edge to be machined to determine edge dimensions and/or its actual position and orientation at such preselected locations relative to a cutting tool holder and to the workpiece fixture, and generating and storing data indicative thereof, and machining the edge of the workpiece under the direction of a machine program which accesses that data and other known preselected part design data which has been stored and causes a cutting tool to follow the actual edge of the part, cutting the edge to preselected dimensions as the cutting tool travels relative thereto, the workpiece and the cutting tool being reoriented relative to each other as the tool being reoriented relative to each other as the tool moves along the edge to maintain the tool in appropriate angular and positional relation to the workpiece over the length

Abstract: During synchronous control, a first servo motor controls a position of a first spindle system and a second spindle system having a second servo motor makes calculations for estimating the torque required for the second servo motor and gives a command, so that, when a rotational phase difference between the two servo motors exceeds a predetermined value, the rotational phase difference is made equal to zero by a rotational phase difference signal. A torque command to the first servo motor, an inertia ratio between the first and second servo motors, the rotational resistance of the two spindle systems and so on are input to a torque estimator which makes calculations for estimating the torque required for the second servo motor. The estimated torque is used to control the second servo motor. The two servo motors thus generate the appropriate torque when a work held between the two spindle systems is processed. It is therefore possible to significantly reduce the torsional torque applied to the work.

Abstract: An NC statement preparing system of an interactive numerical control device. Whether a tool (2) is a one-way cutting tool or a tool capable of multi-directional cutting is determined, and an NC statement is prepared by choosing between an NC statement composed of a tool passage for the one-way cutting tool and an NC statement composed of a tool passage for the multi-directional cutting. Accordingly, a machining program for a short machining time can be prepared.

Abstract: A method of calculating an amount of offset for a wire electrode in a wire cut electric discharge machining operations. The offset amount for each of machining steps from coarse machining to finish machining are calculated with reference to a data table including a plurality of offset data each including a combination of a first machining margin to be removed by the wire electrode per se and a second machining margin to be removed by an electric discharge. The method is capable of reducing the number of data required for determination of the offset amounts for plural machining steps.

Abstract: A reference-point return method for a numerical control system. When a return is made to a reference point, a numerical control unit (21) reads an absolute position of a motor (23) within one revolution thereof from an absolute position detector (24), obtains a distance B from a predetermined motor point (a grid point) to the absolute position that has been read, and initially sets the distance B as a command position REF.sub.n from the grid point. Thereafter, the numerical control unit (21) outputs a move command value .DELTA.R.sub.n to a digital servo-circuit (22) every predetermined time .DELTA.T, updates a commanded position REF.sub.n in accordance with the equationREF.sub.n +.DELTA.R.sub.n .fwdarw.REF.sub.nobtains REF.sub.n after a deceleration limit switch (25) is depressed, and outputs (N-REF.sub.n) to the digital servo-circuit (22) as a final commanded traveling distance .DELTA.R.sub.n to return the movable element to a reference-point position set at a predetermined grid point.

Abstract: A method of forming configuration data for a CNC machine tool having a CNC (computerized numerical control unit) comprising a CPU (central processing unit), a memory, input/output means, and servo drive means. According to final configuration data train inputted for a workpiece, an edge-corrected configuration data block train is formed with the edge configuration of a cutting tool taken into accound, and configuration data are formed for a remainder which is created in said workpiece because of the edge configuration correction, so that the workpiece is automatically machined.

Abstract: A method of correcting and playing back positional instruction data in a robot which performs the teaching by moving an arm or wrist axis constituting a robot body and recording its locus at intervals of a predetermined time or a predetermined moving distance corrects positional data recorded after the completion of the teaching onto a predetermined pattern such as a straight line or a circular arc and plays back the corrected positional data. Further, the method corrects the positional data onto the predetermined pattern before the beginning of the playback previously and records the corrected data.

Abstract: A positioning controlling device for improving the machining accuracy of a work of a non-circular shape. A control axis is driven in accordance with an input function consisting of position instruction data corresponding to a machining shape of a work, and a response function of the position of the control axis is measured actually. Then, a transfer function of the servo system is determined from Fourier transformation of the input function and Fourier transformation of the response function, and a corrected input function with which a response function of the control axis ideally corresponds to the machining shape of the work is obtained from the transfer function. Even if the control axis is driven in accordance with the corrected input function, a response function obtained does not correspond to the ideal machining shape of the work.

Abstract: A profiling control system for a multiple-degree-of-freedom working machine having at least two degrees of freedom has at least one force control loop. The control loop has a detector for detecting the force applied to a working tool from a work surface, an error detector for determining the difference between the detected force and a command f.sub.ro of urging force of the working took, a processor for computing a velocity command u.sub.z of the working tool on the basis of the determined error, a drive system for moving the multiple-degree-of-freedom working machine on the basis of the velocity command. Further, the multiple-degree-of-freedom working machine is moved on the basis of a velocity command u.sub.x. The control system provides a moving velocity v.sub.zof in an urging direction of the working tool, which occurs as the result of a gradient tan .alpha. of the work surface with respect to a feed direction when the working tool is fed with the velocity command u.sub.

Abstract: In a servo motor system, consisting of a servo motor unit, a servo driver unit, power transmission lines for supplying electric power from the servo driver unit to the servo motor unit, and signal transmission lines for supplying electric signals from the servo motor unit to the servo driver unit, to the end of reducing the number of the signal transmission lines without requiring any particularly high-speed or high-quality signal transmission lines, the servo motor unit comprises a parallel-serial signal conversion circuit for converting outputs from a pole sensor, a rotary encoder, and an abnormal condition sensor into a single serial signal which is transmitted to the servo driver unit via one of the signal transmission lines. The servo driver unit comprise a serial-parallel signal conversion circuit for separating from the serial signal the aforementioned outputs from the various sensors.

Abstract: A real-time machining control system is provided which includes a conventional computer numerical control and a dimensional measurement system which continually measures the actual diameter of the rotating workpiece and provides an error signal representing the difference between the actual diameter of the workpiece and that of the part program. The error signal is used to directly control the movement of the cutting tool to assure that the final actual machined profile and dimensions of the workpiece conform to the part program.

Abstract: A tool posture control method for a robot is provided, which is capable of always controlling the posture of a tool as intended, between a starting point and an ending point of operation, in moving the tool from the starting point toward the ending point along a straight line or a circular arc. Based on positions and postures of the tool at a starting point and an ending point, previously given to the robot for instruction, and a tool position at an intermediate point, additionally given as required for instruction, a control device calculates (S2) a first angle formed between the tool and a datum plane, at the starting point, a second angle formed between the tool projected on the datum plane and a datum line set on the datum plane, at the startingt point, and the rotational position of the tool at the starting point around a tool axis, and then calculates (S3) the first angle, the second angle, and the rotational position around the tool axis, at the ending point.

Abstract: This invention relates to a method of creating NC data for rough machining, in which a cutting path (QLi) for rough machining is outputted using points on an i-th point sequence path (PLi) from among a plurality of point sequence paths repeatedly digitized at a predetermined interval in a predetermined direction. The next cutting path for rough machining is created and output using a projected point sequence path (PLk') which, among those projected point sequence paths spaced away from the i-th point sequence path by a distance greater than a tool radius (Tr), is that nearest an i-th projected point sequence path (PLi').

Abstract: A method for contactless profiling is performed while tilting an optic axis of a distance measuring probe (PB), which is capable of measuring a distance optically, by an angle .theta. from the vertical axis. When a point (P.sub.1) at which distance measurement is impossible is reached and measurement of distance the thus becomes impossible, the movement of the distance measuring probe (PB) is halted and the distance measuring probe is rotated to tilt the optical axis thereof from the vertical axis by the angle .theta. in the opposite direction, after which contactless profiling is resumed. Thereafter, when the points (P.sub.2, P.sub.3) at which distance measurement is impossible are reached, the distance measuring probe (PB) is made to perform the same operations so that contactless profiling may continue.

Abstract: A numerical control apparatus having a function of cutting the interior of an area bounded by a closed curve in a workpiece and a method for preparing a machining program for the area cutting. The numerical control apparatus is capable of machining a workpiece completely as required, even if tool paths have an intersection or intersections with themselves.

Abstract: A method and apparatus for computerized numerical control of machine tools includes a computer program and a controller for establishing an arbitrary plane with respect to the principal planes for providing cutter radius compensation. The processor precalculates structured data portions of the program that affect motion of the cutter. The precalculated data is stored and, in coordination with other inputs, is utilized to control machine tool servo drives to provide a "determine position loop error" function.

Abstract: To avoid variation between the resultant paths of multiaxis motions of a machine element for different override curves, distance-time curves of the axis motions are stored for an override value of 100%, and a relevant distance-time curve is subjected, in synchronism with a time sequence of selectively varied override values for each axis, to a time expansion which is inversely proportional to the respective override value.

Abstract: An axis feedrate output system for CNC equipment which controls the position of a machining table in each axis by effecting feedrate control in accordance with a residual error between a position command and detected positional information in each axis. A current feedrate of the machining table in each axis is derived from the residual error, and a current actual feedrate of the machining table is synthesized using the current feedrate for the respective axes an output which represents the current actual feedrate of the machining table in the form of a ratio to a predetermined maximum feedrate is generated. An error register stores the residual error (servo error) between the position command for each axis from an MPU in the CNC equipment and the positional information detected by a position sensor and provides a feedrate command for effecting feedrate control.

Abstract: The method of the invention includes obtaining points discretely on a three-dimensional curved surface, by using data specifying the three-dimensional curved surface (CSF), in such a manner that the points line up in both a first direction (BC direction) and second direction (DC direction), obtaining the center (P.sub.c) of a circular arc passing through three consecutive points (P.sub.i,j-1 P.sub.i,j, P.sub.i,j+1) in e.g. the first direction, and computing a normal vector by adopting a direction from the center of the circular arc to the middle point (P.sub.i,j) among the aforementioned three points as the normal line direction of the three-dimensional surface at the middle point.

Abstract: In an automatic lathe, a touch trigger probe (4) is calibrated (datumed) against an item (6) having a known reference dimension, instead of against the lathe chuck (2) or against a surface machined in a workpiece. The calibrated probe is then used to touch two diametrically opposed points of a feature (11) centered with respect to the axis of rotation of the chuck (2). From the mean of the co-ordinates of the two points touched, there is calculated an offset related to the difference between the assumed axis of rotation and the actual axis of rotation. This calibrates the machine to compensate for any drift between the actual axis of rotation and the machine's measurement origin.

Abstract: A method for controlling a working robot which is adapted to grip a workpiece for transporting it to a position where the workpiece is positioned against a working tool to be worked by the tool. The robot is positioned at a work starting position and at a work end position and in each of the positions the tool length vector is calculated. Based on the tool length vector values in the starting and end positions, intermediate tool length vector values are calculated for respective incremental points on a path along which the work is to be done by the tool for carrying out incremental compensations.

Abstract: A method and an apparatus for automatic zero adjustment of an injection-molding machine, in which an axis driven by a servomotor can be automatically returned to its origin with accuracy and speed. When a one-revolution signal is produced after the axis reaches a deceleration position, a preset coordinate position of a reference point is written in a current-value register. Subsequently, when the axis driven toward an absolute position reaches the absolute position, the preset coordinate position of the reference point is corrected with use of a correction value calculated on the basis of a known coordinate position of the absolute position and the register value. When the axis driven toward the reference point reaches the corrected position, the preset reference point coordinate position is written in the current-value register.

Abstract: A method and apparatus are disclosed for providing continuous position information in a position servo system having position information signals 162, 164 coming from encoder 160 and which provide indirect position information over selected ranges, and a reference position information signal 153 coming from transducer 140 and which provides reference position information at discrete intervals. In the preferred embodiment, the distances between selected positions of two position information signals are combined, and in response to position offset information obtained from the reference position signal 153, thereafter used in selecting which of the position information signals 162, 164 will be used for determining position information. The position determination techniques are further employed in positioning the transducer apparatus 140 relative to a rotating storage medium 142 through the use of an externally commutated positioning apparatus, such as motor 100, under control of a processing element 30.

Abstract: This disclosure describes a method and apparatus in the manufacture of flat tension mask cathode ray tubes, for detecting the edges of a mask receiving surface in a plane, recording its coordinates and subsequently delineating the path of an attachment device for permanently affixing a tensed foil shadow mask to the mask receiving surface of a mask support structure.

Abstract: A servo system for controlling the position of an object in accordance with a servo signal, employing an A/D converter to normalize an error in the position of the object and to enable digital correction of any offset in the system and digital compensation for track jumping and drop outs.

Abstract: A system is provided for measuring tool wear of a rotating end mill. The system measures wear by monitoring the side-loading forces on the tool during cutting. The resultant side-loading forces FRES have tangential FT and radial FR components. The radial component FR increases correspondingly with tool wear. FRES and FT are measured directly and on the basis of these measurements FR is determined mathematically to provide an indication of tool wear.

Abstract: A method is provided for effecting numerically controlled machining operations at a predetermined location. A reference feature is fixed proximate to the predetermined location and the location of a reference surface thereon is measured prior to machining to produce reference surface signals representing the coordinates of the reference surface. Location correction signals are produced in response to the reference surface signals, the location correction signals representing the difference between the measured location of the reference surface and the actual location thereof. The machining operation is performed in response to the location correction signals to effect the machining operation at the predetermined location.

Abstract: A system for establishing data defining a path for machining tool such as a three-axes milling machine tool. The machining tool path is established within a three-dimensional rectangular coordinate system which corresponds to a machine coordinate system for numerical control. The tool path is established along a first coordinate axis. The tool path is shifted to an adjacent path along the first coordinate axis in a second axis direction. The shifting pitch of the path corresponds to the interval of said path along the first the coordinate axis. The tool is shifted in third axis direction during travel along the path defined in the first and second axis direction.

Abstract: In reference point return control, a grid point position at which a one-revolution signal (RTS) is first generated by a rotary encoder (24) following restoration of a deceleration limit switch (29) is adopted as a reference point. When a zero point return mode (ZRN="1") for returning a movable element to the reference point is in effect, a numerical controller (21) regards the position at which the one-revolution signal (RTS) is generated by the rotary encoder (24) as being zero. A commanded position REF.sub.n, until the next one-revolution signal is generated, is monitored at every predetermined time, such monitoring of the commanded position being repeated until the movable element arrives in the vicinity of the reference point. When the movable element approaches the reference point and the deceleration limit switch (29) is restored, the commanded position REF.sub.n at an initial time every .sub..DELTA. T is obtained, a distance (N-REF.sub.

Abstract: A numerical control system has a tool holder which supports tools . . . attached to at least two intersecting sides, preferably three sides of a rectangular shape. The tool holder is movable along plural axes, e.g., X and Y-axis directions. A memory circuit is provided for storing the positional data regarding the tips of the tools and a workpiece diameter when the tool holder is predetermined reference points. When a workpiece is to be machined by a selected tool, the data regarding the selected tool and the workpiece diameter are called from the memory circuit, the distance from the tool tip to the outer periphery of the workpiece is computed, and the tip of the tool is moved to the outer periphery of the workpiece. With this arrangement, tools can be changed quickly.

Abstract: A system for setting a tool coordinate system brings directions ( , , ) of respective basic axes of the tool coordinate system into coincidence with directions (X, Y, Z) of basic axes of a robot reference coordinate system. A tool center point (TCP) serves as an origin, and the system causes a robot to memorize metric values on each motion axis of the robot at the moment of coincidence as setting information for setting the tool coordinate system. The system uses this setting information as information for subsequent robot motion. With the present invention, the setting of tool coordinates, which was a troublesome operation in the prior art, can be performed easily and accurately through a simple method.

Abstract: The invention relates to a surface cutting method for back-and-forth surface cutting of the interior of an area (AR) bounded by a closed curve.The surface cutting method includes repeating the following steps:a step of obtaining points of intersection P.sub.i, Q.sub.i between an i-th cutting path (PT.sub.i) and an offset curve offset (OFC') by (T+C+R) to the outer side of the closed curve, as well as points of intersection P.sub.i+1, Q.sub.i+1 between the offset curve and an (i+1)th cutting path (PT.sub.i+1), where T, C and R represent excess thickness, amount of clearance and tool radius, respectively;a step of obtaining a coordinate value, in the cutting path direction, of an outermost point R.sub.i on the offset curve (OFC') between the points of intersection Q.sub.i, Q.sub.i+1, where Q.sub.i is a point of intersection on a cutting end point side of the i-th cutting path (PT.sub.i) and Q.sub.i+1 is a point of intersection on a cutting starting point side of the (i+1)th cutting path (PT.sub.

Abstract: The present invention relates to a surface cutting method for cutting a surface within an area (AR) bounded by a predetermined closed curve (CCL) by moving a tool (TL) along a cutting path (PT.sub.i) in a predetermined direction (direction of arrow A) to cut the surface within the area, thenceforth moving the tool along an adjacent cutting path (PT.sub.i+1), obtained by a shift of a predetermined amount, to cut the surface, and repeating these surface cutting operations.

Abstract: An apparatus for setting a work coordinate system of a machine tool is disclosed. A work coordinate system is set on the basis of a position from the surface to be machined of a work by automatic input of a tool mounting dimension. The apparatus is composed of a means for inputting/outputting machining data, an instrumentation means for measuring the positon of a blade tip of a tool, a tool reference point setting data memory for storing tool reference point setting data, an NC machining program data memory for storing an NC machining program for machining a work, a first processor for operating the tool reference point setting data and the machine coordinate value data to obtain the mounting dimesion data for each tool, and a second processor for obtaining work coordinate system data and the tool mounting dimension data.

Abstract: A circular path control apparatus and method for a multi-axis servomechanism having a plurality of driving shafts. Any disturbance to a command circular path is calculated from the amount of contour error of a circular path or a square of a circular-arc center angle error and a control for cancelling the disturbance is added, thereby improving the circular path accuracy of the multi-axis servomechanism.

Abstract: A general safe retract and return function is provided for a machine tool which is easily programmed for all cases to avoid collision and interference between the workpiece and tool and to reduce the damage or imperfection in the surface of the machined workpiece caused by the termination and/or resumption of machining. The general safe retract and return function includes parameters defining incremental retract and entry vectors relative to the direction of the machining path in the region of the interrupted point. Preferably the tool and workpiece are reengaged at the interrupted point along an entry ventor which is at a grazing angle with respect to the reverse of the tool feed direction along the machining path, thereby avoiding remachining of the workpieces but providing a smooth surface finish.

Abstract: A method of determining an operating status of an adjusting drive of a printing machine having an electric motor drivable with varying direction of rotation, and a gear transmission arrangement includes determining a value of at least one of a torque produced by the electric motor and a variable dependent upon the torque, comparing the value with a corresponding value existing during an adjustment of the adjusting drive in a constant direction, and applying the value for a torque deviating by a given threshold value from the torque occurring during the adjustment of the adjusting drive in the constant direction as a criterion for an operating status deviating from the adjustment on the constant direction.

Abstract: A playback system grinding robot is disclosed which includes a No. 2 arm attached for ocillation to the head of a No. 1 arm turning around a main axis, a drive arm arranged adjacent to the No. 1 arm so as to drive the No. 2 arm, and abrasive tool attached to the No. 2 arm head axis and pressed perpendicularly downward by a fluid cylinder to be freely turnable in different directions, and possessed of a dual degree-of-freedom of control in the polar coordinate system. A positional data generator for indicating a horizontal movement position of the abrasive tool is also provided as is a memory to store directional data together with positional data in the memory at the time of "teaching", especially to input turnback point data on the tool traveling locus exactly into the memory in accordance with a change of the directional data.

Abstract: The present invention relates to an area cutting method for cutting an area (AR) delimited by a curve (OLC) of an external shape and at least two closed curves (INC.sub.1, INC.sub.2) which lie within the curve of the external shape. The area cutting method has a step of calculating first and second offset curves (INF.sub.1, INF.sub.2) offset outwardly from the respective closed curves (INC.sub.1, INC.sub.2) by an amount dependent upon tool diameter, a step of checking whether the offset curves intersect each other, a step of ascertaining that an overlap portion (CSA) incapable of being area-cut exists when the offset curves intersect each other, and a step of cutting only an area from which the portion (CSA) incapable of being area-cut is omitted when the overlap portion exists.

Abstract: A wire electric discharge machining method for cutting a workpiece (WK) by moving a wire electrode (WR) relative to the workpiece and producing an electric discharge across the wire electrode and workpiece, the method including preparing and entering path data specifying contours to be cut on upper (APL) and lower (BPL) planes of the workpiece, separately preparing and entering such auxiliary data as an amount of wire diameter compensation, workpiece mounting position and guide positions necessary for moving the wire electrode (WR) relative to the workpiece (WK), obtaining relative path data between the workpiece and an upper guide (UG) tensioning the wire electrode as well as relative path data between the workpiece and a lower guide (DG) tensioning the wire electrode by using the path data and the auxiliary data, and taper cutting contours commanded on the upper and lower planes of the workpiece by moving the upper and lower guides relative to the workpiece using both path data.

Abstract: A method of approach in area cutting includes giving in advance an angle .theta. between a workpiece plane (WPL) and a straight line (SL) connecting an approach starting point (P.sub.A) and a cutting starting point (P.sub.i), and a distance dz between the approach starting point (P.sub.A) and the cutting starting point (P.sub.i) in a direction perpendicular to the workpiece plane. Coordinate values of the approach starting point (P.sub.A) are calculated using the angle .theta. and the distance dz in such a manner that a projection (SL') of the straight line (SL) on the workpiece plane (WPL) is brought into orientation with a direction of a normal line at the cutting starting point (P.sub.i) on a curve (OLC) of the external shape. A tool (TL) is positioned at the approach starting point (P.sub.A) in a rapid-traverse mode, and the tool is subsequently moved to the cutting starting point (P.sub.i) in a cutting-feed mode. Thereafter, cutting is started.