JP2003291032A - Method for establishing machining conditions in die sinking electrical discharge machining and numerical control power source device for die sinking electrical discharge machining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately establish a switching position of machining conditions corresponding to change of electrical discharge area and to reduce load of an operator for inputting data. <P>SOLUTION: A memory device 50 stores machining characteristics inputted through an input output device 30, attribute data given to three-dimension shape model of a tool electrode, and machining condition file. A computing device 80 of a numerical control power source device determines sampling data of electrical discharge area by calculating electrical discharge area at a position of machining depth by an electrical discharge area calculating means 823 of a three dimension data management means 82. A switching position establishing means 824 determines positions of machining depth corresponding to a plurality of electrical discharge areas as switching positions of machining conditions. A machining current calculating means 843 calculates machining current suitable for electrical discharge area at the switching position. The machining condition establishing means 824 select a combination of machining conditions suitable for machining current from the machining condition file and establishes the same. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machining condition setting method for setting a machining condition suitable for a result expected by an operator based on some set values inputted by an operator, and a numerical value of a die-sinking electric discharge machine. More particularly, the present invention relates to a machining condition setting method for selecting machining conditions based on the discharge area of at least the machining depth position of a tool electrode, and a numerical control power source device for a die-sinking electric discharge machine.

[0002]

2. Description of the Related Art In electric discharge machining, a tool electrode and a work piece are arranged to face each other, and energy generated by an electric discharge which is repeatedly generated intermittently in a machining gap formed between the tool electrode and the work piece is utilized. Processing method for forming a desired shape on a workpiece. Due to these properties, in electrical discharge machining,
Machining characteristics such as machining speed, machining surface roughness, machining shape accuracy, and tool electrode wear greatly depend on electrical machining conditions such as the discharge current peak current value, pulse width, and dwell time. Since the discharge energy is easily affected by changes in the machining environment, variations easily occur, and it is difficult to obtain the same machining results under the same electrical machining conditions.Therefore, electrical discharge machining can be applied to other metal machining such as cutting. Compared with this, it is more difficult to set the processing conditions. Therefore, in order to obtain an excellent machining result, the worker is required to have a high level of proficiency familiar with electric discharge machining.

It is the discharge current value for each discharge that influences the magnitude of the energy for each discharge. Simply stated, the size of the discharge trace and the amount of material removed contributes to the electric discharge machining. It is closely related to the magnitude of the discharge current, that is, the machining current. Further, it is known that the waveform of the discharge current pulse has an important influence on the processing characteristics. Further, when the electric discharge machining is regarded as finally removing the required material by repeating each electric discharge, the total amount of energy supplied to the electric discharge machining in a unit time is the number of discharge current pulses in the unit time, in other words, It depends on the repetition frequency. Therefore, it can be said that the machining conditions regarding the machining current value have the greatest influence on the machining characteristics, and other machining conditions are generally set based on the machining conditions regarding the machining current value.

When the machining current value is relatively large, the amount of material removed at one time is relatively large, and if the rest time is the same, the machining speed becomes faster and the size of each discharge mark becomes large, resulting in a large machining surface. Roughness is relatively coarse. Further, when the pause time is relatively short, the machining speed becomes high if the repetition frequency is high and the machining current value for each discharge current pulse is the same. At this time, even if the single-shot discharge energy and the repetition frequency of the discharge current pulse are the same, the machining characteristics differ depending on the discharge area and the waveform of the discharge current pulse. However, since the finally expected machining speed and finished surface roughness have a contradictory relationship and the required machined surface roughness differs depending on the application of the product to be electrical discharge machined, whether the machining speed is fast or slow, Alternatively, whether the processed surface roughness is rough or fine is a relative value, and whether or not the electrical processing conditions are appropriately set depends on the required processing characteristics.

In the die-sinking electric discharge machining, it is necessary to consider that the tool electrode is consumed as one of the features of the electric discharge machining. When it is a processing mode in which the shape of the tool electrode is transferred to the workpiece by using the tool electrode of the full shape, particularly,
When machining a relatively complex shape such as bottomed machining where the product has a bottom surface or stepped machining where there are steps, the consumed tool electrode shape should be transferred due to wear of the tool electrode. In many cases, the desired processed shape accuracy cannot be finally obtained.

Therefore, in die-sinking electric discharge machining,
One electric discharge machining process is divided into a plurality of machining steps for electric discharge machining. In this electrical discharge machining method,
At first, the machined surface roughness is relatively large and the machining surface is rough, but the machining speed is fast, and the energy in each machining process is gradually reduced. Finally, the machined surface roughness is fine with relatively small energy. Has a slow machining speed. Roughing is mainly used for machining with comparatively large energy focusing on machining speed, and finishing is for machining with comparatively small energy with emphasis on finished surface roughness. The machining process in which the machining surface roughness is made uniform in order to obtain roughness is called medium machining or semi-finishing machining, but the range of the machining current and the machining surface roughness value in each machining process is not always clear. Therefore, in the present invention, regardless of the size of the processing conditions, the first processing step is called rough processing, the final processing step is finish processing, and the other intermediate processing steps are all called middle processing.

As described above, when the electric discharge machining is divided into several machining steps, the machining hole becomes larger as the electric discharge machining progresses, or the tool electrode is consumed to increase the machining gap, while each machining step is performed. The machining current value set in is changed stepwise to a smaller value and the discharge gap becomes smaller.Therefore, the machining gap becomes larger than the required discharge gap, so the tool electrode can be used as it is in the depth direction of the machining hole. The side surface of the machined hole is less likely to be machined than the bottom surface of the machined hole only by moving the machine. Therefore, simply speaking, it is necessary to prepare and prepare tool electrodes of the same shape having different sizes by the number of processing steps. Therefore, a machining method called shifting machining or oscillating machining is adopted, in which not only the depth direction of the machining hole but also the lateral direction of the machining hole is relatively moved to perform the electric discharge machining by relatively moving the tool electrode and the workpiece. Since this machining method promotes the discharge of machining chips and diffuses the machining chips, it is effective in preventing abnormal discharge on the bottom surface of the machining hole and secondary discharge on the side surface of the machining hole.

When a single electric discharge machining process is divided into respective machining steps for electric discharge machining, selection of machining conditions in each machining step, particularly the first machining step, is the most important factor for efficient and desired machining. It will be one of. Regarding the energy in the final machining process, basically an approximate machining current value is determined in order to obtain the desired finished surface roughness and machining shape accuracy, and machining is performed with the smallest energy compared to other machining processes. Since the processing conditions are set like this, if the setting of the processing conditions up to the final finishing process is incorrect, the finishing process will take a surprisingly long processing time, which is completely inefficient. This is because processing is inevitable.

Therefore, in the die-sinking electric discharge machining, it is necessary to prepare a machining plan for obtaining the desired finished surface roughness and machined shape accuracy prior to machining. Specifically, select the processing conditions of roughing and finishing that can obtain the desired finished surface roughness and processing shape accuracy, and based on these processing conditions,
Considering the expected machining time and the reduction amount of the tool electrode (hereinafter simply referred to as the reduction amount), the process of electrical discharge machining is divided into each machining process and finally the electrical discharge machining can be performed under the machining conditions of finishing machining. The processing conditions for each processing step are determined.

In order to reduce the burden on the operator in drafting such a machining plan, it has been conventionally considered to facilitate the setting of machining conditions in each machining process. The initial die-sinking EDM machine obtains the relationship between a plurality of electrical machining conditions optimal for the machining from energy suitable for a certain machining, and stores a plurality of combinations of these electrical machining conditions in a storage device. In addition, the optimum processing condition can be selected by pushing the button. In addition, a series of electrical machining condition combinations set for each machining process in this way is stored for each process of electrical discharge machining, and a button is pressed when performing the same electrical discharge machining. There was an EDM machine configured to recall a series of data stored by. However,
A system for setting the discharge conditions in this way is rarely used at present, and a numerical control device (N
C, Numerical Controller) is installed, and then N
It has evolved into a system that sets and corrects the initial machining conditions of each machining process in association with the C program.

Although there are a wide variety of processing condition setting systems, JP-A-62-130130 and Japanese Patent Publication No.
Japanese Patent Publication No. 49415, Japanese Patent Publication No. 7-75815, Japanese Patent Application Laid-Open No. 63-7231, Japanese Patent Application Laid-Open No. 2-153476, Japanese Patent Application Laid-Open No. 3-136725, Japanese Patent Application Laid-Open No. 6-114.
The technique disclosed in Japanese Patent No. 637 is referred to.

By the way, since the conventional machining condition setting system of the die-sinking EDM machine calculates the machining current value by using the bottom area of the machining hole as the electric discharge area, it is not suitable for actual electric discharge machining. The condition may not be set. For example, in the case of the electric discharge machining example shown in FIG. 12, the tool electrode EL is actually moved relative to the workpiece WP, and the discharge area S where the tool electrode EL and the workpiece WP face each other is the tool electrode EL. At the machining depth position Z of. However, in the above-described machining condition setting system, only one machining condition combination is set in each machining process.

Therefore, it is difficult to say that the processing conditions set in this way are appropriate, and the processing time tends to be long. In the first place, the operator tends to set a processing condition in which there is a low possibility of processing failure in consideration of an unpredictable change in the processing state, so that the processing condition tends to be set at a relatively low processing speed. In particular, if the amount of removal in the rough machining process is small or the machining surface is uneven, the machining time in the subsequent machining process becomes long.
In addition, if the tool electrode is not a simple shape, there will be some areas that cannot be completely removed, and the machining shape accuracy will not improve,
Processing time tends to be long.

Japanese Patent No. 2750378 and Japanese Patent No. 31
As in the electric discharge machine disclosed in Japanese Patent No. 036753,
A system is also considered in which preset machining conditions are adjusted according to the machining situation that changes depending on the shape of the tool electrode. Since this type of adaptive control system temporarily switches the preset machining conditions, the technical concept of the pillar is essentially different, but it is possible to compensate for the error in the setting of the initial machining conditions. it can. However, the adaptive control system cannot significantly change the initial machining conditions for obtaining the desired machined surface roughness and machined shape accuracy, so it is important to set the initial machining conditions as appropriately as possible. There is no change.

However, if the accurate three-dimensional shape data of the tool electrode and the machining depth position are given, the discharge area can theoretically be calculated. Therefore, the discharge area at a certain machining depth position is obtained. It is possible to set a machining condition by obtaining a suitable machining current value. In fact, there has been considered an apparatus that simulates machining from attribute data given to a three-dimensional shape model (hereinafter, referred to as a solid model) of a tool electrode or a machining shape to set machining conditions corresponding to a discharge area. This type of processing condition setting system can change the processing condition setting according to the discharge area or the removal amount. Specifically, Japanese Patent Publication No. 58-24215
JP-A-61-146420, JP-A-62-146420
-19324, JP-A-3-146133,
Reference is made to the known techniques disclosed in JP-A-9-9424 and JP-A-9-253943.

[0016]

In such a conventional machining condition setting system, setting the initial machining conditions on the basis of the discharge area or the amount of removal which changes from moment to moment is infinite because the set values are infinite. Therefore, the processing conditions are set with reference to an appropriate unit processing depth position. However, since the change in the discharge area with the progress of electrical discharge machining varies depending on the machining shape, the appropriate machining depth position where the initial machining conditions should be set also differs depending on the desired machining shape. A system that sets processing conditions based on the position is not sufficient. For example, in the case of the example of electric discharge machining shown in FIG. 12, it can be seen that the initial machining conditions set are not very appropriate in the α, β, γ sections, as shown in FIG. .

In the first place, if an attempt is made to construct a high-level machining condition setting system, the operator will be required to input more data. Therefore, for each unit machining depth position,
Alternatively, it is considered inefficient to obtain the discharge area for each specific machining depth position and set the machining conditions in view of the entire electric discharge machining process including setup. However, a three-dimensional model design support system (CA that uses computer equipment with high information processing capability)
D, Computer Aided Design System) is used for N in the manufacturing support system (CAM, Computer Aided Manufacturing) by using the attribute data given to the solid model created by
When creating a C program, it is not inefficient. However, even if a computer is used, it takes a certain amount of time to calculate the discharge area, and in the case of die-sinking EDM, which has difficulty in reproducibility, the NC program created by the die designer is used for EDM. Since there are many occasions in which the worker of the above frequently makes corrections with the numerical control power supply device, it cannot be said that it is sufficient as a die-sinking EDM device.

In view of the above problems, it is an object of the present invention to provide a method of setting machining conditions in die-sinking electric discharge machining, which allows more appropriate setting of initial machining conditions corresponding to the machining shape. It is another object of the present invention to provide a numerically controlled power supply device for a die-sinking electric discharge machine that allows an electric discharge machining operator to more easily and more appropriately set initial machining conditions corresponding to a machining shape. Some specific advantages obtained by the processing condition setting method and numerical control power supply device of the present invention will be referred to in the detailed description of the invention together with specific embodiments.

[0019]

In order to solve the above-mentioned problems, the method for setting machining conditions in die-sinking electric discharge machining of the present invention stores the attribute data given to the solid model of the tool electrode in the desired electric discharge machining. A process, a process of storing machining characteristic data including at least a desired surface roughness, a process of calculating a discharge area at a predetermined unit machining depth position based on attribute data, and a process of calculating A step of obtaining sampling data of the discharge area based on the discharge area, a step of obtaining a machining depth position corresponding to each predetermined unit discharge area based on the sampling data as a machining condition switching position, and each switching position The machining current value suitable for the discharge area is calculated, and the combination of machining conditions suitable for the machining current value is stored in a plurality of pre-stored parameters. To the step of setting by selecting each from a combination of conditions, the arrangement comprising a.

Further, the numerical control power supply unit of the die-sinking electric discharge machining apparatus of the present invention has at least the desired combination data of the machining conditions and the attribute data given to the solid model of the tool electrode in the desired electric discharge machining. A storage device (5) for storing data relating to machining characteristics including surface finish roughness of
0) and discharge area calculation means (823) for calculating discharge area for each predetermined unit machining depth position based on attribute data and obtaining sampling data of discharge area, and based on the sampling data of discharge area A switching position setting means (824) for obtaining a machining depth position corresponding to a predetermined unit discharge area as a switching position for machining conditions, and a machining current calculating means (calculating a machining current value suitable for the discharge area at the switching position ( 843) and a machining condition setting means (842) for selecting and setting a combination of machining conditions adapted to the machining current value from a plurality of combinations of machining conditions stored in the storage device (50). Equipment (80)
The configuration includes and. However, the reference numerals are added for convenience of description, and the configuration of the numerical control power supply device of the present invention is not limited to the embodiment.

According to the machining condition setting method of the present invention, the sampling data of the discharge area is obtained and the machining condition switching position is set for each predetermined discharge area based on the sampling data. It is possible to accurately obtain the switching position of the machining conditions that adapts to the change in the discharge area without changing the shape, and to perform die-sinking discharge machining using a tool electrode that causes the discharge area to change indefinitely as the discharge machining progresses. Even at this time, the setting of the processing conditions can be switched at a more appropriate processing depth position.

Further, according to the numerical control power supply device of the die-sinking electric discharge machine of the present invention, the operator inputs at least a desired surface roughness and the solid model of the tool electrode provided by the designer is given. Since it is possible to obtain a suitable machining condition switching position and machining condition based on the attribute data, it is more appropriate even when machining a machining shape in which the discharge area changes indefinitely as the machining progresses. It is possible to switch the setting of machining conditions at various machining depth positions and reduce the burden on the operator of electric discharge machining.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a front view showing the general outline of a die-sinking electric discharge machine. The die-sinking electric discharge machining device is configured to include a machining machine main unit 1, a numerical control power supply device 2, and peripheral devices such as a machining fluid tank (not shown). Processing machine Main machine 1
Various known configurations are adopted. In the embodiment, the head 11 is machined in the depth direction (Z axis), the ram 12 is moved in the front-back direction (Y axis) by a servomotor such as a linear motor.
The table 13 is reciprocally moved in the lateral direction (X axis) to move the tool electrode EL and the workpiece WP at least vertically 1.
Allows relative movement in three axial directions simultaneously in the axial and horizontal two-axis directions. The tool electrode EL is fixed to a mounting plate provided at the lower end of the head 11, and the workpiece WP is mounted on a surface plate installed on a table 13 surrounded by a processing tank 14.
The numerical control power supply device 2 is installed adjacent to the processing machine main unit 1 and supplies power and control signals to the processing machine main unit 1 through the cable CB.

FIG. 2 shows an embodiment of a numerical control power supply unit of a die-sinking electric discharge machine of the present invention, and is a three-dimensional configuration diagram schematically showing the arrangement of equipment installed inside a casing. A unit composed of a box or a printed circuit board is attached to a frame or a rack (not shown) in the space of the housing 20 of the numerical control power supply device 2 by using attachment members such as bolts, pins and screws. The units to be attached are the numerical control unit 21, the general-purpose control unit 22, the processing power supply unit 23, the processing control unit 24, the peripheral device control unit 25, the display unit 26, and the operation panel unit 2.
7, the disk drive unit 28, but the components of each unit do not have to be integrally provided for each unit. Other units such as a cooler unit are omitted.

The numerical control unit 21 includes a plurality of arithmetic units (CPU, Central Processing Unit) including a microprocessor arranged on one or more printed circuit boards, and an IC memory chip (ROM, Read Onl) that cannot write data.
y Memory) and an IC memory chip (RAM, Random Access Memory) that can read and write data freely.
C itself is a microcomputer dedicated to die-sinking EDM. The numerical control unit 21 of this embodiment is
Main of numerical control including a function of decoding an NC program, a function of outputting position data based on numerical control data, and a function of outputting command data to the discharge control unit 24 or the peripheral device control unit 25 based on the numerical control data And a motor control device (MC, Mo that performs a relative movement control function that outputs a control signal to the servo motor based on the position data and controls the positioning of the servo motor based on the detected detection signal fed back.
tion Controller).

The general-purpose control unit 22 is a microcomputer having almost the same functions as a personal computer. Structurally, a group of arithmetic components including at least one CPU and ROM arranged on a board called a mother board and a group of accessory components such as cooling equipment, an additional RAM inserted in a dedicated slot, and an extension slot inserted in an expansion slot. Further, a group of extended components arranged on the printed circuit board are stored in one box. It also has several connectors, pin jacks and modular jacks.

In the type in which the general-purpose personal computer is mounted on the NC as it is, the numerical control unit 21 and the general-purpose control unit 22 are clearly distinguished as hardware, and the numerical control unit 21 and the general-purpose control unit 22 are RS. 232C (Recommended Standard 232
C) and a serial communication line such as USB (Universal Serial Bus).

The machining power supply unit 23 substantially forms an electric discharge machining circuit, and includes one or more DC power supply devices including a rectifier for rectifying commercial AC, and a plurality of resistance elements inserted in the electric discharge machining circuit. It is composed of a resistance plate that is arranged, a relay circuit that switches the electric discharge machining circuit, a printed circuit board that has a plurality of switching elements that turn on and off the discharge voltage pulse supplied to the machining gap, and other elements in the electric discharge machining circuit, Electric power is supplied to the adjacent machining main machine 1 through the cable CB, and discharge energy is supplied to the machining gap through the machining gap line connected to the tool electrode of the machining main machine 1 and the workpiece.

The discharge control unit 24, in accordance with command data output from the numerical control unit 21, gate signals to a plurality of switching elements of the machining power supply unit 23, switching signals to variable elements, switching to control a relay circuit. An apparatus is included for processing signals, signals for controlling electrical discharge machining such as signals from sensors provided in the electrical discharge machining circuit.

The peripheral device control unit 25 is used for the processing tank 14
Detecting device for detecting the liquid surface of the electric discharge machining liquid, automatic electrode changing device (ATC, Auto Tool Changer), and device for controlling the operation of peripheral devices such as the spindle angle indexing device and auxiliary devices.

The display unit 26 displays a liquid crystal display (LCD, Liquid Crystal Display) and graphic data sent from the general-purpose control unit 22 on the LCD.
It is equipped with a dedicated LSI (Large Scale Integration) that executes the scaling function for arranging on the screen.

The operation panel unit 27 is arranged so as to be fitted into the front surface of the housing 20. A keyboard and buttons are provided on the front surface of the operation panel unit 27,
It is equipped with a receiving device for receiving the radio signal of the mouse and a pin jack of a microphone for capturing the voice. Further, the operation panel unit 27 is the L of the display unit 26.
It includes a touch panel provided so as to cover the screen of the CD.

The disk drive unit 28 corresponds to an extension device of the microcomputer of the general-purpose control unit 22. The disk drive unit 28 has means for fetching at least two types of data from the outside. One is optical disc (CD, Compact Disc) and high-density optical disc (DVD, Digital Versatile Disc)
It is a means for fetching software necessary for controlling the microcomputer of the general-purpose control unit 22 from such a storage medium (hereinafter, referred to as a medium). Another one
One is a magnetic disk drive (FDD), a writable optical disk drive (CD-R, Compact Disc-Recorda).
ble) or phase change recording type optical disk drive (CD-
RW, Compact Disc-ReWritable).

Numerical control device with computer (CNC, Co
mputerized Numerical Controller) does not need to be clearly distinguished between numerical control and control other than numerical control in terms of functionality. In fact, in most CNCs, the program that operates the NC is software that operates a general-purpose microcomputer. The configuration is such that the NC cannot operate unless a general-purpose microcomputer is activated. Therefore, the CNC often has a configuration in which the entire numerically controlled power supply device can be regarded as an NC, and in the embodiment, each unit will be described as a numerically controlled power supply device without particularly distinguishing each unit. Also, in FIG.
Although it is shown that all the components included in each unit are installed integrally and arranged at each mounting position, in the actual numerical control power supply device, the components of each unit are designed to be separated and separated from each other. May be provided in.

FIG. 3 is a block diagram showing the details of a part of the numerical control power supply unit of the die-sinking electric discharge machine of the present invention. It is considered that there are a plurality of devices such as an arithmetic device, a storage device, and an input / output device arranged in FIG. 3, and the arrangement of parts is arbitrarily changed in design.

The input / output device 30 is a device that connects the worker and the numerical control power supply device 2. Specifically, the input / output device 30 includes an operating device 31, a reading device 32, and a recording device 33. Although the connecting device that connects the processing machine main unit 1 and the numerical control power supply device 2 or the interface itself that connects the units is also an input / output device, it is distinguished from the input / output device 30 of the present invention.

The operation device 31 includes an input device including a keyboard, a mouse, a microphone arranged on the operation panel unit 27 shown in FIG. 2 and a touch panel provided on the display unit 26, and an input device provided on the general-purpose control unit 22. It comprises an input / output interface including an output bus (I / O Bus) and a data line connecting the input / output device and the input / output interface. The operator operates the operation device 31.
Is operated to input at least the desired surface roughness data out of the required processing characteristics data.
Further, the operator operates the operating device 31 as necessary to input the material and the reduction amount of the tool electrode and the workpiece, or the parameters of the processing conditions and the correction value of the NC program.

The reading device 32 is an input device with a flat cable such as a CD drive in the disk drive unit 28 shown in FIG. 2 and an interface (E-IDE, Enhanced Integrated Drive Elec) dedicated to the drive.
tronics) or an extended skagy interface (SCSI, Small Computer System Interface). The data captured by the numerical control power supply device 2 through the reading device 32 is, for example, system software (OS, Operating System) of a personal computer.
stem Program), software that manages CAD data, software that manages numerical control, application software (Application Software Program) such as software that supports the creation of NC programs, and attribute data given to the solid model of the tool electrode. Unique data regarding desired electrical discharge machining, machining condition file consisting of a combination of plural machining conditions, machining database such as machining condition-reduction amount file, NC program creation tool file etc. ,.

The data in the database is pre-installed by the operator of the manufacturer, and the attribute data of the solid model, which is unique data relating to the desired electric discharge machining, is basically installed by the operator. The attribute data given to the CAD solid model includes at least dimensions, names, and definitions. Definition data is a unit shape element,
Contains all the data needed to define the model, such as boundaries, regions and coordinates. In the present invention, unless otherwise specified, the attribute data indicates the above data given to the solid model.

The recording device 23 comprises an FDD and an interface dedicated to FDD in the disc drive unit 18 shown in FIG. 2 or a CD-R drive and an interface dedicated to the drive or an expansion interface. The recording device 23 also includes a device such as a printer that outputs data to recording paper as necessary. The recording device 23 records the created NC program or the modified attribute data on the medium.

The communication device 40 is a LAN adapter (Local
It is a device for connecting to a computer network such as an Area Network Adopter, and is a means for controlling data transfer with another computer or NC located at a distant position. For example, attribute data given to a solid model created by CAD by a designer from a personal computer at a distant position can be taken into the numerical control power supply device 2 through the communication device 40.

The storage device 50 stores data obtained from the outside of the numerically controlled power supply device 2 through the input / output device 30 and data obtained by calculation of a calculation device 80 described later,
It is a means for retaining the stored contents even after the power of the numerical control power supply device 2 is turned off. In addition, the data in the storage device 50 can basically be freely manipulated by an operator. Therefore, the storage device 50 is preferably a device having a large storage capacity, and more specifically, a hard disk drive (HDD, Ha
rd Disc Drive) and dedicated interface (E-ID
E, SCSI, USB) is adopted. The storage device 50 stores data of a combination of a plurality of machining conditions, attribute data given a solid model of a tool electrode in desired electric discharge machining, and data regarding machining characteristics including at least a desired finished surface roughness.

The storage device 60 is a means for temporarily storing data that needs to be stored only while the numerical control power supply device 2 is activated, and is the most widely used RAM chip. Memory module (DI
MM, Double Inline Memory Module) are adopted. Specifically, the storage device 60 temporarily stores all or part of the programs of the OS and application software, data obtained by the arithmetic device 80, and the like, and stores the data after the power of the numerical control power supply device 2 is turned off. The contents are basically erased.

The display device 70 includes at least a graphics dedicated bus (AGP, Accelerated Graphics Port Bus) of the general-purpose control unit 22 shown in FIG. 2, a graphics dedicated bus slot, and graphics attached to the bus slot. Board (video card)
And an LCD provided in the display unit 26. The graphic board is a dedicated LSI
And D like VRAM (Video RAM) suitable for image processing
It is equipped with a RAM (Dynamic RAM) and can display display data for drawing, for example, a three-dimensional model of the machining shape and the relative movement path of the tool electrode on the LCD.
It is suitable for the numerical control power supply device of the present invention that dynamically displays a three-dimensional image.

The arithmetic unit 80 includes one or more CPUs and a CP.
A ROM that is installed in parallel with U to store a program of a specific basic operation process, and an RA that stores basic setting data
Comprising M. A plurality of CPUs mounted on the numerical control unit 21 manage the functions of the numerical control unit 21. On the other hand, at least one CPU mounted on the general-purpose control unit 22 manages most of the operations of software necessary for the operator to operate the numerically controlled power supply device 2.

The arithmetic unit 80 is, concretely, at least a system management unit 81 and a three-dimensional data management unit 8.
2, numerical control management means 83, and NC program creation support means 84. The system management means 81 is a BIO
Based on S (Basic Input Output System) and OS, the three-dimensional data management means 82 is software for managing CAD data, the numerical control management means 83 is software for managing numerical control, and the NC program creation support means 84 is an NC program. Each operation is controlled by software that supports the creation of the.

The system management means 81 is a known means that controls the basic operation of the general-purpose control unit 12 of the numerical control power supply device 2. The system management unit 81 has many functions, but includes at least a setting control unit 811, an operation control unit 812, a compatibility control unit 813, a drawing data creation unit 814, and a communication control unit 815.

The setting control means 811 stores the OS setting data newly input from the input / output device 30 or when the setting data change is instructed by another means in the arithmetic unit 80. The set value of each device of the numerical control power supply device 2 is changed to the device 50, and the set value is stored in the storage device 5.
Store to 0.

The operation control means 812 is used when a new command is input from the input / output device 30 or the arithmetic unit 8
Each unit of the numerical control power supply device 2 is operated directly or indirectly when a command is issued by other means of 0.

The compatibility control means 813 shares data with a connected unit, a plurality of means, and computers at distant positions so that the same data can be used by a plurality of application software. To do. Further, the compatibility control unit 813 links different application software programs that are running at the same time to enable data transfer.

The drawing data creating means 814 is the arithmetic unit 8
The drawing data is created based on the data given from the other means of 0 and output to the display device 70. For example, when solid model data is given from the three-dimensional data management means 82, solid model drawing data is created, and when relative tool movement path data is given from the numerical control management means 83. , Create tool path drawing data.

The communication control means 815 converts the data given from the other means of the arithmetic unit 80 into data of a predetermined format and outputs it to the communication device 40. Further, the data obtained from the communication device 40 is converted into data of a predetermined format and stored in the storage device 50.

The three-dimensional data management means 82 includes at least a data analysis means 821, a surface model creation means 822, a discharge area calculation means 823, and a switching position setting means 824. The data analysis unit 821 reads and analyzes the attribute data given to the predetermined three-dimensional shape stored in the storage device 50 in accordance with a command given from another unit. When the operator changes the predetermined attribute data, the predetermined attribute data is changed and stored in the storage device 50, the changed attribute data is analyzed, and the analysis data is given to the drawing data creating means 814. . Further, the surface model creating means 822 creates a surface model of a specific part of the tool electrode from the solid model of the tool electrode and gives attribute data to the surface model.

The discharge area calculation means 823 calculates the surface area, volume, mass, center of gravity, etc. of the solid model. Also,
The discharge area calculating means 823 calculates the discharge area for each predetermined machining depth position based on the attribute data given to the surface model obtained from the solid model, and obtains the sampling data of the discharge area. Further, the switching position setting means 824 obtains the machining depth position corresponding to each predetermined discharge area that is predetermined based on the sampling data, as the machining condition switching position.

The numerical control managing means 83 is means for managing the operation of the numerical control unit 21 and the units under its control which are required by the operating device 31 or other means of the arithmetic unit 80. Specifically, for example, the communication control means 81
5, the NC program stored in the storage device 50 is transferred to the numerical control unit 21, and the numerical control unit 21 is made to decode the NC program through the operation control means 812 to output control data such as position data. Also,
Setting values and coordinate values relating to numerical control are displayed on the display device 70 through the drawing data creating means 814, or machine settings are changed through the setting control means 811.

The NC program creation support means 84 includes a data acquisition means 841, a machining condition setting means 842, a machining current calculation means 843, an estimated machining time calculation means 844, a relative movement value calculation means 846, a machining plan display means 845, and an NC program. The production means 847 is included.

The data acquisition means 841 requests, from the data necessary in the calculation process of the NC program creation support means 84, data that cannot be obtained by the NC program creation support means 84 to other means.

The machining condition setting means 842 selects and sets a combination of machining conditions adapted to the machining current value obtained by the machining current calculation means 843 from a plurality of machining condition combinations stored in the storage device 50. To do. More specifically, the method of switching the machining conditions in each machining process that is adapted to the machining current value at each switching position is selected from the machining condition-reduction amount file, and the combination of machining conditions is selected from the machining condition file and set. To do. Further, the rocking shape, the condition of the jump of the tool electrode, or the method of supplying the machining liquid jet (liquid processing method) is set according to the basic data from the attribute data given to the solid model as needed.

The machining current calculation means 843 calculates a machining current value for each predetermined unit discharge area in one or more machining steps. In a limited manner, the machining current value for each predetermined discharge area in the rough machining process is calculated, and the machining current value in each machining process is calculated if necessary.

The estimated machining time calculating means 844 obtains the dimension values such as the feed amount, the offset and the oscillation amplitude in each machining step from the already obtained parameter values of the machining current, and determines the removal amount in each machining step. The machining time estimated from the machining speed is calculated.

The machining plan display means 845 includes the combination of machining conditions obtained by the machining condition setting means 842, or the estimated machining time obtained by the estimated machining time calculation means 844 and the dimension values such as the feed amount and the swing amplitude. Data of one or more processing plan tables are created, and one or more processing plan tables are displayed on the display device 70 through the drawing data creating means 814.

The relative movement value calculating means 846 obtains the relative movement amount in the machining depth direction from the attribute data given to the solid model of the tool electrode and the dimension value obtained in the estimated machining time 844. In addition, the set swing shape and the estimated machining time 8
The relative movement amount in the side surface direction is obtained from the dimension value obtained in 44.

The NC program creating means 847 uses the relative movement amount obtained from the relative movement value calculating means 846 to the data serving as the base of the NC program from the storage device 50 and the numerical value of the machining condition created and selected by the machining plan display means 845. Create an NC program by assigning control codes and the like.

FIG. 4 is a flow chart showing an embodiment of a method for setting machining conditions in die-sinking electric discharge machining according to the present invention. FIG. 5 is an example of a machining condition file, FIG. 6 is an example of a machining condition-reduction amount file, and FIG. 7 is an example of a machining plan table. Further, FIG. 8 is a perspective view of a certain tool electrode and a plan view of the tool electrode as viewed from below, and FIG. 9 is a graph showing a discharge area corresponding to a unit machining depth position in the tool electrode shown in FIG. 10 is a graph showing a machining depth position corresponding to a unit discharge area in the tool electrode shown in FIG. 8, and FIG. 11 is a cross-sectional view showing a relationship between dimensions of the tool electrode and a workpiece. Hereinafter, with reference to FIGS. 3 to 11, an example of a specific process of the method for setting the processing conditions according to the present invention will be described.

The basic data required for the processing condition setting system are as follows. Required surface roughness and reduction amount Combination of tool electrode and workpiece material Processing shape or tool electrode shape and dimensions Combination of multiple processing conditions Combination of multiple reduction amounts and processing conditions

A desired finished surface roughness as data of required machining characteristics is input by an operator. As shown in FIG. 11, the finished surface roughness is the height of the peak schematically shown on the bottom surface and the side surface, and a numerical value is input. The machining shape accuracy is affected by factors related to the discharge gap, such as the reduction amount and the liquid treatment method. The reduction amount is basically input by the operator, but the method of the present invention does not necessarily require the input by the operator.

The combination of the material of the tool electrode and the workpiece is C
When included in the attribute data given to the solid model obtained when the tool electrode is designed using AD, the data acquisition means 841 is the data analysis means 821.
To the storage device 50 by the data analysis means 821.
It is obtained by being extracted from the attribute data stored in. When the combination of the material of the tool electrode and the material of the workpiece is not included in the attribute data, the operator selects and sets from some candidates displayed on the display device 70. It is understood that the above data is data input by the operator, and that the numerical control power supply device of the present invention requires very little data to be input by the operator.

Since the attribute data includes the dimensions, names and definitions necessary to restore the solid model, the three-dimensional shape and dimensions of the tool electrode can be obtained by obtaining the attribute data of the solid model of the tool electrode. To be Further, when the solid model of the tool electrode and the die is designed by CAD, the reduction amount is calculated by obtaining the difference between the size of the tool electrode and the size of the machined hole.

The data of a combination of a plurality of processing conditions is generally called a processing condition file. Since the combination of the processing conditions is related to the specifications of the processing power supply unit and includes know-how, the processing condition file is created by the operator of the manufacturer and is stored in the storage device 50 in advance through the reading device 32. . In the processing condition file, a worker inputs a value from the operating device 31 to add a new processing condition combination, delete an unnecessary processing condition combination, or change a parameter value. You can modify the file.

The processing condition file data shown in FIG. 5 stores a combination of a maximum of 1000 kinds of processing conditions from C000 to C999, using the processing condition number data, which is the alphabet C with a 3-digit number, as an identifier. Can be kept. The data of this identifier matches the C code of the NC program and is used to read the data of the combination of the predetermined machining conditions from the NC program. In addition, according to the data of this identifier, for example, the data of C100 to C199 is determined in advance as the combination of the processing conditions of the low wear processing when the tool electrode is copper and the workpiece is steel, and the combination of the processing conditions is set in advance. The data of can be saved corresponding to the processing purpose. In addition, the value of each processing condition is shown by the value of a parameter instead of a real value.

Data of a combination of a plurality of reduction amounts and processing conditions is created by the operator of the manufacturer as a processing condition-reduction amount file and stored in the storage device 50 for the same reason as the processing condition file. . As shown in FIG. 6, the processing condition-reduction amount file is data in which the reduction amount and the switching method of the processing conditions in each processing process are accumulated. The processing condition-reduction amount file exists for each desired combination of the surface roughness, the material of the tool electrode and the material of the workpiece, and several files form a single database. In this embodiment, the value of the parameter of the machining current is adopted as the machining condition.

The worker has an NC program creation support means 84.
To input at least the finished surface roughness numerically, and if necessary, the combination of the reduction amount, the tool electrode and the material of the workpiece, and the LCD of the display device 70 by the touch panel of the operation device 31. The button displayed on is operated (S1). The data acquisition unit 841 operates the surface model creation unit 822, and the surface model creation unit 822 reads out the attribute data given to the solid model of the predetermined tool electrode from the storage device 50, and for each unit machining depth position. A surface model of the tool electrode is created, and attribute data is given to the obtained surface model (S2).

When a surface model is created from a solid model and attributes are given, there are several calculation methods. Basically, the solid model of the tool electrode is divided at a predetermined machining depth position based on the data of the three-dimensional shape of the tool electrode and the unit machining depth position, and the surface model is reconstructed from the attribute data of the solid model. Define and get a given dimensional value. The unit machining depth is arbitrary, but it is considered that 0.5 μm to several μm is preferable because the smaller the unit working depth, the more accurately the change in the discharge area can be obtained. However, a high-performance microprocessor is required,
Even so, the calculation time becomes considerably long. Therefore,
It is preferable that the realistic unit processing depth in the system for setting the processing conditions of the numerical control power supply device is about 5 μm to 1000 μm. In FIG. 9, the unit working depth is 5 mm for convenience of description.

Next, the discharge area calculation means 823 obtains the surface area of the tool electrode for each unit working depth based on the attribute data given to each surface model obtained by the surface model creation means 822. The surface area of the surface model corresponds to the discharge area at each unit machining depth position. These discharge areas are stored in the storage device 50 as sampling data (S3). The surface area and volume of the surface model can be calculated based on the idea of forming an aggregate of Voxel (Volume Cell). However, this calculation method is not the only method for calculating the discharge area and volume, and other calculation methods such as an approximation method can be used.

Next, the switching position setting means 824 reads the sampling data of the discharge area from the storage device 50 to obtain the machining depth position corresponding to the unit discharge area. For example, as shown in FIG. 10, discharge area calculation means 823
By taking the value of the discharge area with respect to the unit machining depth position obtained in the above, the machining depth position with respect to the value of the discharge area is inversely calculated by the approximation method (S4). The embodiment uses the Newton-Raphson method and the iterative method. Since this calculation method gradually approaches the required value and calculates a more accurate approximation value at a certain place, the calculation time is shorter than that obtained by one approximation method and the tool electrode is used. You can find places where there are sudden changes, such as when there is a step in. For convenience of explanation, FIG. 10 shows that the machining depth position is obtained for each 50 mm ² of the discharge area, but the method of determining the predetermined discharge area is arbitrary.

The switching position setting means 824 requires the machining depth position Z1 with respect to the top surface and the machining depth position Z11 with respect to the bottom surface as essential machining condition switching positions, and the other machining condition switching positions are obtained by calculation. The machining depth positions Z2, Z3, ... Also,
The switching position setting means 824 of this embodiment sets the processing depth position where it is determined that there is a step as the processing condition switching position. By this calculation process, basically, the machining depth position corresponding to the change of the predetermined discharge area can be set as the machining condition switching position, and the three-dimensional shape of the tool electrode is complicated and the discharge area is complicatedly changed. Even in this case, the processing conditions can be switched appropriately. This can be understood by comparing FIGS. 9 and 10.

Further, the method of calculating the machining depth position corresponding to the predetermined discharge area by the sampling data of the discharge area with respect to the unit machining depth position and setting it as the machining condition switching position is as follows: The number of corresponding discharge area data can be reduced. In the process of generating the surface model and calculating the discharge area, the load on the arithmetic unit 80 is heavy considering the amount of data for each surface model and the number of surface models.
There is an advantage that the time required for the calculation process for setting the switching position of the appropriate processing condition is reduced to the time that can be practically executed.

However, if it is required to more precisely determine the machining depth position corresponding to the predetermined discharge area,
There is a concern that it is necessary to increase the number of data to be sampled, in other words, to reduce the value of an arbitrary unit machining depth position. However, since the switching of the initially set machining conditions depends on the capability of the die sinking electric discharge machine itself, a slight error does not cause much problem. In particular, when performing electric discharge machining with a machining power supply device that employs a non-energizing electric discharge machining circuit with switching transistors, which is the mainstream of the die-sinker electric discharge machine, supply it to a machining gap that the machine can perform. Since the real value with respect to the value of the parameter of the obtained machining current has a certain range, there is little benefit in setting the position where the initial machining conditions are switched so as to correspond to a slight error.

Next, the machining current calculating means 843 sequentially operates the switching positions Z11 from the switching position Z11 on the basis of the bottom surface.
The value of the parameter of the machining condition of the machining current suitable for the rough machining step of n is set based on the maximum average current density. The maximum average current density differs depending on the combination of the material of the tool electrode and the material of the workpiece and the specifications of the power supply circuit for processing, and is therefore calculated based on a program that defines some setting processes. The maximum average current density (A) is a value obtained by multiplying the discharge area (mm ² ) by the current density per unit area (A / mm ² ). For example, when the tool electrode is copper and the workpiece is steel. The current density per unit area in the case of a rectangular wave discharge current pulse is 0.1 to 0.15 A / mm ² . In the die-sinking electric discharge machine, the value of the machining current actually supplied to the machining gap corresponding to the value (IP) of the predetermined machining current parameter is measured and calculated. The value of the parameter of the machining condition of the machining current suitable for each switching position in the rough machining process can be obtained. The value of this parameter is stored in the storage device 60 together with the maximum average current density (S5).

If the reduction amount has already been given, the processing condition setting means 842 is provided from the processing condition-reduction amount file corresponding to the specific tool electrode and the material of the workpiece. Based on the reduction amount, the desired machining surface roughness, and the parameter value of the machining current at the machining depth position with respect to the bottom surface reference of the rough machining process, which is obtained by the machining current calculation unit 843. The data of the combination of the values of the parameters is extracted from the storage device 50. Processing condition-If there is no data that exactly matches the reduction amount in the reduction amount file, the closest value may simply be retrieved. Also, if the reduction amount is not given,
Machining condition-One or more data corresponding to desired machining surface roughness and machining current parameter values obtained by the machining current calculating means 843 within a range of possible reduction amount from the reduction amount file. Extract (S6).

The estimated machining time calculating means 844 calculates the estimated machining time from the parameter value of the machining current in each machining process obtained by the machining condition setting means 842. The estimated processing time estimated by the calculation is the sum of the times obtained by dividing the removal amount (mm ³ ) by the volume processing speed (mm ³ / min) and multiplying the processing efficiency (min) in each processing step. The machining efficiency is a correction value that has already been obtained through experience, and is considered because the machining time actually required for electric discharge machining varies depending on the machine. Referring to FIG. 11, the removal amount in the rough machining step corresponds to a value obtained by adding the volume corresponding to the machining gap to the volume of the tool electrode, and the removal amount in the subsequent machining steps is removed by each machining step. Since it corresponds to the power surface roughness, the removal amount is the data of the overcut, the feed amount, the surface roughness, the swing amplitude, and the remaining margin of each machining process from the dimension value obtained from the attribute data given to the solid model. Is calculated. Calculated overcut, feed amount, surface roughness,
The swing amplitude, the data of the remaining margin, and the estimated machining time are temporarily stored in the storage device 60 (S8).

The processing condition setting means 842 retrieves and acquires data of a combination of processing conditions suitable for the parameter value of the processing current from the processing condition file. If no completely matching data exists in the processing condition file, the closest value may simply be retrieved. Further, a known method of retrieving and acquiring an approximate value such as determining the value by a calculation method based on the fuzzy theory or neural network theory can be adopted (S9).

The machining condition setting means 842 creates an oscillating shape suitable for the shape of the tool electrode obtained from the attribute data from the NC program creating tool file, or selectively sets it from the basic shape. Further, the processing condition setting means 842 selectively sets the jump condition and method and the liquid processing method suitable for the shape of the tool electrode from the basic data stored in the storage device 50.

The machining plan display means 845 is based on the data obtained by the machining condition setting means 842, the estimated machining time calculation means 844, and the relative movement value calculation means 846, and one or more machining plan tables as shown in FIG. Is created, and the data of the machining plan table is given to the drawing data creating means 824 and displayed on the display device 70. When a plurality of machining plan tables are displayed, the operator selects one of the machining plan tables, but basically, the one whose estimated machining time is short is selected (S1).
0).

When the operator looks at the machining plan table displayed on the display device 70 and operates the operation device 31 to input a value as necessary, the machining condition setting means 842 processes the machining already created. The value on the planning table is changed. In this way, when the operator appropriately corrects the processing conditions, the swing shape, the parameter values such as the jump of the tool electrode, etc.,
When a machining condition number composed of the alphabet C and a three-digit number is newly given, the data of this machining condition combination is added and stored in the machining condition file stored in the storage device 60. The setting of the processing conditions is completed by the above work.

Further, the operator makes N based on the machining plan table.
When the user desires to create a C program, the buttons displayed on the display device 70 are operated using the touch panel of the operation device 31. The relative movement value calculation means 846 obtains data relating to dimensions such as the feed amount and data relating to relative movement such as the assigned rocking shape from the data of the machining plan table already stored in the storage device 50. Then, the relative movement amount of the tool electrode in the machining depth direction and the side surface direction is calculated (S1).
1).

Then, NC program creating means 847
Is the relative movement value obtained by the relative movement value calculation means 846 by extracting the base data of the NC program for die-sinking electric discharge machining and the necessary NC code data from the NC program creation tool file stored in the storage device 50. An NC program is created by assigning a quantity and a machining condition number. The created NC program data is given to the drawing data creating means 814 and displayed on the display device 7.
0 is displayed (S12). The operator can operate the operating device 31 to modify the NC program, and can store the data in the storage device 50 by adding a data file name and selecting save, or through the recording device 33. Can be recorded on media.

In the machining condition setting system of this embodiment, the machining conditions for the rough machining process are set in accordance with changes in the discharge area. However, the machining condition setting system of the present invention can set the machining conditions adapted to the discharge area even in other machining steps, and although it is not as effective as the rough machining step, it is still useful. is there.

For example, in the case where the tool electrode has a stepped shape, the machining conditions suitable for machining are different between the case where electric discharge machining is performed at a stepless place and the case where electric discharge machining is performed at a stepped place. . Therefore, when electric discharge machining is performed in one machining process under a machining condition that is one safe value, a leftover is formed especially at a step, and the machining time becomes long and desired machining shape accuracy cannot be obtained. is there. In such a case, the processing time is shortened by applying the processing condition setting method of the present invention so as to switch the processing conditions in accordance with the change in the discharge area.
Alternatively, it is expected to improve the precision of the processed shape.
However, in the machining process in which electrical discharge machining is performed under relatively small machining conditions, the range of machining current parameters that can be initialized is relatively narrow, so it can be selectively adopted according to the shape of the solid model of the tool electrode. preferable. Further, it is possible to employ a system for adaptively controlling the average machining current value corresponding to the machining depth position.

In order to automatically perform the process of selectively changing the initial setting of the machining conditions adapted to the discharge area corresponding to the solid model of the tool electrode, for example, the memory device 50 can be preliminarily provided with a specific base. A system in which a solid model is registered and a given solid model and a basic solid model are compared by an approximate calculation can be considered. In this case, the NC program creation support means 84 of the arithmetic unit 80 is provided with a three-dimensional shape comparison means having this arithmetic process.

Further, in order to configure the system for adaptively controlling the average machining current value in accordance with the machining depth position, for example, the current in the electric discharge machining circuit in the machining power supply circuit in the machining power supply unit can be set. A device capable of continuously adjusting the value or a device capable of adjusting the base current value of the switching element is provided. At the same time, the NC program creation support means 84 of the arithmetic unit 80 is read by the R
A current value adjusting means for changing the set value stored in the AM is provided. The machining current value is the machining current calculation means 84.
3 is used and the data stored in the storage device 60 is used. With such a configuration, the machining conditions initially set so that the machining current value calculated corresponding to the predetermined machining depth position is supplied are calculated as the average machining current value based on the discharge area data calculated little by little. Allows to adjust according to.

The processing condition setting system of the embodiment is
Also, the discharge area to be sampled is calculated by calculating the surface area of the surface model of the tool electrode, but this calculation process can be replaced by calculating the projected area from the solid model of the tool electrode. . This replaced calculation process is not suitable as compared with the process of calculating the discharge area by calculating the surface area of the surface model in that the discharge area itself is accurately calculated. In the processing condition setting system of the present invention, which switches appropriate initial setting processing conditions corresponding to, there is still a practical advantage.

The process of calculating the discharge area to be sampled by the projected area can be realized by the following calculation method, for example. FIG. 8 shows a plan view of a certain tool electrode as viewed from below. First, the sectional shape and size of the tool electrode having the largest area can be obtained from the attribute data given to the solid model of the tool electrode. According to the dimension of the cross-sectional shape having the largest area, 0.4 mm to 0.
A plot is provided every 8 mm, and a vertical line (Ray) is provided for each plot.
Down and calculate the intersection with the horizontal plane where the cross section is cut. The lengths of the vertical lines from the plot to the intersection are calculated, and the vertical lines are accumulated. Then, the projected area at the predetermined processing depth position is approximately calculated by the number of perpendiculars existing at the predetermined processing depth position. The plot interval is arbitrary, but an appropriate value is determined depending on the time required for calculation and the accuracy of the projected area to be obtained. This calculation process
This can be achieved by configuring the discharge area calculation means 824 of the three-dimensional data management means 82 of the arithmetic unit 80 to calculate the surface area and selectively execute it.

Modifications, combinations, and additions are possible without departing from the technical idea of the present invention described above. Examples of changes, combinations and additions in the embodiments have already been described. Further, the machining condition setting system in the die-sinking electric discharge machining of the present invention can be selectively adopted in combination with a known machining condition setting system depending on the shape of the solid model of the tool electrode. Even at this time, the operator does not need to input the data of the desired tool electrode, which is still useful.

[0095]

As described above, according to the machining condition setting method for die-sinking electric discharge machining of the present invention, the machining depth positions corresponding to a plurality of predetermined electric discharge areas are obtained to switch the machining conditions. Since the position is set, the machining conditions suitable for the discharge area at the machining depth position are set even if the shape of the tool electrode is complicated. As a result, it is expected that the machining speed will be faster and the finished surface roughness will be more uniform in the rough machining process, or the machining time accuracy in each machining process can be shortened and the machining shape accuracy can be stabilized, and the overall discharge This has the effect of improving the efficiency of the processing process.

Further, according to the numerical control power supply device of the die-sinking electric discharge machine of the present invention, the switching position of the machining conditions suitable for the electric discharge area is set, and the effect of improving the efficiency of the whole electric discharge machining process is obtained. Play. Also, since the attribute data given to the tool electrode or the solid model of the machining shape designed by the designer is used, the operator calculates sampling data of the discharge area corresponding to a large number of machining depth positions, and it is appropriate from the discharge area. Since it is not necessary to perform the difficult work of setting the switching position of various machining conditions and it is not necessary to input the data of the tool electrode for calculation, the burden on the operator is reduced.

[Brief description of drawings]

FIG. 1 is a front view showing the general outline of a die-sinking electric discharge machine.

FIG. 2 is a three-dimensional configuration diagram showing an embodiment of a numerical control power supply device of a die-sinking electric discharge machine of the present invention.

FIG. 3 is a block configuration diagram showing details of a part of the numerical control power supply device of the die sinking electric discharge machine of the present invention.

FIG. 4 is a flowchart showing an embodiment of a method of setting machining conditions in die sinking electric discharge machining of the present invention.

FIG. 5 is a diagram showing an example of a processing condition file.

FIG. 6 is a diagram showing an example of a processing condition-reduction amount file.

FIG. 7 is a diagram showing an example of a processing plan table.

8A and 8B are a perspective view of a tool electrode and a plan view of the tool electrode seen from below in the working example shown in FIG.

9 is a graph showing a discharge area corresponding to a unit machining depth position in the tool electrode shown in FIG.

10 is a graph showing a machining depth position corresponding to a unit discharge area in the tool electrode shown in FIG. 8 and a diagram showing an example of calculation of a discharge area by an approximation method.

FIG. 11 is a cross-sectional view showing a relationship between dimensions of a tool electrode and a workpiece.

FIG. 12 is a cross-sectional view of a tool electrode and a workpiece showing a machining example.

13 is a graph showing a discharge area corresponding to a unit machining depth position in the machining example shown in FIG.

[Explanation of symbols]

30, input / output device 31, operating device 32, reader 33, recording device 40, communication device 50, storage device 60, storage device 70. Display device 80, arithmetic unit 81, system management means 82, three-dimensional data management means 821, data analysis means 822, Surface model creating means 823 Discharge area calculation means 824, switching position setting means 83. Numerical control management means 84, NC program creation support means 841, data acquisition means 842, processing condition setting means 843 Processing current calculation means 844, Estimated processing time calculation means 845 Processing plan display means 846, relative movement value calculation means 847, NC program creating means

Claims (2)

[Claims] 1. A method of setting machining conditions in die-sinking EDM for setting a combination of machining conditions suitable for required machining characteristics, wherein attribute data given to a three-dimensional shape model of a tool electrode in desired EDM is used. A step of storing, a step of storing machining characteristic data including at least a desired finished surface roughness, and a step of calculating discharge areas at a plurality of predetermined machining depth positions predetermined based on the attribute data And a step of obtaining discharge area sampling data based on the calculated discharge area, and a machining depth position corresponding to a plurality of predetermined discharge areas predetermined based on the sampling data as a machining condition switching position. Calculate the machining current value suitable for the discharge area at the switching position and obtain the machining current value. A method of setting a machining condition for die-sinking electrical discharge machining, comprising: selecting and setting a suitable combination of machining conditions from a plurality of combinations of machining conditions stored in advance; 2. A numerical control power supply device for a die-sinking electric discharge machine that sets a combination of machining conditions suitable for required machining characteristics, data of a combination of a plurality of machining conditions, and a tertiary of a tool electrode in a desired electric discharge machining. A storage device that stores attribute data given to the original shape model and data relating to machining characteristics including at least a desired surface finish roughness, and discharges at predetermined machining depth positions predetermined based on the attribute data. A discharge area calculating means for calculating the area and obtaining sampling data of the discharge area, and a switching position setting means for obtaining a machining depth position corresponding to each predetermined discharge area predetermined based on the sampling data as a machining condition switching position. A machining current calculating means for calculating a machining current value suitable for the discharge area at the switching position, and an addition device adapted for the machining current value. Numerical control of a die-sinking electric discharge machining apparatus comprising: a processing condition setting means for selecting and setting a condition combination from a plurality of machining condition combinations stored in the storage device. Power control device.