JP4017292B2 - Machining condition setting method and apparatus for electric discharge machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a machining condition setting method and apparatus for an electric discharge machine, and in particular, between an electrode and a workpiece in a machining liquid filled in a machining tank or in a machining liquid in which powder is mixed in the machining liquid. The present invention relates to a machining condition setting method and apparatus for an electric discharge machine that applies a pulse voltage to the workpiece and processes the workpiece while relatively moving the electrode and the workpiece.
[0002]
[Prior art]
In general, in order to improve machining efficiency and machining accuracy in electrical discharge machining, the workpiece is first machined under the desired rough machining conditions, and then the machining energy is changed (reduced) in several stages, including the medium machining conditions and finishing machining conditions. However, the workpiece is finished so that a desired processing dimension and surface roughness can be obtained. This machining energy is determined by the product of the peak value of the machining current supplied between the electrode and the workpiece and the pulse width. However, it is difficult to reduce the machining current pulse width. By reducing the peak value, small energy is obtained in the finishing process. Further, in the finish machining, the distance between the electrode and the workpiece during the electric discharge machining, that is, the so-called discharge gap is made minute so that stable electric discharge machining can be obtained between the electrode and the workpiece with a small machining energy. Normally, in an electric discharge machine, a pulse voltage is applied from the machining power supply between the electrode and the workpiece, and when the distance between the electrode and the workpiece becomes small due to relative movement between the electrode and the workpiece, Electric discharge is generated between the electrodes and processing is performed.
[0003]
Various techniques for improving the machining accuracy of a workpiece machined by such an electric discharge machine have been proposed. For example, in Japanese Patent No. 2667183, an electrode is fed to a workpiece from a predetermined position in a predetermined depth direction, and the workpiece is processed while controlling the electrode feed in the order of a series of machining steps from roughing to finishing. In addition, there is disclosed a machining error correction control method in die-sinking electric discharge machining that improves machining accuracy by correcting machining errors that occur during machining.
[0004]
The machining error correction control method in the sculpting electric discharge machining described in Japanese Patent No. 2667183 is intended to eliminate the alignment error before machining and the gap error during machining, thereby improving the accuracy of the electric discharge machining.
In the first machining error correction control method of the above-mentioned patent, a minute discharge is performed for a predetermined time under a gap detection condition in which a gap between an electrode and a workpiece set at a predetermined position is set to a predetermined value before the machining is started, and the position is detected. After setting the reference surface in the machining depth direction, start the prescribed machining, and then when the electrode feed reaches the specified depth during the machining from the first roughing to the end of finishing Measure the electrode position during machining in, and switch from the machining condition to the gap detection condition where the gap is a specific value, converge the gap while generating a micro discharge for a predetermined time, and then measure the electrode position at that time The amount of error in the machining gap or the amount of error in the machining depth with respect to the predetermined value at the time of machining planning is calculated from the amount of change in both measured values, and then the electrode feed amount is controlled so as to correct the error amount. To resume machining That.
[0005]
In the second machining error correction control method of the above-mentioned patent, after setting the reference surface in the same manner as described above, predetermined machining is started, and thereafter, in the process of steps from the first rough machining to the end of finishing machining. After the electrode position in the depth direction reaches the specified target value and finishes the processing of that step, after switching to the gap detection condition where the gap becomes a specific value and converging the gap while generating a minute discharge for a predetermined time Measure the electrode position at that time, find the depth after machining of the step from the measured value, calculate the error amount of the machining depth at the time of machining planning, and corrective processing is necessary from this calculation result If it is determined, the machining is performed by controlling the electrode feed amount so as to correct the error amount.
[0006]
On the other hand, various techniques related to a machining end determination method in electric discharge machining have been proposed. For example, in the electric discharge machining method described in Japanese Patent No. 2717474, the end of machining is determined when a specified time has elapsed from the start of machining, and only the actual machining time during discharge between the electrode and the workpiece is determined. With the time management function that finishes machining when the specified time is reached, machining is performed without excess or deficiency.
[0007]
[Problems to be solved by the invention]
Generally, from at least one of the material of the electrode used for electric discharge machining, the material of the workpiece, the applied voltage between the electrodes and the workpiece, the relative movement speed between the electrode and the workpiece, and the surface roughness of the workpiece. In electrical discharge machining with the same machining conditions, the larger the discharge area between the electrode and the workpiece, the smaller the amount of machining waste per unit volume in the machining fluid interposed between the electrode and the workpiece, Since the electrical insulation degree between an electrode and a workpiece | work becomes small, a discharge gap becomes small and electrode consumption increases. As a result, there is a problem that unprocessed parts are left, the processing dimensions are reduced, reworking is required, and the processing time is increased.
[0008]
In addition, the electrode and workpiece are mixed in a powder-mixed working fluid in which a carbon-based material such as graphite, a metal such as chromium, or a semi-metallic conductive powder such as silicon is mixed in a normal working fluid such as oil. There is an electric discharge machining method in which finishing is performed while interposing the above powder between the two. In this case, in electric discharge machining with the same machining conditions, the higher the concentration of the powder mixed in the machining fluid, the greater the amount of powder per unit volume in the machining fluid interposed between the electrode and the workpiece. As a result, the degree of electrical insulation between the electrode and the workpiece increases, so that there is a problem that the discharge gap increases, the actual machining allowance becomes excessive, and the machining dimension increases, resulting in machining failure.
[0009]
FIG. 7 is a diagram showing an example of a workpiece machining defect according to the conventional technique when the powder concentration is high. When excessive processing occurs when the concentration of the powder is high, as shown in FIG. 7, there is a problem that a sagging 701 occurs at the inlet and the squareness becomes worse.
The machining error correction control method in the sculpting electric discharge machining described in the above-mentioned Japanese Patent No. 2667183 is a machining in which machining is left behind as the discharge area is larger, and machining is more excessive as the concentration of powder mixed in the machining liquid is higher. There is no disclosure about the problem of accuracy and the problem of a decrease in machining efficiency due to an increase in machining time corresponding to the remaining machining.
[0010]
In addition, by using the time management function in the electric discharge machining method described in the above-mentioned Japanese Patent No. 2717474, in the method of terminating machining before the electrode feed reaches a specified depth, eliminating machining excess and reducing machining time Depending on the discharge area and / or the concentration of the powder mixed in the machining liquid, the operator must set the machining time set value to be shortened for each machining condition. There is a problem that skill level is required, and individual differences of operators affect processing accuracy.
[0011]
Therefore, the present invention solves all the above-mentioned problems, and considers the discharge area or the concentration of the powder mixed in the machining liquid in the electric discharge machining with the same machining conditions, and repeats the specified finishing machining. An object of the present invention is to provide a machining condition setting method and apparatus for an electric discharge machine that finishes machining at a time without requiring machining and improves machining accuracy and machining efficiency.
[0012]
[Means for Solving the Problems]
The machining condition setting method of the electric discharge machine according to the first embodiment of the present invention that achieves the above object is to apply a pulse voltage between the electrode and the workpiece in the machining liquid filled in the machining tank, and In the machining condition setting method of the electric discharge machine that processes the workpiece while relatively moving the electrode and the workpiece, Read the discharge area of the electrode input by the input means, For the discharge area of the electrode Against Leftover amount of processing Is calculated from experimental data indicating a proportional relationship with the discharge area of the electrode. Set the machining depth or rocking radius by increasing the machining remaining amount. Ruko And features.
[0013]
The machining condition setting device for an electric discharge machine according to the first embodiment of the present invention that achieves the above object applies a pulse voltage between the electrode and the workpiece in the machining liquid filled in the machining tank, and In the machining condition setting device of the electric discharge machine that processes the workpiece while relatively moving the electrode and the workpiece, Read the discharge area of the electrode input by the input means, For the discharge area of the electrode Against Leftover amount of processing Is calculated from experimental data indicating a proportional relationship with the discharge area of the electrode. Further, the present invention is characterized by comprising a relative movement amount setting means for setting the processing depth or the rocking radius by increasing the amount of the processing remaining amount.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic block diagram showing an embodiment of an electric discharge machine having a machining condition setting device according to the present invention. FIG. 1 shows a sculpting electric discharge machine that applies a pulse voltage from a machining power supply 5 between electrodes 1 and a workpiece 3 and processes the workpiece 3 by generated electric discharge. The workpiece 3 is placed in a processing tank 7 provided on the XY moving table 9. The workpiece 3 is immersed in a processing liquid filled in the processing tank 7 and mixed with powder of a conductive material. Although not shown, the processing liquid is supplied from the processing liquid tank through a supply pipe such as a hose to the processing tank 7 by the processing liquid supply pump, and the used processing liquid in the processing tank 7 is provided in the processing tank 7. From the exhaust port, it is circulated between the processing tank 7 and the processing liquid tank so as to be collected and stored in the processing liquid tank through a discharge pipe such as a hose.
[0018]
The machining power source 5 has a search power source used to ignite the discharge between the electrodes and a main power source for supplying electric discharge machining energy. An applied voltage from the machining condition setting means 19 to the electrodes, τON (discharge time) ), ΤOFF (resting time) and the like, and a pulse voltage is supplied between the electrode 1 and the workpiece 3 in accordance with these parameters.
[0019]
The XY movement table 9 moves in the X-axis and Y-axis directions by driving the X-axis servomotor 11 and the Y-axis servomotor 13, respectively. As a result, the workpiece 3 is moved in the XY-axis direction or is swung as necessary. On the other hand, the electrode 1 is held by a main shaft (not shown), and moves together with the main shaft in the Z-axis direction by driving a Z-axis servo motor 15 attached to a column (not shown). Thereby, the positioning of the electrode 1 in the Z-axis direction during non-electric discharge machining and the control of the inter-electrode distance (discharge gap) during electric discharge machining are performed. The X-axis servo motor 11, the Y-axis servo motor 13 and the Z-axis servo motor 15 each have an encoder (not shown), and a signal indicating the rotation angle of the X, Y and Z-axis motors to the servo control means 17, That is, the position signals of the electrodes 1 in the X, Y, and Z axis directions are fed back.
[0020]
The servo control means 17 sends servo outputs to the X-axis feed motor 11, the Y-axis feed motor 13 and the Z-axis feed motor 15 based on the control data from the NC program, and the electrode head (not shown) of the electric discharge machine. And for controlling the movement of the spindle on which the electrode 1 is mounted.
The Z-axis feed motor 15 controlled by the servo control means 17 moves the electrode 1 mounted on the main shaft moving in the electrode head in the machining progress direction. In other words, it is a servo motor that feeds or retracts the workpiece 3, and the X-axis feed motor 11 and the Y-axis feed motor 13 are configured so that the electrodes 1 mounted on the spindle are mutually connected in a plane perpendicular to the machining progress direction. This is a servo motor that moves in the direction of two axes perpendicular to the axis. In this way, by combining the movements by the X-axis feed motor 11 and the Y-axis feed motor 13, the electrode 1 can be moved in a two-dimensional swing relative to the work 3. The electrode 1 can be moved relative to the work 3 in a three-dimensional swinging manner by combining the movements by the Y-axis feed motor 13 and the Z-axis feed motor 15. As described above, the electric discharge machining apparatus of the present invention interposes the powder between the electrode 1 and the workpiece 3 in the machining liquid and performs relative movement between the electrode 1 and the workpiece 3 as needed. The workpiece 3 is subjected to electric discharge machining by giving a swing motion.
[0021]
The machining condition setting means 19 sends XY axis control parameters for moving the XY movement table 9 in the X-axis and Y-axis directions to the table feed control means 21, while Z for moving the electrode 1 in the Z-axis direction. The axis control parameter is sent to the electrode feed control means 23.
The data input unit 25 is a unit for inputting various data to the machining condition setting unit 19 and includes a keyboard, a CRT, and the like (not shown).
[0022]
The machining condition setting means 19 is based on the input data from the data input means 25 and the inter-pole state signal received from the inter-pole state detection means 27, and parameters for the machining power source necessary for machining the workpiece 3 and control to each servo motor. Set the parameters.
The processing condition setting means 19 can also read a processing program read by a paper tape reader or floppy disk drive (FDD) (not shown) for each block.
[0023]
The inter-electrode state detection means 27 indicates that the inter-electrode state between the electrode 1 and the workpiece 3 has not yet started discharging after applying the search voltage between the processing power source 5 or the short-circuit state, or It has a function of detecting whether it is an effective discharge state or an abnormal discharge state after the main voltage is applied between the electrodes. The machining condition setting unit 19 receives the inter-electrode state signal from the inter-electrode state detection unit 27 and sends the above-described machining power source parameters suitable for processing to the machining power source 5.
[0024]
The inter-electrode state detection unit 27 detects a state between the electrodes by detecting a pulse voltage applied between the electrodes 1 and the workpiece 3, and sends, for example, an average voltage between the electrodes to the calculator 29.
The arithmetic unit 29 sends a signal indicating a deviation amount, which is a difference between the detection amount received from the inter-electrode state detection unit 27 and the target reference value received from the machining condition setting unit 19, to the electrode feed control unit 23. The electrode feed control means 23 outputs the advance / retreat amount of the electrode 1 to the servo control means 17 based on the Z-axis control parameter sent from the machining condition setting means 19 and the error amount sent from the calculator 29.
[0025]
The machining depth correction value calculation means 31 receives the data of the discharge (machining) area of the electrode 1 that performs the current machining input from the data input means 25 before the start of the electric discharge machining of the predetermined workpiece 3, and the machining depth in advance. From the table shown in FIG. 2, which will be described later, stored in the correction value storage means 33, a set value of the machining depth corresponding to the machining conditions, that is, data for calculating the feed amount in the Z-axis direction (bottom surface remaining amount) is read. Then, the machining depth set value is calculated, and the target reference value sent from the machining condition setting means 19 to the calculator 29 is replaced with the calculated machining depth set value. Here, the target reference value is a set value of the machining depth calculated by the machining condition setting means 19 according to the machining conditions based on the table shown in FIG. 2 stored in the machining depth correction value storage means 33. That is.
[0026]
The oscillating radius correction value calculating means 35 receives the data of the discharge (machining) area of the electrode 1 to be processed this time, which is input from the data input means 25 before the start of the electric discharge machining of the predetermined workpiece 3, and previously oscillates the radius. From the table shown in FIG. 2 stored in the correction value storage means 37, data for calculating the set value of the rocking radius according to the machining conditions, that is, the rocking radius in the X-axis and Y-axis directions (side surface remaining amount). , The set value of the rocking radius is calculated, and the XY axis control parameter sent from the machining condition setting unit 19 to the table feed control unit 21 is corrected with the calculated set value of the rocking radius. Here, the XY axis control parameter is the set value of the swing radius calculated by the processing condition setting unit 19 according to the processing conditions based on the table shown in FIG. 2 stored in the swing radius correction value storage unit 37. This is a control parameter for moving the XY movement table 9 obtained from the above in the X-axis and Y-axis directions.
[0027]
The electric discharge machining control apparatus 100 that performs the functions of the respective means described above includes, for example, a CPU, ROM, RAM, B (battery backup) RAM, various input interfaces, and various output interfaces connected to each other by a bidirectional bus (not shown). It is configured as a provided microcomputer system. A keyboard and an A / D converter are connected to the input interface. For example, an analog voltage between the electrodes is input to the A / D converter at a low level via an attenuator and is converted into digital data. A display device such as a CRT, a printer, a D / A converter, and the like are connected to the output interface.
[0028]
Next, a method for calculating the set values of the machining depth and the rocking radius will be described below.
FIG. 2 is a diagram showing a table of data set in advance according to the machining conditions in order to calculate the set values of the machining depth and the rocking radius. The machining conditions are selected from at least one of the following: electrode material, workpiece material, applied voltage between the electrode and workpiece, relative movement between the electrode and workpiece, and workpiece surface roughness. . In the example shown in FIG. 2, the surface roughness of the work surface of the workpiece is selected as the processing condition, and data for the processing conditions of numbers 1 to 4 is stored in the table. The surface roughness under each processing condition is 60 μm Rmax when the processing condition number is 1, 40 μm Rmax when the processing condition number is 2, 20 μm Rmax when the processing condition number is 3, and 10 μm Rmax when the processing condition number is 4. The table shown in FIG. 2 indicates that a total of four finishing processes are performed in the order of the processing condition numbers 1 to 4 under the four processing conditions. The table shown in FIG. 2 stores the bottom surface remaining amount and side surface remaining amount corresponding to the processing condition numbers 1 to 4. Next, the bottom surface remaining amount and the side surface remaining amount will be described below.
[0029]
FIG. 3 is a diagram showing an example of finishing. The processing depth D is the distance in the feed axis (Z-axis) direction of the electrode from the upper surface 301 of the workpiece to the processed surface 302 of the workpiece after finishing. A value obtained by subtracting the bottom surface remaining amount G1 from the processing depth D is a set value of the processing depth in the finishing processing. For example, when the processing depth is 5 mm and the processing condition number is 1 shown in FIG. 2, when the discharge area and the concentration of the powder mixed in the processing liquid are ignored, the set value of the processing depth is 5 to 0.28. = 4.72 mm, and in the case of the machining condition number 2, the set value of the machining depth is 5-0.19 = 4.81 mm.
[0030]
On the other hand, the swing radius is the amount of movement in the XY axis direction perpendicular to the Z axis. The value obtained by subtracting the remaining side surface amount from the electrode one side reduction amount G2 is the set value of the oscillation radius. For example, when the electrode one side reduction amount is 0.25 mm and the processing condition number is 1 shown in FIG. 2, when the discharge area and the concentration of the powder mixed in the processing liquid are ignored, the set value of the oscillation radius is 0. .25−0.18 = 0.07 mm, and in the case of the machining condition number 2, the set value of the swing radius is 0.25−0.13 = 0.12 mm.
[0031]
Next, a method of calculating the set values of the processing depth and the rocking radius when the density of the powder mixed in the processing liquid is ignored in consideration of the discharge area will be described below.
FIG. 4 is a diagram showing the relationship between the discharge area and the amount of machining remaining. In FIG. 4, the horizontal axis represents the discharge area, and the vertical axis represents the remaining amount of machining. If the finishing process is performed while ignoring the discharge area between the electrode 1 and the workpiece 3, the larger the discharge area, the smaller the discharge gap and the more the electrode is consumed. As described above, it becomes smaller. FIG. 4 is a diagram obtained from an experimental result showing that the remaining amount of machining increases as the discharge area increases, and these are in a proportional relationship. From this experimental result, if the remaining amount of machining corresponding to the discharge area is corrected to increase, the remaining machining in the finishing process can be almost eliminated.
[0032]
Therefore, in consideration of the discharge area, the set value of the processing depth when the concentration of the powder mixed in the processing liquid is ignored is, for example, a discharge area of 200 mm. ² When the machining depth is 5 mm and the machining condition number 1 shown in FIG. 2 is, the discharge area is 200 mm. ² 4 is 0.078 mm from FIG. 4, the processing depth setting value is 5-0.28 + 0.078 = 4.798 mm. In the case of the same processing condition number 2, the processing depth is set. The value is 5-0.19 + 0.078 = 4.888 mm.
[0033]
On the other hand, in consideration of the discharge area, the set value of the rocking radius when the concentration of the powder mixed in the machining liquid is ignored is, for example, the machining condition number shown in FIG. In the case of 1, the setting value of the rocking radius is 0.25−0.18 + 0.078 = 0.148 mm, and in the case of the same machining condition number 2, the setting value of the rocking radius is 0.25−0.13 + 0. 0.08 = 0.198 mm.
[0034]
Next, a method for calculating the set values of the processing depth and the rocking radius when the discharge area is ignored in consideration of the concentration of the powder mixed in the processing liquid will be described below.
FIG. 5 is a graph showing the relationship between the powder concentration and the discharge gap increase rate. In FIG. 5, the horizontal axis represents the concentration of the powder mixed in the working fluid, and the vertical axis represents the discharge gap increase rate. If the finishing process is performed ignoring the concentration of the powder mixed in the machining fluid, the higher the concentration of the powder mixed in the machining fluid, the larger the discharge gap, the more machining allowance, and the machining dimension I explained about the growth earlier. FIG. 5 is a diagram obtained from experimental results showing that the discharge gap increase rate increases as the powder concentration increases, and these are in a proportional relationship. From this experimental result, it can be seen that the machining allowance is excessive depending on the concentration of the powder. Therefore, if the bottom surface residual amount and the side surface residual amount are corrected so as to decrease in accordance with the concentration of the powder, it is possible to substantially eliminate the excessive processing in the finishing process. From FIG. 5, the discharge gap increase rate is 10% when the powder concentration is 1 g / l (gram / liter), and the discharge gap increase rate is 20% when the powder concentration is 2 g / l (gram / liter). Further, the correction coefficients for the bottom surface remaining amount and the side surface remaining amount are respectively set as 0.9, 0.8,... As shown in the table of FIG.
[0035]
Therefore, in consideration of the concentration of the powder mixed in the machining liquid, the set values of the machining depth when the discharge area is ignored are, for example, a powder concentration of 1 g / l and a machining depth of 5 mm. In the case of processing condition number 1 shown in FIG. 2, since the correction coefficient for the powder concentration of 1 g / l is 0.9, the setting value of the processing depth is 5-0.28 × 0.9 = 4.748 mm. When the powder concentration is 1 g / l, the processing depth is 5 mm, and the processing condition number is 2 shown in FIG. 2, the setting value of the processing depth is 5-0.19 × 0.9 = 4.829 mm. When the powder concentration is 2 g / l, the processing depth is 5 mm, and the processing condition number is 1 shown in FIG. 2, the correction coefficient for the powder concentration is 2 g / l is 0.8. The set value is 5-0.28 × 0.8 = 4.776 mm, the concentration of the powder is 2 g / l, and the processing depth is 5 mm. If the machining condition number 2, the processing depth of the setting value becomes 5-0.19 × 0.8 = 4.848mm.
[0036]
On the other hand, in consideration of the discharge area, the set value of the rocking radius when the concentration of the powder mixed in the machining liquid is ignored is, for example, a powder concentration of 1 g / l and an electrode one-side reduction amount of 0. In the case of the processing condition number 1 shown in FIG. 2 at 25 mm, the set value of the swing radius is 0.25-0.18 × 0.9 = 0.148 mm, the powder concentration is 1 g / l, and the electrode one side is reduced. In the case of the machining condition number 2 shown in FIG. 2 when the size is 0.25 mm, the set value of the rocking radius is 0.25−0.13 × 0.9 = 0.198 mm, and the concentration of the powder is 2 g / l, when the electrode one side reduction amount is 0.25 mm and the machining condition number is 1 shown in FIG. 2, the set value of the swing radius is 0.25−0.18 × 0.8 = 0.106 mm, Is 2 g / l, the machining depth is 5 mm, and the machining condition number 2 shown in FIG. 2 is 0.25 to 0.13. A 0.8 = 0.146mm.
[0037]
Next, a method for calculating the processing depth and the set value of the rocking radius in consideration of the discharge area and the concentration of the powder mixed in the processing liquid will be described below.
The processing depth setting value in consideration of the discharge area and the concentration of the powder mixed in the machining fluid is, for example, a discharge area of 20000 mm ² (100 mm × 200 mm), powder concentration is 1 g / l, processing depth is 5 mm, and processing condition number 1 shown in FIG. ² 4 is 0.078 mm from FIG. 4, and the correction coefficient for the powder concentration of 1 g / l is 0.9. Therefore, the set value of the processing depth is 5−0.28 × 0. .9 + 0.078 = 4.826 mm, when the powder concentration is 1 g / l, the processing depth is 5 mm, and the processing condition number is 2 shown in FIG. 2, the setting value of the processing depth is 5-0.19 × 0.9 + 0.078 = 4.907mm and discharge area is 20000mm ² When the powder concentration is 2 g / l, the processing depth is 5 mm, and the processing condition number is 1 shown in FIG. 2, the discharge area is 20000 mm. ² 4 is 0.078 mm from FIG. 4 and the correction coefficient for the powder concentration of 2 g / l is 0.8. Therefore, the processing depth setting value is 5−0.28 × 0. In the case of 8 + 0.078 = 4.854 mm, the powder concentration is 2 g / l, the processing depth is 5 mm, and the processing condition number is 2 shown in FIG. 2, the setting value of the processing depth is 5-0.19 × 0. .8 + 0.078 = 4.926 mm.
[0038]
On the other hand, the setting value of the rocking radius when considering the discharge area and the concentration of the powder mixed in the machining fluid is, for example, a discharge area of 20000 mm ² When the powder concentration is 1 g / l, the electrode one-side reduction amount is 0.25 mm, and the processing condition number is 1 shown in FIG. 2, the setting value of the rocking radius is 0.25-0.18 × 0.9 + 0 .078 = 0.226mm and discharge area is 20000mm ² When the powder concentration is 1 g / l, the electrode one-side reduction amount is 0.25 mm, and the processing condition number 2 shown in FIG. 2, the setting value of the rocking radius is 0.25-0.13 × 0.9 + 0 .078 = 0.276mm and discharge area is 20000mm ² In the case where the concentration of the powder is 2 g / l, the reduction amount on one side of the electrode is 0.25 mm, and the processing condition number is 1 shown in FIG. .078 = 0.184mm and discharge area is 20000mm ² When the powder concentration is 2 g / l, the processing depth is 5 mm, and the processing condition number is 2 shown in FIG. 2, the set value of the swing radius is 0.25−0.13 × 0.8 + 0.078 = 0. .224 mm.
[0039]
As described above, when electric discharge machining is performed in a powder-mixed machining fluid in which conductive powder is mixed in a normal machining fluid such as oil, the processing takes into account the discharge area or the concentration of the powder mixed in the machining fluid. The method for setting the depth or the rocking radius and the apparatus for carrying out the method have been described. Needless to say, this can also be applied to electric discharge machining in a normal machining fluid such as oil not containing powder.
[0040]
【The invention's effect】
As described above, according to the machining condition setting method and apparatus for an electric discharge machine according to the present invention, a specified finishing process is performed in consideration of at least one of the discharge area and the concentration of the powder mixed in the machining liquid. Thus, the machining can be completed at once without requiring reworking, and the machining accuracy and the machining efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram showing an embodiment of an electric discharge machine having a machining condition setting device according to the present invention.
FIG. 2 is a diagram showing a table of data set in advance according to machining conditions in order to calculate set values of machining depth and rocking radius.
FIG. 3 is a diagram showing an example of finishing.
FIG. 4 is a diagram showing a relationship between a discharge area and a remaining amount of machining.
FIG. 5 is a graph showing the relationship between powder concentration and discharge gap increase rate.
FIG. 6 is a view showing a table of correction coefficient data for the bottom surface amount and the side surface remaining amount with respect to the powder concentration.
FIG. 7 is a diagram showing an example of a workpiece machining defect according to the prior art when the powder concentration is high.
[Explanation of symbols]
1 ... Electrode
3 ... Work
5 ... Processing power supply
7 ... Processing tank
19 ... Machining condition setting means
25. Data input means
31 ... Machining depth correction value calculation means
33 ... Processing depth correction value storage means
35 ... Oscillation radius correction value calculation means
37 ... Oscillation radius correction value storage means

Claims (2)

In a machining condition setting method for an electric discharge machine that applies a pulse voltage between the electrode and the workpiece in the machining liquid filled in the machining tank and processes the workpiece while moving the electrode and the workpiece relative to each other. ,
Reads the discharge area of the electrode which is input by the input means, a removal failure of working against the discharge area of the electrode read calculated from the experimental data indicating a proportional relationship between the discharge area of the electrode, machining depth or rocking Set the dynamic radius by correcting the increase with the amount of unprocessed machining,
A machining condition setting method for an electric discharge machine characterized by In a machining condition setting device for an electric discharge machine that applies a pulse voltage between electrodes and a workpiece in a machining fluid filled in a machining tank and processes the workpiece while moving the electrode and the workpiece relative to each other. ,
Reads the discharge area of the electrode which is input by the input means, a removal failure of working against the discharge area of the electrode read calculated from the experimental data indicating a proportional relationship between the discharge area of the electrode, machining depth or rocking A machining condition setting device for an electric discharge machine, comprising: a relative movement amount setting means for setting a moving radius to be corrected by increasing the machining remaining amount.

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