JP2002307238A - Method of automatic electrode wear compensation in equal depth pore electric discharge machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of automatic electrode wear compensation in equal depth pore electric discharge machining that can minimize an error, shorten a process per machining and effectively improve work efficiency. SOLUTION: In setting the machining depth value D of a pore electric discharge machine, the machining depth value D is computed as the sum of the machining depth Z of a workpiece, an electrode wear rate W and a correction value (offset), and a machining electrode performs pore electric discharge machining to the actual workpiece on the basis of the numeric value and a machining program. In order to set the wear rate W of the pore machining electrode to the moving state value of automatic measuring calculation, the Z-axis value of the machining electrode to the workpiece surface measured in first pore machining is made the reference value, and the Z-axis value of the electrode to the workpiece surface in second pore machining is reduced, that is, the actual electrode wear value in preceding pore machining is measured, and the measured electrode wear value can be inputted as the electrode wear value in the following pore machining.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of automatic electrode wear compensation for a kind of equi-depth pore electric discharge machining. In particular, the present invention relates to a method of equi-depth pore discharge machining automatic electrode consumption compensation for minimizing a kind of error, shortening a process per machining, and effectively improving work efficiency.

[0002]

2. Description of the Related Art In a machining program apparatus, a machining depth value is first input and set, and then a discharge power source is started to perform an electric discharge machining operation. As shown in FIG. 1, in the setting of the machining depth value (D) of the known pore discharge machine, 1. The processing depth (Z) of the workpiece; Numerical values such as the wear rate (W) of the processing electrode and the correction value (offset) (ie, D
= Z + W + offset). Thus, the machining electrode performs electric discharge machining on the workpiece based on the input machining depth value. On the other hand, the machining depth values are all fixed values. Since the wear rate of the electrode is inversely proportional to the length of the electrode, the wear rate of the machining electrode is set to a fixed value in the conventional product. Separately, the setting of the correction value is mainly to ensure complete penetration of the machining electrode into the workpiece when drilling a hole, or to add the machining depth value (D) to the electrode wear value (W), As a result, the penetration of the workpiece is ensured, or the intended machining depth is achieved.

When a new electrode is used, the electrode is perfect, and both the end face and the diameter are perfect, so that the depth tends to be deep when the first hole is formed. This is because the electrode is less consumed. After the electrode has machined the second hole, the electrode wear rate gradually increases, but this is due to the reaction speed of the working process, and the electrode wear rate increases as the electrode becomes shorter. Especially when using smaller diameter electrodes,
Extremely clear (0.3mm, 0.4mm, 0.5mm, etc.
Or 1.5 mm or less), which is the main cause of the uneven working depth. In other words, in order to make the processing of all holes uniform, as the processing depth becomes smaller, the electrode wear value (W) is set to the maximum electrode wear value at which drilling is possible (that is, the electrode wear value at the shortest electrode). ) Must be set. Therefore, when processing is performed in place of a new electrode, the consumption depth of the electrode is a fixed value, and the processing depth of the first hole using the new electrode is deeper than the other holes. That is, the working depth gradually decreases with the number of working holes. Thus, an excessive machining depth adds to the problem of slag discharge and consumes a great deal of machining time.

[0004] The disadvantages are integrated as follows. 1. As shown in FIG. 2, the maximum electrode consumption value is set each time the pore machining electrode performs the pore electric discharge machining on the workpiece. For this reason, a completely new machining electrode is extremely often the case where the electrode penetrates the bottom of the workpiece from the first hole electric discharge machining to the last one hole. Further, the machining time is increased, and in addition, the reaction force of the high-pressure machining fluid spouting from the electrode end causes the electrode to shift, causing the hole at the bottom of the workpiece to expand and decrease, and There is also a risk of causing damage. In a known pore electric discharge machine, such a defect exists because the consumption of the electrode is set to a fixed value. 2. In the setting of the known electric discharge machining depth value (D), the electrode is set to a fixed maximum consumption value. However, this setting method can completely penetrate the workpiece and only allows the machining to be performed. On the other hand, it is not possible to perform elaborate and accurate non-through hole processing. For example, as shown in FIG. 3, when the workpiece is set to the actual depth of the unpenetrated hole (blind hole) to be processed, the correction value (offset) is zero. As a result, if the pore-forming electrode continues to be drilled and consumed, there is a very large difference in the depth of the non-through hole to be machined on the workpiece, and a phenomenon is seen in which the machining depth gradually decreases.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned drawbacks of the known structure, an object of the present invention is to provide a method of automatically compensating for the consumption of an electrode at the same depth of pores by EDM. Since the present invention uses the dynamic electrode wear compensation method, the error of the machining depth is extremely small, so that the process of one electric discharge machining can be shortened, and the working efficiency can be effectively improved. Furthermore, since the consumption value (W) of the pore processing electrode for processing the processing depth value (D) is set to the dynamic value of the automatic measurement calculation, the error value can be reduced, and the pore processing electrode is set. The machining depth value (D) is accurately machined, and the error of the machining depth value of each hole is minimal. In addition, by adopting the method for automatically compensating for the consumption of the electrode by fine pore discharge machining according to the present invention, the correction value (off
If (set) is set to zero, it is possible to effectively perform electric discharge machining of a non-through hole having a very small depth error value.

[0006]

In order to solve the above-mentioned problems, the present invention provides the following equi-depth pore electric discharge machining automatic electrode wear compensation method. In order to obtain the machining depth value (D) in setting the electrode machining depth value (D) of the pore discharge machine, it is necessary to: 1. The processing depth (Z) of the workpiece; 2. electrode wear rate (W); A correction value (offset) or the like is input to calculate the sum thereof, and the machining electrode calculates an actual machining depth value by a machining program based on the numerical value, and performs pore discharge machining on the workpiece. In order to set the consumption rate (W) of the pore processing electrode to the dynamic value of the automatic measurement calculation, the processing electrode measured and obtained by the first hole processing uses the value of the electrode with respect to the workpiece surface as a reference value, Decrease the value of the two-hole electrode for the workpiece surface. That is, if an accurate electrode wear value at the time of processing the first hole is calculated, the electrode wear value can be input as an electrode wear value of the second hole. Since the electrode consumption values of the adjacent processing holes are very similar, the error of the processing depth value relatively calculated in this way is very small.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 4, 5 and 6, in the present invention, when setting the processing depth value (D), the processing depth (Z) and the correction value (offset) of the workpiece are directly changed. input. In the present invention, the consumption value (W) of the processing electrode is set as a dynamic value of automatic measurement calculation. Therefore, the machining electrode measures the value at the time of machining the previous hole (first hole), uses the value measured relative to the surface of the workpiece as a reference value, and processes the next hole (second hole). Subtract the value measured relative to the workpiece surface at the time of the electrode. Therefore, an accurate electrode wear value at the time of machining the previous hole (first hole) can be calculated, and the electrode wear value at the time of machining the currently processed hole (ie, the second electrode wear value) can be calculated. (Electrode wear value of the hole). Subsequent processing is performed in accordance with this.

[0008] When the electrode performs the first discharge with the workpiece at the time of the electric discharge machining of the first hole, the measured value of the Z axis is assumed to be Z0.
And When the processing of the first hole is completed, the worktable moves to the processing position of the second hole. When machining the second hole, the value of the Z-axis measured when the electrode performs the workpiece and the first discharge is Z1. That is, the electrode consumption value (W) of the second hole processing depth value (D) formula is calculated in a very short time when the electrode contacts the workpiece surface (W0 is the value of Z1 minus Z1), and Substituted into the calculation formula. That is, the machining depth value (D) is a numerical value obtained by adding the dynamic electrode wear value (W0) and the drilling correction value (offset) to the machining depth (Z) of the workpiece. When machining the third hole, the value of the Z axis measured when the electrode performs the first discharge with the workpiece is Z2. That is, the third electrode processing depth value (D) formula electrode wear value (W1)
Is calculated in a very short time when the electrode contacts the surface of the workpiece (W1 is the value of Z2 minus Z2), and is further substituted into the calculation formula. That is, the machining depth value (D) is a numerical value obtained by adding the dynamic electrode wear value (W1) and the drilling correction value (offset) to the machining depth (Z) of the workpiece. The same applies to the subsequent processing (see FIG. 5).

[0009] The correction value (offse
t) is set to zero (see FIG. 4). Electrode wear value (W)
Specially memorizes the electrode wear value of the first hole processing of the new electrode, W
Set to 0. Others are set to W1 and recorded for each hole. Also, based on the effective length of the electrode, the number of the corresponding electrode wear value is substituted into the machining depth calculation formula. For example, the machining depth value (D) of the pore electric discharge machining is: 1. The processing depth (Z) of the workpiece; 2. consumption rate of the working electrode (W); Correction value (o
ffset), ie, D = Z + W (W0, W
1, W2,..., WN) + offset. The pore machining electrode wear value input at the start of machining can be an approximate value, and thus the data of the first electro-discharge machining can be used as a basis for the subsequent machining.
Further, when the wear value is set to zero and the processing depth reaches a value obtained by adding a correction value (offset) to the processing depth (Z) of the workpiece (set to zero when processing a non-through hole), the processing is stopped.
Raise the machining axis to separate it from the workpiece surface. Further, the work table is moved to the non-machining plane, and the Z-axis value is obtained by contact of the electrode with the surface of the workpiece. Subsequently, the value measured this time is subtracted from the Z-axis value obtained relative to the immediately preceding workpiece surface. As described above, the electrode consumption rate when the current hole is machined can be calculated, and the actual machining depth can be obtained. Subsequently, a rework depth value is calculated based on the electrode consumption rate at the time of machining the hole, returned to the original machining position, and unfinished machining is performed until machining is completed.
The processing process is as shown in FIG. This input method can avoid human input errors and improve processing efficiency.

At present, the processing depth of the workpiece to be processed is 20 MM, and the correction value is 3 MM. in this case,
First, the machining depth (D) that can be input in the program is a numerical value obtained by adding the electrode wear rate (W) of zero and the correction value (offset) of 3MM to the depth (Z) of 20MM to be machined. When the electrode starts electric discharge machining on the workpiece, the value of the Z-axis at which the first discharge point is obtained is assumed to be 31.
5MM (Z0) position. 292MM (minus 23
When processing is performed to the MM) position, the controller stops the processing, rises, and moves away from the workpiece surface. continue,
Move the platform to a planar position and touch a surface that has not been subjected to electrical discharge machining. The position of the Z axis obtained at this time is assumed to be 30
Assuming 7.3MM, the electrode wear is 7.7MM (315-
307.3). At the same time, the actual machining depth is 15.
3MM and the electrode wear rate is about 50% (7.7 / 1
5.3). Therefore, the remaining machining depth can be obtained by adding the electrode wear rate to 4.7 MM. Thus, the calculated accurate machining depth is 281.
It is the position of MM of 94 (292-7.06-3). Subsequently, the work table returns to the original processing position, continues unfinished processing until a predetermined depth is achieved, and the processing axis is raised to a safe altitude and moves to the processing position of the second hole.

The discharge is resumed and the first discharge contact Z
The numerical value 304.94 (Z1) of the axis position is obtained. Therefore, the electrode consumption value (W0) of the first hole processing of the new electrode is 315.
Subtract 304.94, which is 10.06. Substituting this into the processing depth calculation formula (D = Z + W + offset) gives 20 + 10.6 + 3 = 33.06. Therefore, the machining stop point of this hole is at the Z-axis position 271.88 (304.9).
4-33.06). After machining is completed, the machining axis is raised to a safe altitude, and the worktable moves to the third hole machining position.
The discharge is restarted, and a value 294.84 (Z2) of the Z-axis position of the first discharge contact is obtained. Therefore, the electrode consumption value (W1) of the second hole processing is 304.94 minus 294.84.
Is 10.10. This is calculated using the machining depth calculation formula (D =
Z + W + offset), 20 + 10.1
0 + 3 = 33.10. Therefore, the processing stop point of this hole is the Z-axis position 261.74. After the machining is completed, the machining axis is raised to a safe altitude, and the worktable moves to the fourth hole machining position. The same applies to the subsequent processing.

[0012]

As described above, the error between the second hole processing and the third hole processing is 0.04 (10.10-10.06) divided by 1.
5 (1 + 0.5), which is about 0.027 MM. The electrode wear value obtained using the above processing depth is the electrode wear value of the adjacent holes, and the values are very close. In other words, since the pore electric discharge machine uses this dynamic electrode wear compensation method, the error of the machining depth is extremely small, so that the process of one electric discharge machining can be shortened, and the working efficiency can be effectively improved. Can be improved. Furthermore, since the consumption value (W) of the microporous electrode for achieving the processing depth value (D) can be set to the dynamic value of the automatic measurement calculation,
The error value can be reduced. For this reason, the fine hole machining electrode is accurately machined to the set machining depth value (D), and the error of the machining depth value of each hole is extremely small. In addition, if the correction value (offset) is set to zero by operating the method of automatic electrode discharge compensation of the pore discharge machining according to the present invention, the electric discharge machining of the non-through hole (blind hole) can be effectively performed. Can be. It goes without saying that the depth error value of the non-through hole is very small.

[Brief description of the drawings]

FIG. 1 is a principle of calculating a depth value of a pore discharge machining.

FIG. 2 is an operation reference diagram of a pore discharge machining by a known pore discharge machine.

FIG. 3 is a cross-sectional reference view of a known non-through hole processing operation.

FIG. 4 is a calculation principle of a dynamic pore processing electrode consumption rate of the automatic electrode consumption compensation according to the present invention.

FIG. 5 is a block chart of the processing process of the present invention.

FIG. 6 is a block chart of a first hole forming process of the present invention.

[Explanation of symbols]

D Machining depth value Z Machining depth of workpiece W Electrode wear rate (value) offset correction value Z0 Temporary value measured by first discharge of Z axis Z1 Temporary value measured by second discharge of Z axis Z2 Z axis Numerical value measured by the third discharge of W0 Temporary numerical value of the second pore dynamic electrode consumption W1 Temporary numerical value of the third pore dynamic electrode consumption

Claims (3)

[Claims] In order to obtain a machining depth value (D) mainly in setting a machining depth value (D) of an electrode of a pore discharge machine, it is necessary to: 1. The processing depth (Z) of the workpiece; 2. electrode wear rate (W); A machining method of calculating a sum of numerical values such as a correction value (offset) and calculating an actual electrode machining depth value based on a machining program based on each of these numerical values, thereby performing a pore discharge machining on a workpiece. In order to set the consumption rate (W) of the pore processing electrode to the dynamic value of the automatic measurement calculation, it is measured at the time of processing the previous hole (first hole),
Using the obtained Z-axis value of the electrode with respect to the workpiece surface as a reference value, subtracting the Z-axis value with respect to the workpiece surface at the time of processing the next hole (second hole) to calculate the electrode wear value, By inputting the electrode wear value as the electrode wear value at the time of processing the next hole (that is, the electrode wear value of the second hole), the processing depth error of the processing electrode is minimized, and the same processing is performed. Equal depth pore electric discharge machining automatic electrode wear compensation method. 2. When the correction value (offset) is zero, accurate electric discharge machining of the non-penetrated holes is possible, and the depth error of each non-penetrated hole subjected to the electric discharge machining is extremely small. 2. The method of claim 1, wherein the electrode is automatically compensated for wear of the electrode at the same depth. 3. An extremely accurate machining depth is obtained by automatically correcting the electrode wear value (W) by performing the measurement on the workpiece surface many times during machining. Item 3. The method for automatic electrode wear compensation of equal depth pore electric discharge machining according to Item 1.