JPH02160424A - Correcting method for position of wire electrode in wire electric discharge machining device - Google Patents

Abstract

PURPOSE:To always set the relative position between a wire and a workpiece following to decision of a machining program and improve accuracy of machining by searching for corrective movement quantity of a workpiece and a nozzle driving table based on a detected displacement quantity, and correcting the position of a wire electrode against the workpuiece according to this corrective movement quantity. CONSTITUTION:Machining liquid is supplied to a machining part through a pair of nozzles 7, 11 guiding and positioning a wire electrode, and displacement quantity of these nozzles in the horizontal and vertical directions are detected with detectors 30a - 30d. Corrective movement quantity of a workpiece driving table and a nozzle driving table 10 are searched by computing based on the detected displacement quantity. Following to the searched corrective movement quantity, the position of the wire electrode against the workpiece 5 is corrected, by correctively moving the workpiece driving table and the nozzle driving table 10. Hereafter, following to the machining program, electric discharge is generated between the wire electrode and the workpiece 5 while supplying the machining liquid, and the expected electric discharge machining is performed by moving the workpiece 5.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for correcting the position of a wire electrode in a wire electrical discharge machining device, and in particular a position correction method that enables high-precision machining without being affected by machining fluid pressure. It is related to.

[Prior Art] FIG. 4 is a configuration diagram showing a general wire electric discharge machining device, and FIG. 5 is a configuration diagram showing a portion of the device deformed by machining fluid pressure. Incidentally, as a prior art related to the conventional example, there is one described in Japanese Patent Application Laid-Open No. 81-297019.

In the figure, (1) is the bed, (2) is an L-shaped column erected on the bed (1), (3) is a workpiece drive table that can freely run on the bed (1), and (4) ) is a surface plate fixed on the workpiece drive table (3), (5) is the workpiece placed on the surface plate (4), and (8) is the arm extending horizontally from the column (2). , (7) is the lower nozzle provided at the tip of the arm (6), and (8) is the lower nozzle (7).
(9) is a vertically movable z-axis provided hanging from the tip of column (2), (lO) is 2
A horizontally movable nozzle drive table provided at the tip of the ring (9), (11) is a nozzle drive table (10)
The lower nozzle (7) is installed between the workpiece (5) and the lower nozzle (7).
The upper nozzle (12) is installed in the upper nozzle (11) and guides and positions the wire electrode, and (13) is the upper diamond die that drives the workpiece drive table (3). 1 table drive motor, (
14) is a second table drive motor that drives the nozzle drive table (10), (15) is a wire bobbin provided on the column (2), and (te) is a wire electrode (hereinafter referred to as "te") wound around the wire bobbin (15). (referred to as "wire")
, (17) are provided in the column (2), and the wire (1B)
(18) is an upper guide roller provided on the column (2), (19) is a lower guide roller provided on the arm (6), (20) is provided adjacent to the bed (1) The wire collection box (21) is a winding roller provided on the wire collection box (20), (2
2) is a wire take-up roller that drives the take-up roller (21), (23) is a workpiece/nozzle drive table (3), (
(10) is a numerical control device (hereinafter referred to as an NC device) that performs drive control, etc., (24) is an upper and lower nozzle (11),
(7) is a machining fluid supply device that supplies machining fluid (25) to the machining fluid (25).

The operation of the wire electrical discharge machining apparatus configured in this way will be explained.

First, the wire (
16) is a brake device (17) that applies the necessary tension.
), upper guide roller (18) and upper nozzle (11)
is supplied to the processing section of the workpiece (5), and after processing, it is wound up by the winding roller (21) via the lower nozzle (7) and the lower guide roller (19), and then sent to the wire collection box (20 ) will be discarded. The wire (16) in the processing section of the workpiece (5) is guided and positioned by an upper diamond die (12) in the upper nozzle (11) and a lower diamond die (8) in the lower nozzle (7), Machining energy is supplied between the wire (16) and the workpiece (5) from a machining power source (not shown), and electrical discharge machining of the workpiece (5) is performed. During this electrical discharge machining, high-pressure machining fluid (25) is supplied from the machining fluid supply device (24) to the machining portion of the workpiece (5) through the upper and lower nozzles (11) and (7). At this time, the upper and lower nozzles (
11), the gap between (7) and workpiece (5) is 0.05
It is managed at ~0.1 level. In this way, the workpiece (5
) The reason why machining fluid (25) is supplied to the machining part is that in wire electrical discharge machining, if discharge occurs in the air, the wire will break and become unworkable, so to prevent this, fluid is supplied to the machining section. This is because it is necessary to discharge the battery inside. Furthermore, as high-speed machining has become required in recent years, there is a tendency to increase the machining fluid pressure because it is necessary to more reliably and sufficiently supply machining fluid to the wire being worked.

Also, during electrical discharge machining, machining fluid (
25) and a command given to the first table drive motor (13) from the NC device (23), the first table drive motor (13) operates and the workpiece drive table (3) Perform plane movements. As a result, the workpiece (5) attached to the surface plate (4) on the workpiece drive table (3) moves relative to the wire (1B), and is machined into a predetermined shape. In addition, in FIG. 4, only one motor, the first table drive motor (13), is shown as the motor that drives the workpiece drive table (3), and the workpiece drive table (3) is shown in the direction perpendicular to this. Other driving motors are omitted. In addition, the workpiece (
When performing taper processing on the wire (16), the second table drive motor (14) is driven by a command from the NC device (23) to move the nozzle drive table (10) in a plane.
Lean. In addition, in Fig. 4, the nozzle drive table (1
A second table drive motor (
Only one motor (14) is shown, and other motors that drive the nozzle drive table (10) in a direction perpendicular to this motor are omitted.

[Problems to be Solved by the Invention] As described above, in the wire electrical discharge machining device, the machining fluid supply device (
24) Higher pressure machining fluid (25) flows through the upper and lower nozzles (
11), the workpiece (5) on the surface plate (4) via (7)
During electrical discharge machining, the hydraulic pressure of the machining fluid (25) causes the nozzle drive table (10) having the upper nozzle (11) and the lower nozzle (7) to be supplied to the machining section.
The arm (6) with the upper and lower nozzles (1
The positions of the upper and lower diamond dies (12) and (8) that guide the wire (16) in 1) and (7) are as shown by the broken lines in FIG. Lower diamond die (
8) is displaced by ΔX, Δz2. For this reason, the wire (1G) deviates from the Taber angle set with respect to the workpiece (5), resulting in poor shape accuracy.
6) and the workpiece (5) are shifted, resulting in poor positional accuracy and a problem in that highly accurate processing cannot be performed.

This invention was made in order to solve this problem, and it is possible to perform high-precision machining by correcting the positional deviation of the upper and lower nozzles, which have upper and lower diamond dies that guide the wire using machining fluid pressure. The purpose of this invention is to obtain a method for correcting the position of a wire electrode in a processing device.

[Means for Solving the Problems] A method for correcting the position of a wire electrode in a wire electrical discharge machining apparatus according to the present invention includes a step of supplying machining fluid to a workpiece through a pair of nozzles for guiding and positioning a wire electrode, Detecting horizontal and vertical displacement of the pair of nozzles due to hydraulic pressure, a workpiece drive table for moving the position of the workpiece based on the detected displacement, and the position of one of the nozzles of the pair of nozzles. calculating the corrected movement amount of the nozzle drive table to move the nozzle drive table; correcting the position of the wire electrode with respect to the workpiece by moving the workpiece drive table and the nozzle drive table in accordance with the corrected movement amount obtained by the calculation; It is made up of stages.

[Function] In this invention, a pair of wire electrodes that guide and position a wire electrode that is fed in a certain direction that occurs when electrical discharge machining is performed by supplying machining fluid at a predetermined hydraulic pressure to the machining part of a workpiece. The amount of horizontal and vertical displacement of the nozzle is detected in advance, and the position of the workpiece is moved based on the detected amount of displacement.The position of the workpiece drive table and one nozzle of a pair of nozzles is moved. The corrected movement amount of the nozzle drive table is calculated, and the position of the wire electrode relative to the workpiece is corrected by moving the workpiece drive table and nozzle drive table according to the calculated correction movement amount.1 ．． When electrical discharge machining is performed, the positional relationship between the wire and the workpiece is always set as set by the machine program.

[Example 1] Fig. 1 is a block diagram showing the machining part of a wire electric discharge machining apparatus in which the method of the present invention is implemented, and Fig. 2 is an explanatory diagram showing how to obtain the corrected movement amount in the method of the present invention. In the figures, the same components as those of the conventional wire electric discharge machining apparatus are denoted by the same reference numerals, and redundant explanation of the components will be omitted. (30a) in Figure 1
- (30d) are all electric micrometers. (
30a) detects the horizontal displacement Δx1 of the upper diamond die (12) installed in the upper nozzle (11), and (30b) detects the vertical displacement Δz1 of the upper diamond die (12). (30c) is the horizontal displacement amount Δx2 of the lower diamond die (8) installed in the lower nozzle (7).
(30d) is used to detect the vertical displacement amount Δz2 of the lower diamond die (8).

(7a), (8a), (lla) in Figure 2,
(12a) shows the lower nozzle, lower diamond die, upper nozzle, and upper diamond die before applying hydraulic pressure from the machining fluid; (7b), (8b), (
llb), (12b) shows the lower nozzle, lower diamond die, upper nozzle, and upper diamond die that are displaced after applying hydraulic pressure from the machining fluid;
c) and (12c) show the upper nozzle and upper diamond die after position correction. (40a) shows the intersection of the wire (16) and the upper surface of the workpiece (5) when no hydraulic pressure is applied, and (40b) shows the intersection of the upper diamond die (12) (12c) when hydraulic pressure is applied. ) shows the intersection of the wire (16) and the top surface of the workpiece (5).

Next, regarding the method of this invention, the explanatory diagram of FIG.
This will be explained based on the flowchart shown in the figure.

First, machining conditions are set based on the thickness, material, etc. of the workpiece (5) based on the carnivorous program (step 81).

Next, the workpiece (5) is fixed on the surface plate (4) in a state to be processed, and the gap between the upper nozzle (10) and the workpiece (5) is set to a predetermined value. When performing normal machining, before electrical discharge machining, machining fluid is applied to the machining part of the workpiece (5) through the upper nozzle (11) and the lower nozzle (7) in the same way as during machining with a predetermined hydraulic pressure. supply In this case, the positions of the upper diamond die (12) of the upper nozzle (11) and the lower diamond die (8) of the lower nozzle (7) are shifted, as shown in FIG. Detection is performed using electric micrometers (30a) to (30d) as shown in FIG. 1 (step 82). The horizontal and vertical displacement amounts ΔX, Δz1 of the upper diamond die (12) detected by the electric micrometers (30a) to (30d) and the horizontal and vertical displacement amounts ΔX, Δz2 of the lower diamond die (8) The value of N
Import into the memory in the C device.

In addition, when performing Taber processing, the upper nozzle (11) is horizontally shifted from the lower nozzle (7) as shown in Fig. 2, and is located at the processing part of the workpiece (5). The wire (5) is set to run obliquely and have a Taber angle. Then, machining fluid is supplied in advance to the machining portion of the workpiece (5) at a predetermined hydraulic pressure before electrical discharge machining in the loose setting state. Then, as shown in Figure 2, the lower diamond die (8) moves from the position (8a) before applying hydraulic pressure to the position (8b) after the hydraulic pressure is relieved, and the upper diamond die (12) The wire also moves from (12a) before applying hydraulic pressure to the position (12b) after applying hydraulic pressure, and the wire (1
The Taber angle of G) changes. The displacement amount of these upper and lower diamond dies (12) and (8) is detected by each electric micrometer (30a) to (30d) (step S2).
) ～(30d) detected the upper diamond die (
12) horizontal and vertical displacement amounts ΔX, Δz1
And the values of the horizontal and vertical displacement amounts ΔX and Δz2 of the lower diamond die (8) are taken into the memory in the NC device.

Next, upper and lower diamond dice (12), (8)
Upper and lower diamond dies (12
), calculate the corrected movement amount of (8) (step 93
).

This corrected movement amount is calculated as follows.

When the machining fluid is supplied to the workpiece (5), the upper and lower diamond dies (12) and (8) are displaced and the taper angle of the wire (16) changes as described above, so the machining fluid is supplied. When performing electrical discharge machining while
It is necessary to correct the Taber angle of the wire (16) before electrical discharge machining so that B) maintains the initially set Taber angle. To correct the Taber angle of this wire (1B), the position of the upper diamond die (12) is shown in Figure 2 (L
It is sufficient to move from 2b) to (12c). This is because the Taber angle is the same as the originally set wire (1G). Therefore, the Taber angle of the wire (IB) is corrected by moving the upper diamond die (12) in the horizontal direction, and the amount of movement of the upper diamond die (12) becomes the corrected movement amount X8.

This corrected movement amount XB can be determined as follows. Let g be the thickness of the workpiece (5), that is, the vertical distance between the position of the upper diamond die (12) and the position of the lower diamond die (8), and the thickness of the upper diamond die (12) when no machining fluid is supplied. ) and the position of the lower diamond die (8) is defined as X, then the following equation (1) holds true.

Therefore, the corrected movement amount XB of the upper diamond die (12) is expressed as the following equation (2).

X B"" Xi + ΔX1 + Δx2 Here, Δxl゛ ΔX 2 and ΔZ 1r Δz2 are determined by electric micrometers (30a) to (30d), and 47 and Xl are both known values set as processing conditions, Both are stored in the memory within the NC device, and XB can be calculated and determined by the CPU of the NC device.

Therefore, the Taber angle of the wire (16) is corrected by moving the nozzle drive table (3) to which the upper nozzle (11) having the upper diamond die (12) is attached by a correction movement amount XB.

Next, after the above-mentioned correction of the Taber angle of the wire (16), the intersection of the wire (16) and the upper surface of the workpiece (5) is shifted by the amount of shift XA, which causes the wire (1B) and the workpiece to This is a relative error with the workpiece (5).

This deviation amount XA can first be expressed by equation (3).

X −ΔX +Δz −tan θ
--------(3) A 2 2 It can be determined from the formula (4) shown below.

The calculation of this equation (4) is also performed by the CPU of the NC device.

This shift'I! Correction of kXA is performed by shifting the workpiece drive table (1o) to which the workpiece (5) is attached gkXA
This is done by moving the corrected movement amount by the same amount.

In this way, after the workpiece drive table (3) and the nozzle drive table (10) are moved and corrected based on the position command, the workpiece (5) is moved according to the control program.
) while supplying machining fluid at a predetermined pressure to the machining section of the machine (16), an electrical discharge is generated between the wire (16) and the workpiece (5), and the workpiece drive table (3) is moved to perform electrical discharge machining. (Step 84). Then, when the electrical discharge machining is completed, it is stopped (step S5).

Furthermore, if the electrical discharge machining has been completed for -block and the machining conditions are different in the next block, the same correction as described above is performed and the electrical discharge machining of the next block is performed.

Furthermore, although the above-mentioned correction is explained as a case where the workpiece (5) is subjected to taper processing, when the workpiece (5) is subjected to normal processing, that is, when the wire (16)
The method of this invention can also be applied when the angle is vertical.

In the above example, the amount of displacement was determined by measurement, but the amount of displacement was stored in memory in advance, and depending on the machining conditions,
A similar effect can be obtained by calculating the numerical values in the memory. That is, the upper and lower diamond dies (12>
, horizontal and vertical displacement amount ΔX of (8),
ΔX, Δ2, and Δz2 vary depending on the hydraulic pressure of the machining fluid and the position of the upper diamond die (12), that is, the thickness of the workpiece (5), and these values ΔXi to Δz2 are detected in advance under multiple conditions. Then, by registering it in the memory in the NC device, the upper diamond die (1
The value at position 2) can be estimated and obtained. In other words, for example, if the displacement amount when the hydraulic pressure of the machining fluid is high and low is registered as data in the memory in the NC device, then when the hydraulic pressure of the machining fluid is in the middle, or even more than when the pressure is high as described above. The amount of displacement when the amount of displacement is high can be determined by the estimation DI, and thereby it is also possible to calculate the corrected movement amount and perform correction.

[Effects of the Invention] As explained above, this invention guides the electrode wire that is fed in a certain direction that occurs when electrical discharge machining is performed by supplying machining fluid at a predetermined hydraulic pressure to the machining part of the workpiece. The amount of displacement in the horizontal and vertical directions of a pair of nozzles to be positioned is detected in advance, and the position of the workpiece is moved based on the detected amount of displacement. Calculate the corrected movement amount of the nozzle drive table whose position is to be moved, and correct the position of the wire electrode relative to the workpiece by moving the workpiece drive table and nozzle drive table in accordance with the calculated correction movement amount. Therefore, when performing electric discharge machining, the positional relationship between the wire and the workpiece is always performed as set by the machine program, and there is an effect that highly accurate machining can be performed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the machining part of a wire electrical discharge machining apparatus in which the method of the present invention is implemented, Fig. 2 is an explanatory diagram showing how to obtain the corrected movement amount in the method of the invention, and Fig. 3 is a diagram showing the method of the invention. Flowchart, FIG. 4 is a configuration diagram showing a general wire electric discharge machining device, and FIG. 5 is a configuration diagram showing a portion of the same device deformed by machining fluid pressure. In the figure, (3) is the workpiece drive table, (5) is the workpiece, (7) is the lower nozzle, (8) is the lower diamond die, (10) is the nozzle drive table, (11)
is the upper nozzle, (12) is the upper diamond die, (
30a), (30b), (30c), (3
0d) is an electric micrometer (displacement detector). In each figure, the same reference numerals indicate the same or corresponding parts. Agent Patent Attorney Muneharu Sasaki Figure 1 Diagram 4

Claims (1)

[Scope of Claims] A step of supplying machining fluid to the machining portion of the workpiece through a pair of nozzles that are placed across the workpiece and guide and position a wire electrode that is fed in a fixed direction; a step of detecting the amount of horizontal and vertical displacement of the pair of nozzles due to the hydraulic pressure of the machining fluid; a step of detecting the displacement amount of the pair of nozzles in the horizontal and vertical directions; calculating a corrected movement amount of a nozzle drive table for moving the position of one of the nozzles; a step of calculating the corrected movement amount of the nozzle drive table for moving the position of one of the nozzles; A method for correcting the position of a wire electrode in a wire electrical discharge machining apparatus, comprising the step of correcting the position of the wire electrode with respect to an object.