JP3582953B2 - Wire electric discharge machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wire electric discharge machine for processing a desired shape on a workpiece by relatively moving a wire electrode and the workpiece.
[0002]
[Prior art]
Generally, in a wire electric discharge machine, a machining trajectory program which is a movement trajectory of a center position of a wire electrode is created according to a desired shape to be machined on a workpiece, and a radius of a wire electrode to be used and machining of rough machining and finish machining are performed. The amount obtained by combining the discharge gap (machining gap) according to the conditions and the like is defined as the offset amount, and the movement amount obtained by adding the offset amount to the movement amount according to the machining path program of the wire electrode or the work is moved. It is instructed to the means.
[0003]
However, not only is there a manufacturing error in the electrode diameter of the wire electrode, but there is also a variation in each location, which has an adverse effect on the command of the offset amount of the wire electrode, which leads to a reduction in processing accuracy. If the required processing accuracy of the workpiece is high, a wire electrode with high dimensional accuracy may be used, but manufacturing such a wire electrode with high dimensional accuracy involves a considerable increase in cost. . In addition, the wire electrode may be stretched by the tension during traveling, causing a change in the wire diameter.
[0004]
As a conventional technique for solving such a problem, by comparing the electrode diameter of the wire electrode after the electric discharge machining measured after the desired electric discharge machining with the electrode diameter of the wire electrode after the electric discharge machining under the optimal machining conditions stored in advance. Japanese Patent Application Laid-Open No. 7-60551 discloses a technique in which desired processing conditions are adjusted to discharge voltage or discharge current and work moving speed under optimum processing conditions.
[0005]
[Problems to be solved by the invention]
However, the wire electrode is not always consumed uniformly by electric discharge machining, and its cross-sectional shape is often uneven, and the electrode diameter of the wire electrode after electric discharge machining is measured as in the above-described conventional technique. Also, there is a difference in the shape and dimension of the electrode diameter depending on the position to be measured, so that an accurate electrode diameter of the wire electrode cannot be obtained, and it is difficult to incorporate the error in the electrode diameter of the wire electrode into the offset amount.
[0006]
Therefore, the present invention provides a wire electric discharge machine capable of improving machining accuracy by measuring the electrode diameter of a wire electrode before electric discharge machining and reflecting a shape error of the electrode diameter in an offset amount. Aim.
[0007]
[Means for Solving the Problems]
The present invention, in order to achieve the above object,
An electrode diameter measuring means for measuring an electrode diameter of the wire electrode before electric discharge machining, preferably, the measuring unit is rotatable 360 ° around a central axis of the wire electrode and rotatable, and the wire is perpendicular to the machining direction. An electrode diameter measuring means capable of measuring the electrode diameter of the electrode; and a wire electrode electrode which is a correction amount of the offset amount from the electrode diameter of the wire electrode stored in the processing program and the electrode diameter of the wire electrode measured by the electrode diameter measuring means. And an offset correction amount calculating means for calculating a diameter error, and has the following configuration.
[0008]
(1) In a wire electrode processing machine that runs a wire electrode and relatively moves the wire electrode and a workpiece to process a desired shape on the workpiece.
Relative movement means for relatively moving the wire electrode and the work,
Electrode diameter of the wire electrode, an offset amount according to the electrode diameter of the wire electrode and a discharge gap, an electric discharge machining program reading means for reading an electric discharge machining program comprising a machining shape program according to the desired shape,
In consideration of the offset amount in the machining shape program of the electric discharge machining program, a relative movement amount between the wire electrode and the work is calculated, and a movement amount calculation unit to send to the relative movement unit,
Indexing is provided before the electric discharge machining part of the wire electrode and the work, and the measuring part is indexed around the central axis of the wire electrode and rotated to measure an electrode diameter of the wire electrode before electric discharge machining. Equipped with a rotating means, electrode diameter measuring means for measuring the electrode diameter of the wire electrode from a direction always perpendicular to the processing progress direction ,
An error of the electrode diameter of the wire electrode is calculated from the read electrode diameter of the wire electrode and the measured electrode diameter of the wire electrode, and the offset correction amount calculating means is sent to the moving amount calculating means as a correction amount of the offset amount. When,
A wire electrode machine for correcting a shape error of the wire electrode before electric discharge machining when the wire electrode and the workpiece are relatively moved.
[0009]
[Action]
When machining a desired shape on a work by a wire electric discharge machine, an electric discharge machining program reading means includes an electrode diameter of a wire electrode, an offset amount according to an electrode diameter of a wire electrode and a discharge gap, and a machining shape program according to the desired shape. And the like. The movement amount calculating means calculates the relative movement amount between the wire electrode and the work by taking the offset amount into consideration into the machining shape program of the electric discharge machining program, and sends it to the relative movement means between the wire electrode and the work.
[0010]
Then, at the same time as the workpiece is processed while the wire electrode and the workpiece are relatively moved, the electrode diameter before the electrical discharge machining of the wire electrode is measured by an electrode diameter measuring means provided in a stage preceding the electrical discharge machining part of the wire electrode and the workpiece, The error of the electrode diameter of the wire electrode is calculated from the difference from the electrode diameter of the wire electrode read into the electric discharge machining program reading means by the offset correction amount calculation means, and is sent to the movement amount calculation means as a correction amount of the offset amount. Therefore, it is possible to take in the dimensional error of the wire electrode used for processing as a correction amount of the offset amount.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an enlarged view of a main part of a wire electric discharge machine including a machining control block diagram showing an embodiment according to the present invention, and FIG. 2 is a diagram showing a wire electrode diameter measuring means of the wire electric discharge machine of the present invention. FIG. 3B is a front view, FIG. 3B is a cross-sectional view taken along the line AA, and FIG.
[0012]
As shown in FIG. 1, a desired tension is applied to a wire electrode (hereinafter, referred to as a wire) 1 supplied from a wire supply means (not shown) such as a wire bobbin by a wire tension generating means (not shown). The direction is changed by the upper guide roller 3, passes through the electric discharge machining section 7 for the work 5, is changed by the lower guide roller 9, and is collected by a wire collecting means (not shown). In addition, an upper head 15 provided with a power supply 11 and an upper wire guide 13 and a lower head 21 provided with a power supply 17 and a lower wire guide 19 are provided above and below the work 5. The power is supplied to the wire 1 via the power supply 11 and the power supply 17 of the lower head 21. Further, a voltage opposite to that of the wire 1 is supplied to the work 5, and electric discharge machining is performed between the wire 1 and the work 5 whose paths are regulated by the upper wire guide 13 and the lower wire guide 19.
[0013]
By the way, as the wire 1 serving as an electrode of a wire electric discharge machine, various diameters such as 0.1 mm, 0.2 mm, 0.25 mm, and 0.3 mm are used. There is an error, and an attempt to reduce the error inevitably increases the cost. However, it is difficult to obtain a uniform wire having no error over the entire length of the wire.
[0014]
In the above description of the conventional technique, in the wire electric discharge machine, a machining path program which is a movement path of the center position of the wire electrode is created according to a desired shape to be machined into a work, and a wire path of a wire electrode to be used is created. The amount obtained by adding the radius and the discharge gap (machining gap) according to the machining conditions of rough machining or finish machining is defined as the offset amount, and the offset amount is added to the movement amount according to the machining path program of the wire electrode or the work. It has been described that the moving amount is instructed to the wire electrode or the moving means of the work. However, if there is an error in the wire electrode diameter, it will appear as a processing error in the processed product, and precise processing cannot be performed.
[0015]
Therefore, in the present invention, a wire diameter measuring device 23 for measuring an electrode diameter of the wire 1 before the electric discharge machining is provided at a stage preceding the electric discharge machining section 7 for the workpiece 5, and the electrode diameter of the wire 1 is measured. The processing accuracy is improved by reflecting the movement amount of the wire 1 or the work 5 in accordance with the processing locus program.
[0016]
The measurement of the electrode diameter of the wire 1 may be performed every predetermined time, also, the wire diameter measurement device 23 indexing 360 ° about the central axis of the wire 1, and rotatable in, always wire 1 performed by for to the machining direction of travel and the wire traveling direction with respect to the workpiece 5 to be able to measure the electrode diameter of the vertical direction of the wire 1, a precise machining even when the wire electrode section is not the perfect circle by be able to.
[0017]
Next, the configuration of the wire diameter measuring device 23 will be described with reference to FIG.
In FIG. 2, (a) is a front view, and (b) is a cross-sectional view taken along the line AA. A gear 27 rotatably supported by a support plate 25 is provided with a wire 1 passing through a central shaft portion of the gear 27. A wire through hole 29 is provided, and a light emitting element group 33 for projecting a large number of light beams 31 on a plane perpendicular to the traveling direction of the wire 1 and a light receiving element group facing the light emitting element 33 with the wire 1 interposed therebetween. 35 is provided on a base 37 on the gear 27.
[0018]
In the light receiving element group 35, a large number of light receiving elements are arranged in a state corresponding to the large number of light beams emitted by the light emitting element group 33, and as shown in FIG. The electrode diameter of the wire 1 is measured by counting the number of blocks. However, the amount of received light may be measured regardless of the number of received light. The wire diameter measured in this way means that the line width of the projected light is measured even if the wire cross section is not a perfect circle. In the present embodiment, the shadow of the projected light beam is used for the measurement of the electrode diameter, but a measuring unit other than the projected light may be used.
[0019]
Therefore, if a value obtained by adding half of the line width to the discharge gap amount is used as the offset amount in the electric discharge machining, accurate machining can always be performed even if there is an error in the wire electrode diameter.
[0020]
However, as shown in FIG. 1, since the machining shape trajectory 39 by the electric discharge machining is not always in a fixed direction, the place where the wire 1 faces the machined surface changes. Therefore, the wire diameter measuring device 23 is required to correspond to the machining shape trajectory 39 of the workpiece 5 so that an accurate finished surface can be obtained by always adding half of the line width measured by the wire diameter measuring device 23 to the discharge gap amount. by so rotates around the wire 1, the side on which pairs toward the finishing operation surface by measuring the line width of the wires 1, one side, by utilizing the result, the offset amount due to the error in wire diameter Can always be an accurate value.
[0021]
That is, as shown in FIG. 2, the gear 27 of the wire diameter measuring device 23 rotatably supported on the support plate 25 meshes with the gear 43 of the servomotor 41 also supported on the support plate 25, and The wire diameter measuring device 23 is rotated by the control rotation of 41. Then, the processing proceeding direction determined from the XY direction movement of the machining shape trajectory 39 which is set in advance, always measure the wire diameter from a direction perpendicular to the processing direction of travel. For example, when processing a circle, the wire diameter measuring device 23 rotates.
[0022]
Note that a block diagram for using the detected value by the wire diameter measuring device 23 of the electric discharge machine for processing of the electric discharge machine is shown in FIG. 1 and will be briefly described.
[0023]
In a conventional electric discharge machine without a wire electrode diameter measuring device, the signal from the electric discharge machining program reading means 45 (the numerical value of the wire electrode diameter is also taken into account) indicates the connection between the wire 1 and the work 5 as shown by a chain line. The electric discharge machining of the work 5 is performed by operating the relative movement means 49 between the wire 1 and the work 5. Of course, the relative movement may be to move the wire 1 or to move the work 5.
[0024]
In the present invention, the wire diameter measuring device 23 is provided, and the measured value is transferred to the electric discharge machining program reading means 45 by the offset amount computing means 53 provided between the electric discharge machining program reading means 45 and the moving amount computing means 47. The signal is multiplied by a signal from the controller to calculate an offset correction amount based on an error in the wire diameter, the result is transmitted to a conventional moving amount calculating unit 47, and a relative moving unit 49 is further operated. . It should be noted that the offset amount correction control method for the shape and size of the wire 1 in the wire electric discharge machine is shown in a flowchart of FIG.
[0025]
Further, by making the wire diameter measuring device 23 rotatable around the traveling direction of the wire 1, it is possible to eliminate the roundness error of the wire 1. That is, as shown in FIG. 2, a rotary drive unit including a servomotor 41 and a gear 43 for the wire diameter measuring device 23 is provided, and as an indexing rotary unit 51 shown as a block diagram in FIG. Is used to measure the line width of the wire 1 in the direction facing the processing surface moving along the processing shape trajectory 39 of the workpiece 5, and the offset correction amount due to the perfect circular error of the wire electrode diameter can be considered. Thus, the measurement result is input to the offset correction amount calculating means 53.
[0026]
Further, by turning the wire diameter measuring device 23 around the wire 1 in accordance with the machining shape trajectory 39 of the work 5, the wire width of the wire 1 in the direction facing the machining surface is measured, Using the result, the offset correction amount due to the wire electrode diameter error and the perfect circle error can always be set to an accurate value.
That is, the position where the electrode diameter of the wire 1 is measured by the wire diameter measuring means 23 is controlled so as to coincide with the position of the electric discharge machining between the workpiece 5 and the electric wire.
[0028]
【The invention's effect】
As described above, since the electrode diameter of the wire electrode before the electric discharge machining is measured, it is possible to obtain an accurate electrode diameter of the wire electrode at the time of machining the work, and to use the measured value to make an accurate discharge. Processing can be performed. That is, the offset amount correction amount is calculated from the difference between the measured electrode diameter of the wire electrode before the electric discharge machining and the electrode diameter of the wire electrode in the electric discharge machining program, taken in, and the movement amount is calculated. Even if the electrode diameter varies, the processing accuracy can be improved without using a wire electrode having high dimensional accuracy.
[Brief description of the drawings]
FIG. 1 is an enlarged view of a main part of a wire electric discharge machine including a machining control block diagram showing an embodiment according to the present invention.
FIGS. 2A and 2B are diagrams showing a wire diameter measuring means of the wire electric discharge machine according to the present invention, wherein FIG. 2A is a front view and FIG.
FIG. 3 is a flowchart showing a method of controlling offset amount correction for the shape and dimensions of a wire electrode in the wire electric discharge machine of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wire electrode 3 Upper guide roller 5 Work 7 Electric discharge machining part 9 Lower guide roller 23 Wire diameter measuring device 27 Gear 29 Wire through hole 31 Light beam 33 Light emitting element 35 Light receiving element 39 Processing shape locus 41 Servo motor 43 Gear 45 Electric discharge machining program Reading means 47 Moving amount calculating means 49 Relative moving means 53 Offset correction amount calculating means

Claims (1)

In a wire electrode processing machine that runs a wire electrode and relatively moves the wire electrode and the work to form a desired shape on the work.
Relative movement means for relatively moving the wire electrode and the work,
Electrode diameter of the wire electrode, an offset amount according to the electrode diameter of the wire electrode and a discharge gap, an electric discharge machining program reading means for reading an electric discharge machining program comprising a machining shape program according to the desired shape,
In consideration of the offset amount in the machining shape program of the electric discharge machining program, a relative movement amount between the wire electrode and the work is calculated, and a movement amount calculation unit to send to the relative movement unit,
Indexing is provided before the electric discharge machining part of the wire electrode and the work, and the measuring part is indexed around the central axis of the wire electrode and rotated to measure an electrode diameter of the wire electrode before electric discharge machining. Equipped with a rotating means, electrode diameter measuring means for measuring the electrode diameter of the wire electrode from a direction always perpendicular to the processing progress direction ,
An error of the electrode diameter of the wire electrode is calculated from the read electrode diameter of the wire electrode and the measured electrode diameter of the wire electrode, and the offset correction amount calculating means is sent to the moving amount calculating means as a correction amount of the offset amount. When,
Wherein the wire electrode machine corrects a shape error of the wire electrode before electric discharge machining when the wire electrode and the workpiece move relative to each other.

Images