JP2010023188A - Swing discharge machining method and swing discharge machining apparatus in engraving discharge machining operation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a desired machining condition of a machining operation such as a drilling operation, a through-hole boring operation or the like having multi-stage machining conditions combined by an NC program, without modifying or changing the program, only by inputting and setting the number of divisions and a feed quantity of the division. <P>SOLUTION: A position is selected that is located at a prescribed length before a feed finish position in the direction of a machining depth by the NC program. A machining feed length to a machining feed finish position from this position and a swing quantity of an enlarged swing in the direction of a side surface at the position before the feed finish position are divided into micro machining sections of a previously selected number of divisions. A swing discharge machining operation from the position before the feed finish position by the movement in the direction of depth and the direction of swing for each of the micro division machining sections is sequentially advanced to the feed finish position without changing an electric machining condition to the position before the feed finish position by deciding whether or not the machining operation is completed for each of the micro division machining sections to switch to a next machining operation of the NC program. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an oscillating electric discharge machining method in sculpture electric discharge machining and an oscillating electric discharge machining apparatus used for the implementation of the oscillating electric discharge machining method.

Die-sinking electric discharge machining is to form a hole of a desired shape in the workpiece, and using the electrode of the total shape having a shape corresponding to the desired shape, the shape of the electrode is transferred to the workpiece. And a processing method called a contour processing or a creation processing for processing a desired shape on a workpiece by using a simple shape electrode, for example, a small columnar electrode.

When electric discharge machining is performed by dividing one machining shape into several machining processes such as rough machining to finishing machining, the values of each electrical machining condition set in each machining process are different. The degree of wear of the electrodes and the size of the discharge gap are different. Therefore, for each machining process, an electrode is manufactured in consideration of the discharge hole based on the contour shape of the machining hole targeted in the machining process and the electrical machining conditions, and the electrode is prepared and machined for each machining process. There is a need to. For this reason, when the number of processing steps becomes large, the corresponding number of electrodes is required, and manufacturing a plurality of similar electrodes is complicated and requires time, so that one processing shape is processed. Therefore, the work time required for the whole process is considerably long.

Therefore, in order to reduce the number of electrodes used in electrical discharge machining of one machining shape as much as possible, and to use the same shape electrode even if there are a plurality of electrodes used, the electrodes are formed in the depth of the machining hole. In addition to the relative movement (including servo feed operation) with respect to the workpiece only in the vertical direction (hereinafter referred to as the machining depth direction), the electrode is also moved relative to the side direction perpendicular to the machining depth direction. The method of machining at the same time in the lateral direction is known as the so-called oscillating electric discharge machining method. Feeding of relative movement by servo control in the machining depth direction of the electrode and relative machining by setting of the side direction or servo control. An oscillating electric discharge machining method in which feed movement is combined or combined in various ways is known.

Japanese Patent Laid-Open No. 03-154717 Japanese Patent Laid-Open No. 03-270825 Japanese Patent No. 3856159 Japanese Patent No. 3807189 JP 56-27743 A

A basic specific example of such a swing electric discharge machining method will be described with reference to the drawings. FIGS. 4 and 5 show the movement in the four-step machining process from rough machining to finishing of the electrode and workpiece in the swing electric discharge machining as described above, machining in the machining depth direction (FIG. 4), This is divided into processing in the side direction perpendicular to this [FIG. 5] and is shown in a side view.

That is, FIG. 4 is an explanatory view of the feed length HD fed in the machining depth direction by the above four stages of machining steps in the machining depth direction (Z axis) between the electrode 1 and the workpiece 2. Is the electrode, E0 is the position at the start of processing, E1 to E4 are the positions of the electrodes when processing in each of the above four steps is completed, and GD0 and GD1 to GD4 are similarly set processing conditions Machining gap length (or machining depth or overcut in the bottom direction), RD1 to RD4 are the bottom surface roughness at the end of each machining process, D is the depth of the machining hole for machining, and B0 is the finished hole The processing after the second stage of the machining process at the bottom of the machining is set to remove the machining surface roughness formed on the bottom of the machining hole by machining in the machining process immediately before or at the minimum. The feed amounts HD1 to HD4 in each processing stage are D, GD0~GD3, it is possible to determine the like RD1～RD3, it is possible to know the position of the electrode E tip.

FIG. 5 is a diagram for explaining an example of a method of setting the oscillation amplitude HS in the side surface direction perpendicular to the machining depth direction between the electrode 1 and the workpiece 2, and the four-stage machining in FIG. 4 described above. Corresponds to processing by process. In the case of this figure, the enlarged swing amplitudes HS2 to HS4 of the respective machining steps are constant during the machining of each machining section, but according to the feed position in the depth direction during each machining step as will be described later. Further, the enlargement range of the swing can be successively increased continuously.

In the figure, E1 to E4 indicate the positions of the electrodes with respect to the sidewalls of the processing holes when the above four processes are completed, GS1 to GS4 are also the values of the respective overcuts, and RS1 to RS4 are the same side Wall surface roughness, S0 is the finished surface of the side wall and its position, LE is an electrode reduction value when the rough machining of the first machining process is machined with the amplitude of the oscillating motion being 0, HS2, HS3 and HS4 are the second Since the amplitude dimension of the swinging motion after the machining process is an index indicating the increment relative to that of the previous machining process, and in this case, HS1 = 0 of the first machining process as described above, the second machining process is performed. In this case, the amplitude of oscillation is equal to HS2 in that case, the amplitude of oscillation in the next third machining step is HS2 + HS3, and the amplitude of oscillation in the final machining step is HS2 + HS3 + HS4. .

Therefore, as in the case of determining the feed amount HD in the machining depth direction, the machining after the second machining process is substantially or minimally formed on the sidewall of the machining hole by the machining of the previous machining process. Assuming that the processed surface roughness portion is removed, the swing amplitude increments HS2 to HS4 in each processing step of the swing processing are the surface roughness RS1 to RS3 and overcut values GS1 to GS4. Can be obtained by calculation.

FIG. 6 is an explanatory diagram in the case where a hole 2H having a depth D is drilled or drilled at once by swing electric discharge machining in the workpiece 2 by the rod-shaped electrode 1, and in the case shown, the axis center of the non-rotating electrode is The swing trajectory formed by expanding in the lateral direction as it is fed deeper in the machining depth direction is represented by the servo feed speed VS in the machining depth direction and the swing feed speed VL by setting or servo control in the lateral direction. A case is shown in which the spiral swing expansion angle Lθ is machined to a predetermined depth D with a constant swing swing locus LL from the minimum swing amplitude to the maximum swing amplitude LM. Of course, the locus LL of the enlarged swing can have various shapes according to the contour shape of the cross section of the electrode 1 in the direction perpendicular to the machining depth direction.

In FIG. 6, a hole 2H having a depth D from the upper surface of the workpiece 2 is formed between the electrode 1 and the workpiece 2 immersed in a machining liquid in a machining tank (not shown). Processing is advanced by a processing program in which electrical processing conditions of processing, intermediate finishing processing, finishing processing, and other necessary processing conditions are controlled and given at a predetermined processing depth position in the processing depth direction, The hole 2H having the depth D is processed at a stretch from the surface of the workpiece 2 to the bottom surface of the hole 2H.

That is, the one-step machining in the machining hole 2H shown in FIG. 6 is the first first-stage machining in the four-stage machining process of the swing electric discharge machining described in FIGS. This is any one of the second stage machining, the third stage machining, or the final fourth stage machining.

As described above, in electrical discharge machining such as drilling and contour creation, the electrical machining conditions are mainly set from strong machining conditions to weak machining conditions between the start of machining and the end of machining. However, the selected machining conditions deviate from the appropriate machining conditions as the amount of machining in each machining process corresponds to the machining site. If this happens, an unstable state of processing is likely to occur, and a plexus is generated on the processed surface or a shape error is caused, which makes it difficult to perform additional correction processing later.

In addition, for example, in the second or third stage of the machining process of FIGS. 4 and 5 described above, the machining site where the machining in the machining process is scheduled is minimized according to the machining conditions set in the machining process. If the machining process is switched to the next process without performing a limited amount of machining, the machining conditions for the subsequent machining process are usually the same as before. Since the setting is weaker than the processing conditions, even if the processing is shifted to the switched third or fourth stage processing step or the processing is further advanced to finish the processing, It is necessary to rework and modify the irregular shape, and the processing such as the correction must be performed under weak processing conditions such as the third or fourth stage. With or there is an increase of Worn, to such modification work that became necessary in a post-process requires a variety of labor, there has been a problem that forced a heavy burden.

Such a problem occurs after the machining condition region of the intermediate machining except for the first so-called rough machining stage in the case of oscillating electric discharge machining such as drilling. It can be said that it does not easily occur until the stage of processing such as roughing, intermediate processing of dimension and shape forming, or even if it occurs, it is not so much a problem because it is relatively easy to correct.

Accordingly, an object of the present invention is to generate a discharge by intermittently applying a required machining voltage to a machining gap formed by an electrode and a workpiece, in a machining gap formed by the electrode and the workpiece. Die-sinking electrical discharge machining, wherein the electrode and the workpiece are moved relative to the machining depth direction and the side surface direction of the machining hole perpendicular to the machining depth direction to machine the workpiece. Because
When the feed position in the machining depth direction reaches the feed end position in the predetermined machining depth direction according to a preset machining program, and the amount of fluctuation in the lateral direction reaches a predetermined value, the machining in the machining section is finished. Then, the machining conditions including the feed depth in the machining depth direction, the lateral swing fluctuation amount, and the electrical machining conditions are switched to the machining conditions set in the machining program of the next machining process. In the oscillating electric discharge machining method, the electric discharge machining clearance (dimensions and shape) in the machining depth direction and the side surface direction of the workpiece from the position at the end of feeding in the machining depth direction at which the machining conditions are switched to the required area immediately before that. (Accuracy) evenly and consistently and precisely according to the set machining program, so that the machining can be smoothly transferred to after the machining conditions have been switched. Located in.

The objects of the present invention are as follows: (1) A required machining voltage is intermittently applied to a machining gap formed by an electrode and a workpiece to generate an electric discharge, and the electrode and the workpiece are machined to a machining depth. Die-sinking electric discharge machining, which is configured to process the workpiece by moving relative to the side direction of the processing hole perpendicular to the vertical direction and the processing depth direction,
When the feed position in the machining depth direction reaches the feed end position in the predetermined machining depth direction according to a preset NC program and the amount of fluctuation in the lateral direction reaches a predetermined value, the machining in the machining process is finished. Then, the machining conditions including the feed length in the machining depth direction, the amount of fluctuation in the lateral direction, and the electrical machining conditions are switched to the machining conditions set in the NC program of the next machining process. In the swing electric discharge machining method,
From the feed end position in the machining depth direction set in the NC program for machining in the desired machining process, a position in front of a predetermined length selected in advance is set, and from this position to the feed end position of the machining process. The processing feed length and the remaining swing amount of the swing expansion in the lateral direction at the position in front of the processing step are each divided into a preselected division number of minute processing sections,
Oscillating electric discharge machining from the front position by swinging in the machining depth direction and swing enlargement direction for each minute divided machining section without changing the electrical machining conditions of the machining up to the front position , The end of the machining is sequentially progressed for each minute divided machining section, the machining in the minute machining section is sequentially advanced, and the machining end is determined by machining to the feed end position set in the NC program of the machining. This is achieved by using an oscillating electric discharge machining method that switches to NC program machining in the next machining step when it is determined to be finished.

In addition, the object of the present invention is as follows: (2) When the machining in the machining depth direction according to the NC program of the desired machining process reaches the previous position, the completion of the machining is determined and a predetermined completion state is confirmed After that, the swing electric discharge machining method according to the above (1) in which the portion of the divided minute machining section is shifted to the sequential machining from the previous position is achieved.

Further, the object of the present invention is as follows: (3) The swing electric discharge machining according to (1), wherein the division of the minute machining section of the predetermined number of divisions is adjusted so as to be an equal division by an integer. This is achieved by a method.

Further, the object of the present invention described above is as follows: (4) The position determination associated with the relative movement between the electrode in the side direction perpendicular to the processing depth direction and the processing depth direction and the workpiece is determined. This is achieved by the swing electric discharge machining method according to (1), which is contact detection or spark-out state detection with respect to a predetermined reference position between the position detection and the electrode workpiece.

The object of the present invention described above is (5) sequential determination for the regions divided in the radial direction with respect to the processing surface in the processing depth direction and / or the enlarged surface in the side surface direction. This is achieved by the swing electric discharge machining method described in (1) above.

The object of the present invention is as follows: (6) The division number and the divided feed amount which is the length of the divided minute machining section can be directly input and set by the control device independently of the machining NC program. This is achieved by the swing electric discharge machining method described in (1) above.

The above-mentioned object of the present invention is as follows: (7) The division width allocated to the minute division feed machining section d is set or formed with the type / purpose of machining, the type / combination of electrodes / workpieces, and the like. This is achieved by the swing electric discharge machining method described in (1) above, which is determined in advance according to the machining conditions and the like.

Further, the object of the present invention is as follows: (8) The front position is determined by a product of the division feed amount d of the preset division feed processing and a preset division number N. This is achieved by the swing electric discharge machining method described in (1) above.

The above-mentioned object of the present invention is to (9) generate a discharge by intermittently applying a required machining voltage to a machining gap formed by an electrode and a workpiece, and to connect the electrode and the workpiece. Die-sinking electric discharge machining, which is configured to process the workpiece by moving relatively to a machining depth direction and a side direction of a machining hole perpendicular to the machining depth direction,
When the feed position in the machining depth direction reaches the feed end position in the predetermined machining depth direction according to a preset NC program and the amount of fluctuation in the lateral direction reaches a predetermined value, the machining in the machining process is finished. Then, the machining conditions including the feed length in the machining depth direction, the amount of fluctuation in the lateral direction, and the electrical machining conditions are switched to the machining conditions set in the NC program of the next machining process. In the swing electric discharge machine
Division feed machining section setting control for setting a section from the feed end position in the machining depth direction set in the NC program for machining in the desired machining process to a position in front of a predetermined minute length selected as a divided feed machining section. Means, and a division number N for which the division feed machining section is selected in advance,
The length from the previous position to the feed end position of the machining step and the remaining amount of swing expansion in the lateral direction at the front position are a minute length of the process feed amount d divided by the number of divisions, and Forming control means for the divided feed machining section formed by the product of
Machining control means for split feed machining, in which machining from the front position side of the divided feed machining section is sequentially performed for each divided feed amount without changing the electrical machining conditions for machining up to the previous position. When,
This is achieved by using an oscillating electric discharge machining apparatus equipped with

The above-mentioned object of the present invention is as follows. (10) The processing means for determining the end of machining in which the control means for the divided feed machining advances the sequential machining operation for each of the divided feed amounts while judging the completion of the machining. This is achieved by using the swing electric discharge machining apparatus as described in (9) above.

Further, the object of the present invention described above is that (11) the number of divisions and the divided feed amount which is the length of the divided minute machining section can be set and input to the control device independently of the machining NC program. This is achieved by using the swing electric discharge machining apparatus according to the above (9).

According to the present invention, from the roughing process to the final finishing process, usually in the process of multiple stages of about 3 to 8 stages, in the process of the previous process stage with respect to the process of the subsequent process stage, The previous machining so that the discharge clearance (in relation to the overall uniformity of the gap at each point in the fitted state at a predetermined position between the machining surface and the work surface) is not taken over. The step of swing electric discharge machining in this stage is divided into a machining feed length in the machining depth direction and a swing enlargement amount in the side direction into each of two or more N minute machining portions (divided feed amount), Without changing the electrical machining conditions, the number of divisions is divided into the number of divisions, the feed is divided into divided parts, and the parts are processed in order, so that the overall discharge clearance is fine. Approach uniform and constant No surface unevenness approaches the constant size and shape, results electrode wear is reduced as an effect such as it is also shortened the required machining time.

According to the present invention, it is possible to input and set the number of divisions and the divided feed amount without modifying or modifying the drilling, drilling and the like combining multi-stage machining conditions by the NC program. As a result, there is no need to select electrical machining conditions and the like, and machining that can achieve the desired machining conditions can be performed, so the practical advantage is enormous.

FIG. 1 is a side cross-sectional explanatory view of a processed hole portion for explaining a processed hole 2D formed in a workpiece 2 for explaining an embodiment of the present invention. In contrast to FIG.
As an aspect in the depth direction of the processing hole, the electrode E is a small predetermined length before the predetermined electrode position E2, E3, or E4 where the processing of the second, third, or fourth stage ends. In position,
Therefore, as an aspect of the swing expansion direction perpendicular to the depth direction of the above-described machining hole, the electrode E is from the electrode position E2, E3, or E4 where the machining of the second, third, or fourth stage is completed. It shows a state that is in a position in front of a predetermined small predetermined length,
At this predetermined position, a desired small machining section from a temporarily stopped state to the machining end position at each machining stage is divided into a desired plurality of further divided machining sections (in the case of the illustrated embodiment, the number of divisions). N = 4, the depth direction of the machining hole is divided into length or width d, and the perpendicular direction is divided into width s) (usually equally divided). It is intended to describe a mode in which machining is sequentially performed from the part while performing machining end determination for each minute machining section.

That is, according to the present invention, the feed length position in the machining depth direction reaches the feed end position in the predetermined machining depth direction by a preset machining program, and the swing amount of the lateral swing enlargement is set in the machining program. When the predetermined value is reached, the machining of the machining process is finished, and then the machining conditions including the feed length in the machining depth direction, the amount of fluctuation in the oscillation in the side surface direction, and the electrical machining conditions are set to the next machining level. Machining of the machining part immediately before the electrical machining conditions such as the discharge pulse are switched to a weaker condition, such as switching to the machining conditions set in the NC machining program of the process. By dividing it into fine multiple stages in the feed direction and finishing by dividing the divided minute processing sections one by one in order, and processing with careful hands It is said that the required work time etc. can be reduced as a result compared with the case where it finishes to the accuracy of the planned discharge clearance surely and the correction work in the post process is done without adopting the present invention. The aspect of the swing electric discharge machining is as follows.

FIG. 1 shows that the machining process of the oscillating electric discharge machining by the NC program is, for example, the amount of increase in the oscillating amplitude in the direction perpendicular to the feed length in the machining depth direction (HD3 in FIG. 4), which is machining in the third machining process. When most of the machining (HS3 in FIG. 5) has been completed and the electrode has approached the machining end position (E3 in FIGS. 4 and 5) of each of the machining steps, each becomes a “predetermined predetermined position”. When it reaches, it is switched to the swing electric discharge machining mode of the present invention. According to claim 1, the “predetermined predetermined position” is set in the machining NC program of the desired machining process. This means a “front position” in which “a position in front of a predetermined length selected in advance is set from the feed end position in the machining depth direction”.

In addition, the “division number N” point of the machining process in which the region from the “front position” to the “feed end position” is divided into a plurality of processes and sequentially processed is also “from the previous position”. A machining feed length up to the feed end position of the machining step and a remaining swing amount of the swinging expansion in the lateral direction at the front position of the machining step are each a minute machining section of a predetermined number of divisions. Therefore, at least two or more and at most about several tens of divisions are used.

As a result, it becomes clear when collating with the following, but the “machining feed length from the previous position to the feed end position of the machining process” is divided into “preliminarily selected number of small machining sections”. "The minute machining section" d in the machining depth direction is a unit of division in the machining depth direction in which the minute machining section can be changed and set. “The remaining amount of oscillation in the lateral expansion at the position of“ is divided into minute machining sections of a predetermined number of divisions ”means“ minute machining section ”s perpendicular to the machining depth direction. Is a unit of division of the remaining oscillation amount in the side surface direction perpendicular to the machining depth direction in which a minute machining section can be changed.

Thus, the present invention provides a condition immediately before the machining conditions for swing electric discharge machining such as digging consisting of a plurality of programmed machining steps, particularly electrical machining conditions such as electric discharge pulses, are switched to weaker conditions than before. This is to ensure that the processing of the area portion is finished with a predetermined size, shape and accuracy.

Therefore, the present invention sets a position in front of a predetermined length from the feed end position in the machining depth direction of the machining process in the desired machining process set in the NC program of the sculpture swing electric discharge machining,
The processing feed length to the previous position and the feeding end position of the processing step,
The remaining swing amount of the swing expansion in the lateral direction at the position in front of the processing step,
Each is divided into minute machining sections of a preselected number of divisions,
Without changing the electrical machining conditions for machining up to the front position, the swing electric discharge machining from the front position by the movement in the machining depth direction and the swing enlargement direction for each minute divided machining section, While performing the end of machining for each minute divided machining section, the machining of the minute machining section is sequentially advanced,
Machining is sequentially performed up to the feed end position set in the NC program for the machining, and the machining end determination is made. When it is determined that the machining has been completed, the process is shifted to machining in the machining process of the next NC program. .

That is, in the conventional oscillating electric discharge machining, machining at a certain machining step programmed in the NC program is performed from the machining start position of the machining step to the feed end position in the machining depth direction, which is the machining target position. Up to this point, all the sections were processed at once as one processing section, but in the present invention, the feed end position in the processing depth direction, that is, the processing of the next processing section set in the NC program is performed. Outside the position to switch,
The first half of the machining section is processed at a stroke from the start position of the machining process, and the final portion of the latter half between the feed end position where the electrical machining conditions are switched, and a position before a predetermined length. The latter half of the last part is processed by the method of the present invention.

Here, as partially described above, the feed end position which is the machining target position in the machining depth direction is 2B,
The number of divisions selected in advance is N, and the depth or length of one minute machining section divided in the machining depth direction (referred to as a divided feed amount) is d: the divided feed amount in the machining depth direction is 1 A numerical value of depth or length to be processed such as 0.0 mm or 1.1 mm is set.
One minute enlarged swing amount divided in the direction perpendicular to the machining depth direction is s: a swing enlarged amount to be processed, such as 0.1 mm or 0.15 mm, in a step of swing swing amount or amplitude divided swing amount step. The amount width is set.
As a result, the feed final position 2B, which is the machining target position in the machining depth direction, is located at a position of a predetermined length: dN set in advance from the previously set position, and the swing enlargement is performed. The maximum swing amount, which is the final target, is step sN.

With the above settings, the machining distance or machining length to the nth target position is nd, the target step is ns, and dn = dN−d × (N−n), respectively.
sn = sN−s × (N−S)
Can be expressed as
In FIG. 1, when the division number N is N = 4, the machining that is switched or temporarily stopped at the previous position is performed without changing the electrical machining conditions. Machining is performed using step s1, that is, the divided feed amount d1 in the machining depth direction is fed by servo-controlled feed, whereas the divided swing amount step s1 in the side surface direction is synchronized with the feed of the servo feed control. Move and process,
When the processing up to d1 is finished, each of the regions d (= d2-d1 = d3-d2 = ...) of a plurality of divided swing amounts in a minute processing section is used so that processing up to d2 is performed using the next step s2. .. = Dn−dn−1 =...) Are sequentially processed, and finally, when the processing of the divided feed amount dN using the step sN is completed, the processing ends.

In the present invention, the processing for each divided feed change amount or swing amount d1, s1; d2, s2;... "..." means that, for example, if the feed to the target position is detected by the feed position detection or the like, there is no leftover of machining at the machining position under the machining conditions. Alternatively, whether or not the finish is uniform with a predetermined accuracy as a whole is measured by relative position movement, contact detection, spark-out determination, etc., and is performed many times instead of once or twice, and the next step s2 is used. After the machining of the divided feed amount d2 is performed, and the rework processing is performed to sufficiently improve the finishing accuracy of the machining in this way, the machining conditions and positions are processed by the NC program after the machining of the divided feed amount dN is completed. And it is to permit the processing condition to the switching transition programmed to have next processing step. In that sense, it is preferable that the end of processing at the position is first determined at the front position.

FIG. 2 is a modified embodiment in which a part of the first embodiment of FIG. 1 is changed. As shown in FIG. 6, the swing amount of swing enlargement is constant according to the increase of the feed length in the machining depth direction. FIG. 6 is an explanatory diagram of the positions of electrodes on the machining bottom surface and the side wall surface in the case of oscillating electric discharge machining in which the angle of the oscillating shaft with respect to the machining depth direction is set to be inclined as desired. N is the number of divisions, mddv is a minute feed amount with a minute one-piece feed length in the machining depth direction, and mdsv is a minute one-divided amplitude step with a rocking amount for swing expansion in the side direction. The distance dn to the target position and the step sN are
dn = D (= dN) − [mddv × (N−n)]
sn = STEP (= sN) − [mdsv × (N−n)]
Is required.

Then, in the first processing, after processing up to d1 using step s1, the processing returns to the division return point R, and this processing is repeated a plurality of times, and then the end of processing is determined, and the processing ends while it is repeated a plurality of times. It is determined that the processing up to d1 is finished.
In the next processing, after processing up to d2 using step s2, the processing returns to the division return point R and this is repeated a plurality of times. In the last processing, after processing using STEP to the processing end position, the processing ends at that point. In the processing of each divided portion, it is important to perform the processing operation a plurality of times or a necessary number of times, and to detect and measure the end of processing.

Then, the divided feed amount d in the depth direction and the swing amount s of the swing expansion in the side surface direction of the minute machining section divided into the minute parts are applied to the processing of the steel material for metal molds or the like. If the former d is about 1.0 mm, the latter s is set to about 0.1 mm, and the relative oscillating feed control in the processing depth direction and the side surface direction is set. Since the minimum unit of command and drive is usually 0.1 μm or less, the swing movement control can be performed with a sufficient margin.

FIG. 3 is a block diagram explanatory diagram of an embodiment control device used in the implementation of the swing electric discharge machining method of the present invention. The control device includes an internal storage device 10, an external storage device 20, a storage medium reader 30, A display device 40, an input device 50, a central processing unit 60, a temporary storage device 70, an input / output device 80, and the like are provided. The central processing unit 60 is further connected to a motor via the input / output device 80. The control device 90 and the electric discharge machining power supply device 100 are connected.

The built-in storage device 10 is a main storage device such as a hard disk drive provided in an electronic computer unit of a numerical controller attached to the die-sinking electric discharge machine, and this built-in storage device can freely read and write data. The stored data is held even when the power supply of the numerical control device is cut off. Therefore, the storage device is one of means for storing and storing the NC program.

The external storage device 20 is an auxiliary storage device that can store data through an output port provided in an electronic computer unit, such as a USB flash memory (USB Memory, Universal Serial Bus), for example. Data can be freely read and written, and it can be attached to an output port to exchange data with an electronic computer unit, removed from the output port, and carried with data stored. Therefore, this external storage device can also be one of means for storing and holding the NC program.

The storage medium reader 30 is an auxiliary storage device that is provided in the electronic computer unit and includes a storage medium (medium) that can be removed from the main body and a drive device that reads and writes data from and to the storage medium. Specifically, for example, an optical disk drive such as a DVD drive (DVD, Digital Video Disc) or a CD drive (CD, Compact Disc), or a magnetic disk such as an FD drive (FD, Floppy (registered trademark) Disk) Therefore, the storage medium reading device is means for storing and holding the NC program in the storage medium.

The display device 40 is, for example, a color display (monitor) such as a liquid crystal display (LCD) attached to the numerical control device, and the display device is optionally connected to an electronic computer unit with a graphic adapter ( When a video card is provided, it includes a graphics adapter.

The input device 50 is a switch, keyboard, mouse or the like of an operation panel attached to the numerical control device, and further includes a touch sensor provided on the liquid crystal display device. This is a means for giving various operation data to the electronic computer unit.

The temporary storage device 70 is a random access memory (RAM) provided in the electronic computer unit. The temporary storage device 70 stores data necessary for the operation when the central processing unit 60 performs the operation, and stores the operation result. It is to hold.

The arithmetic unit 60 is a main processor of a numerical control unit configured by a central processing unit (CPU) provided in the electronic computer unit, and inputs various programs, data, and the like from the various storage units described above. According to the input data, commands, etc. of the device 50, it is taken in and calculated, and an operation command is given to the motor control device 90 and the machining power supply device 100 of the electric discharge machine via the input / output device 80 to perform the required swing electric discharge machining. The control is performed by detecting and feeding back the processing state and result as required.

The oscillating electric discharge machining method of the present invention, in particular, the feeding end from the front position without changing the electrical machining conditions by feeding the machining depth to the minute divided section (divided feed amount) and swinging in the lateral direction. In order to execute processing up to a position (referred to as a division feed processing or a division feed processing step), the central processing unit 60 of the control device inputs numerical data of the division number N and the division feed amount d. However, there are the following three methods in general.

First, as a first method, the division number N and the divided feed amount d are given as numerical data as set values from the input device 50, and the input division number and the divided feed amount d are stored in the temporary storage device 70. Remembered.

Next, or as another method, the NC program in the desired processing is read from the internal storage device 10, the external storage device 20, or the storage medium reader 30, and the NC program is displayed on the screen of the liquid crystal display device 40. In this case, a specific NC code, the number of divisions, and the divided feed amount are additionally written to the NC program from the input device 50. The rewritten NC program is stored in the temporary storage device 70. When necessary, the NC program file data in the internal storage device 10, the external storage device 20, or the storage medium reader 30 is overwritten. To remember.

As another method, the division processing is selectively designated according to the menu of the setting screen in the processing condition setting system of the processing power supply apparatus 100, and the processing conditions and feed obtained according to the processing condition setting system are sent to the arithmetic unit 60. The number of divisions and the divided feed amount are automatically determined by a predetermined process based on the machining shape including the amount. Then, the determined division number and division feed amount are added to the NC program together with the NC code, or are stored in the temporary storage device 70 as set values.

A simple method for determining the division number and the divided feed amount based on the machining conditions and the machining shape including the feed amount is to prepare a data table corresponding to the machining shape including the machining conditions and the feed amount ( An existing database can be used), and the optimum value can be read and determined.

The number of divisions and the division feed amount are usually the same in the machining depth direction and the rocking direction, and the latter is given as a different value, but may be the same, depending on the purpose of machining, etc. Various selections are made. The processing depth direction will be described below.

The first method of setting the number of divisions and the division feed amount is easy to realize because it is only necessary to directly input and set numerical data from the input device 50. Since the data cannot be saved, there is a problem that it is necessary to input and reset the set value for each processing.

On the other hand, the method of adding the NC code to the second NC program can save the number of divisions and the divided feed amount together with the NC program, but requires a relatively specialized knowledge from the operator, and the burden on the operator is reduced. large. That is, for example, there is a possibility that the number of divisions and the division feed amount may be set incorrectly, and it is necessary to rewrite the NC program again when this division feed machining is not performed.

In addition, the method using the machining condition setting system has an advantage that the burden on the operator is relatively small, but there is a problem that it is required to change the application program of the machining condition setting system on a large scale. In this way, in the above case, it is generally recommended to use a method of inputting numerical data from the input device 10 when comparing the advantages and disadvantages due to the difference in the input setting method. Hereinafter, the split feed processing when this method is employed will be described.

When the operator starts electric discharge machining, the numerical controller in the numerical controller sequentially outputs movement command values (position data, etc.) to the motor controller while decoding the NC program. Servo control of the axis servo motor and output of machining condition data to the machining power supply apparatus 100. The machining power supply apparatus 100 including the pulse control apparatus operates circuit components to apply voltage pulses that meet the machining conditions to the machining gap. The required machining current is supplied intermittently.

The numerical control device includes a counter for inputting the output movement command value, and obtains a current movement amount (cumulative movement amount from a machining start position at a certain time when machining is not finished).
Since the processing start position is known, the arithmetic device 60 can obtain the current position from the current movement amount (this method is general because the method is safe). Alternatively, the current position data can be obtained by inputting a position detection signal from a position detector attached to the motor to the numerical controller.
Since the processing start position is known, the arithmetic device 60 can obtain the current movement amount from the current position.

The NC program describes the divided feed amount and the swing amount in each machining step. The arithmetic unit 60 obtains the number of divisions and the divided feed amount from the NC data obtained by decoding the NC program, and the divided feed. The machining start position (start position arrival feed amount) of the divided feed amount of each machining process is calculated. The calculated starting position reaching feed amount for each of the divided machining steps is stored in the temporary storage device 70.

The number of divisions is the number of times of dividing the feed amount of the entire machining process for the division feed processing, and includes the feed amount of the whole machining process. The divided feed amount is a feed amount in one divided portion divided into a preset number in the divided feed processing, and the divided feed amount can set the divided feed amount for each machining process to different values. However, since the degree of freedom for changing the value is small and the machining result is hardly affected, the values of the divided feed amounts are usually set to be the same.

For example, the swing electric discharge machining process by the NC program is the above-mentioned third machining process or the fourth machining process. For example, the total length of the feed length (or amount) in the depth direction of the machining hole in the third machining process is When the number of divisions N is 4 and the division feed amount d is set to 10 μm at 50 mm (50000 μm),
Since the number of divisions includes the feed amount when reaching the machining target position,
The feed amount 49.970 mm (49970 μm) obtained by subtracting 30 μm (10 μm × 3) from the feed amount 50 mm in the machining step is the start position of the first divided feed machining in the divided feed machining (position before the predetermined length previously selected) ) The reached feed amount, and the position at this time is the start position (see FIG. 1).
Similarly, the machining start position arrival feed amount with respect to the machining feed amount of the second divided feed machining is 49.980 mm, and the third start position arrival feed amount is 49.990 mm.

The computing device 60 acquires the current position in a predetermined cycle while outputting the movement command value, and reads the machining start position arrival feed amount with respect to the divided feed amount of the first divided feed machining from the temporary storage device 70, The starting position arrival feed amount is compared with the current movement amount.

When the current movement amount reaches the machining start position arrival feed amount with respect to the divided feed amount, the arithmetic device 60 temporarily outputs the movement command value because the position is the machining start position with respect to the divided feed amount of the divided feed processing. While stopping and not feeding the electrode beyond the start position, the so-called end of machining is determined. Since the end of processing is described in detail above, it will not be described in detail here.

The arithmetic unit 60 executes the process of determining the end of machining and, when it is determined that the process of split feed processing for one split feed amount is finished, obtains the current travel distance in a predetermined cycle while outputting the movement command value again. At the same time, the start position arrival feed amount of the divided feed processing for the second divided feed amount portion is read from the temporary storage device 70, and the start position arrival feed amount and the current movement amount are compared.
When the machining of the NC program reaches, for example, the feed end position of the machining process of the fifth oscillating electric discharge machining, the arithmetic device 60 similarly performs the machining end determination process and finishes the machining. The movement command for the NC program at the next stage is output.

The swing electric discharge machining method of the present invention is useful when applied to electric discharge machining of die-sinking electric discharge machining.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which showed the step of the process of one Example of this invention as a diagram. Similarly, explanatory drawing of the Example which changed a part. The block diagram explanatory drawing of the Example control apparatus used for implementation of the method of this invention. Explanatory drawing of the step of the some process of the machining depth direction in the swing electric discharge machining of a prior art example. Similarly, explanatory drawing of the stage of the some process of the side surface direction orthogonal to a process depth direction. Similarly, explanatory drawing of the swing electric discharge machining of another conventional example.

Explanation of symbols

1, E, electrode 2, workpiece 2F, surface 2D of workpiece, machining hole (side wall thereof)
2B, bottom surface N of machining hole, number of divisions d, minute divided feed length dn in the machining depth direction, division variation s, minute divided oscillation expansion amplitude sn on the side surface perpendicular to the machining depth direction, step 10 , Built-in storage device 20, external storage device 30, storage medium reading device 40, display device 50, input device 60, central processing unit 70, temporary storage device 80, output device 90, motor control device 100, electric discharge machining power supply device

Claims (11)

A required machining voltage is intermittently applied to a machining gap formed by the electrode and the workpiece to generate a discharge, and the electrode and the workpiece are placed in a machining depth direction and perpendicular to the machining depth direction. Die-sinking electric discharge machining that moves relative to the side surface direction of the machining hole to machine the workpiece,
When the feed position in the machining depth direction reaches the feed end position in the predetermined machining depth direction according to a preset NC program and the amount of fluctuation in the lateral direction reaches a predetermined value, the machining in the machining process is finished. Then, the machining conditions including the feed length in the machining depth direction, the amount of fluctuation in the lateral direction, and the electrical machining conditions are switched to the machining conditions set in the NC program of the next machining process. In the swing electric discharge machining method,
From the feed end position in the machining depth direction set in the NC program for machining in the desired machining process, a position in front of a predetermined length selected in advance is set, and from this position to the feed end position of the machining process. The processing feed length and the remaining swing amount of the swing expansion in the lateral direction at the position in front of the processing step are each divided into a preselected division number of minute processing sections,
Oscillating electric discharge machining from the front position by swinging in the machining depth direction and swing enlargement direction for each minute divided machining section without changing the electrical machining conditions of the machining up to the front position , The end of the machining is sequentially progressed for each minute divided machining section, the machining in the minute machining section is sequentially advanced, and the machining end is determined by machining to the feed end position set in the NC program of the machining. An oscillation electric discharge machining method characterized by switching to NC program machining in the next machining step when it is determined that the process is finished. When the machining in the machining depth direction by the NC program of the desired machining process reaches the previous position, the machining end determination is performed, and after confirming a predetermined end state, the divided minute machining section The swing electric discharge machining method according to claim 1, wherein the portion is shifted to sequential machining from the previous position. The swing electric discharge machining method according to claim 1, wherein the division of the minute machining section of the predetermined number of divisions is adjusted so as to be an equal division by an integer. Whether the end of the machining is determined is a position detection associated with a relative movement between the electrode in the side direction perpendicular to the machining depth direction and the machining depth direction, or a predetermined reference position between the position detection and the electrode workpiece. The swing electric discharge machining method according to claim 1, wherein the method is contact detection or spark-out state detection. 5. The oscillation according to claim 4, wherein the end determination of the processing is sequential determination for a region divided in a radial direction with respect to a processing surface in a processing depth direction and / or an enlarged surface in a side surface direction. Electric discharge machining method. 2. The division number and the division feed amount which is the length of a divided minute machining section can be set by directly inputting by a control device independently of a machining NC program. Swing electric discharge machining method. The divided feed amount allocated to the minute divided feed machining section d is determined in advance according to the type / purpose of machining, the type / material combination of the electrode / workpiece, and the machining conditions to be set or formed. The swing electric discharge machining method according to claim 1, wherein: The front position is configured to be determined by a product of a pre-selected division feed amount d of the division feed processing and a preset division number N. 2. The swing electric discharge machining method according to 1. A required machining voltage is intermittently applied to a machining gap formed by the electrode and the workpiece to generate a discharge, and the electrode and the workpiece are placed in a machining depth direction and perpendicular to the machining depth direction. Die-sinking electric discharge machining that moves relative to the side surface direction of the machining hole to machine the workpiece,
When the feed position in the machining depth direction reaches the feed end position in the predetermined machining depth direction according to a preset NC program and the amount of fluctuation in the lateral direction reaches a predetermined value, the machining in the machining process is finished. Then, the machining conditions including the feed length in the machining depth direction, the amount of fluctuation in the lateral direction, and the electrical machining conditions are switched to the machining conditions set in the NC program of the next machining process. In the swing electric discharge machine
Division feed machining section setting control for setting a section from the feed end position in the machining depth direction set in the NC program for machining in the desired machining process to a position in front of a predetermined minute length selected as a divided feed machining section. Means,
The division number N for which this division feed machining section is selected in advance,
The length from the previous position to the feed end position of the machining step and the remaining amount of swing expansion in the lateral direction at the front position are a minute length of the process feed amount d divided by the number of divisions, and Forming control means for the divided feed machining section formed by the product of
Machining control means for split feed machining in which machining from the previous position side of this divided feed machining section is sequentially processed for each divided feed amount without changing the electrical machining conditions for machining up to the previous position. When,
An oscillating electric discharge machining apparatus comprising: 10. The oscillation according to claim 9, wherein the division feed machining control unit includes a machining end determination control unit that advances a sequential machining operation for each divided feed amount while performing a machining end determination. Electric discharge machine. The division number and the divided feed amount that is the length of a divided minute machining section are configured to be input-set to a control device independently of a machining NC program. Item 10. The swing electric discharge machining apparatus according to Item 9.

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