JPH0241821A - Wire electric discharge machining device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of seams by providing a means for detecting the remaining quantity of a wire electrode, a calculating means for calculating the accumulated value of wire electrode consumption for each machining level in each machining shape in the machining order determined for a workpiece, and a judging means for judging the machining level capable for being machined. CONSTITUTION:Before the start of electric discharge machining, the remaining quantity of a wire electrode 5 being stored in a wire reel 6 is detected by a NC unit 31 via the detection signal of a load meter 28. And, the accumulated value of wire electrode consumption is previously obtained in accordance with the machining order for each machining level in each machining shape. Next, the detected remaining quantity of the wire electrode 5 is compared with the obtained accumulated value of the wire electrode consumption, and it is judged that machining up to what machining level can be possible. The result or judgment is displayed on a display unit. Even after the start of electric discharge machining, by comparing the detected remaining quantity of the wire electrode 5 with the consumption of the wire electrode 5 in the machining level of the next stage, the machining level before the interruption of machining can be securely known, thus the interruption of machining in one machining level can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wire electrical discharge machining apparatus for electrical discharge machining a workpiece into an arbitrary shape using a wire electrode.

[Prior Art] A wire electrical discharge machining device is a device that intermittently generates electrical discharge between a wire and a workpiece, thereby machining the workpiece into an arbitrary shape. An outline of such a wire electric discharge machining apparatus will be explained with reference to the drawings.

FIG. 4 is a system diagram of the wire electrical discharge machining apparatus.

In the figure, 1 is the wire electrical discharge machining device main body, 2 is an X-Y table fixed on the main body 1, and 3 is placed on the X-Y table 2 via a stand 4 (only a part is shown). It is a workpiece that has been 5 is a wire electrode, 6 is a wire reel in which the wire electrode 5 is wound around a bobbin and accumulated. 67 to 12 are reels, and these reels allow the wire electrode 5 to pass from the wire reel 6 through the workpiece 3. be drawn out. 13
14 is a tapering device attached to the head 13, 15 and 16 are wire guides, and 17 is a wire packet containing the used wire electrode 5. 18 is a power source of the wire electric discharge machining apparatus; 19 and 20 are current-carrying terminals that connect the wire electrode 5 and one electrode of the power source 18;

The machining operation of such a wire electric discharge machining device is shown in Fig. 5 (a
This will be explained with reference to the processing diagram shown in ).

In FIG. 5(a), 3 is the workpiece shown in FIG. 4, and its plane is shown. Reference numeral 22 indicates a through hole previously drilled in the workpiece 3, and 23 indicates a machining trajectory. The wire electrode 5 has reels 7 to 10, a wire guide 15, a through hole 22 of the workpiece 3,
The wire is pulled out from the wire reel 6 through the wire guide 16 and the reel 11.12 while maintaining constant tension. One electrode of a power source 18 is connected to the wire electrode 5, and the other electrode of the power source 18 is connected to the workpiece 3, and discharge is intermittently generated between the two. The workpiece 3 is cut into a predetermined shape by this electric discharge.

This process is performed as shown in FIG.
2, and is performed in the direction of the arrow along a machining trajectory 23 that is a predetermined machining shape. Such machining trajectory 2
3 can be obtained by appropriately controlling the tilting movement of the X-Y table 2 and the taper processing device 14. During this processing, the wire electrode 5 is pulled out from the wire reel 6 at a predetermined feeding speed determined by the magnitude of the discharge energy, the thickness of the workpiece 3, the material of the wire electrode 5, etc., and the wire electrode 5 is processed. The finished portions are sequentially stored in the wire packet 17.

The wire electrical discharge machining apparatus is controlled by an NC device (not shown).

In the case of machining shown in Fig. 5(a), the workpiece 3 is machining path 2
It is cut out in the shape of 3. When performing such processing,
Normally, cutting is first performed by rough machining with a higher discharge energy, and then finishing is performed several times with successively lower discharge energy to finish the machined surface to a finer surface roughness. The number of finishing operations is determined depending on various conditions, but is usually 1 to 10 times.

FIG. 5(b) is a diagram showing a machining mode when a plurality of machining processes are performed on one workpiece, and parts corresponding to those shown in FIG. 5(a) are given the same reference numerals. A.

B, C, and D indicate the processed shapes of each process. When machining is to be transferred from one machining shape to another machining shape having a through hole 23, the wire electrode S is automatically cut after the machining of the previous machining shape is completed, and a device (not shown) is used to transfer the machining shape to another machining shape. The wire electrode 5 is automatically inserted into the through hole 23. In this way, the workpiece 3 is automatically machined into a plurality of machining shapes A to D.

[Problems to be Solved by the Invention] As mentioned above, wire electrical discharge machining rarely completes machining with only one rough machining process for one machined shape, and in most cases several finishing processes are required. Processing is done. Therefore, the amount of wire electrode 5 consumed reaches a considerable amount. and,
When a plurality of shapes are processed, the amount of wire electrode 5 consumed becomes extremely large, and the amount of wire electrode 5 stored in wire reel 6 is often insufficient.

If there is a shortage of wire electrodes 5 in this way, machining will be interrupted midway, but if machining is interrupted in the middle of finishing machining, when replenishing wire electrodes 5 and continuing machining again, the same location (where machining was interrupted) will be interrupted. There was a problem in that the machined area) was subjected to electric discharge machining twice, resulting in streaks on the machined surface and deterioration of the quality of the machined surface. Particularly, when unmanned operation is carried out at night when the operator does not perform any monitoring, the occurrence of the above-mentioned problem cannot be avoided.

SUMMARY OF THE INVENTION An object of the present invention is to provide a wire electrical discharge machining apparatus that can solve the problems of the prior art described above and prevent the generation of streaks on a machined surface.

[Means for Solving the Problem] In order to achieve the above object, a first invention provides a wire electrical discharge machining apparatus for machining the workpiece by generating an electric discharge in the gap between the wire electrode and the workpiece. a detection means for detecting the remaining amount of the wire electrode; a calculation means for calculating the cumulative value of the consumption amount of the wire electrode for each machining level of each machining shape in a predetermined machining order for the workpiece; The present invention is characterized by being provided with a determining means for determining the machining level at which machining is possible by comparing the remaining amount of the wire electrode with each of the calculated cumulative values, and a display means for displaying the determination result of the determining means. do.

A second aspect of the present invention provides a wire electrical discharge machining apparatus for machining a workpiece by generating an electric discharge in a gap between a wire electrode and a workpiece, including a detection means for detecting a remaining amount of the wire electrode, and a detection means for detecting a remaining amount of the wire electrode; calculating means for calculating the consumption amount of the wire electrode for each machining level of each machining shape in a predetermined machining order; and comparing the detected remaining amount of the wire electrode with the calculated consumption amount. The present invention is characterized in that it is provided with a determining means for determining whether machining at the next stage of machining level is possible, and a display means for displaying the determination result of the determining means.

[Operation: Before starting electrical discharge machining, the remaining amount of wire electrode accumulated on the wire reel is detected. Further, the cumulative value of wire electrode consumption is determined in advance for each machining level of the machining shape in accordance with the machining order. Next, the detected remaining amount of wire electrode,
The obtained cumulative value of wire electrode consumption is compared to determine to which processing level machining is possible. The determination result is displayed on a display device. Even after the start of discharge, the machining level before machining interruption can be reliably known by detecting the remaining amount of the wire electrode and comparing it with the consumption amount of the wire electrode at the next machining level.

[Example] Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 1 is a partial system diagram of a wire electrical discharge machining apparatus according to an embodiment of the present invention. In the figure, 1 is the main body of the wire electrical discharge machining apparatus, 5 is a wire electrode, and 6 is a wire reel, which are the same as those shown in FIG. 6S is wire reel 6
, 25 is a mounting member for mounting the wire reel 6 to the main body 1, 25a is an arm portion of the mounting member 25, 26 is a bearing provided on the mounting member 25 and rotatably supports the shaft 6S, 27 is a lower part of the mounting member 25 This is an edge member that supports the. A load meter 28 detects the load applied from the arm portion 25a of the mounting member 25, and outputs an electric signal proportional to the detected load. The configuration of other parts of the wire electrical discharge machining apparatus of this embodiment is the same as the configuration shown in FIG. 4, so illustration and description thereof will be omitted. 29 is load cell 2
30 is an interface that A/D converts the output signal of amplifier 29 and adjusts the digital signal to a predetermined level; 31 is interface 3;
This is an NC device that executes predetermined processing by inputting a zero signal and performs control similar to that of conventional devices.

The storage section of the NC device 31 stores various data necessary for control by the NC device 31, and these data also include data on the wire electrodes 5. The data of this wire electrode 5 is shown in the following table.

Next, the operation of this embodiment will be explained with reference to the explanatory diagram of the cumulative amount of wire at the machining level shown in FIG. 2 and the flowchart shown in FIGS. 3(a) and 3(b).

In this embodiment, before starting machining, it is determined to which machining level the wire electrode 5 currently wound around the wire reel 6 can be machined. where - as an example, one workpiece 3
A case will be described in which four shapes A to D are processed as shown in FIG. 5(b). In this case, shape A has three processing levels, shape B has five processing levels, shape C has four processing levels,
Regarding the shape, it is assumed that processing can be performed at each of three processing levels. This is shown in FIG.

Before starting processing, the NC device 31 measures the weight of the wire (the weight of the entire wire reel 6) based on the output signal of the load meter 28 (step S□ shown in FIG. 3(a)). Next, N.C.
The device 31 calculates the weight of the wire bobbin (
(known from the above-mentioned table) is subtracted, and the remaining amount WR of the wire electrode 5 currently wound around the wire reel 6 is calculated (hand 1'lN S , ). Next, the cumulative amount of wire W'l is calculated for each processing level (step S3).
. In addition, in the wire cumulative amount W', W' indicates the wire cumulative amount itself, and the subscript i indicates the machining level shown in FIG. Indicates the number when serial numbers are attached. In the example of FIG. 2, the number i is from 1 to 15.

The wire cumulative amount W′ 1 is the cumulative value of the consumption amount of the wire electrode 5 at each processing level. Therefore, the NC device 31 first calculates the wire consumption FiW for each processing level. This wire consumption amount W is expressed by the following equation, where L: machining circumference ■=machining speed ■=wire feeding speed d: wire diameter γ: wire specific gravity. Note that the machining speed V is a machining distance per unit time, and a standard value is determined by the NC device 31 based on machining conditions such as the material of the workpiece 3, the plate thickness, and the discharge energy.

In Fig. 2, for example, the wire consumption W of the first (machining level 1 of shape A) to the fifth (machining level 2 of shape B) is WA□l WA□t, respectively.
WAl1 WPI□, W, 2. Therefore, the first
The cumulative amount of wire W' in the second processing level is WAl, that in the second processing level is (WA□+WA2), and that in the third processing level is (WA□10WA□10w A-=
WA), and that of the fourth processing level is (WA+
WB□), that of the fifth processing level is (WA+wn
WORK + WB □). In this way, the storage section of the NC device 31 stores at least the cumulative wire amount W' for each processing level.

Next, 1 number i is set to 1, step S4), and the wire remaining amount WR is the cumulative amount of wire at the first machining level W', (=
W A4 ) Check whether it is greater than or equal to (step S,).

In step S, if the wire remaining amount WR is greater than or equal to the cumulative wire fJt amount W', then check whether the machining level i is the final machining level n (n=15 in the example shown in FIG. 2). is determined (step S6), and if it is not the final machining level, 1 is added to the 1 number i (hand J'@S, ) to take out the cumulative amount of wire for the next machining level, and the process of step S is performed. . In this way, the processes from step 85 to step S7 are repeated to obtain the wire stacking amount W' at the final processing level n. Also (WR≧W
'. ), the display device (not shown) of the NC device 31 displays the remaining wire amount WR and the fact that two-level machining of the entire jaw is possible with this remaining wire amount (step S, ). On the other hand, during the repetition of steps S and S7, the wire remaining amount WR is changed to the wire cumulative amount w' in step S.
If it is determined that the remaining wire amount WR and the machining level i that can be processed are displayed on the display device (
According to step Ss), by looking at the display device before starting electrical discharge machining, the operator can know to what stage machining is possible with the current wire reel 6, and If the wire electrode 5 runs out at a stage, appropriate measures can be taken, such as replacing the wire reel 6 or setting the electrical discharge machining to automatically stop at the midway stage or a previous machining level. Note that streaks that occur when machining is interrupted occur when machining is interrupted in the middle of one machining level, and do not occur even when it is interrupted between one machining level and the next machining level. Therefore, the above automatic stop is executed at the end of one machining level.

The operations before the start of electrical discharge machining have been described above.

Next, the operation after the start of electrical discharge machining will be explained.

First, the machining level number i is set to 1 (first machining level) (step S□□ shown in FIG. 3(b)).

Then, it is constantly determined whether or not the machining at that machining level has been completed (step 502). When the NC device 31 determines that the machining is complete, 1 is added to the number j (step S, , ).
That is, the machining level is set as the next machining level, and the remaining wire iw is calculated by the same process as in the operation before starting machining (step S14.Sl).

Next, the wire consumption iwt of the i-th machining level is calculated (step S machining). This calculation is obtained by subtracting the cumulative amount of wire at the previous machining level from the cumulative amount of wire at that machining level.
! You may memorize the amount and take it out for use.

Next, this wire consumption amount WL is multiplied by a safety factor α (step SF). Electrical discharge machining does not necessarily require the set machining speed V.
, the wire feeding speed is not necessarily carried out at V, and may vary depending on the processing state. When such a change occurs, the amount of wire consumed at that processing level naturally changes as well. Therefore, in order to reliably prevent the occurrence of streaks, the actual wire consumption is expected to be larger than the wire consumption ff1W calculated by formula (1), and the calculated wire consumption WL is multiplied by an appropriate safety factor α. Take action.

Next, this multiplication value (α·W t ) and the remaining wire amount WR are compared (step S, 11), and when the remaining wire amount Wa is greater than or equal to the multiplication value (α·W t ), the wire is not connected to the display device. The remaining amount WR and the fact that machining at the next machining level is possible are displayed (Step S). Then, it is determined whether the machining level i is the last machining level n (step S2°), and if it is not the last machining level n, the process returns to step S12 again. On the other hand, if it is determined in step S111 that the wire remaining fflWR is less than the multiplication value (α・Wt), a message indicating that the wire reel 6 should be replaced is displayed on the display device 1 (hand J'l ¥82□), the completion of the exchange of the wire reel 6 is monitored (step S2□), and when the exchange is completed, the process of step 5211 is performed.

In this way, in this embodiment, before starting machining, the cumulative amount of wire is calculated for each machining level, and by comparing these with the remaining amount of wire, it is displayed to what machining level machining is possible. This makes it possible to take appropriate measures such as exchanging the strainer wire before machining, prevent the machining from being interrupted in the middle of the machining level, and prevent the occurrence of streaks. or,
After starting machining, just before machining each machining level, the amount of remaining wire is compared with the amount of wire consumed considering the safety of that machining level, and it is determined whether machining at that machining level can be performed without interruption. Therefore, the occurrence of streaks can be reliably prevented.

In addition, in the description of the above embodiment, an example was explained in which the remaining amount of wire is determined by measuring the weight of the wire, but it is not limited to this, and it can also be determined by measuring the outer diameter of the wire of the wire reel 6. In addition, the amount of wire used can be determined from the wire running speed and processing time, and the remaining amount of wire can be determined from this.Furthermore, the amount of wire used can be determined from the rotation time or cumulative number of rotations of the wire reel 6 and the wire running speed. The remaining amount of wire can also be determined by

Furthermore, it is clear that the safety factor may be used in calculations performed before the start of electrical discharge machining.

Furthermore, in addition to the display device, an alarm device and an automatic electrical discharge machining stop device can also be used.

[Effects of the Invention] As described above, in the present invention, since the fi amount of the wire electrode and the cumulative value for each machining level are compared in order, the level at which electrical discharge machining is possible can be known, and one machining process can be performed. Interruption of machining at the level can be prevented, and as a result, generation of streaks on the machining surface can be prevented. Moreover, since it is determined whether machining at the first stage machining level is possible even during machining, the generation of the streaks can be more reliably prevented.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a part of the wire electrical discharge machining apparatus according to the embodiment of the present invention, Fig. 2 is an explanatory diagram of the cumulative amount of wire, and Fig. 3 (
a) and (b) are flowcharts explaining the operation of the apparatus shown in Fig. 1, Fig. 4 is a system diagram of the wire electric discharge machining apparatus, and Fig. 5 (a) and (b) are diagrams of the machining mode of the workpiece. be. 1... Wire electrical discharge machining equipment main body, 5...
-Wire electrode, 6...Wire reel, 28...Load cell, 31...NC device. Figure 3 (CI) Figure 2

Claims (2)

[Claims] (1) A wire electrical discharge machining device that processes the workpiece by generating electrical discharge in the gap between the wire electrode and the workpiece, including a detection means for detecting the remaining amount of the wire electrode, and a predetermined machining method for the workpiece. a calculation means for calculating the cumulative value of the consumption amount of the wire electrode for each processing level of each processing shape in the order, and processing by comparing the detected remaining amount of the wire electrode with each calculated cumulative value. A wire discharge device characterized in that it is provided with a determining means for determining the machining level that is possible, and a display means for displaying the determination result of the determining means. (2) A wire electrical discharge machining device that processes the workpiece by generating electrical discharge in the gap between the wire electrode and the workpiece, including a detection means for detecting the remaining amount of the wire electrode, and a predetermined machining method for the workpiece. calculation means for calculating the consumption amount of the wire electrode for each machining level of each machining shape in the order; A wire electric discharge device characterized in that it is provided with a determining means for determining whether machining is possible at a machining level, and a display means for displaying the determination result of the determining means.