JPS63120030A - Wire-cut electric discharge machining - Google Patents

Abstract

PURPOSE:To remove a taper of a work body as well as to aim at highly accurate machining for a vertical cutting surface, by machining it as giving tilting control at an angle corresponding to a wire diameter dimensional difference due to electrode consumption between inlet and outlet ports of a through groove of an electrode to a gap between the wire electrode and the work body, in both feed and rectangular directions. CONSTITUTION:A work body 5 is cut into feed form by machining feed, but a wire electrode 1 is consumed by discharge during a while till it enters a machining groove from top of the work body 5 and gets out of the backside, so that the wire electrode 1 to be opposed to the work body 5 becomes thinner of its wire diameter as far as d-d' when it is moved to an outlet than when it is an inlet of the machining groove. With this, a taper is formed on the cut surface of the work body 5 cut. And, consumption length at the outlet side of the wire electrode comes to X=plate thickness X tantheta. Therefore, it tilting feed of an angle theta is given to the wire electrode 1, X at the outlet side of the wire electrode 1 comes to zero, thus the taper of the cut surface of the work body is removable, and a vertical section is cuttable.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to improvements in wire cut electric discharge machining.

[Prior art and problems]

In recent years, the machining performance of wire cut electrical discharge machining has greatly improved.
20 using a wire electrode with a wire diameter of around 0.3II 1mφ
High-speed machining performance of about 0 to 300 m1/win can now be obtained. As the machining speed increases, the wear of the wire electrode increases according to a predetermined wear ratio, and the dimensions of the entrance and exit of the machining groove change, causing a problem of taber formation. This has the disadvantage that as the thickness of the workpiece increases, the taper also increases. In order to reduce the occurrence of taper in the machined groove width due to wear of the wire electrode, it is considered to move the wire electrode rapidly by increasing the traveling speed of 10 to 15 m/ll1n, which is more than double the conventional speed. However, this increases the consumption of the wire electrode and is not practical and economical.Also, the high-speed movement of the wire electrode causes tension fluctuations, vibrations, etc., making stable machining impossible and causing streaks on the machined surface. The disadvantage is that there are many disconnections.

[Four steps to solve the problem] In view of the above points, the present invention proposes a processing method that sufficiently reduces the running speed of the wire electrode to reduce the taper generated on the machined surface. The method is characterized in that machining is performed while applying angle inclination control in a direction perpendicular to the machining feed, corresponding to the wire diameter size difference due to electrode wear between the entrance and exit of the machining groove through which the wire electrode penetrates relative to the workpiece. .

〔Example〕

The present invention will be explained below with reference to an embodiment of the drawings.

In FIG. 1, 1 is a wire electrode, 2 is a wire supply reel, 3 and 4 are upper and lower guides of the processing section, and a workpiece 5 is processed while facing the wire electrode 1 running between these guides. 6
is a UV axis cross table installed on the support arm of the upper guide 3, which supports the guide 3 and uses motors 61 and 62 to
Controls axis movement.

An arm 7 supports the lower guide 4, an XY-axis cross table 8 supports the workpiece 5 and provides machining feed, and XYY movement control is performed by motors 81 and 82. Note that the XY axes and the UV axis are provided in parallel. 9 is a brake roller provided on the supply side of the wire electrode 1; 10 is a brake device;
A pinch roller 11 is pressed against the wire electric bridge roller 9 by a spring 12. 13 is a winding roller provided on the winding side of the wire electrode, 14 is a drive motor, 15 is a pinch roller,
The wire electrode 1 is pressed against the take-up roller 14 by the spring 16. The winding roller 13 and the brake roller 9 apply a predetermined tension to the running wire electrode 1 to move it at a predetermined speed. 17 is a take-up reel, 18 is a CNC device that outputs signals to each part control device, 19 is an information storage device, 20 is a display device, 21 is a manual input device for processing conditions, etc.
22 is a tape input device, 23 is an XY axis motor 81.82
17) Control device, 24 is UV axis-E-161, 6217
) A control device, 25 is a control device for the winding drive motor 14, 2
6 is a control device for the brake device 10, and signals are supplied from the CNC device 18 to each control device.

In the above, the information storage device 19 stores various control signals, including the wire diameter and material used, the thickness and material of the workpiece, the tension of the wire electrode, the traveling speed, and the processing. A wear correction value of the wire electrode 1 calculated by the CNC device 18 according to pulse conditions or the like, or a wear correction value determined by a preliminary experiment and inputted through the manual input bag @21 is stored.

The CNC device 18 sends signals to the control devices 25 and 26 to control the winding motor 14 and the brake device 10 to control the tension and speed of the running wire electrode 1 to predetermined optimum values according to the processing conditions. As a result, the wire electrode 1 is moved linearly between the upper and lower guides 3.4 with a predetermined tension and speed. The workpiece 5 is attached to the wire electrode 1 between the guides.
Machining liquid is normally jetted into the gap facing the upper and lower guides 3 and 4 from a nozzle provided so as to surround the upper and lower guides 3 and 4, and a pulse is applied between the wire electrode 1 and the workpiece 5 from a pulse power source (not shown) to generate a pulse discharge. Process. A programmed machining shape signal is input from the tape input device 22, and the CNC device 1
The sending signal calculated by 8 is applied to the control device 23,
The XY-axis motors 81 and 82 are driven to give the workpiece 5 relative shape feed with respect to the wire electrode 1.

Of course, it detects the machining gap signal and, in the event of an arc or short circuit, stops or retreats the feed and performs adaptive control to follow the progress of machining. The workpiece 5 is cut into the feed shape by this machining feed, but the wire electrode 1 enters the machining groove from the top surface of the workpiece 5 and is consumed by electrical discharge until it exits from the back surface, so as shown in FIG. As shown, the wire diameter of the wire electrode 1 facing the workpiece 5 becomes smaller when it is at the entrance of the processing groove and when it moves to the exit (dd'). As a result, a taper is formed on the cut surface of the processed workpiece 5. This wear of the wire electrode 1 is determined as follows.

First, the processing amount W of the workpiece that is processed during the time from when one point of the wire electrode enters the processing groove to when it passes through the exit is determined by the electrical processing conditions (τon, τoff, Ip, r) and the line of the wire electrode. The diameter d, the material, the travel speed F1, the material (specific gravity ρ) of the workpiece, the plate thickness, etc. are determined by the following, and if machining of average length A is performed during passing as shown in Figure 3, then the hatching part, however, , D is the machining groove width, which is determined by the machining expansion margin determined by the wire diameter d and the machining conditions, and is determined in advance, and ω is the machining amount by one discharge, which is determined by the machining conditions, and A is determined from this.

The wire diameter consumption A' of the electrode is determined by the consumption ratio γ (%) determined according to the machining conditions with respect to the machining amount of the workpiece, A' = □・γ・A A' is the average value when the plate thickness is t. In reality, the wire electrode is worn out as shown in FIG. 2, so the worn length X on the exit side of the wire electrode is calculated as follows: tanθ=2A'x=ttanθ=2A'. Therefore, if the wire electrode 1 is fed obliquely at an angle θ, X on the exit side of the wire electrode 1 becomes O, the taper of the cut surface of the workpiece can be removed, and a vertical cross-section can be cut.

The above-mentioned calculation of the inclination angle can be performed by inputting various conditions such as machining conditions, electrodes, workpiece conditions, etc. into the CNC device 18 using the manual input device 21 and storing the calculations in the storage device 19. Often, pre-calculated values may be entered by manual input device 21. During machining, the CNC device 18 controls the control device @2 so that the predetermined inclination angle is 1q while calling up the stored amount.
4, the motors 67 and 62 are driven to drive the cross table 6 along the LIV axis, and the fixed upper guide 3 is moved to tilt the wire electrode 1 between the guides 3 and 4.

The direction of inclination is perpendicular to the processing feed direction by the control device 23, that is, the motor 81 is controlled by the processing feed distribution signal.
When the machining feed is to be sent in the X-axis direction, the motor 62 is driven by the corresponding distribution signal to feed the V-axis a predetermined amount and tilted, and when the machining feed is to be sent in the Y-axis direction, the U-axis is given a tilted feed. related to control. Moreover, the inclination is made to slope toward the product side of the workpiece to be processed, that is, when cutting off the left side of the workpiece 5 and using the right side as the product in FIG. 2, the upper part of the wire electrode 1 is cut off. Perform tilt control to the left. As a result, the contour cut surface of the workpiece 5 cut into the desired shape has equal upper and lower dimensions and is always cut on a vertical plane, making it possible to completely eliminate taper.

According to experiments, the electrode consumption is determined by plate thickness 50111+1 t.
, the average machining voltage VIl with a wire electrode with a wire diameter of 0.3 mmφ
When processing under the conditions of +=50V and average current In-835A, the running speed of the wire electrode and the electrode wear were as follows.

The inclination angle can be determined in advance using various wire electrodes. By inputting this experimental value using the manual input device 21 and storing it in the information storage device 19, the inclination of the wire electrode 1 can be controlled during machining, and high precision machining can be achieved.

As described above, the taper generated on the cut surface of the workpiece can be removed by controlling the inclination of the wire electrode, so that the traveling speed of the wire electrode 1 controlled by the take-up roller 13 and the brake roller 9 can be made sufficiently low. It is possible,
1/3 to 1/3 of conventional high-speed movement to the extent that the wire does not break.
10 or less, and the processing current can also be 20 to 30A.
It is possible to perform high-speed processing by increasing the degree of processing.

Incidentally, the tilt control may be applied to the workpiece side, and the machining feed may be applied to the wire electrode side.

〔Effect of the invention〕

As described above, the present invention provides angle inclination control for machining feed that corresponds to the wire diameter dimension difference due to electrode wear between the entrance and exit of the machining groove that the wire electrode penetrates between the wire electrode and the workpiece. Since the machining is performed while feeding in the right angle direction,
The taper that occurs in the workpiece can be removed by wire cutting, and vertical cutting surfaces can always be machined with high precision.

Therefore, the traveling speed of the wire electrode can be made sufficiently low, and the wire consumption can be economically processed to 1/3 to 1710 times less than that of the conventional method. Further, by controlling the movement of the wire electrode at a low speed, shocks and the like in the wire travel path are reduced, tension fluctuations are eliminated, and the stable constant tension eliminates wire breakage and the like, making it possible to perform stable and highly accurate machining. Further, since there is no taper caused by electrode wear, the machining current is sufficiently increased, and a large current can be passed to enable high-speed, high-efficiency machining. Furthermore, finishing can be performed by reducing the number of glue cuts after high-speed machining, resulting in extremely efficient machining.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory side view of the present invention, and FIG. 3 is an explanatory top view thereof. 1...Wire electrode 3.4...Guide 5...Workpiece 6...Uv cross Table 61.62・
......UV axis drive motor 8...
・XY cross table 81.82......X
Y-axis drive motor 9...Brake 13...Take-up roller 18...CNC device 19... Storage device 20...Display device 21...Manual input device 22...Tape input device 23...
...XY-axis control device 24 ......Uv-axis control device patent applicant Kiyoshi Inoue, representative of Inoue Japax Laboratory Co., Ltd.

Claims (1)

[Claims] A wire that is machined by performing pulse discharge while giving a machining feed that follows the machining shape in the gap between a wire electrode that is moved in one direction between both guides of the machining section with a predetermined tension and speed, and the workpiece facing each other. In the cutting and electric discharge machining method, the inclination of the angle is controlled to correspond to the wire diameter size difference due to electrode wear between the entrance and exit of the machining groove that the wire electrode penetrates between the wire electrode and the workpiece. A wire cut electric discharge machining method characterized by machining while applying feed in a direction perpendicular to the feed.