JPS6238097B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire-cut electric discharge machining apparatus, and more particularly to improvements in its electrode delivery device.

In known wire cut electric discharge machining equipment,
A wire electrode supply drum and a recovery device are provided inside the column or on one side of the column, and a pair of upper and lower arms are fixed to the column or supported so as to be able to rise and fall freely. In addition to being provided with various guides for defining the electrode path, a capstan and a pinch roller are provided inside or on the surface of one arm, or in the column, and a brake device is provided inside or on the surface of the other arm, or in the column. Furthermore, a pair of processing section positioning guides are provided at the free ends of both arms at positions facing each other.

The wire electrode pulled out from the supply drum passes through auxiliary guide rollers provided as necessary, and is drawn into a column or arm equipped with a brake device, where it is subjected to a predetermined braking force by the brake device. First, it passes through an auxiliary guide roller provided as necessary to exit the arm from the processing section positioning guide, then passes through the processing section positioning guide on the other side and an auxiliary guide roller provided as necessary, and then passes through the capstan and the pinch. into the arm or column where the rollers are located;
It is configured to be collected by a collection device through an auxiliary guide provided as necessary, between a capstan and a pinch roller.

Therefore, when attempting to improve the processing accuracy in wire cutting processing, the problem is the straightness of the wire electrode between the pair of processing section positioning guides.

This straightness is obtained by applying strong tension to the wire electrode, but since the wire electrode is usually a red copper wire or brass wire with a diameter of about 0.2 mm, there is a limit to the tension that can be applied, and excessive tension is applied. When tension is applied to the wire, it becomes deformed and wire breakage occurs frequently, but it is impossible to completely correct the curling and bending of the wire electrode if the tension is below a certain safety limit. Furthermore, in conventional devices, curvature of the wire electrode due to discharge pressure also causes processing errors that cannot be ignored.

The present invention has been made to solve the above-mentioned problems, and its purpose is to improve the linearity of the wire electrode in the processing section without making the structure particularly complicated. be.

Therefore, the gist of the present invention is that in conventional devices, at least one or two auxiliary guide rollers are provided between the processing part positioning guide and the capstan or the brake device, and the rollers are connected to the capstan from the brake device. The electrode path between the pair of processing part positioning guides was extended in a straight line, and the brake device, capstan, and pinch roller were installed on each extended line. In other words, the electrode path from the brake device to the capstan and pinch roller, including the machining part, is provided with no auxiliary guide other than the machining part positioning guide; The electrode path portion is configured to be in a straight line.

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

FIG. 1 is a partially cutaway side view showing essential parts of a wire-cut electrical discharge machining apparatus according to the present invention, and FIG. 2 is an explanatory diagram showing an example of a wire electrode path in a known apparatus.

Therefore, in Figure 1, 1 is the machine base, 2 is the column,
3 and 4 are arms that are supported in the column 2 so that they can be raised and lowered; 5 and 6 are lifting screw shafts or rod worms and worm wheel lifting mechanisms; or hydraulic cylinders; 7 are slide tables 8 and 9; and DC or pulse motors. A cross table consisting of 10, 11 and others, 12 a workpiece, 13 a clamp, 1
4 is a wire electrode supply drum, 15 is a wire electrode,
16, 16 are brake rollers, 17, 18 are processing section positioning guides, 19 is a capstan, 20 is a pinch roller, 21, 22 are electrode collection rollers that rotate in synchronization with the capstan 20, 23, 23 are auxiliary guide rollers, 24 is cutter unit, 2
5 is a chute, 26 is a cut wire electrode, 2
7 is a scrap box, 28 is a processing fluid supply pipe,
Reference numeral 29 denotes a machining fluid spray nozzle, which is also provided on the lower side as required. In this figure, parts unrelated to the present invention, such as a power supply circuit, a machining fluid supply device, a guide supporting the arm, a capstan drive motor, a brake roller torque control device, etc., are omitted to simplify the explanation. There is.

In the conventionally known wire cut electrical discharge machining apparatus, as shown in FIG. At least one or two auxiliary rollers 23', 23'', 23 are provided between the pinch rollers 20', respectively.
are provided, and the wire electrode 15' connects the brake rollers 16', 16' and the capstan 19',
It is drawn in a U-shape between pinch rollers 20'.

Therefore, the tension applied by the capstan 19' is reduced by the auxiliary rollers 23, 23 and transmitted to the wire electrode between the processing section positioning guides 17', 18'.
3'', 23', the brake roller 1
6', 16', each auxiliary roller 23', 23'', 2
The torque of 3.23〓 is not necessarily stable, nor is it so small that it can be ignored. Therefore, the electrode tension between the workpiece positioning guides 17' and 18' is smaller than that provided by the capstan 19' and is somewhat unstable.

Further, the wire electrodes are connected to the brake roller 16',
While passing through a relatively long path from 16' to capstan 19', it is subjected to high tension, and during that time, each auxiliary roller performs a strong bending process that exceeds the elastic limit, so there is no possibility of elongation or breakage due to creep. The risk of occurrence increases. Therefore, the limit of the tension that can be applied by the capstan 19' is significantly lower than the allowable value simply calculated from the tensile strength and elongation of the wire itself. In addition, in the conventional device, the wire electrode 1
Auxiliary rollers 23'', 23 receiving the final tension of 5'
, or wire electrode 1 between guides 17' and 18'
The length of the wire electrode 5' is not taken into consideration with respect to the thickness of the workpiece 12 to be machined, and the length of the wire electrode is usually several times the thickness of the workpiece. However, even if the wire electrode is subjected to a treatment such as annealing to give sufficient tension and linearity, the linearity of the wire electrode between the guides is not good, in other words, there is a drawback that sufficient linearity cannot be maintained. Ta.

Therefore, the tension applied to the wire electrode in the conventional method is insufficient to completely correct the bend in the wire and make it completely straight at the processed portion.

However, even with this level of tension, if strong bending is performed under that tension, not only will there be a risk of wire breakage, but the cross section of the wire electrode will become non-circular and flat, which also affects processing accuracy and processing. A problem arose in that the required time etc. varied depending on the processing direction.

On the other hand, in the device of the present invention, the electrode path from the brake rollers 16, 16, through the processing section positioning guides 17, 18, to the capstan 19 and the pinch roller 20 is a straight line, as shown in FIG. Moreover, the total length of the route between them is 1/3 to 1/4 of that of conventional equipment.

For this reason, the time that the wire electrode is under high tension is short, so there is little creep deformation, and the tension applied by the capstan 19 is directly transmitted to the processing part electrode, and is directly connected to the braking force of the brake roller. Since it is in equilibrium, it has extremely good stability.

Furthermore, in the case of a wire electrode path as shown in FIG. 2 in a conventionally known device, the wire electrode 15'
When it passes through the brake rollers 16', 16', it is subjected to a slight rolling process and is elongated and the curls are removed, but when it is then bent by the auxiliary rollers 23', 23'', new curls are formed. was discovered.

The present invention was completed based on such knowledge, and in the case of the wire cut electrical discharge machining apparatus according to the present invention, the wire electrode 15 is rolled with the brake rollers 16, 16. Since it passes through the processing part positioning guide 17 and is stretched between it and the other positioning guide 18, there is no room for curling during the period from passing through the brake rollers 16, 16 until reaching the processing part. There is no
This ensures the linearity of the wire electrode.

Therefore, in the device of the present invention, a stronger tension can be applied to the wire electrode than in the conventional device without deforming the electrode cross section or risking wire breakage, and the straightness of the electrode can be improved.

In this case, by simply keeping the torque of the brake rollers 16, 16 constant and rotating the capstan 19 at a constant speed, a stable and strong tension can be applied to the wire electrode, and the wire electrode can be made more perfectly straight. be. Also, if you configure it like this,
Since the wire electrode is not bent under great tension, it can be used for processing while maintaining its perfectly circular cross section.

In this way, if the straightness and roundness of the electrode are improved, the amount of metal that must be removed during processing will be reduced, and accidents such as short circuits and disconnections will not occur even if the processing feed rate is increased. This can improve not only machining accuracy but also machining speed.

Furthermore, when wire cutting is performed using the apparatus of the present invention, the processing part positioning guide 17,
It is recommended that the spacing between the two holes be adjusted to about 10 times the thickness of the workpiece 12 or more, and that the work be performed at approximately the center of the workpiece 12. In this way, the influence of bending of the wire electrode due to wire cutting pressure and discharge pressure is minimized, and the guide 1
This is because the wire electrode between 7 and 18 maintains true linearity.

Since the present invention is constructed as described above, various problems caused by non-linearity and cross-sectional deformation of the wire electrode can be solved, and machining accuracy and machining speed can be significantly improved. .

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view showing essential parts of a wire-cut electrical discharge machining apparatus according to the present invention, and FIG. 2 is an explanatory diagram showing an example of a wire electrode path in a known apparatus. 1: Machine base, 2: Column, 3, 4: Arm, 1
4: Supply drum, 15: Wire electrode, 16,1
6: Brake roller, 17, 18: Processing part positioning guide, 19: Capstan, 20: Pinch roller, 21, 22: Electrode collection roller, 23, 2
3: Auxiliary guide roller, 24: Cutter unit.

Claims (1)

[Claims] 1. In a wire cut electric discharge machining device equipped with an electrode delivery device consisting of a pinch roller, a capstan, a pair of processing section positioning guides, a brake device, a plurality of auxiliary guide rollers, etc., in order to supply, use, and recover the wire electrode, the brake The brake device, the pair of processing section positioning guides, the capstan, and the pinch roller are arranged so that the electrode path from the device to the capstan and pinch roller via the pair of processing section positioning guides is approximately in a straight line. The above-mentioned wire cut electrical discharge machining device is characterized by: