JPH03251324A - Metal cutting method - Google Patents

Abstract

PURPOSE:To mass-productively perform cutting of a complicated shape with improvement of the surface roughness of the cutting surface, by executing electric discharge machining on the cutting surface by the following work with one part of the metal work cut by laser cutting as the electrode, after laser cutting. CONSTITUTION:In laser cutting, a fitting hole 20 in the specific shape to the chuck of an electrode head 9 is formed at a specified position of an initial work 18 and thereafter a required work shape is subjected to cutting. Then, the fitting hole 20 of the work (mold electrode) 19 whose one part is cut off is correctly arranged to the lower part of an electrode head 9 and the mold electrode 19 is fixed to the electrode head 9. A work liquid is then poured into a work tank to perform diesinking rocking electric discharge machining. After completion of the electric discharge machining, the work liquid is recovered from the work tank and a series of metal compound work is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for cutting a metal workpiece using laser cutting and die-sinking electrical discharge machining.

Prior art When cutting metal workpieces, it is difficult to process complex shapes using pure mechanical means such as shearing and turning, and additionally, a grinding device is required for precise finishing. In this respect, laser cutting allows complex shapes to be cut at high speed (approximately 1500 mm/min, plate thickness IQ mm). but,
The surface roughness of the cut surface is relatively large (about 50μRmax)
In some cases, finishing of the cut surface was required.

On the other hand, die-sinking electrical discharge machining has a small surface roughness (10μRma
x), three-dimensional curved surfaces can be precisely machined, but the processing speed (feed depth) is slow (0.1mm/mi).
n) Above, the mold electrode must be made using another machine tool, and if the mold has a complicated shape, the manufacturing process is very time consuming and costly.

Conventionally, laser cutting equipment and electrical discharge machining equipment exist independently, and when a workpiece that has been laser cut is attempted to be finished by die-sinking electrical discharge machining, the positioning of the workpiece and electrode may be difficult in the later equipment. becomes very difficult. Furthermore, the problem of having to prepare mold electrodes that are difficult and expensive to manufacture during die sinking electric discharge machining is not solved.

Problems to be Solved by the Invention The present invention provides a metal cutting method that allows laser cutting and electrical discharge machining to be performed on a metal workpiece in series and accurately, and that eliminates the need to separately prepare electrodes for electrical discharge machining. The challenge was to provide it.

Means to solve the problem First, the required shape is processed by laser cutting the metal workpiece.

Next, one of the cut workpieces is used as an electrode as it is, and die-sinking electrical discharge machining is performed on the cut surface obtained by the machining.

Operation Laser cutting performs rough machining of the workpiece, and die-sinking electrical discharge machining performs finishing machining of the cut surface.

A configuration in which one side of the cut workpiece is used as an electrode is,
To easily provide a mold electrode with a complicated shape and eliminate the need to separately manufacture the mold electrode. It also eliminates the need for troublesome alignment between the workpiece and the electrode.

Embodiment As shown in FIG. 2, the NC laser/discharge combined machining apparatus 1 for carrying out the method of the present invention includes a laser oscillation device 3, a power supply device 4 for electric discharge machining, a machining fluid device 5, and a mechanical device 2.
It has a configuration in which the C control device 6 is combined.

As shown in Fig. 3, the mechanical device 2 includes a table mechanism 7 consisting of an X-axis table and a Y-axis table, and a vertical movement mechanism 8 in the Z-axis direction, and each of the Z-axis, Y-axis, and Z-axis is operated by a zarpo motor. Driven.

At the lower end of the vertical movement mechanism 8, an electrode head 9 and a laser head 10 for electrical discharge machining are provided adjacent to each other. The laser head 10 has an assist gas injection function, and
It is protected by a protective tube to prevent contamination from machining fluid splash during electrical discharge machining. Note that the tip portion is located at approximately the same vertical position as the electrode head 9 so as not to be submerged in the machining fluid during discharge application.

The electrode head 9 is of a chuck type as shown in FIG. 4.5. This chuck is equipped with two wooden claws 11 that move up and down in the vertical direction, and each mold 11 has a horizontal engaging part 12 facing outward at the lower end and a positioning part 13 formed in a prismatic shape upward from its upper surface. The head 9 descends from the holding part 14 of the head 9 with a narrowed gap, then widens the gap and grips the mold electrode 19 (one of the cut workpieces), and then ascends to place the mold electrode between it and the holding part 13. 19 is clamped and fixed.

Reference numeral 15 denotes a processing tank, which is attached to the upper surface of the table mechanism 7. Reference numeral 16 denotes a beam duct which is equipped with a reflecting mirror inside, and whose tip is formed into a telescopic auxiliary duct 17. The auxiliary duct 17 is fixed to the vertical movement mechanism 8 and moves together with it, and the laser head 10 described above is attached to the tip thereof.

The laser oscillation device 3 is a commercially available continuous beam type C02 gas laser device with an output of 2 kW, and outputs a stable and powerful laser beam to the beam duct 16.

The electric discharge machining power supply device 4 is a known one developed for die engraving, uses a pulse generation method using a transistor, and requires a power supply of 9 KVA. The pulses are supplied to the electrode head 9 as processing power.

The machining fluid device 5 has the ability to supply the machining fluid necessary for electrical discharge machining to the machining tank 11 and to recover the machining fluid to empty the machining tank. It has a function to circulate the water.

The NC control device 6 is a conventional one in which an input/output section, a memory part consisting of RAM and ROM, a processor part, and an operating program and a program are stored in the memory part. The operation program processes data such as the machine program, signals from sensors placed in various parts, or commands input from the outside through a part of the processor, and manages the overall operation of the NC laser/discharge combined machining device 1. It is.

The Ni program records the shape of the workpiece to be machined and the shape of the mounting hole to be formed in the part that will become the mold electrode 19, together with data.

The NC control device 6 is connected to the mechanical device 2, the laser oscillation device 3, the electric discharge machining power supply device 4, and the machining fluid device 5 through input/output sections, and controls the rotation and oscillation of the sarpo motor and turning on the power in each.・It is designed to control the opening and closing of OI"F or a solenoid valve.

Now, when it is necessary to cut a precise half-moon-shaped cutout hole (female shape) in the workpiece 18 as shown in FIG.
is fixed to the table mechanism 7 and the composite processing device 1 is operated.

The multi-tasking device 1 basically consists of a part of the processor and the first
The process of the flow shown in the figure, that is, the method of the present invention is executed, and the laser cutting mode is first entered.

According to the operating program, the vertical movement mechanism 8 moves to the position where the focal position of the laser head 10 is on the surface of the workpiece 14.
The table mechanism 7 is lowered along the axis and then moved at high speed along the cutting program, while cutting is performed using the beam from the laser oscillation device 3 along with the injection of assist gas.

In this processing, first, a mounting hole 20 of a specific shape for the chuck of the electrode head 9 is formed at a predetermined position of the workpiece 18 (step 1), and then the desired processing shape is cut. (Step 2).

Note that the desired machining shape corresponds to rough machining that leaves a finish machining allowance of Q, 3 mm width from the programmed machining path.

As a result, the rough machining is completed and the mold electrode 19 (
male form) is formed. This mold electrode 19 is 0.5m away from the workpiece (product side...female type) due to the laser cutting margin.
There is an interval of about m. Moreover, it naturally has the same thickness as the workpiece 18, and its peripheral surface becomes the processing electrode surface.

When the cutting process is completed, the laser oscillation and gas supply are stopped, the vertical movement mechanism 8 is returned to the home position, and then the table mechanism 7 is moved along the X-axis and Y-axis by the positional deviation between the laser head 10 and the electrode head 9. The cut workpiece 18 (female type) is moved along with the mold electrode 19 (male type), and the mounting hole 20 of the mold electrode 19 is inserted into the electrode head 9.
(Step 3).

In addition, in this example, the cutout male shape (type electrode 1
9), as shown in FIG. 8, the receiver in which a number of needles are implanted, which are previously arranged on the lower surface, is supported by the stand 21 and is only slightly lower than the upper surface of the female shape.

Next, the composite device 1 enters the oscillating electric discharge machining mode, and the vertical movement mechanism 8 descends while keeping the chuck claws 11 of the electrode head 9 extended downward, and inserts the claws 11 into the mounting holes 20 of the mold electrode 19. Then, the mold electrode 19 is fixed to the electrode head 9 by increasing the distance and lifting it up (step 4). At this time, the mold electrode 19 is held between the engaging part 12 of the claw 11 and the holding part 14, so that the horizontal position and the vertical position are changed.
The position in the rotation direction is accurately determined by fitting the prismatic positioning part 13 with the correspondingly shaped part of the mounting hole 20.

The electromagnetic valve of the machining fluid device 5 is opened, machining fluid is supplied to the machining tank 11, and the workpiece 14 is placed in the machining fluid (step 5).

When the completion of machining fluid supply is confirmed by a level switch or the like, pulsed power is applied from the electric discharge machining power supply 4 to the mold electrode 19.
and the workpiece 18, and the table mechanism 7 moves the workpiece 18 at a low speed from a radius of a little less than 0.5mm to a radius of a little less than 0.6mm (
It is driven to maintain the discharge interval (approximately 20μ) necessary for sustaining the discharge while performing circular oscillation to reach the set value (set value). Further, the Z axis is fixed while maintaining the vertical position between the workpiece 18 and the mold electrode]9. That is, the cut surface of the cutout hole in the workpiece 18 is precisely finished by die-sinking oscillating electrical discharge machining (step 6).

When electrical discharge machining is completed, the supply of pulse power to the mold electrode 19 is stopped, the chuck claws 11 are closed, the vertical movement mechanism 8 returns to the home position leaving the mold electrode 19, and the machining fluid is discharged from the machining bath 11. Recovered (Step 7)
, a series of metal composite processing is completed.

It should be noted that the specific processing in each of these steps is the same as the well-known laser cutting processing and die-sinking oscillating electrical discharge machining, respectively, but both processing are executed based on a common work program and machine program.

In the above, the surface roughness of the cut surface due to the laser cutting process is about 50 μRmax as described above, but the unevenness is random and there is no correlation between the cut surfaces on both sides. Therefore, if oscillating electrical discharge machining is performed with surfaces with such random uneven surface roughness facing each other,
That is, if one of the workpieces cut by laser cutting is used as a mold electrode as it is, the protruding portion will wear out and swing will be added to this, causing the facing surface to shift, so that the machining action will be averaged out. For this reason, it is difficult to correct waviness errors with large pitches on the machined surface, but unevenness with small pitches will wear out on both surfaces and the surface roughness will be efficiently improved.

In addition, if die sinking electrical discharge machining is performed between two pieces of the same material,
It is said that the wear of the electrode and the workpiece is the same, making it impossible to perform machining with good shape accuracy. However, in the present invention, only the finishing machining of the cut surface after laser cutting is performed, so the amount of machining is small and it is possible to work with the same material. However, the shape accuracy is not so bad and is sufficient for manufacturing mass-produced products. In fact, in the present invention, the fact that the wear rates of the workpiece and the electrode are about the same produces better results.

Also, the total machining time is about 5
The roughness of the machined surface is reduced by 0 to 1/100 times, and the surface roughness of the machined surface is reduced to about 2 to 1/3 of that by laser cutting alone. This is done by rough-machining a complex shape by laser cutting, and then using one of the cut parts as a die electrode for die-sinking electrical discharge machining to improve the roughness.

Since both laser cutting and electrical discharge machining are performed continuously using the same device, there is no positional shift when transferring the workpiece 18 from the laser cutting device to the electrical discharge machining device.

The above are examples.

In the present invention, in addition to electric discharge machining using circular oscillation, it is also possible to finish by electric discharge machining.

Further, the finishing allowance, the range of swing, the size of the offset, etc. are arbitrary, and appropriate values are selected for both laser cutting and electrical discharge machining.

One side of the cut workpiece, which is made into a 1 2 type electrode, may be either female or male depending on the purpose.

The mechanism of the chuck in the electrode head 9 and the specific shape of the mounting hole formed in the workpiece are not limited to those in the embodiment.

Effects of the invention: Cutting of complex shapes can be done by improving the surface roughness of the cut surface.
It can be mass-produced.

There is no need to separately prepare a molded electrode that is expensive and time-consuming to manufacture.

[Brief explanation of drawings]

Figure 1 is a basic flow diagram of the process, Figure 2 is a block diagram of the configuration, Figure 3 is a perspective view of the mechanical device, Figure 4 is a front view of the chuck, and Figure 5 is a view of the electrode head from below. bottom view,
FIG. 6 is a perspective view of the workpiece (after rough machining), FIG. 7 is a perspective view of the mold electrode (female shape after rough machining), and FIG. 8 is a front view showing the state of support of the workpiece in cross section. DESCRIPTION OF SYMBOLS 1... NC laser/discharge combined processing device, 7... Table mechanism, 8... - Vertical movement mechanism, 9... Electrode head, 10... Laser head, 18... Work, 19
...type electrode. qconn) area

Claims (2)

[Claims] (1) A metal cutting method for cutting a metal workpiece, which comprises performing electric discharge machining on the cut surface of the workpiece after the laser cutting process, using one side of the workpiece as an electrode. . (2) The metal cutting method according to claim 1, wherein during the laser cutting process, a mounting hole for a chuck of the electrode head is also formed in one of the workpieces that will become the electrode.