JPS6355416B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-dimensional machining method that makes it possible to perform three-dimensional machining efficiently and in a short time, that is, for example, know-how machining of a plastic mold.

When forming a three-dimensional curved surface on a workpiece, conventionally, this is generally done by mechanical processing such as milling or grinding, electrical discharge machining or electrolytic machining, or a combination of milling and electrical discharge machining.

An object of the present invention is to provide a three-dimensional processing method that can process three-dimensional curved surfaces, particularly cavity-shaped molds, etc., more quickly and efficiently than such conventional methods.

The present invention involves drilling a large number of holes over the entire surface of a workpiece using a machining drill to a predetermined depth corresponding to the location of each hole, and then applying electric discharge machining or electric discharge machining to the area where the holes were drilled. It is characterized in that a three-dimensional machined surface is formed by processing using a full-form processing electrode using an electric processing method such as electrolytic processing.

The present invention will be explained below with reference to the drawings. Figure 1A,
B and FIG. 2 schematically show the processing method of the present invention. In the present invention, as shown in FIGS. A large number of holes 3 are drilled one after another at a predetermined depth using the drill 2 (4 is the final machined surface, 5 is the
(indicates a machining area line), and then, as shown in FIG. 2, a three-dimensional curved surface is processed and formed by electrical machining such as electrical discharge machining or electrolytic machining using the full-form machining electrode 6.

When drilling holes using the drill described above, drilling may be performed using a single-diameter drill, but as shown in the figure, the holes 3a are first drilled at a predetermined pitch using a large-diameter drill 2a, and the final machining of each part is performed. The diameter of the drill is automatically changed by drilling the hole to the depth of the surface 4, then using the medium diameter drill 3b, and then using the small diameter drill 2c to drill holes 3b and 2c in the gap between the holes 3a. By sequentially changing the number, etc., it is possible to more densely and efficiently remove the workpiece material from the workpiece 1 in the entire area inside the processing area line 5. In addition to the above, a plurality of slanted holes 3d are diagonally drilled from various directions using an slanted drill 2d to provide a circulation path for suction and ejection of electrical discharge machining fluid and electrolytic machining fluid in the subsequent electrical machining process. By doing so, it is possible to improve the flow of these machining fluids and increase the machining efficiency of electrical machining. In addition, by drilling holes 3a to 3c using the respective drills 2a, 2b, and 2c at a depth corresponding to the final machined surface 4, the amount of removal by drilling as mechanical processing of the removed portion of the workpiece can be reduced. It is possible to reduce the amount of machining by electrical machining in the subsequent process and improve the machining speed of the entire machining process.

Various methods can be adopted for drilling holes in the machining area within the machining area line 5, but as an example, as shown in FIG. at regular intervals (x ₂ - x ₁ = x ₃ - _{x 2} =
..., y ₂ - y ₁ = y ₃ - _{y 2} = y ₄ - y ₃ =...) with large diameter hole 3
a, for example, the center position coordinates of the drill 2a axis (x ₁ , y ₂ ), (x ₁ , y ₃ )..., (x ₂ , y ₁ ), (x ₂ , y ₂ )
After drilling in the order of ..., (x ₃ , y ₁ ), (x ₃ , y ₂ )..., the large diameter hole 3a is drilled with the medium diameter drill 2b.
There is a method in which a medium-diameter hole 3b is drilled between the holes, and a hole 3c is drilled around the entire hole-drilled portion using a small-diameter drill 2c. When using this method, the machining area line 5
The X, Y coordinates of
Distance between the periphery of a', 3b'3c' and processing area line 5
w ₁ is within a certain range (w ₀ ≦w ₁ ≦w ₂ ) (however, w ₀ ,
w ₂ is a constant value). Further, the depth of each drill is set so that Δz from the lower end of each drill to the final machined surface 4 is constant, as shown in FIG. That is, the coordinates of the final machined surface 4 are memorized in advance on the paper tape, etc., and the coordinates from the bottom surface of the drill to each coordinate point (x _i , y _i , z _i ) within the radius r from the center point 0 of the drill are stored in advance on the paper tape or the like. The distance in the drill penetration direction (z direction) is determined, and the drill depth is set so that the minimum value Δz is constant. The paper tape, etc. that has been programmed in this way is applied to a numerical control device, which controls a vertical or horizontal machining center with an automatic tool changer, or a radial drilling machine with an automatic tool changer to perform drilling or perforation processing. Drilling, which is a mechanical cutting process, is performed by executing these steps one after another.

5 to 7 show an example of an apparatus for carrying out the method of the present invention. As shown in FIG. 11 was installed,
An X-axis moving table 12 with a numerically controlled drive motor 12a is installed thereon, and a fixing table for the workpiece 1 or a tank 13 for electric discharge machining is installed thereon.
Further, a threaded rod 15 rotated by a numerically controlled drive motor 14 for Z-axis movement is attached to the column vertical part of the bed body 10, and a rotatable circular tool mounting body 16 is supported on the threaded rod 15. body 1
7, and the support 17 has a
A balance weight 18 is connected to one end, and the other end of a wire 20 that is hung around a roller 19 is connected. The tool mounting body 16 is rotated by a numerically controlled drive motor 21 on a support body 17, and is mounted so that tools or electrodes can be selectively exchanged.As shown in FIG. The drills 2a to 2n and electrical discharge machining electrodes 6a to 6m are attached, and when each drill 2a to 2n is attached to the tool attachment body 16, each bevel gear 22 that has been attached to the corresponding position of the tool attachment body 16 in advance.
is configured to be connected to. Reference numeral 23 denotes a rotary drive shaft which is rotatably attached to the support 17 and positioned slightly below the center of rotation of the tool mount 16, and the bevel gear 26 at one end is connected to the output of the drill rotation drive motor 24. Bevel gear 2
5, and the bevel gear 27 at the other end is engaged with the tool mounting body 1.
When a drill to be driven is selected by rotation of 6 and set in a predetermined position such as downward, it is configured to mesh with a bevel gear 22 connected to the drill.

On the other hand, the general electrode 6a for electric machining such as electric discharge machining etc.
6m is attached to the tool mounting body 16 via an insulator 28 and a conductive holder 29, as shown in FIG.
It is connected by a wire 42 to a contact 41 attached to the surface of the tool mount 16 facing the support. A cylinder 44 is attached to the support 17 via an insulator 43, and a piston 45 made of a conductive material is connected to the contact 41 by supplying pressure oil to the cylinder 44 through an oil path 46 and a valve 47. By protruding, the electrodes 6a, 6b,
6m is power source 4 for electrical processing such as intermittent voltage pulse power source
9 through an electric wire 50. In addition, the internal cylinder of the support body has
A spool 52 made of an insulating material and having a through hole 52a for liquid flow in the center is attached to the oil passage 46.
By supplying pressure oil to the internal cylinder through the valve 53, the spool 52 protrudes and is fitted into the tapered receiving hole 54 of the electrode, and the tank 55 moves the pump 56, the filter 57, the hose 58 and the valve 59.
The machining fluid is introduced to the machining fluid supply hole 60 of the electrode. Further, the tank 13 in which the workpiece 1 is set is connected to a machining tank 55 via a machining fluid supply hose 71 having a valve 70, and the machining fluid outlet of the tank 13 is connected to the X-axis moving table 12.
It is connected to the tank 55 via a hose 75 having a discharge hole 73 and a valve 74 provided in the tank 55 .
Further, the other pole of the power source 49 is connected to a stand 77 inside the tank 13 via an electric wire 76.

When performing machining using this device, drills 2a to 2n with different diameters to be used for the tool mounting body 16.
At the same time, the electrodes 6a to 6m are attached, and after setting the workpiece 1 on the stand 77, a magnetic tape or paper tape program created using an appropriate numerical control program creation device such as CAD or CAM (not shown) is created. , or operate a numerical control device (not shown) according to an MDI input program to drive the numerically controlled drive motors 11a, 12a, 14, 21, 2.
4. Controls and drives the others, for example, by driving the tool selection motor 21, first, for example, the large-diameter drill 2a is vertically facing downward and facing the workpiece 1 mounted on the table 77. None, X,
Each motor 11a of the Y-axis moving table 12, 11,
12a to set the drilling position of the workpiece 1,
The motor 14 is driven to lower the selected drill together with the support 17 and the tool mounting body 16, and the drill rotation motor 24 is driven and the amount of descent by the motor 14 is controlled to move the workpiece 1 to a predetermined area within the machining area line 5. A drill hole with a predetermined diameter and a predetermined depth is drilled at the location to perform so-called rough machining or rough cutting. After performing such operations sequentially by numerical control for a predetermined number of holes, the drill is replaced with one with a smaller diameter and the same drilling operation is performed.

After drilling a drill hole for mechanical cutting, the motor 21 is driven to first roughen one of the electrodes 6a to 6m depending on the shape of the final machining surface 4 and the machining area line 5. The machining electrode, then the semi-machining electrode, and finally the finishing machining electrode are positioned facing each other on the workpiece 1, and the positions are set by moving the X and Y axis moving tables 12 and 11, and the motor 14 is driven. and put the electrode into the tank 13,
Hydraulic pump (not shown), machining fluid supply pump 5
6 and open the valves 70 and 74 to circulate and renew the machining fluid in the tank, open the valve 47 to bring the piston 45 into contact with the contactor 41, and connect the electrode 6a to one output pole of the power source 49. Then, the valve 53 is opened and the tip of the spool 52 is fitted into the receiving hole 54 of the electrode, and the valve 59 is opened to supply machining fluid from the liquid supply hole 60 to the machining section while performing electrical machining such as electrical discharge machining. Medium machining (rough machining in normal electrical machining)
I do. After that, by the same operation, another electrode 6
b and 6m in sequence, changing the machining conditions by the power source 49, and further changing the machining fluid supply jet conditions as necessary to perform finishing machining and final finishing machining. During this electrical processing, the motor 1
4 is used as a processing feed and interval control servo motor, but this processing feed and servo motor and its mechanisms may be provided and configured separately from the motor 14.

In this way, rough machining is performed by mechanical cutting using drilling, and then electrical machining such as electrical discharge machining is used to perform semi-machining (rough machining of electrical machining), finishing machining (medium machining of electrical machining), and final finishing machining. The reason why we decided to perform this process (machining that is more than finishing in electrical machining) is that mechanical cutting (drill machining) differs greatly depending on the type and material of the drill tool and the workpiece, but workpiece 1 is SKD6 , SKD11 or
The approximate machining speed (workpiece removal amount (g)/machining time (min)) when using ordinary mold iron material such as S55C is approximately 1000 g/min, which is referred to as rough machining in the present invention, and is used in the next process. Approximately 30% in electrical discharge machining
Rough machining at a rate of about 0.5 g/min or less is considered as semi-machining in the present invention, and the next process is electric discharge machining, and semi-machining at a rate of about 0.5 g/min or less is considered to be finishing machining in the present invention. However, another machining method may be used, but in the case of electric discharge machining, finishing machining of about several mg/minute is performed as the final finishing machining in the present invention, and the average machining speed is 3.5 mg/min at a high machining speed.
This means that it is possible to process and mold a mold with a dimensional curved surface. And this is the machining speed for conventional milling (approximately 50
g/min, approximately 1g/min for the same medium processing, and approximately 1g/min for the same finishing processing.
0.1g/min, compared to 0.01mg/min with hand finishing).
This means processing and forming at extremely high speeds.

In this way, the reason why high-speed machining is possible by using drilling as a mechanical cutting process for rough machining and using electric machining such as electrical discharge machining as a post-process in combination is that milling machines as a mechanical cutting process In this method, a lateral load is applied to the rotation axis of the cutting tool, and there is a limit to the thickness of the cutting tool, so it is difficult to perform rough cutting with a cutting force as large as drilling. This is because the pressurizing direction of the drill coincides with the rotation axis of the tool, so machining can be performed with high cutting pressure. Also,
Even if electric machining such as electrical discharge machining is combined with the above-mentioned milling, it is better to use electric discharge machining on a surface with many holes and unevenness due to drilling than on a surface that follows a shape like a milled surface. This is because electrical machining can be performed smoothly and the electrical machining speed can be increased, and during electrical discharge machining, the drilled holes 3a, 3b, 3c are difficult to remove until the middle stage of electrical discharge machining. It can be used as a debris accumulation hole or a discharge hole for machining fluid and machining debris, and since a large amount of machining fluid is present near the machining gap, it is suitable for high-load (high-current) machining. These things can also contribute to increasing the processing speed. Furthermore, as mentioned above, if the diagonal inclined hole 3d is formed by drilling, an insulating tube can be inserted into the hole 3d and the tube can be inserted and removed until the middle of the machining process. Alternatively, by appropriately providing small holes on the side surface to suck in or eject machining fluid, removal of machining debris and renewal of machining fluid becomes extremely smooth, allowing efficient machining and further improving machining speed. can. Moreover, it goes without saying that machining can be performed at a higher speed than machining using only electrical discharge machining or electrolytic machining.

Note that when carrying out the present invention, machining with a drill and electrical discharge machining may be performed using separate machine tools, and the machining mode with a drill can be variously changed depending on the shape to be machined.

As described above, in the present invention, after rough machining is performed by drilling, semi-finishing and finishing machining are performed by electrical machining such as electrical discharge machining or electrolytic machining. Alternatively, the machining speed can be significantly increased compared to cases where milling and electrical machining are combined.

[Brief explanation of the drawing]

FIG. 1A is a side view showing an example of the drilling state when using the processing method of the present invention, FIG. FIG. 3 is an explanatory diagram showing an example of the procedure of hole drilling, FIG. 4 a and b are explanatory diagrams showing an example of setting the drilling depth, and FIG. FIG. 6 is a front view of the tool mounting body of the device shown in FIG. 5, and FIG. 7 is a cross-sectional view illustrating the state when electrical discharge machining is performed by the device. .

Claims (1)

[Scope of Claims] 1. Drilling is performed over the entire machining area of a workpiece to a predetermined depth in each part, such as by drilling a large number of holes with a drill, and then A three-dimensional machining method characterized by forming a three-dimensional machining surface by electrical machining by an electric machining method such as electrical discharge machining or electrolytic machining using a full-form machining electrode corresponding to the shape. 2. Three-dimensional processing according to claim 1, characterized in that when drilling a hole with the drill, the hole is drilled by sequentially replacing a drill with a large diameter with a drill with a small diameter. Method. 3. When holes are drilled using the drill, each hole is drilled to a depth that corresponds to the shape to be finally machined. 3. Dimensional processing method. 4. When drilling holes with the drill, some of the holes are drilled diagonally, and the diagonal holes are used as injection or absorption passages for machining fluid or electrolyte in electrical discharge machining or electrolytic machining. A three-dimensional processing method according to claim 1.