JPS5830946B2 - Electric discharge coating processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric discharge coating processing apparatus that forms a coating layer such as a hardened layer or a built-up layer on the surface of a workpiece, and performs surface treatments such as polishing, grinding, and hardening.

Conventionally, the surface of a workpiece is hardened by passing a pulse or other current between the workpiece and an electrode using a hardening agent, or by using the electrode itself as a hardening material to form a welding layer on the surface. Processing to form, processing by applying processing deformation to the surface, and other processing are used, and the conventional method is to polish and finish the hardened layer formed in this way.

In these cases, a process of forming a coating layer and finishing by grinding or polishing must be performed.

Furthermore, it is not easy to form a coating layer that is uniform, flat, and thick.

Furthermore, finishing such as polishing required work to grind the coated part to fit the thin part, and there were points that needed improvement in terms of workability and efficiency.

In view of the above-mentioned current state of the conventional technology, the present invention aims to improve surface hardening and other surface treatment techniques.

To this end, the object of the present invention is to provide a special tank bottom tool electrode that doubles as a polishing or grinding surface processing tool and a discharge coating electrode.

The object of the present invention is to provide a machining device that can perform discharge coating machining by pulse or electric discharge, polishing, and other operations using this tool electrode.

Next, the present invention will be explained in detail.

In the present invention, a rotating shaft is attached to one end of a rotating cylinder (including a solid body), and 2 to 20 covering material electrode wires are attached and fixed to the other end.

This wire is a thin wire with a circular, polygonal or combination of cross-sections, and the wire itself is made of a material suitable for hardening or other surface treatment.When the cylinder rotates, the fixed end of the attached electrode wire It is held in place, but it opens outward at the free end.

It comes into contact with the surface to be machined at an acute angle, and discharges between it and the workpiece to form a coating layer.

In addition to the coating process using electrical discharge, the surface of the workpiece is polished by an electrode wire, resulting in a uniform and flat surface that is easier to work with than when electrical discharge coating is performed using normal contact-release vibration. , can be obtained efficiently.

The amount of coating can also be increased sufficiently compared to the conventional method.

Pulse current or other current is applied as a power source.

During surface treatment, a surface treatment agent can be added between the surface to be processed and the electrode wire to increase the effectiveness of the electrode.

For example, during surface hardening treatment, a fine wire made of tungsten carbide is used as the electrode wire, tungsten carbide or other hardening agent is added to the surface to be processed, and electrical discharge coating is performed while the electrode wire is brought into contact with and rotated.

In addition to hardening, the surface can be coated with a corrosion-resistant, wear-resistant stellite coating, or coated with an electrically conductive metal.
Similarly, the method of the invention could be applied.

Next, some embodiments of the present invention will be described.

Fig. 1 is a perspective view of a tool electrode according to an embodiment of the present invention, Fig. 2 is an illustrative surface view of the tool electrode, where a is a diagram showing a stationary state and a rotating state, and Fig. 3 is a diagram showing a state in which the tool electrode is in a rotating state. An example configuration diagram is shown.

As shown in Fig. 1, the tool electrode is attached to a rotating cylinder 1.
The covering material electrode wire 3 is attached and fixed in the axial direction to the IA surface at one end.

It is preferable to plant the seeds parallel to the axial direction or with the tips shriveled.

It is preferable to plant two or more electrode wires 3 symmetrically about the central axis of the cylinder 1, so that rotation can be made smoothly.

Provide the rotating shaft 2 on the surface of the other end 1B.

When the rotating cylinder 1 is rotated as shown in Figure 2, the electrode wires 3, which were in a parallel or concave state like the tip of a brush when they were left stationary as shown in Figure A, will now have their free ends 3A facing outward. When it opens, it comes into contact with the surface 6A of the object 6 to be processed.

In FIG. 3, 4 is a rotating motor, and 5 is its control power source, which rotates the electrode wire 3 while controlling its spread, rotational force, etc. by controlling the rotational speed or torque.

Reference numeral 7 denotes a processing power source, 8 a resistor for detecting the state of the gap, and 9 a control circuit for controlling the power source 5 in accordance with a detection signal.

On the surface to be machined 6A, a pulse current supplied from the machining power supply 7 between the workpiece 6 and the electrode wire 3 generates electric discharge as the electrode wire 30 rotates in contact, and a coating to which the electrode wire is welded is formed. Then, surface coating forming processing such as surface hardening is performed from the process of processing by electric discharge and the action of polishing or grinding due to friction by the rotating fibers.

Compared to the conventional coating process in which a non-abrasive electrode is applied perpendicularly and electrical discharge is caused by contact-release vibration, an extremely uniform flat surface can be obtained and a thick layer can be easily formed.

As described above, the tip of the electrode wire 3 at the tip of the tool electrode expands as it rotates, and when the rotation is stopped, it returns to its original state and the electrode wire 3 collapses.

Therefore, the configuration is such that the spread of the electrode 3 can be controlled by the rotation speed.

Now, when the electrode wire 3 that is spread by the high-speed rotation by the motor 4 is brought into contact with the processing surface of the workpiece 6 as shown in the figure, the electrode wire 3 planted in the cylinder 1 will bend due to the rotational movement and become bent. Each electrode wire 3 comes into contact with the machining surface 6A while being in a state of being fitted to the machining surface 6A, rubs and moves, and each rotation leaves the machining surface 6A and spreads due to the rotational centrifugal force, rotates and collides with the machining surface 6A. It fits onto the machined surface while giving a beating, causes contact friction, moves and passes, and this is repeated one after another by each line due to rotation.

During this time, a machining pulse is applied from the machining power source 7 to generate a pulse discharge, and the portion of the electrode wire 3 at the discharge point is melted and welded to the surface 6A of the workpiece 6 to form a coating layer 6A of electrode material. Become so.

Since welding coating by electric discharge is performed by repeatedly moving the discharge point one by one by repeated pulse discharge, the coating layer surface 6A usually has a satin-like unevenness, but the electrode wire 3 is As described above, since it comes into contact with the processed surface 6A one after another and moves through it by friction, it has polishing properties, and the uneven surface of the coating layer is polished and ground into a smooth surface.

The discharge coating and the polishing action are simultaneously carried out in a dusting manner along with the rotational movement of the electrode wire 3, and the discharge coating process is always continued on the polished smooth surface, so that a uniform flat surface can be easily obtained.

On the other hand, in electrical discharge coating processing, if the surface becomes uneven due to the coating process, it becomes difficult to stack more electrical discharge coating on top of the coating layer, and if you dare to continue electrical discharge, you may even lose weight, but as mentioned above, The coating surface is constantly smoothed by the abrasive action caused by the friction of the rotating electrode wire 3, and discharge is performed while smoothing, so it is possible to stack coatings on the coating layer, and the amount of coating increases with processing time to achieve the desired thick coating. Any hardened layer that can be easily formed
This has the effect that the desired overlay layer can be easily obtained.

In addition, in the circuit shown in FIG. 3, the discharge state in the gap is detected by the resistor 8, and the control circuit 9 automatically controls the control power source 5 of the motor 4, so that the motor 4 rotates depending on the contact state of the electrode wires 3, friction state, etc. The speed, torque, etc. are controlled to the optimum conditions, and therefore the coating process in which both coating and polishing are performed is controlled to the best condition, resulting in the effect that stable surface treatment can be continued and efficient processing can be performed.

In some cases, a surface treatment agent is interposed on the processed surface to assist the treatment by electric discharge.

Regarding the case where the surface treatment is surface hardening treatment of steel, electrode wires include piano wire, tungsten carbide wire,
Titanium nitride wire, boron carbide wire.

Iron-chromium alloy wire could be used. As the hardening agent, powder strips made of the same material as the electrode wire, such as piano wire strips, are used.

Further, metal nitride powder can also be used.

Hard materials such as tungsten carbide, boron carbide, diamond, and boron nitride are attached to the core wire, bonded, painted,
It can be used by coating.

It is also possible to carry out the process in a special atmosphere to obtain, for example, a charcoal-impregnated or aluminum-impregnated or nitrided surface.

This process creates a spark discharge to thicken the hardened layer.
It was confirmed that a good surface could be obtained.

The diameter of the electrode wire should be thin, from 0.1 to 9.5 muφ to around 1 mmφ, and flexible, but it should be made of a resilient wire, and the number should be at least 2, or around 20 if there are many. ,
Good results were obtained when they were attached at equal distances in symmetrical positions.

Round wire, square wire, etc. are used. As an example, it was found that the diameter of the tungsten carbide wire was 0.1 to 1.0 mm, and the rotational speed of the cylinder could be in the range of about 500 to 2000 ORPM.

As the discharge conditions, a pulse current with a peak value 1p of 80 amperes and a pulse width τon of 60 to 50 μs was applied, and when the discharge coating was applied, the surface roughness was 10 μRmax (micron Rmax).

The processing speed was 4 to 5 times faster than the conventional method.

After this processing, it was confirmed that the surface roughness could be further improved by reducing the current or turning off the current and rotating the cylindrical body, that is, polishing with an electrode wire.

In addition, as the finishing discharge conditions, the pulse current was set to 1p50 amperes, τon was set to 2 μs, and the rotational speed of the cylinder was set to 10
When processed as 00 ORPM, the surface finish is
It became 6μRmax (micron Rmax).

It was also confirmed that when tungsten carbide powder was interposed between the tungsten wire and the surface to be hardened and a spark discharge was generated, the thickness of the hardened coating increased and there was no change in flatness.

What has already been described is the formation of a tungsten carbide coating layer and the finish of the machined surface, but similarly good results were confirmed with hardening using other materials.

In addition to hardening, corrosion resistance and wear resistance, such as stellite processing and overlay coating processing, can be performed in the same way. , coating with manganese steel can also be obtained in the same way.

As described above, the present invention uses a specially configured tool electrode, performs rotational friction, applies a pulse or other current, and if necessary, interposes a surface treatment agent such as a hardening agent to perform electrical discharge coating processing. depending on the process, and during processing or at the end.
By performing a polishing action using an electrode wire while occasionally weakening the current flow, the desired machined surface can be obtained in good condition.

Furthermore, it can be expected to be used more widely in surface treatments due to changes in atmosphere, etc.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a tool electrode according to an embodiment of the present invention, Fig. 2 is a surface measurement diagram, in which a is a stationary state, b is a rotating state diagram, and Fig. 3 is an entire device of an embodiment of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Cylindrical body, 3... Covering material electrode wire, 2... Rotating shaft, 3A... Free end, 4... Rotating motor, 5...
Control power supply, 6... Workpiece, 6A... Processing surface, 7.
... Power supply for processing, 9... Control circuit.

Claims (1)

[Scope of Claims] 1. A tool electrode in which two or more covering electrode wires are attached to one end face of a cylindrical body that is a hollow body or a solid body in the direction of the axial center of the cylindrical body, and the other side of the cylindrical body. a rotary motor provided at an end surface of the tool electrode for rotating the tool electrode around the cylindrical body;
A machining power source for causing a pulse discharge between the tool electrode and the workpiece is connected to a discharge coating machining device through an electric circuit, and the tool electrode rotated by the rotary motor is coated. The tool electrode is brought close to the machining surface of the workpiece, and each coating material electrode wire at the tip of the tool electrode rotates to collide with and contact the workpiece machining surface, frictionally slides, and then moves away, repeating the above-mentioned movement. A discharge coating machining device characterized in that a machining power supply causes electrical discharge between each coating material electrode wire and a workpiece to perform coating machining. 2. The covering material electrode wire is attached to the end face of the cylindrical body in a state in which it is parallel to the center of the rotation axis of the cylindrical body, or in a state where the tip of the electrode wire converges. The electric discharge coating processing apparatus according to item 1. 3. The covering material electrode wire is a plurality of wires attached to one end surface of the cylindrical body at positions symmetrical about the rotation axis of the cylindrical body, as set forth in claim 1. Electric discharge coating processing equipment. 4. The discharge coating according to claim 1, wherein the covering material electrode wire is formed by coating, painting, adhering, or adhering a layer made of a hard covering material to the surface of the electrode wire. Processing equipment.