JPH0657402A - Electric discharge coating device - Google Patents

Abstract

PURPOSE:To make improvement in such a manner that the roughness of a coating surface is finely smoothed by electric discharge coating and a uniformly hardened layer is easily obtd. CONSTITUTION:A hollow pipe electrode 2 which is an electrode of a coating material is fixed and supported to the front end of a revolving spindle 3 by a chuck 4. This pipe electrode is rotated by a revolving motor 5 and is servo fed by a servo motor 9. The electrode 2 is disposed to face a work piece 1 fixed to a working table 10 and is held in light contact therewith. Working pulses are supplied in this state from a working power source 16 to a spacing subjected to the rotation and the servo feed control to execute pulse electric discharge, by which the electrode 2 material is transferred and deposited by slight amt. each to the work piece 1. Gas, liquid, power or the like of reactant is supplied through the pipe electrode 2 to the above-mentioned electric discharge coating space from a reactant supplying device 19 and the work piece is coated with the reactant while a chemical reaction with the electrode 2 material is induced by the electric discharge, by which the work piece is coated with the hardened layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge coating processing apparatus.

[0002]

2. Description of the Related Art Conventionally, an electric discharge for coating an electrode material on a workpiece by repeating a pulse discharge between the tip-shaped coating material electrode and the workpiece by vibrating or rotating contact with the workpiece. Although coating processing is known, the conventional coating processing apparatus cannot always control the optimum state because the control of the contact gap between the coating material electrode and the workpiece is manually adjusted. Therefore, the amount of dissolution at the minute discharge point of the coating material electrode increases or decreases, which causes a difference in the amount of transfer welding to the workpiece, and the formation of the coating layer by the aggregation of transfer welding of minute amounts according to the discharge repetition. However, there are drawbacks in that it cannot be made smooth and the hardness of the coating layer is not uniform.

[0003]

DISCLOSURE OF THE INVENTION The present invention is to improve the coating surface roughness by electric discharge coating so that it can be finely processed into a smooth surface and a uniform hardened layer can be easily obtained.

[0004]

A coating material electrode is provided with a hollow pipe electrode, and a gas, a liquid, or a reactant gas is passed through the pipe electrode.
A reactant supply device for supplying powder or the like is provided, the pipe electrode for ejecting the reactant supplied from the reactant supply device is held, and rotation is given with the tip facing the workpiece and servo feeding. And a machining power supply for supplying a discharge pulse between the pipe electrode and the workpiece.

[0005]

According to the present invention, as described above, the coating material electrode is provided with the hollow pipe electrode, and the gas of the reactant is passed through the pipe electrode.
A liquid, a powder, etc. are supplied and discharged to cause an electrical discharge between the workpiece and the workpiece, and the coating is performed while chemically reacting with the coating material or the workpiece, so that carbides, nitrides, borides, silicides , Other complex compounds can be easily coated, and since the pipe electrode is rotated in a light contact state with the workpiece and is also servo-fed, a constant gap can always be maintained. It is possible to supply a reactant at a constant flow rate therethrough, whereby the coating process by reaction can be stably and uniformly performed, and a uniform and smooth good coating layer can be formed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment of the drawings. In FIG. 1, 1 is a workpiece, 2 is a hollow pipe electrode, and this electrode 2 is a chuck 4 at the tip of a rotary spindle 3.
Fixed by. Reference numeral 5 is a spindle rotation motor, 6 is a ram that supports the rotation motor and the spindle, and is supported so as to be vertically movable. A screw 7 is coupled to the upper end of the ram, and a rotary shaft 8 is engaged with the screw to provide vertical feed. Reference numeral 9 is a Z-axis servomotor, and 10 is a processing table for fixing the workpiece 1, which is drive-controlled to the X-axis and Y-axis of a plane orthogonal to the Z-axis where the electrodes 2 face each other. Reference numerals 11 and 12 denote the shaft drive motors, 13 denotes an NC control device for supplying control signals to the respective shaft motors, and 16 supplies current to one of the opposing electrodes 2 via a conduction electron 14, and connects the other to the workpiece 1. The processing power source 15 is a torque sensor provided on the rotary motor 5. Reference numeral 17 is a signal detection circuit that detects the gap state by using the voltage between the electrode 2 and the workpiece 1 as a signal, and 18 is a servo feed control circuit that applies this control signal to the servo motor 9 to perform servo. Reference numeral 19 denotes a reactant supply device for supplying the reactant gas, liquid, powder or the like, which is supplied to the electrode pipe 2 through a hollow passage communicating with the rotary spindle 3 and jets from the tip.

The NC controller 13 drives the X-axis motor 11 and the Y-axis motor 12 to position and control the electrodes 2 on the workpiece 1 so as to face each other. The tip of the hollow pipe electrode 2 comes into contact with the workpiece 1, and in this contact state, the rotary motor 5 is driven and controlled to make a rotary contact movement. Therefore processing power supply 1
By supplying a machining pulse from 6 and repeating the pulse discharge between the electrode 2 and the workpiece 1, minute portions of the discharge point melted portion of the electrode 2 material are transferred and welded to the workpiece 1. A voltage of the gap is detected by the detection circuit 17 and the detection signal is discriminated by the control circuit 18 or a difference from a reference value is output to the electrode 2 during processing to output a servo signal, and the servo motor 9
Is driven to apply servo feed, the tip of the electrode 2 maintains a constant light contact gap with respect to the workpiece 1, and the coating process can be continued stably. NC controller 1
The drive control of each axis motor by 3 controls so that the rotational torque of the electrode 2 becomes constant by the detection signal of the torque sensor 15, and the consumption of the electrode 2 is maintained by the servo of the servo motor 9 so that the light pressure state is always maintained. Control is performed so that stable machining can be performed, and the X-axis and Y-axis motors 11 and 12 are driven according to the programmed shape to perform plane feed, so that arbitrary shape coating can be easily performed.

Further, after a series of processing is completed by the programmed shape feeding, the same shape feeding can be performed again and the layers can be coated on the coating layer. Coating material electrode 2
For this purpose, a hollow pipe having an outer diameter of 1 to 5 mmφ and a wall thickness of 0.1 to 1 mm, preferably about 0.3 to 0.5 mm is used, and the tip discharge surface in contact with the workpiece 1 is hollow and rotates. The whole surface of the contact is moved by, and the moving speed is controlled to be about 1 m / s or less, whereby the welding mark at the discharge point is extended in the rotational direction, and the surface of the welded material is friction-polished to be processed into a smooth surface. It A reactant such as a reaction gas is supplied to the discharge coating gap during processing. That is, it is supplied from the reactant supply device 19 to the pipe electrode 2 through the hollow passage of the rotary spindle 3 and is injected into the gap from the tip of the pipe electrode. This jetted gas causes a chemical reaction with the coating material by the discharge, and a compound is generated and welded. The supply of this reaction gas also maintains a constant gap by servo feed,
A certain amount of the reactant is stably supplied, and the reactant is uniformly coated while causing a stable chemical reaction. The reactant supplied from the reactant supply device 19 is supplied as a gas, a liquid, or a powder, but when combining carbides, CH, CH
₂ , CH ₃ , CH ₄ . ． ． ． Etc., the compounds of the nitride _{N 2, N 2 O, NH} 3. ． ． ． Etc., C for compounding silicide
HSi, SiH ₄ . ． ． ． Etc., graphite powder, B
Powder, etc., and further mixed gas, mixed powder, etc. are supplied to cover the electrodes 2 with Ti, W, Nb, Ta, Zr, Hf.
Ti, WC, B ₄ C, Ta
Carbides such as ₂ C, nitrides such as TiN, TaN, ZrN and NbN, and borides such as TiB ₂ , ZrB and HfB ₂ can be reactively coated. Further, the reaction can also produce a complex compound by a complex chemical reaction.

Next, a specific embodiment will be described.
A Ti material having an outer diameter of 3 mmφ and a wall thickness of 0.5 mm is used for the pulp electrode, and N ₂ gas is supplied at 15 ml / min from this pipe electrode.
When the coating process was performed by ejecting at, and discharging for Ip = 15 A, τon = 5 μs, the thickness of the surface of the S55C material was 15 μm.
Of TiN could be coated. Also, using a 3 mmφ W electrode,
Graphite particles of 5 μφ were supplied from this pipe electrode using Ar gas as a carrier at a flow rate of 10 ml / min,
A composite compound of W ₂ C and WC could be synthesized when discharge coating was performed under the same discharge conditions. Also, using the Ti material pipe electrode described above, graphite powder and B powder were mixed with Ar gas for 20 m.
When ejected at a flow rate of 1 / min, T
i, B and C synthetic materials can be coated and the hardness is 4200 Hv
I was able to get In any of the above processes, the pipe electrode was processed while detecting the voltage in the gap and using this as a signal to perform servo feed in the Z-axis direction. When the TiN coating process was performed without this servo, the N / Ti was 0.35 at the best and the lattice constant was 4.217Å, but by servoing, the N / Ti was 1.10 and the lattice constant was 1.10. It was 4.225Å. In addition to the voltage between the electrodes and the object to be processed, the average current, resistance impedance, pressing force, and the like can be detected as signals for the servo feed.

[0010]

As described above, according to the present invention, the coating material electrode is provided with the hollow pipe electrode, and the gas, liquid, powder or the like of the reactant is supplied through the outer pipe electrode and ejected to discharge the workpiece. Since the coating process is performed while chemically reacting with the coating material or the workpiece, it is possible to easily coat carbides, nitrides, borides, silicides, and other complex compounds. Since the servo feed is applied to the workpiece in a state of light contact with the workpiece, a constant gap can always be maintained, and a constant flow rate of the reactant can be supplied to the gap. The coating process can be performed stably and uniformly, and a uniform and smooth favorable coating layer can be formed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

[Explanation of symbols]

 1 Workpiece 2 Pipe electrode 3 Rotating spindle 4 Chuck 5 Rotating motor 8 Rotating shaft 9 Servo motor 10 Processing table 11, 12 Motor 13 NC control device 16 Processing power supply 17 Gap state detection circuit 18 Servo control circuit 19 Reactant supply device

Claims (1)

[Claims] 1. A coating material electrode is provided with a hollow pipe electrode, a reactant supply device for supplying gas, liquid, powder, etc. of the reactant through the pipe electrode is provided, and the reactant supplied from the reactant supply device is provided. A machining power source is provided which holds the jetting pipe electrode, rotates the tip of the pipe electrode in a state of facing the workpiece, and sends a servo signal, and supplies a discharge pulse between the pipe electrode and the workpiece. An electric discharge coating machining apparatus characterized by being provided.