CN101138806B

CN101138806B - Supersonic frequency impulse plasma arc cutting method and device

Info

Publication number: CN101138806B
Application number: CN2007101340960A
Authority: CN
Inventors: 王加友; 王晓梁; 杨峰
Original assignee: Jiangsu University of Science and Technology
Current assignee: Jiangsu University of Science and Technology
Priority date: 2007-10-19
Filing date: 2007-10-19
Publication date: 2010-06-02
Anticipated expiration: 2027-10-19
Also published as: CN101138806A

Abstract

The present invention discloses a cutting method and a device of ultrasonic frequency impulse plasma arc, which belongs to a field of plasma arc cutting technology. The device consists of an ultrasonic frequency power supply, a coupling capacitance, a plasma arc cutting power supply, an isolating inductance and a cutting torch. Wherein, a DC alternate signal and an ultrasonic frequency alternate signal are respectively isolated by the coupling capacitance and the isolating inductance. Parallel connection of the low power ultrasonic frequency impulse power supply and the common plasma arc cutting power supply makes the ultrasonic frequency alternate signal enter the cutting arc through capacitance coupling, realizes an ultrasonic frequency impulse modulation of broad band and low cost of plasma cutting arc, and enlarges stiffness and frapping degree of electric arc to make the electric arc generate ultrasonic frequency vibration, thereby improving the cutting speed of plasma arc, reducing attached slag on a notch largely, enhancing figuration quality of the notch and decreasing noise of the impulse electric arc. The present invention has advantages of low cost and good practicality, which is applicable for various materials and requirements of cutting technology with different plate thickness under the different medium conditions.

Description

Superaudio impulse plasma arc cutting method and device

Technical field

The present invention relates to a kind of Superaudio impulse plasma arc cutting method and device, belong to the Plasma Arc Cutting Technology field.

Background technology

Plasma arc cutting is the plasma jet that utilizes high temperature and high speed, makes metal works local melting and blowing immediately, forms a kind of thermal cutting processing method of narrow otch.Because of it has quick, efficient and meticulous advantage, in modern manufacturing industry, obtained extensive use.According to the difference of its used gas flow of ions kind, generally can be divided into kinds of processes such as the cutting of argon plasma arc, the cutting of nitrogen plasma arc, air plasma arc cutting and the cutting of oxygen plasma arc again.Adopt straight polarity during plasma arc cutting, promptly workpiece connects the positive pole of cutting power supply.

The patent No. is 94240308.8 disclosed a kind of " high-frequency impulse air plasma cutters ", adopts single loop list on-off circuit, and power transistor directly is serially connected in the cutting power supply major loop, produces cutting power electric pulse; The patent No. is 200520074418.3 disclosed a kind of " pulse control units of CUT ", be to control conventional current control circuit in the CUT, reach and produce the purpose of cutting with the power electric pulse by the weak electric pulse signal that this device produces.Above-mentioned prior art is a kind of with cutting power supply main circuit and the incorporate impulse plasma arc cutting of output pulses generator main circuit (or control) device, its advantage is the whole integrated level height of device, shortcoming is: 1. be subjected to the restriction of used high power device (as power transistor) and fly-wheel diode response by frequency, the cutting current pulse frequency is carried not high, is generally several KHzs.2. electric arc is operated in non-supersonic range, thereby arc noise is big, and the processing performance of supersonic range pulse plasma arc cutting brilliance can not get performance.3. the high-frequency pulse current amplitude can not be adjustable continuously, can only divide 2～3 grades of adjustings by the tap of afterflow reactor, and Technological adaptability is relatively poor.

The application in other fields such as welding about high-frequency impulse or Superaudio impulse technology, existing both at home and abroad report, as number of patent application is 01143444.9 disclosed " a kind of electric arc method for exciting ultrasonic waves of using ", and number of patent application is 200410009170.2 disclosed " a kind of titanium alloy welding methods based on arc-ultrasonic ", by the supersonic frequency electric pulse being introduced welding or being smelted electric arc, excite electric arc emission ultrasonic wave, influence the smelting and the crystallization process of metal, reach the welding quality of improving metal or the effect of metallurgical effect.In the prior art, do not see and relate to application and the cutting technique effect of the generation report thereof of supersonic frequency electric pulse in the plasma arc cutting.

Summary of the invention

In order to overcome the deficiencies in the prior art, the present invention proposes a kind of Superaudio impulse plasma arc cutting method and device, can improve metal works cut quality and efficient, improve the environment of plasma arc cutting operation.

The Superaudio impulse plasma arc cutting method that the present invention proposes is characterized in that this method may further comprise the steps successively:

1. the plasma arc cutting positive source is connect workpiece, join with cutting torch after its negative pole serial connection is isolated inductance; 2. the end in the output of Superaudio impulse power supply is connected in series every straight coupling capacitance, and Superaudio impulse power supply and plasma arc cutting power supply can be powered to electric arc with parallel way; 3. after plasma-arc ignited, the alternating signal that the Superaudio impulse power supply is produced formed the Superaudio impulse modulating action of article on plasma arc cutting through being superimposed upon after the Capacitance Coupled on the direct current arc cutting; 4. plasma arc cutting technology is routinely cut.

Described Superaudio impulse alternating signal selection dutycycle is 50% symmetrical square wave, and the pulse current amplitude that is superimposed upon on the electric arc can be 2%～50% of average cutting current, and frequency is adjustable continuously in 16～200KHz.

Realize the device of above-mentioned Superaudio impulse plasma arc cutting method, comprise the plasma arc cutting power supply, isolate inductance, Superaudio impulse power supply, coupling capacitance and cutting torch, its architectural feature is: the negative pole of plasma arc cutting power supply joins afterwards with the isolation inductance and the electrode in the cutting torch is connected, and the positive pole of plasma arc cutting power supply links to each other with workpiece; The electrode of one end in coupling capacitance and cutting torch of Superaudio impulse power supply joins, and the other end is connected with workpiece.

The present invention compared with prior art, its advantage is: 1. adopt small-power Superaudio impulse generating means and conventional cutting power supply parallel way, realized the broadband of plasma arc cutting, Superaudio impulse modulation cheaply; 2. Superaudio impulse plasma arc cutting pressure, deflection and the degree of bringing together are big, and can produce the ultrasonic vibration effect, influence heat transmission, metal molten and slag discharge process, improved cutting speed significantly, reduced the otch dross significantly, improve the cut sides perpendicularity simultaneously, reduced kerf width and cut sides hardness; 3. Superaudio impulse plasma arc cutting is operated in supersonic range, has reduced the noise of hf electric arc significantly, has improved the cutting operation environment; 4. the pulse current continuous parameters is adjustable, can adapt to the cutting technique needs under unlike material and thickness of slab, the different medium condition, has improved Technological adaptability.

Description of drawings

Below in conjunction with the drawings and specific embodiments the present invention is described in further detail:

Fig. 1 is the schematic diagram of the inventive method, and wherein: ia represents arc current.

Fig. 2 be in the cutting process detected arc current and in being cut workpiece detected supersonic frequency vibration signal waveforms figure, wherein: A is the arc current signal, B is a detected supersonic frequency vibration signal in the workpiece.

Fig. 3 is the otch back side dross situation comparison diagram of the inventive method and conventional cutting method, and wherein: the otch dross situation of the conventional cutting method when C is no pulse, D is the otch dross situation of the inventive method.

Fig. 4 is the structure connection diagram of apparatus of the present invention.

The specific embodiment

As shown in Figure 1, plasma arc cutting power supply and cutting torch can be selected for use commercially available universal, for preventing that the Superaudio impulse signal from scurrying into the cutting power supply major loop and influencing its operate as normal, be serially connected with the isolation inductance of inductance value greater than 0.03mH at the plasma arc cutting power output end; Cutting is individual layer or bilayer with nozzle; corresponding ion gas and protection gas can select for use air, oxygen, nitrogen, argon gas, nitrogen and argon gas mist and with the possible mist of hydrogen in a kind of, air-flow can select to rotate or not rotation mode send into cutting torch.The Superaudio impulse supply unit is made up of pulse signal generation circuit, control circuit, regulating circuit (or device), power driving circuit, high-speed high-power on-off circuit and corresponding absorption and coupling circuit (or device) etc., can produce frequency and be 16～200KHz, dutycycle and be 50%, the ac square wave of positive and negative half-wave symmetry, pulse amplitude is adjustable continuously in 5～250V scope.In order to prevent to ring the operate as normal of Superaudio impulse power supply, be serially connected with the capacitance of capacitance greater than 1 μ F at the output of Superaudio impulse power supply from the high power DC film of cutting power supply.During cutting operation, treat that the plasma-arc back of igniting inserts the Superaudio impulse electric current, the preferred 20～80KHz of pulse frequency, the pulse current amplitude that is superimposed upon on the electric arc can be 2%～50% of average cutting current, wherein should preferred 10%～25%; Then, plasma arc cutting technology routinely carry out cutting operation, utilize Superaudio impulse arc pressure and deflection big, bring together and the tangible characteristics of dither effect, influence the processes such as heat transmission, metal molten and slag blowing in the plasma arc cutting process, play the effect that improves plasma arc cutting quality and efficient.

For the validity of this method is described, be object with the plasma arc cutting of carbon steel, carried out a series of Superaudio impulse plasma arc cutting experiment, the pulse frequency of selection comprises 16～100KHz, pulse current amplitude comprises 2～50% of average cutting current.

Pulsed arc electric current (ia) signal waveform that Fig. 2 is 20KHz for detected a kind of frequency in the cutting process, and act on supersonic frequency vibration signal waveforms in the cut workpiece by being placed on the detected pulsed arc of piezoelectric transducer on the surface of the work.As seen from Figure 2, by on arc cutting, applying the Superaudio impulse electric excitation, can in workpiece, produce the ultrasonic vibration of same frequency.Fig. 3 is a comparison of the otch back side dross situation of the inventive method and conventional cutting method, as seen from the figure, the otch dross is serious when adopting the conventional cutting method of direct current no pulse, and the otch dross greatly reduces when adopting Superaudio impulse plasma arc method of the present invention to cut.In addition, experimental result also shows: compare with conventional cutting method, when adopting the inventive method to cut, the cutting speed maximum can improve more than 40%, and kerf width, cut sides inclination angle, otch hardness etc. obviously reduce.Therefore, make plasma arc cutting quality and efficient significantly improve, saved cutting cost.

As shown in Figure 4, the structure of the present invention on device is: the positive pole of plasma arc cutting power supply 1 is linked to each other with workpiece 6, and the negative pole of plasma arc cutting power supply 1 joins with isolation inductance 2.The electrode that one end of Superaudio impulse power supply 3 is electrically connected in straight coupling capacitance 4 backs and cutting torch 5 joins, and the other end is connected with workpiece 6.Superaudio impulse power supply 3 and plasma arc cutting power supply 1 are connected on the cutting torch 5 with parallel way, and cutting torch 5 plasma arc cutting technologies routinely are to workpiece 6 cuttings.The isolation inductance 2 of this device can be installed in the same cabinet with plasma arc cutting power supply 1 body, and coupling capacitance 4 can form an integral body with Superaudio impulse power supply 3.

Claims

1. Superaudio impulse plasma arc cutting method, it is characterized in that: this method may further comprise the steps successively: 1. the plasma arc cutting positive source is connect workpiece, its negative pole and cutting torch join; 2. Superaudio impulse power supply and plasma arc cutting power supply are powered to cutting torch with parallel way; 3. after plasma-arc ignites, insert the alternating signal that the Superaudio impulse power supply produces, form the Superaudio impulse modulating action of article on plasma arc cutting, the Superaudio impulse current amplitude that is superimposed upon on the plasma-arc is 2～50% of an average cutting current; 4. plasma arc cutting technology is routinely cut.

2. Superaudio impulse plasma arc cutting method according to claim 1 is characterized in that: described step 1. in, join with cutting torch again after the negative pole of plasma arc cutting power supply serial connection isolated inductance; Described step 2. in, the end serial connection of Superaudio impulse power supply output is in parallel again after straight coupling capacitance.

3. Superaudio impulse plasma arc cutting method according to claim 1 and 2 is characterized in that: described Superaudio impulse alternating signal selection dutycycle is 50% symmetrical square wave, and frequency is adjustable continuously in 16～200KHz.

4. Superaudio impulse plasma arc cutting method according to claim 3 is characterized in that: the pulse current amplitude that is superimposed upon on the electric arc can be 10～25% of average cutting current, and frequency is adjustable continuously in 20～80KHz.

5. Superaudio impulse plasma arc cutting method according to claim 2 is characterized in that: the inductance value of described isolation inductance is greater than 0.03mH, every the capacitance of straight coupling capacitance greater than 1 μ F.

6. device of realizing the described Superaudio impulse plasma arc cutting method of claim 1, comprise plasma arc cutting power supply (1), isolate inductance (2), Superaudio impulse power supply (3), coupling capacitance (4) and cutting torch (5), it is characterized in that: the negative pole of plasma arc cutting power supply (1) joins afterwards with isolation inductance (2) and the electrode in the cutting torch (5) is connected, and the positive pole of plasma arc cutting power supply (1) links to each other with workpiece (6); The electrode of one end of Superaudio impulse power supply (3) in coupling capacitance (4) and cutting torch (5) joins, and the other end is connected with workpiece (6).