ARC WELDING CONTROL METHOD AND ARC WELDING APPARATUS

• US 20130068744A1
• Filed: 05/10/2012
• Published: 03/21/2013
• Est. Priority Date: 06/03/2011
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Matsui, Kaito, Kawamoto, Atsuhiro, Hirota, Yukinori
• Granted Patent: US 9,114,472 B2
• Time in Patent Office: Days
• US Class Current: 219/137.R
• CPC Class Codes: B23K 9/092 characterised by the shape of the pulses produced
• CPC Class Codes: B23K 9/0953 using computing means
• CPC Class Codes: B23K 9/173 and of a consumable electrode

Abstract

In an arc welding control method of repeating a short circuit and an arc to perform welding, control is carried out to conduct a welding current having a first polarity for a short circuit period, and a first commutation to commutate the welding current from the first polarity to be a polarity of the welding current for the short circuit period to a second polarity to be opposite to the first polarity is carried out for an arc period subsequent to the short circuit period. Furthermore, control is performed to carry out a second commutation to commutate the welding current from the second polarity to the first polarity for the arc period in which the first commutation is executed. Consequently, it is possible to reduce an energy input amount to a base metal, thereby suppressing burn-through in welding of a thin plate.

Claims

1. An arc welding control method of repeating a short circuit and an arc to perform welding, comprising:

controlling a welding current to conduct a welding current having a first polarity for a short circuit period;

carrying out a first commutation to commutate the welding current from the first polarity to be a polarity of the welding current for the short circuit period to a second polarity to be opposite to the first polarity for an arc period subsequent to the short circuit period; and

controlling the welding current to carry out a second commutation to commutate the welding current from the second polarity to the first polarity for the arc period in which the first commutation is executed.

2. The arc welding control method according to claim 1, wherein the first commutation is carried out after a first predetermined time passes since a start of the arc period.

3. The arc welding control method according to claim 1, wherein the second commutation is carried out after a second predetermined time passes since the execution of the first commutation.

4. The arc welding control method according to claim 1, wherein welding is carried out at such a wire feeding speed as to cyclically change, in a predetermined cycle and a predetermined amplitude, feed of a welding wire into forward feeding to be carried out in a direction of a welding target and backward feeding to be carried out in a reverse direction to the forward feeding.

5. The arc welding control method according to claim 4, wherein the first predetermined time is determined based on the wire feeding speed for carrying out the cyclic change in the predetermine cycle and the predetermined amplitude.

13. The arc welding control method according to claim 2, wherein welding is carried out at such a wire feeding speed as to cyclically change, in a predetermined cycle and a predetermined amplitude, feed of a welding wire into forward feeding to be carried out in a direction of a welding target and backward feeding to be carried out in a reverse direction to the forward feeding.

14. The arc welding control method according to claim 3, wherein welding is carried out at such a wire feeding speed as to cyclically change, in a predetermined cycle and a predetermined amplitude, feed of a welding wire into forward feeding to be carried out in a direction of a welding target and backward feeding to be carried out in a reverse direction to the forward feeding.

6. An arc welding apparatus to repeat a short circuit and an arc to perform welding between a welding wire and a welding target, comprising:

a primary side rectifying unit to rectify an input AC power;

a switching unit to set an output of the primary side rectifying unit into an alternating current;

a transformer to transform an output of the switching unit;

a secondary side rectifying unit to rectify an output of the transformer;

a polarity change-over unit to change over an output of the secondary side rectifying unit into an output having a first polarity or a secondary polarity to be opposite to the first polarity;

a welding voltage detecting unit to detect a welding output voltage;

a short-circuit arc deciding unit to decide a short circuit period or an arc period based on a result of the detection obtained by the welding voltage detecting unit; and

a polarity inversion setting unit to output a polarity inversion control signal to the polarity change-over unit based on a result of the decision obtained by the short-circuit arc deciding unit,

wherein the polarity inversion setting unit outputs a polarity inversion control signal to the polarity change-over unit to conduct a welding current having the first polarity, thereby outputting the welding current having the first polarity for the short circuit period,

the polarity inversion setting unit outputs a polarity inversion control signal to the polarity change-over unit to carry out a first commutation to commutate the welding current from the first polarity to be a polarity of the welding current to a second polarity to be opposite to the first polarity, thereby outputting the welding current having the second polarity for an arc period subsequent to the short circuit period, and

the polarity inversion setting unit outputs a polarity inversion control signal to the polarity change-over unit to carry out a second commutation to commutate the welding current from the second polarity to the first polarity, thereby outputting the welding current having the first polarity for the arc period in which the first commutation is executed.

7. The arc welding apparatus according to claim 6, wherein the polarity inversion setting unit times an elapsed time since a start of the arc period and outputs the polarity inversion control signal to carry out the first commutation after a first predetermined time passes since the start of the arc period.

8. The arc welding apparatus according to claim 6, wherein the polarity inversion setting unit times an elapsed time since the execution of the first commutation and outputs the polarity inversion control signal to carry out the second commutation after a second predetermined time passes since the execution of the first commutation.

9. The arc welding apparatus according to claim 6, further comprising a wire feeding control unit to control feed of the welding wire,

welding being carried out at such a wire feeding speed as to cyclically change the feed of the welding wire, in a predetermined cycle and a predetermined amplitude, into forward feeding to be carried out in a direction of a welding target and reverse feeding to be carried out in a reverse direction to the forward feeding.

10. The arc welding apparatus according to claim 9, wherein the first predetermined time is determined based on the wire feeding speed to carry out the cyclic change in the predetermined cycle and the predetermined amplitude.

11. The arc welding apparatus according to claim 6, further comprising a welding condition setting unit to set a welding condition,

the polarity inversion setting unit storing at least either the first predetermined times or the second predetermined times which are caused to correspond to a welding set current set by the welding condition setting unit, and

the polarity inversion setting unit determining the first predetermined time and the second predetermined time based on the welding set current set by the welding condition setting unit.

12. The arc welding apparatus according to claim 11, wherein the welding condition setting unit has an adjusting amount setting unit to output, to the polarity inversion setting unit, adjusting amounts for adjusting the first predetermined time and the second predetermined time which are determined by the polarity inversion setting unit based on the welding set current set by the welding condition setting unit.

15. The arc welding apparatus according to claim 7, further comprising a wire feeding control unit to control feed of the welding wire,

welding being carried out at such a wire feeding speed as to cyclically change the feed of the welding wire, in a predetermined cycle and a predetermined amplitude, into forward feeding to be carried out in a direction of a welding target and reverse feeding to be carried out in a reverse direction to the forward feeding.

16. The arc welding apparatus according to claim 8, further comprising a wire feeding control unit to control feed of the welding wire,

welding being carried out at such a wire feeding speed as to cyclically change the feed of the welding wire, in a predetermined cycle and a predetermined amplitude, into forward feeding to be carried out in a direction of a welding target and reverse feeding to be carried out in a reverse direction to the forward feeding.