Wire fed arc welding method having abnormal arc or abnormal short circuit welding steps

Patent metadata

Field	Value
Publication number	US-11014186-B2
Application number	US-201515023685-A
Country	US
Kind code	B2
Filing date	Feb 2, 2015
Priority date	Feb 14, 2014
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

An arc welding method preforms reciprocating wire feed so as to alternately perform forward feed and reverse feed. The arc welding method includes a normal arc welding step, a normal short circuit welding step, and an abnormal arc welding step. In the abnormal arc welding step, a short circuit state occurs at a second time point, which is before a lapse of a second period from a first time point at which an arc state occurs. Further, in the abnormal arc welding step, the reciprocating wire feed continues until a third time point after a lapse of a first period from the second time point. At the third time point, the reciprocating wire feed is stopped and the abnormal arc welding step is completed. From the third time point, the welding wire is decelerated and the reciprocating wire feed is restarted.

First claim

The invention claimed is:

1. An arc welding method for an arc welding apparatus of performing reciprocating wire feed so as to alternately perform forward feed for feeding a welding wire toward an object to be welded and reverse feed for feeding the welding wire in a direction opposite the forward feed and using a controller of the arc welding apparatus for alternately generating a short circuit period of a short circuit state and an arc period of an arc state between the welding wire and the object to be welded, the method comprising:
a normal arc welding step performed by the controller of continuing the arc state for a first determination period or more during the arc period while feeding the welding wire in the reciprocating wire feed, the arc state being a condition in which an arc is created between the welding wire and the object to be welded and the first determination period being a period for determining existence of the arc during the arc period;
a normal short circuit welding step performed by the controller of continuing the short circuit state for a second determination period or more during the short circuit period while feeding the welding wire in the reciprocating wire feed under a normal short circuit condition, the normal short circuit condition being a predetermined short circuit detected between the welding wire and the object to be welded, and the second determination period being a period for determining existence of the predetermined short circuit during the short circuit period; and
an abnormal arc welding step performed by the controller of generating the short circuit state at a second time point, which is before a lapse of the first determination period from a first time point at which the arc state is started under an abnormal short circuit condition, the abnormal short circuit condition being a micro short circuit detected between the welding wire and the object to be welded,
wherein, in the abnormal arc welding step, the reciprocating wire feed continues until a third time point after a lapse of a first period from the second time point,
at the third time point, the reciprocating wire feed is interrupted and the abnormal arc welding step is completed,
from the third time point, the welding wire is decelerated and the reciprocating wire feed is restarted,
in normal reciprocating wire feed, a feeding amount of the welding wire in decelerating forward feed is set to a reference feeding amount, and
the first period is set so that a feeding amount of the welding wire from the second time point to time when wire feeding speed first becomes zero after the third time point is equal to the reference feeding amount, and
wherein the first determination period is set to approximately 20% to 50% of the arc period or approximately 10% to 25% of a cycle of the wire feeding speed,
in the normal reciprocating wire feed, the feeding amount of the welding wire in the decelerating forward feed is set to the reference feeding amount, and
the first period is set so that the feeding amount of the welding wire when the wire feeding speed first becomes zero after the second time point and through the third time point is equal to the reference feeding amount.

2. The arc welding method of claim 1 , wherein
in the normal arc welding step, a welding current whose maximum value is a first peak current value flows between the welding wire and the object to be welded, and
in the abnormal arc welding step, a welding current whose maximum value is a second peak current value smaller than the first peak current value flows between the welding wire and the object to be welded.

3. The arc welding method of claim 1 , wherein the first period ranges from 250 microseconds to one millisecond inclusive.

4. The arc welding method of claim 1 , wherein the reciprocating wire feed periodically changes the feeding speed of the welding wire in a predetermined cycle at a predetermined amplitude.

5. The arc welding method of claim 1 , wherein the reciprocating wire feed changes the feeding speed of the welding wire in a sine waveform in a predetermined cycle at a predetermined amplitude.

6. The arc welding method of claim 4 , wherein each of the first determination period and the second determination period is approximately 25% to 50% of the predetermined cycle.

7. The arc welding method of claim 1 , wherein the first period is set to a length that is a period in which a next short circuit occurs certainly.

8. An arc welding method for an arc welding apparatus of performing reciprocating wire feed so as to alternately perform forward feed for feeding a welding wire toward an object to be welded and reverse feed for feeding the welding wire in a direction opposite the forward feed and using a controller of the arc welding apparatus for alternately generating a short circuit period of a short circuit state and an arc period of an arc state between the welding wire and the object to be welded, the method comprising:
a normal arc welding step performed by the controller of continuing the arc state for a first determination period or more during the arc period while feeding the welding wire in the reciprocating wire feed, the arc state being a condition in which an arc is created between the welding wire and the object to be welded, and the first determination period being a period for determining existence of the arc during the arc period;
a normal short circuit welding step performed by the controller of continuing the short circuit state for a second determination period or more during the short circuit period while feeding the welding wire in the reciprocating wire feed under a normal short circuit condition, the normal short circuit condition being a predetermined short circuit detected between the welding wire and the object to be welded, and the second determination period being a period for determining existence of the predetermined short circuit within the short circuit period; and
an abnormal short circuit welding step performed by the controller of generating the arc state at a fifth time point, which is before a lapse of the second determination period from a fourth time point at which a short circuit state is started under an abnormal short circuit condition, the abnormal short circuit condition being a micro short circuit detected between the welding wire and the object to be welded,
wherein, in the abnormal short circuit welding step, the reciprocating wire feed continues until a sixth time point after a lapse of a second period from the fifth time point,
at the sixth time point, the reciprocating wire feed is interrupted and the abnormal short circuit welding step is completed,
from the sixth time point, the welding wire is accelerated and the reciprocating wire feed is restarted,
in normal reciprocating wire feed, a feeding amount of the welding wire in accelerating reverse feed is set to a reference feeding amount, and
the second period is set so that a feeding amount of the welding wire from the fifth time point to time when wire feeding speed first becomes zero after the sixth time point is equal to the reference feeding amount, and
wherein the second determination period is set to approximately 20% to 50% of the short circuit period or approximately 10% to 25% of a cycle of the wire feeding speed,
in the normal reciprocating wire feed, the feeding amount of the welding wire in the accelerating reverse feed is set to the reference feeding amount, and
the second period is set so that the feeding amount of the welding wire when the wire feeding speed first becomes zero after the fifth time point and through the sixth time point is equal to the reference feeding amount.

9. The arc welding method of claim 8 , wherein
in the nor

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Matsui Kaito
• Kawamoto Atsuhiro
• Fujiwara Junji
• Nakagawa Akira

Classifications

• B23K9/125 Primary

  Feeding of electrodes (for stabilising arc B23K9/073) · CPC title

• B23K9/0953

  using computing means · CPC title

• B23K9/173

  and of a consumable electrode · CPC title

• B23K9/092

  characterised by the shape of the pulses produced · CPC title

• B23K9/124

  Circuits or methods for feeding welding wire · CPC title