Method and Apparatus for Air Carbon Arc Cutting

Patent metadata

Field	Value
Publication number	US-2016129518-A1
Application number	US-201414536140-A
Country	US
Kind code	A1
Filing date	Nov 7, 2014
Priority date	Nov 7, 2014
Publication date	May 12, 2016
Grant date	—

Abstract

A method and apparatus for air carbon arc cutting (CAC-A) using a welding-type power supply includes selecting a CAC-A mode and providing current in a CAC-A mode at a selected current setpoint. Start and restrike algorithms can be used that are specifically for CAC-A.

First claim

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1 . A method of air carbon arc cutting (CAC-A) using a welding-type power supply to provide an output, comprising:
having a selected CAC-A mode and a selected current setpoint; disabling stick droop in the output; setting a CAC-A dig slope that is greater than a stick dig slope; setting a CAC-A dig threshold that is greater than a stick dig threshold; setting a CAC-A hot start current that is greater than a stick hot start current; setting a CAC-A hot start time; setting a CAC-A hot start delay time; setting a CAC-A start current that is greater than the current set point; setting a CAC-A start current time; setting a CAC-A slew rate that is less than a stick slew rate; and providing power using the welding-type power supply, wherein
1) when an open circuit is detected and then current is detected within the hot start delay time, the CAC-A start current is provided for the CAC-A start current time, and thereafter when the current is above the CAC-A dig threshold the current provided is increased at the CAC-A slew rate until the current is provided at the current setpoint;
2) when an open circuit is detected and current is not detected within the hot start delay time, providing a hot start current for the CAC-A hot start time; and
3) when an open circuit is detected and current is not detected within the hot start delay time and the output voltage is less than the CAC-A dig threshold, increasing the CAC-A hot start time.

2 . The method of claim 1 , wherein:
setting the CAC-A dig slope includes setting the CAC-A dig slope to at least 24 amps/volt; setting the CAC-A dig threshold includes setting the CAC-A dig threshold to at least 23 volts; setting the CAC-A hot start current includes setting the CAC-A hot start current to about twice the current set point; setting the CAC-A hot start time includes setting the CAC-A hot start time to be about 100 msec; setting the CAC-A hot start delay time includes setting the CAC-A hot start delay time to at least 150 msec; setting the CAC-A start current includes setting the CAC-A start current to be at least 10% is greater than the current set point; setting the CAC-A start current time includes setting the CAC-A start current time to be about 10 msec; and setting the CAC-A slew rate includes setting the CAC-A slew rate to be about 125 amps/msec.

3 . A method of air carbon arc cutting (CAC-A) using a welding-type power supply to provide an output, comprising having a user selected CAC-A mode and providing current in a CAC-A mode at a selected current setpoint.

4 . The method of claim 3 , further comprising disabling stick droop in the output.

5 . The method of claim 4 , further comprising setting a CAC-A dig slope that is greater than a stick dig slope and setting a CAC-A dig threshold that is greater than a stick dig threshold, and providing the output at the dig slope when the output voltage is less than the dig threshold.

6 . The method of claim 5 , wherein setting the CAC-A dig slope includes setting the CAC-A dig slope to about 30 amps/volt and setting the CAC-A dig threshold includes setting the CAC-A dig threshold to about 25 volts.

7 . The method of claim 4 , further comprising:
setting a CAC-A hot start current that is greater than a stick hot start current; setting a CAC-A hot start time; setting a CAC-A hot start delay time; and when an open circuit is detected and current is not detected within the hot start delay time providing a hot start current for the CAC-A hot start time.

8 . The method of claim 7 , wherein setting the CAC-A hot start current includes setting the CAC-A hot start current to about twice the current set point, and setting the CAC-A hot start time includes setting the CAC-A hot start time to be about 100 msec, and setting the CAC-A hot start delay time includes setting the CAC-A hot start delay time to be about 200 msec.

9 . The method of claim 7 , further comprising when an open circuit is detected and current is not detected within the hot start delay time and the output voltage is less than the CAC-A dig threshold, increasing the CAC-A hot start time.

10 . The method of claim 7 , further comprising when an open circuit is detected and then current is detected within the hot start delay time, a CAC-A start current is provided for a CAC-A start current time, and thereafter the current provided is increased at a CAC-A slew rate until the current is provided at the current setpoint.

11 . The method of claim 10 , wherein setting the CAC-A start current includes setting the CAC-A start current to be about 12.5% greater than the current set point, and setting the CAC-A start current time includes setting the CAC-A start current time to be about 10 msec, and setting the CAC-A slew rate includes setting the CAC-A slew rate to be about 125 amps/msec.

12 . The method of claim 10 , wherein setting the CAC-A start current includes setting the CAC-A start current to be about 12.5% greater than the current set point, and setting the CAC-A start current time includes setting the CAC-A start current time to be about 10 msec, and setting the CAC-A slew rate includes setting the CAC-A slew rate to be about 200 amps/msec.

13 . A welding-type power supply comprising:
a user mode selector, including an air carbon arc cutting (CAC-A) mode; a power circuit, disposed to receive an input power and provide CAC-A power, and having a control input; and a controller, having a control output connected to the control input, wherein the controller has a CAC-A control module responsive to the CAC-A mode, and having a feedback input indicative of the output current and indicative of the output voltage.

14 . The welding-type power supply of claim 13 , wherein the CAC-A control module includes a CAC-A start module.

15 . The welding-type power supply of claim 14 , wherein the CAC-A control module includes a CAC-A dig module having a dig threshold that is greater than a stick dig threshold, and having a dig slope.

16 . The welding-type power supply of claim 14 , wherein the CAC-A start module includes a CAC-A hot start current that is greater than a stick hot start current, a CAC-A hot start time, a CAC-A hot start delay time, responsive to the feedback input.

17 . The welding-type power supply of claim 15 , wherein the CAC-A start module includes a CAC-A increased hot start module, responsive to the output voltage being less than a CAC-A dig threshold.

18 . The welding-type power supply of claim 17 , wherein the CAC-A start module includes a weld start module having a CAC-A start current time and a CAC-A slew rate, and responsive to the feedback input.

19 . The welding-type power supply of claim 18 , wherein the CAC-A control module includes a droop disable module.

20 . A welding-type power supply for air carbon arc cutting (CAC-A), comprising:
means for providing welding-type power; user select means for selecting a plurality of modes, including a CAC-A mode; control means, for controlling the means for providing welding-type power, wherein the control means is responsive to the user select means.

21 . The welding-type power supply of claim 19 , wherein the control means includes means for disabling stick droop in the output.

22 . The welding-type power supply of claim 20 , wherein the control means includes means for setting a CAC-A dig slope that is

Assignees

• Illinois Tool Works

Inventors

• Schartner Quinn W
• Vogel Bernard J
• Nelson Andrew D

Classifications

• B23K9/1006 Primary

  Power supply · CPC title

• B23K9/013

  Arc cutting, gouging, scarfing or desurfacing · CPC title

• B23K9/067

  Starting the arc · CPC title

• B23K9/095

  Monitoring or automatic control of welding parameters · CPC title

• B23K9/073 Primary

  Stabilising the arc · CPC title