Illinois Tool Works Inc.

Lin Zhang

Todd Earl Holverson

Jon O Reynolds

Steven Edward Barhorst

Anthony Franklin Nikodym

Richard Martin Hutchison

James Lee Uecker

Richard W Beeson

Tim A Matus

Robert D Steenis

Timm Matus

A method and apparatus for MIG welding is disclosed. When in an ac mode the output is unbalanced, or the balance may be controlled. The balance may be controlled to provide a desired deposition rate and /or to obtain a desired dilution. The frequency may be any frequency, for example 30 Hz, 60 Hz, 90 Hz, or more. The weld path may have groove with angle of less than 50 degrees. A consumable, cored, wire may be used, and provide at rates of 30 or 35 pounds per hour using a single arc. In various embodiments the balance may have a negative portion of at least 1.5 times the positive portion. The process may be started using an extended negative portion, for example 0.5 or 0.75 seconds.

Method and apparatus for welding

Methods and apparatus for initiating an arc (e.g., a welding arc) by placing liquid droplets containing ions in the gap between an electrode and a workpiece. This is done while a potential difference is applied between the electrode and the workpiece. The presence of the ions renders the gap between the electrode and the workpiece more conductive, thereby reducing the voltage threshold needed to initiate an arc between the electrode and the workpiece. When the voltage threshold reaches the level of the applied potential difference, the arc will be initiated.

Method and apparatus for initiating welding arc using chemical spray

A method and apparatus for MIG welding is disclosed. When in an ac mode the output is unbalanced, or the balance may be controlled. The balance may be controlled to provide a desired deposition rate and/or to obtain a desired dilution. The frequency may be any frequency, for example 30 Hz, 60 Hz, 90 Hz, or more. The weld path may have groove with angle of less than 50 degrees. A consumable, cored, wire may be used, and provide at rates of 30 or 35 pounds per hour using a single arc. In various embodiments the balance may have a negative portion of at least 1.5 times the positive portion. The process may be started using an extended negative portion, for example 0.5 or 0.75 seconds.

Methods and apparatus for initiating a welding arc by directing a plasma jet into the space between the tip of the welding electrode and the workpiece. This is done while an electrical potential is applied between the electrode and the workpiece. The ionized plasma gas renders the space between the electrode and the workpiece more conductive, thereby reducing the voltage threshold needed to initiate an arc between the electrode and the workpiece. When the voltage threshold reaches the level of the applied electrical potential, the arc will be initiated.

Method and apparatus for initiating welding arc using plasma flow

A current path for a mig welding gun assures a reliable and stable interface between a welding gun and a weld wire. In one embodiment, the current path is through a conductive insert that fits in the welding gun diffuser. Fingers of the insert resiliently contact the weld wire and thereby provide stable paths for welding power from the gun to the weld wire. In another embodiment, a contact tip assembly comprises a contact tip having resilient fingers in electrical contact with a body. An inner frusto-conical surface of a sleeve is urged against concentric frusto-conical outer surfaces of the fingers to bias the fingers radially inwardly against the weld wire. An insulative liner in the contact tip guides the weld wire between the fingers. A shield surrounds the contact tip and the sleeve. In a further embodiment, a single finger is pivotally connected to the contact tip. A spring biases a finger end against the weld wire. In an alternate embodiment, the finger is wedge shaped and is held in an angled slot in the contact tip.

Contact tip assembly for mig gun

Methods and apparatuses for plasma MIG welding or TIG MIG welding are disclosed. They include a plasma or TIG torch for following along a weld path by a MIG torch (or the order may be reversed). A constant distance may be maintained between the torches, and the angle of the torches, relative to the workpiece, may vary. The MIG process is performed EP or EN in various embodiments.

Plasma MIG welding with plasma torch and MIG torch

Alternate current path for mig gun

A method or apparatus for sub arc/tubular wire arc welding includes providing a first wire to a first welding arc and a first ac power signal to the first welding arc. The first ac power signal is a substantially constant voltage signal. A second wire may be provided to a second welding arc near the first welding arc, and a second ac power signal is then provided to the second arc. A phase relationship between the first and second ac power signals is selected from a plurality of at least three possible phase relationships. Preferably, the frequency and/or balance of at least one of the signals is selectable. Also, the output frequency is preferably controllable such that it can be more or less than the input frequency.

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Appleton, WI, United States of America

Lin Zhang