Gm Global Technolgoy Operations, Inc.

Robert T Thornton

Pei-chung Wang

James Franklin Hengel

Samuel Paul Marin

Kenneth R Schmidt

David P Kelly

Joseph Nida, Jr

Jerry D Ramsden

This invention provides a method of producing a series of substantially uniform spot welds between two metal parts using a servomotor driven movable electrode and an axially opposing fixed electrode. Target values for electrode displacement in producing a weld indentation and electrode squeeze force are determined for the electrodes and workpieces. During welding operations electrode displacement and electrode force measurements are continually taken and compared with the displacement and force target values. While the measured values are within a tolerance range of the target values, welding is continued using the preset parameters. When either or both of the measured electrode displacement or force value falls outside the target range the total welding current is adjusted in small increments to correct the displacement and/or force values and, thereafter, welding is continued using the new total welding current.

Resistance welding control method

A method and apparatus for projection welding a metal fastener (e.g., a nut) to a metal member (e.g., a sheet) is disclosed. The apparatus includes a first electrical contact and a locator assembly having a second electrical contact. For welding the fastener to the member, the locator assembly aligns through-holes of the fastener and sheet and a current is passed through protrusions of the fastener. In turn, the protrusions are softened to bond with the member.

Method and apparatus for welding a metal fastener to a metal member

A method and system for testing joints which join one member to another member are disclosed. The method and assembly are capable of non-destructively testing joints which join such members without damaging the members or the joints.

Method and system for testing a joint which joins a first member with a second member

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Clarkston, MI, United States of America

Robert T Thornton