An apparatus includes a housing, a pin, a mechanism, and a sensor. The housing is configured to receive a weld head. The pin is configured to move linearly relative to said housing. The mechanism is configured to convert a position of said pin into a displacement. The sensor is configured to generate a value representative of said position of said pin based on said displacement.

A method for joining two dissimilar metal plates having different volume resistivity with enhanced joint strength. The method includes overlaying a first metal plate made of first metal and a second metal plate made of second metal with higher volume resistivity and higher melting point in comparison with the first metal, bringing a pair of electrodes into contact with the surface of a portion of the second metal plate overlapping the first metal plate, supplying current between the electrodes so as to resistance-heat the second metal present in a current-flowing region to a temperature lower than the melting point of the second metal and higher than the melting point of the first metal, thereby partially melting the first metal plate with the heat so that an intermetallic compound is generated between the first and second metal plates, and thus joining the first and second metal plates via the intermetallic compound.

A resistance spot welding method includes sandwiching metal plates put on top of one another between a pair of electrodes and performing resistance spot welding sequentially on a plurality of welding points close to each other on the metal plates by performing a current application between the electrodes so as to join the metal plates to each other. A welding current value to form a welding nugget at a welding point to be subjected to the resistance spot welding second or later among the welding points is set to be higher than a first welding current value to form a first welding nugget at a first welding point to be subjected to the resistance spot welding first among the welding points.

A welding apparatus includes: a welding machine having a lower arm member, an upper arm member, and electrodes configured to advance and retreat; a robot device to which the welding machine is mounted; a support member including a vertical member substantially in a vertical direction, and a horizontal member substantially in a horizontal direction. The vertical member is mounted on one of the lower arm member and the upper arm member at a position away from the electrode of the one of the lower arm member and the upper arm member; and a parts-feeding device mounted to the horizontal member and configured to feed parts to the electrode.

A welding device of a robot arm includes a welding machine having a first pressing member which includes a cylindrical first pressing part and a second pressing member which includes a second pressing part inserted into a hollow of the first pressing part. A transformer supplies a positive (+) current to the first pressing member and a negative () current to the second pressing member. The first and second pressing parts have the same co-axis.

A golf club head comprising at least one part manufactured via a metal injection molding process, and attached to another part of the golf club head via electrical resistance welding, is disclosed herein. The present invention is also directed to a method of making said golf club head, the method comprising the steps of providing a first golf club head part made from a first metal material, metal injection molding a second golf club head part from a second, different metal material, and electrical resistance welding the second golf club head part to the first golf club head part to form a combined part.

A dressing system that can appropriately control the dressing amount of the electrode of a spot welding gun so as to not excessively and insufficiently dress the electrode. The dressing system for dressing the electrode of the spot welding gun includes a cutter that dresses the electrode, a controller that controls the rotational operation of the cutter, and a measuring part that measures the dressing amount of the electrode. The controller determines the rotational speed of the cutter based on the dressing amount measured by the measuring part.

After selecting a robot for carrying out a welding operation at a given welding spot, the cross-section of a welding gun with which that robot is provided and the cross-section of a workpiece at the welding spot are compared. Furthermore, a determination is made as to whether or not welding is possible without the welding gun and the workpiece coming into contact. When it is determined to be impossible, a substitute robot for carrying out the welding of the welding spot is selected. With the present invention, the automatic selection of the robot for carrying out the welding operation for the welding spot becomes possible. Therefore, the number of steps for robot selection can be reduced.

In the indirect spot welding apparatus, a lower limit in a stable pressing force region where the pressing force of the spot welding electrode against the metal sheets can be controlled within a tolerance of 10% ranges from 70 N to 200 N and an upper limit in the stable pressing force region ranges from 800 N to 2000 N, and an overshoot OS(%)=(PLAL)/AL100 of the pressing force occurring when the spot welding electrode is pressed against the metal sheets is controlled to be 10% or less.

An oval nugget can reliably be obtained with this indirect spot welding method. In this indirect spot welding method, an electrode end portion of a welding electrode includes a tip of the welding electrode, and as viewed from the tip, the electrode end portion has a two-step dome shape formed by a first curved surface with a curvature radius r.sub.1 (mm) located within a range of a circle of radius R (mm) centering on the tip and a second curved surface with a curvature radius r.sub.2 (mm). 2tR6t (1), 30r.sub.1 (2), and 6r.sub.212 (3), where t is the sheet thickness (mm) of a thinner metal sheet.