Fast response weld head

In a fast response weld head, control means comprising:

• means for selecting a force to be applied by an electrode on an object to enable low impact contact;
• means for varying the speed of movement of the electrode relative to the object;
• means, comprising a linear magnetic actuator, for varying the level of force exerted by the electrode on the object;
• and
• means for increasing the force exerted by the electrode on the object at a predetermined rate prior to the start of weld energy wherein control of the speed of the electrode enables low impact contact with the object minimizing movement of and damage to the object.

A method of rapid precision welding of an object by an electrode with user-controlled parameters comprising:

• (a) providing a movable electrode;
• (b) generating a speed control signal defining a rate of motion of the electrode;
• (c) generating a predetermined force control signal defining a first force to be applied to the object by the electrode;
• (d) generating a position control signal defining a displacement of the electrode relative to the object;
• (e) generating a duration control signal defining a length of time the electrode contacts the object;
• (f) driving the electrode toward and into contact with the object;
• (g) rapidly increasing the force applied by the electrode after contact;
• (h) applying welding energy to the object through the electrode for a predetermined interval;
• (i) generating a transient force greater than said first force for a brief interval during the weld energy interval and prior to the end of the time interval when the electrode contacts the object;
• and
• (j) rapidly decreasing the force applied by the electrode after the weld energy interval to minimize the overall time interval of each welding operation.

In a fast response weld head, force controlling means comprising:

• means for programming a prescribed force control signal representative of a force to be applied by an electrode on an object;
• and
• means, comprising an open loop control circuit, for programming a transient force applied by the electrode to the object;
• and
• means for maintaining the prescribed force and transient force exerted by the electrode on the object for predetermined intervals.

A fast response weld head comprising:

• a support means;
• means for mounting a movable shaft on the support means permitting motion of the shaft relative to the support means;
• driving means, comprising a liner magnetic actuator, for moving the shaft linearly with respect to the support means;
• operator controlled means for controlling a force to be exerted by the weld head;
• means for maintaining the operator controlled force between the electrode and the workpiece for a predetermined duration;
• and
• means for applying a transient amount of force during the force maintaining interval.

A fast response weld head comprising:

• a servo control means for controlling position of an electrode relative to an object;
• detecting means coupled to the servo control means for detecting electrode contact with the object;
• open loop control means for controlling the force exerted by the electrode in response to a current;
• and
• control switching means coupled to the detecting means for changing control of the electrode from the servo control means to the open loop control means upon detection of electrode contact with the object.