MANIPULATORS

Manipulators are powered by electric motors and are used to orient the welding head(s) used with automatic welding machines. Manipulators typically consist of a vertical mast and horizontal boom that carries the automatic welding head. A large welding head manipulator is shown in Figure M-4. Manipulators are powered to move the boom up and down the mast, and in most units the mast swivels on the base. In some cases, the welding head may move by power along the boom, while in others the boom itself may move horizontally on the mast assembly. Most manipulators also have slow-speed vertical and transverse motion control capabilities. This allows the operator to adjust the position of the welding head to compensate for variations along the weld joint.

It is essential during the welding operation that the boom or welding head move smoothly at speeds that are compatible with the welding process being used. The carriage itself must also move smoothly and at constant speeds if the manipulator is designed to move along tracks on the shop floor. In selecting and specifying a welding manipulator, it is important to determine the actual weight to be carried at the end of the boom. The manipulator must be rigid and the deflection minimized during the welding operation. Manipulators are more versatile than side beams because they are capable of linear motion in three axis.

The desirable features that a manipulator should have are:

(1) Safety. Under no conditions of load or failure should the boom crash or slide down the mast.

(2) The maximum vertical deflection should be guaranteed for various rated loads on either end of the beam.

(3) Rigidity should guarantee that the boom will follow a straight line weld joint within the full limits of its length.

(4)The manipulator should be absolutely rigid and steady in all its actions, with no lost motion or wobble.

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