Welding heads

FIs. 1 3.36 Prototype pipe welding system showing external friction stir welded head and internal mandrel (inset). Courtesy of MegaStir, Inc. 

Seamless Head Seamless Shell Seamless Head Welded Shell Welded Head Seamless Shell Welded Head Welded Shell ... 

For TP tapes, a TP welding head has been developed, in conjunction with a hot gas torch. This uses the latter as a heat source to melt the prepreg tow prior to lying down and consolidation with the pressure roller. It does not rely on tension and can therefore be used for concave surfaces. Winding speeds of more than 0.15 m (6 in.)/s has been achieved with graphite/PEEK prepregs. 

Flat Welded Head 1,000-2,000 6 Low Permanent Simple Solid or thin metal liner... 

Fig. 9-30A. Ultrasonic bonding of thermoplastic products is adaptable to complex high volume products as well as for simple pieces. Shown here is a semiautomatic slide table ultrasonic assembly system that uses standard welding heads and power supply to weld polystyrene automotive defroster duct assemblies. The high frequency vibration generated by the head generates heat at the weld line for bonding. Fast welds are achieved by this process. Courtesy Sonics Materials, Inc.)...

A600W, 110A800W, and IIOAIOOOW. Class TC/DOT 1 lOA tanks have fusion-welded heads formed concave to pressure. Class TC/DOT 106A tanks have forge-welded heads formed convex to pressure. 

The second set of numbers is the marked test pressure of the tank, 300 psig (2068 kPa) in the example TC/DOT-105A300W. The last letter, or set of letters, gives information about the tank material and the method of fabrication. The letter W, in the example, indicates a steel fusion-welded tank. If the letters were ALW, it would indicate an aluminum fusion-welded tank. The letter X would signify a tank with a fusion-welded longitudinal seam and forge-welded head seams. If the suffix letter is F, it denotes a forge-welded tank. 

The installation being considered has a welding head permanently fixed to the robot arm as opposed to a gripper. If a gripper had been fitted it would have been necessary to consider the possibility of workpiece ejection and would require a widening of the boundary to include the maximum range of any ejected part. 

A. collision switch (termed a collision emergency stop switch by the robot system manufacturer) is mounted around the welding head which will stop the robot when a collision between another object and the welding head is sensed. It operates via the hardwired emergency stop system. 

A blanket of flux is fed from a hopper in advance of an electric arc created between a consumable electrode wire and the workpiece at the joint line. The arc melts the parent metal and the wire creates the weld as it is automatically fed downwards and traversed along the weld, or the work is moved under welding head. The flux shields the weld pool from the atmosphere preventing oxidation. Any flux that is not used is recycled (see 7.4F). 

Self-contained, mainly automated a.c. or d.c. systems with up to three welding heads. 

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