Auxiliary Equipment: Details of Some Components Used for Subsidiary Services in Aircraft, Missiles and Space Vehicles

The fully automated 90 Inertia Welder made by the Caterpillar Tractor Co. is now available in Europe. In the inertia welding process, the parts to be welded are placed directly opposite one another. One of the parts, for example a valve stem, is held in a spindle collet. A flywheel of predetermined size and weight is attached to the spindle. The other part, the valve head, is automatically clamped in a rigid stationary chuck. The entire spindle assembly including the valve stem and flywheel is then accelerated. At a predetermined speed, the rotating part is disconnected from its drive source. Instantly, the rotating part is forced against its counterpart under precisely controlled pressure. As the flywheel assembly slows down, due to friction, the stored kinetic energy in the flywheel is discharged into the interface, resulting in the required heat and pressure to bring both parts to a desired plastic state. The result is said to be a superior molecular bond, grain refinement of the weld zone and a finished product with the full strength of the parent metal. With the addition of automatic loading and unloading, the cycle time of the Caterpillar 90 Inertia Welder has been reduced to about 8 to 9 sec, enabling it to perform in assembly line fashion under demands of high production, simply, quickly and economically.