THE ELASTOMERIC TUBE SWAGING PROCESS
The elastomeric tube swaging process is a cold forming process which utilizes extremely high radial forces applied to the internal surfaces of a tubular member to displace the tubing into grooves in an external end fitting, or into a shaped die cavity to produce tube end forms such as beads. The internal swaging forces are produced by the controlled linear travel of a high strength drawbolt which compresses an elastomeric expander against a static retainer ring surrounding the drawbolt. During the swaging cycle, controlled compression of the elastomeric material forces the tube wall radially into internal circumferential grooves in the end fitting skirt, producing a strong, leak proof mechanical attachment. During forming, the tube end fitting is contained within a precision matching split die cavity to provide a reactionary force to the forming operation and prevent distortion of the fitting.
This process is widely used in the commercial and military aircraft industry to fabricate tubing assemblies for hydraulic, fuel, oxygen, and similar fluid distribution systems. Currently, elastomeric swaging is used to fabricate tubing assemblies for both low and high pressure fluid systems made from aluminum, steel, stainless steel alloys, and titanium.
Elastomeric swaging of end fittings produces fluid tight connections without the loss of material strength associated with thermal joining methods such as brazing and welding. In addition, elastomeric swaging produces high quality mechanical tube fitting attachments without the wall thinning and local stress concentrations produced by mechanical roller swaging or the older bite type designs.
Elastomeric swaging is a very rapid, efficient, and practical tube end fitting attachment process that eliminates expensive post processing operations such as radiographic or ultrasonic inspection frequently required for welded and brazed connections