Manufacturing Methods for Pipe Fittings

The commonly used manufacturing methods for pipe fittings are stamping, forging, roller, rolling, bulging, stretching, bending, and combined processing methods. Pipe fitting manufacturing process is an organic combination of machining and metal plastic working.

Different processing methods
Forging method: using the swaging machine to extend the pipe end or partial pipe so as to reduce the out diameter. The commonly used forging machines include rotary, connecting rod and roller types.
    
Stamping method: Using a tapered core to extend the pipe end to the required size and shape on the punch.  
    
Roller method: placing the core in the tube, pushing and pressing the periphery, which is the round edge processing.  
Rolling method: usually we use the spindle instead of the inner round edge of the wall thickness.
   
Bending method: there are three commonly used methods for bending process, one is extension, another is stamping, the other is roller which is more familiar to us. There are 3-4 rollers, two fixed roller, an adjustable Roller. After adjusting the fixed roller' distance, the finished pipe fitting is bent. This method is widely used, if you produce spiral pipe, the curvature can be increased. 
    
Bulging method: one is putting rubber in the tube, compressing the top with the punch, forming the tube shape; another is hydraulic bulging forming process, filling the liquid in the middle of the tube, the liquid pressure bulges the tube and forms the shape that we need, most of our commonly used spiral pipes are made in this way.