Radial Point Riveting

the up-to-date riveting process
 

At the beginning there were …….. a man, a hammer and a snap head die (riveting die)

The riveting technology is one of the oldest processes for connecting two components unseparably. In early history already, riveting was done by peening connecting bolts by means of a heavy object (hammer). As the technical revolution moved forward, riveting
became more and more important. With the help of a hammer and a snap die head the workers shaped the rivets by hand. Later, the shaping work was done by presses. The development of special riveting machines yielded a further improvement.

FMW customers and Friedrich engineers pursued the common goal of improving the existing riveting methods. The ever increasing demands towards the quality of riveted joints could no longer be satisfied by conventional methods. The microstructure of the rivet material was deformed by the pressing operation. The high efforts involved and the embrittlement of the rivet bolts were no longer accepted. Though the wobble riveting process succeeded in reducing the physical efforts, hardened areas in the microstructure remained visible because of the linear shaping method. Friction forces produced by the process caused damages to the surface of the rivet head. Radial forces which had to be compensated by the work holding fixtures added to the problem.

The invention that revolutionised riveting
FMW Radial Point Riveting Technology by Friedrich

 

By inventing radial point riveting in 1966, Friedrich laid the foundation for a riveting process which to this day is the most efficient and, at the same time, the most economic process in the market. Step by step, Friedrich’s radial point riveting technology conquered the entire market and only a short time later Friedrich’s capacity was no longer sufficient to meet the demand arising all over the world. As a consequence, licences were granted in 1967, to Switzerland among other countries. Friedrich and their licencees provide for a competition changing in particular the environment of the invention, the CNC control technology as well as the handling and the accessories. By innovative technology, Friedrich are assuring and consolidating their lead in the field of riveting technology.

Advantages of the FMW Radial Point Riveting Process:


• only minor changes in the microstructure of the rivet material thanks to radial point riveting
• little effort needed at a high riveting performance
• low-noise riveting technology
• minimum friction due to a point-by-point reshaping
• little heat development
• suitable for the use of measuring axes as the riveting die is in the vertical position
  during measuring
• riveting and stamping as there is no rotation of the die
• no transverse loads
• large effective bearing areas can be achieved
 

The rivet can be shaped either by
pressing or by hammer blows. In
pressing, a one-time pressure is
sufficient, in hammering several blows
on the rivet in axial direction are needed. The disadvantages: high efforts and loud noise.

The end E of the snap head die rotates in an circular path K around the center line Z of the riveting spindle. The longitudinal axis of the snap die intersects the riveting spindle axis in point M. The shaping of the rivet takes place on a tangent line having the length of the die head.

In point riveting the circular path K is replaced by a loop-shaped path S. The longitudinal axis of the snap die also intersects in point M with the center line of the riveting spindle. The snap die end E again and again passes through the centre line Z. The shaping of the rivet takes place by a point contact of the snap head die and the rivet.