Our Products
PASSION FORMS PERFORMANCE
With more than 400 million individually manufactured parts per year, we are your innovative partner for metal forming technology. Customer-oriented, sustainable, and with perfection. Our comprehensive product range provides an extreme competitive advantage. For you and for us. In addition, we offer you a wide variety of customer-specific solutions including assemblies in a diverse range of material qualities, spring types, spring geometries, stress levels, and surface finishes.
Our Products
Assemblies
Stamped and Bent Parts
TORSION SPRINGS & WIRE FORMED PARTS
EXTENSION SPRINGS
Axle Springs
Production Processes
Cold Forming
The geometry of the helical spring is achieved in the first step through chipless cold forming of the spring wire using a coiling or winding process. The production of torsion springs is usually carried out through a winding process in which the spring wire is wound around a mandrel. Compression and extension springs are formed into the desired shape through a coiling process. The illustration on the right demonstrates the principle of the cold coiling process. The spring-hard material is fed into the coiling pins by means of feed rollers, whereby the setting and position of the coiling pins determines the outer diameter of the manufactured spring. The wire is then pushed out of the coiling center using the pitch pin or pitch wedge. Through the variable positioning of the coiling pins and the pitch pin, a wide variety of spring geometries can be created. Finally, the wire is cut by the cutting blade, which is moved using various methods. With the help of a rotary cut, virtually burr-free spring ends can be achieved. We have more than 50 of the most modern cold forming coiling machines with a wire diameter range from 0.3 mm to 16 mm.
Heat Treatment
The residual stresses created by the plastic deformation of the spring-hard material are relieved through a heat treatment process called tempering. Depending on the spring geometry and production volume, various tempering furnaces are available. The high product quality is ensured through continuous temperature recording.
Spring End Grinding
The design of the end coils is very important for helical compression springs. Closing the end coils and subsequent surface grinding enable the most axial compression possible during force application. VDF-Federn has more than 25 state-of-the-art CNC-controlled spring end grinding machines. Optimal product quality is achieved through effective cooling of the grinding process and the enormous extraction capacity of the filter systems. Numerous grinding machines are also equipped with fully automatic feeding devices.
Shot Peening
For many demanding customer applications, the fatigue strength of the spring used is extremely important. Shot peening can significantly increase the fatigue strength of the spring. Rounded wire shot of defined hardness and size is propelled at high velocity onto the springs using centrifugal wheels. The compressive stresses and work hardening generated in the surface layers of the spring material lead to an increase in fatigue strength. By smoothing the surface, the effects of surface defects are also reduced. Several trough belt shot peening systems and overhead conveyor shot peening systems are available for different products and applications.
Presetting
Presetting of springs, also called setting or pre-setting, is used to achieve both greater material utilization and optimization of spring properties. The residual stresses created during the over-elastic loading of the spring reduce the subsequent operating stress during spring use. This additional operation prevents subsequent length loss (set loss) of the spring in use and increases the load capacity of the spring. Different cold and hot setting devices are available for the various applications of our customers. Here too, the use of automatic feeding devices ensures efficient production.
Surface Treatment
Many of the spring steel wires we use already provide corrosion protection. In addition, numerous surface coating processes are available, such as epoxy, polyester, KTL, Dacromet, Delta coatings, and galvanic treatments.