The Stripwinding Principle

In short the principle of stripwinding can be described as follows: A 0.1 mm thick high-strength steel strip material is wound around a core of hardened tool steel or tungsten carbide. It takes 10 strip layers for each single millimeter in order to build the stripwound container product.

During the winding process, the winding tension is maintained and fully controlled. The optimal stress distribution is obtained by varying the winding tension from strip layer to strip layer. Thus, the winding core and the single strip layers are pre-stressed to a well-defined level providing a very high loadability and safety of the tool.

During the winding process, the inner diameter of the stripwound container product is reduced (or pre-stressed). As a rule of thumb, the contraction is approx. 1% of the original inner diameter of the winding core when it is of steel and 0.5% when it is of carbide.

The yield stress of the high-strength strip material is above 2000 MPa. This ensures that the stripwound container product behaves fully elastic even under very high loads.

The Key Merit of Stripwinding

In a normal compression ring (i.e. single or double ring), there is a maximum equivalent stress at the inside of each ring that leads to high stresses and local plastification. In daily operation, this will appear as an expansion of the inner diameter of the pre-stressing tool, and result in reduced pre-stressing of the die insert. This loss of pre-stressing may be as high as 50% of the prescribed interference level. In the STRECON stripwound container product, the equivalent stress is equally distributed over hundreds or thousands of strip layers, thus avoiding local and damaging stress concentrations. In addition to the increased tool loadability, the stripwound container also remains fully elastic throughout its service life. In daily operation this means an exact interference of the die at the prescribed level, e.g. 0.7%. No other tool systems offer such an enduring strength feature.

Click here to watch the video on the stripwinding principle