[Sheathing of electric cables, ropes and connecting hoses]
Dies extending beyond the head should
be heated. The mandrel through which the product to be sheathed is
passed should be adjustable in the axial direction to allow the
surface quality of the sheath to be influenced. The actual
sheathing process is carried out by the pressure or tubular
process (Fig. 3).
|Fig. 3: Sheathing dies
With the pressure technique, a noncircular
substrate can be topped up to produce a circular cross section.
With the tubular process, a coating of even
thickness is applied, which largely adjusts to the given cross
Adhesion of the Desmopan® or Texin™
extrudate to the carrier material essentially depends on which
sheathing process is used. Good adhesive strength can generally be
achieved by the pressure method. On the other hand, the tube/pipe
extrusion method allows easy peeling off of the sheathing. By
applying a vacuum to the mandrel, adhesion can be adjusted to suit
requirements. It is important to have a dry, grease-free
substrate, otherwise blistering and adhesion problems may occur.