Tread extrusion for retreading


The VMI SharkTread is a combination of a single screw cold feed extruder and a volumetric operating gear pump. The rubber is pumped into the wide tread extrusion head with high accuracy, making the system especially suitable for retreading.

Because of the volumetric operating principle of the gear pump, the tread weight per meter is extremely precise with variations within +0.4% or less. This enables very tight dimensional tread tolerances and thus realizes a minimized mold scrap, resulting in maximum savings.

The linear output of the gear pump in relation to the pump speed, allows for exact control between the extrusion speed and the downstream equipment. At the outlet of the gear pump, a wide extrusion head is mounted with an adjustable top die and adjustable wings. This makes it possible to make quick dimension changes of the profile during extrusion.

The dimensions can either be changed by a manually operated ratchet system or by means of separate servo drives for the wings and top die. Next to this, duplex heads are possible, either fed by two gear pumps or fed by one gear pump and one screw extruder. Making it possible to adapt the solution to your specific requirements.

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