| 摘要 |
An extrusion device for extruding a cladding onto a core, said device having an extrusion chamber, a nozzle extending into the extrusion chamber with a nozzle opening aligned with a die opening so that a core passes through the nozzle opening and then the die opening with the material extruded thereon characterized by an arrangement to increase the friction between surfaces of the nozzle opening and the core to subsequently improve the bond and adhesion of the cladding to the core. This arrangement can include either notches formed in the nozzle opening adjacent the edges so that a portion of the core will be engaged by the extrusion material prior to the rest of the core surfaces exiting the nozzle, a groove in an end surface of the nozzle so that portions of the nozzle can be pressed onto the core or projections or blades on an internal surface of the nozzle opening.
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