| 摘要 |
PURPOSE:To furnish a pipe extrusion molding die, which enables to straighten the bending and warpage of a pipe at its extrusion molding by a method wherein the degree of contact of tubular resin extruded in the trough passage for sizing of a sizing die is controlled. CONSTITUTION:When resin 1 is supplied to a flow passage 2 by extrusion in order to mold pipe by extrusion, the resin 1 is formed in the form of pipe by being extruded from between the inner periphery of the flow passage 2 and the outer periphery of an inner mold 4 in the through passage 5 for sizing of a sizing die 6. While a portion of the air delivered from a delivery port 16 escapes between the inner surface of tubular resin 1 and an air stopping plate 25, its remaining parts flows through exhaust ports 28, which are formed in an air pipe 18, into the air pipe 18 so as to be sent back. The tubular resin 1 extruded out of the sizing die 6 is cooled at a cooling device and cut-off specified lengths in order to be finished to pipe products. |
