| 摘要 |
PURPOSE:To prevent the occurrence of distortion under equalizing the velocity of the progress of cooling, by changing the temperature of cooling medium flowing at a sucked adhesion part and its neighborhood between a hollow part and a part other than the hollow part when an extrusion molded product is passed in a sizing die. CONSTITUTION:A rain gutter 1 enters into the cavity 13 of sizing dies 11, 12 and thin wall parts 5, 6 are, first of all as passing through a slow cooling zone 17, cooled slowly because they do not touch the sizing surfaces 11a, 11b. Thereafter sucked adhesion parts 18, 19 are adhered under sucking alternatively to both surfaces of the thin wall parts 5, 6 to execute cooling and sizing, and equalize the degree of the progress of cooling between both surfaces. On the other hand, sizing surfaces 11a, 12a adhere under sucking substantially wholly the external surface of lug portions 2, 3 and reinforcing portion 4 to cool, therefore they are cooled precedingly as the thin wall parts 5, 6. Furthermore because a cooling medium flowing in paths 14, 15, 16 have temperature lower that in paths 20, 21, the degree of the progress of cooling are equalized. Therefore the distortion of the rain gutter 1 caused by the difference of the degree of the progress of cooling can be prevented. |
