JPS6434704A - Correction of bend of extrusion-molded item - Google Patents

Abstract

PURPOSE:To make it possible to correct immediately variability of thickness, strain and bend of an extrusion-molded item, by adjusting a mechanism for adjusting flow quantity of a mold for extrusion-molding based on the condition of the distance between cut surfaces after cutting the extrusion-molded item. CONSTITUTION:In the case when edges of cut surfaces 4a and 4b are parallel and their distances Dr and Dl are equal just after an extrusion-molded item 4 is cut by means of a cutter 5, no bend occurs in the extrusion-molded item 4. However, when the distance Dr is larger than the distance Dl, the extrusion-molded item bends to the right hand side after cutting, and on the contrary, when the distance Dr is smaller than the distance Dl, it bends to the left hand side. Moreover, when edges of the cut surfaces 4a and 4b are recessed-shapes each other, the thicknesses of the centers of the cut surfaces 4a and 4b are smaller than those of their edges and on the contrary, when edges of the cut surface 4a and 4b are projected-shapes each other, the thicknesses of the centers of the cut surfaces 4a and 4b are larger than those of their edges. Therefore, when the state of the extrusion-molded items is judged based on the distances of the cut surfaces and the flow rate extruded from a mold 1 is controlled by adjusting a mechanism for adjusting flow quantity, the thickness of the extrusionmolded item 4 can be made uniform.