Patent ID: 6682676
Filing Date: 2004-01-27
Classification: B29C,B29K,B29L

Abstract:
A method for molding thermoplastic sandwich material to form a deep-drawn article, the method comprising:positioning a blank of thermoplastic sandwich material having a cellular core and outer skins over a female die having an article-defining cavity defined by inner surfaces of the female die; forcing an inner portion of the blank into the female die along a substantially vertical axis and against the inner surfaces of the female die to obtain deep-drawn material; clamping at least one outer portion of the blank immediately adjacent the female die to guide the at least one outer portion of the blank to travel into the article-defining cavity at an acute angle with respect to the vertical axis during the step of forcing so that thickness of at least one side wall of the deep-drawn material is substantially the same as thickness of the blank of thermoplastic sandwich material and so that the deep-drawn material does not significantly stretch or tear during the step of forcing; removing the deep-drawn material from the female die; and removing any excess material from the periphery of the deep-drawn material to form the deep-drawn article wherein the step of clamping is performed with a clamping force which increases during the step of forcing and wherein the clamping force is applied on the blank outside of the cavity so that a first clamping force is initially applied on the blank to allow the inner portion of the blank to travel into the cavity and a second clamping force, larger than the first clamping force, is later applied on the blank outside the cavity at a plurality of spaced outer portions of the blank as the inner portion of the blank travels into the cavity.