METHOD FOR FORMING PATTERN

PURPOSE:To facilitate forming of a pattern and to improve the quality of a product by holding a core composed of shape memory plastics in a metallic mold, pouring foaming resin to form the pattern and successively, heating the core in the pattern taken out. CONSTITUTION:The same shape as the pattern to be formed, is memorized to the shape memory plastics to form the core 1. This core 1 is held in the metallic mold 2 and foaming resin beads are included at space 3 between the outer face of the core 1 and the inner face of the metallic mold 2 and high temp. steam is poured from pipes 5 to form lost foam pattern 4. Successively, the lost foam pattern 4 together with the core 1 are taken out from the metallic mold 2, and the core 1 is heated to more than shape restoration temp. The core 1 is easily softened at this temp. and taken out from the pattern 4 and further, reused. As the core is formed with the shape memory plastics, the formation of the pattern is facilitated and the quality of the product is improved with the improvement of the accuracy.