| 摘要 |
PURPOSE:To conduct precise blow molding of a synthetic resin product without deflection of thickness, breaks, etc. by a method wherein outer air is blown on the outer surface of a tubular parison supplied into a die and then inner air is blown into this parison. CONSTITUTION:Dies 1, 2 are closed and outer air is blown on the outer periphery of a parison 3 through an air passage 7, an air reservoir 8, each back plate 6. Simultaneously inner air is blown into the parison 3 from an inner air blowing pipe 5. When the dies 1, 2 are clamped, a great portion of the parsion 3 approaches to the inner wall surfaces of the dies 1, 2 but is repulsed by the outer air, floated by the inner wall surfaces of the dies 1, 2, stretched uniformly once and part of the parison is adsorbed by adsorptive pieces 10 having no blowing of the outer air. Then, a cylinder 9 is shrinked, adsorptive pieces 10 are drawn in, the further inner air is blown into the parison 3. Thus, the floating parison 3 is stretched uniformly along the inner wall surfaces of the dies 1, 2, attached tightly to the inner wall surfaces and cooled. |
