| 摘要 |
PROBLEM TO BE SOLVED: To foam a foamed layer in a thick wall intermediate part of a product without adding a foamed material by a method wherein melting conditions of resin materials to be injected, the injecting conditions, and various conditions after the injection are respectively appropriately selected and combined. SOLUTION: A flanged shell constructed product of a Noryl resin containing 10% glass-made shell and tube heat exchanger is manufactured with 7 mm wall thickness T of a shell 3 and about 3 mm a thickness t of an intermediate foamed layer 2. In a manufacture process of the resin product, as molding condition 6, various data such as mold temperature, cylinder temperature, injection time, injection pressure, injection speed, retention pressure and time after injection, cooling time, oil pressure, molding material drying time, etc., are respectively appropriately selected and combined. Consequently a resin product having the foamed layer 2 can be manufactured with a conventional ordinary injection molding machine without using a foaming agent considered conventionally indispensable. Therefore, a product of a double framed wall structured high costed heat exchanger shell or the like can be manufactured at a low cost. |
