Method of making and applying ethylene-propylene diene terpolymer texturized heat shrinkable tubing
Method of injection molding and plastic part formed thereby Patent #: 4709757
ApplicationNo. 173145 filed on 03/25/1988
US Classes:264/237, Cooling264/328.1, Introducing material under pressure into a closed mold cavity (e.g., injection molding, etc.)264/336Ejecting or stripping before full set or cure of work
ExaminersPrimary: Silbaugh, Jan H.
Assistant: Heitbrink, Jill L.
Attorney, Agent or Firm
International ClassB29C 045/40
AbstractA process for forming a plastic part having a tubular portion that is continuous and without an flash/mismatch due to mold parting lines in which an injection mold is provided having a cavity formed with a cylindrical surface portion and a core member removably inserted endwise into the cylindrical portion. A molten plastic material is injected into the cavity so that it extends into the cylindrical portion and around the core member. The core member is then withdrawn in an axial direction from the cylindrical portion after the plastic material therein has solidified enough to retain its tubular shape but before it has completely to thereby enable the plastic material to shrink radially inwardly away from the cylindrical surface. Thereafter, the molded tubular shape and the cylindrical mold surface are moved relative to each other in an axial direction so that they are moved away from each other and the tubular portion is withdrawn from the mold, with the tubular portion yielding or flexing to whatever extent is necessary in order to clear the mold. The inner surface of the tubular portion is formed with a symmetrical discontinuous inner surface to insure even shrinking of the tubular portion during cooling and thereby insure roundness of the tubular portion of the molded part.
Field of SearchCooling
Completing vulcanization or polymerization
UTILIZING HEAT RELEASABLE STRESS TO RESHAPE SOLID WORKPIECE (E.G., ELASTIC MEMORY, ETC.)
Introducing material under pressure into a closed mold cavity (e.g., injection molding, etc.)
Article or material ejecting, core or mold stripping or separating
Ejecting or stripping before full set or cure of work
To complete vulcanization or polymerization