Extrusion die for rigid foam sheet
AssigneeExtrusion Dies, Inc.
InventorVernon Krupa
Life of this patent
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Abstract
An extrusion die for foam sheet including a die body defining a manifold for conducting a split stream of heated and pressurized foamable thermoplastic melt through separate distribution channels to a die terminus. A pair of mating die lips are arranged on opposed sides of the melt and are constructed to adjustably slide toward and away from each other to vary the flow of a melt. The lips are each mounted to slide along an axis which is tilted rearwardly at an acute angle relative to an orthogonal to the sheet being formed. The mandrel is configured and adapted for quick withdrawal and replacement from an end of the die through a passageway extending through the die transverse to the direction of extrusion of a sheet.
Claims23
An extrusion die for foam sheet, comprising:
- die body means defining a manifold comprising separate distribution channels for conducting a split stream of heated and pressurized foamable thermoplastic melt;
- a pair of mating die lips defining a straight-line die exit and arranged on opposed sides of the distribution channels, the lips at least in part forming an outer wall of said channels, the lips being constructed to adjustably slide toward and away from each other to vary the flow of a melt in the channels;
- and
- a mandrel disposed between the die lips and between the separate distribution channels, the mandrel being slidably insertable and removable through a passageway extending through the die transverse to the direction of the melt flow through the distribution channels to enable quick withdrawal and replacement of the mandrel.
An extrusion die for rigid foam sheet, comprising die body means defining a manifold comprising separate distribution channels for conducting a split stream of heated pressurized foamable thermoplastic melt to a die terminus where nearest surfaces of the separate channels are defined at least in part by a intervening mandrel, and where remote surfaces of the separate channels are defined by mating die lips, both lips being constructed and arranged to adjustably slide toward and away from each other to vary the flow of the melt in the distribution channel wherein the mandrel is disposed between the die lips and between the separate distribution channels, the mandrel being slidably insertable and movable through a passageway extending through the die transverse to the direction of the melt flow through the distribution channels to enable quick withdrawal and replacement of the mandrel.
An extrusion die for foam sheet, comprising:
- die body means defining a manifold comprising separate distribution channels for conducting a split stream of heated foamable and pressurized thermoplastic melt;
- a pair of mating die lips defining a straight-line die exit and arranged on opposed sides of the distribution channels, the lips at least in part forming an outer wall of said channels, the lips being constructed to adjustably slide toward and away from each other to vary the flow of a melt in the distribution channels;
- a mandrel disposed between the die lips and between the separate distribution channels, the mandrel being slidably insertable and removable through a passageway extending through the die transverse to the direction of the melt flow through the distribution channels to enable quick withdrawal and replacement of the mandrel;
- and
- a pair of adjustable restrictor bars, one located upstream of each of the lips, for regulating the pressure and melt flow in the separate channels in the region of the lips.
Dependencies are inferred from the claim text.