Injection blow molding with improved cooling
AssigneeFarrell Patent Company
InventorJohn J. Farrell
Life of this patent
Estimating the term…
Abstract
This invention cools the blowing mold and the plastic article blown therein to shorten the time that a core rod must remain at a blowing station of a blow molding machine for making plastic articles. The cooling is performed by conditioned air that is dried to lower its dew point. An air curtain is used to prevent other air from contacting with and depositing moisture on the mold. In order to take advantage of the shorter time at the blowing station, an auxiliary injection device is used to also shorten the time required for the injection operation; and auxiliary cooling is supplied to the core rod at the stripper station.
Claims19
A method of blow molding a plastic parison comprising blowing the parison to form a blown article, cooling a blow mold to cool the article blown in the blow mold, opening the blow mold to remove the article therefrom, and preventing sweating of the confronting cooled surfaces of the blow mold sections that move toward and away from one another by circulating dry air around the space between the open sections of the mold, said air having a dew point lower than the temperature of the confronting surfaces of the blow mold sections including the surface of the wall forming the blow mold cavity, characterized by projecting the dried air as a curtain surrounding the periphery of the mold sections to prevent any air, except air from the curtain, from entering the space between the mold sections during opening of the mold and while the mold is open, wherein said curtain is formed as a continuous curtain around the entire periphery of the space between the blow mold sections and is transversely disposed to the blow mold sections.
A method of injection blow molding comprising injection molding a plastic parison on a core rod, transferring said parison and core rod to a blow mold, blow molding said parison to form a blown article, cooling the blow mold to cool an article blown in the blow mold, opening the blow mold to remove the article therefrom, and preventing sweating of the confronting cooled surfaces of the blow mold sections that move toward and away from one another by circulating dry air around the space between the open sections of the mold, characterized by projecting the dried air as a curtain surrounding the periphery of the mold sections to prevent any air, except air from the curtain, from entering the space between the mold sections during opening of the mold and while the mold is open, wherein said curtain is formed as a curtain aroung the periphery of the space between the blow mold sections and is transversely disposed to the blow mold sections, said air having a dew point lower than the temperature of the confronting surfaces of the blow mold sections including the surface of the wall forming the blow mold cavity, and stripping the blown article from the core rod while cooling the core rod, whereby the time for the blow mold cooling operation is less than the time for the injection molding operation.
A method of injection blow molding in an injection blow molding machine having an injection molding station, a blow molding station, a stripping station and core rods transferrable from station to station, said method comprises injection molding a plastic parison on a core rod by means of a plasticizer in cooperation with means exerting pressure on the injected thermoplastic during recovery of the plasticizer, transferring the parison to a blow mold at the blow molding station, blow molding said parison to form a blown article, cooling the blow mold to cool an article blown in the blow mold, opening the blow mold to remove the article therefrom, and preventing sweating of the confronting cooled surfaces at the blow mold sections that move toward and away from one another by circulating dry air around the space between the open sections of the mold, characterized by projecting the dried air as a curtain surrounding the periphery of the mold sections to prevent any air, except air from the curtain, from entering the space between the mold sections during opening of the mold and while the mold is open, wherein said curtain is formed as a curtain aroung the periphery of the space between the blow mold sections and is transversely disposed to the blow mold sections, said air having a dew point lower than the temperature of the confronting surfaces of the blow mold sections including the surface of the wall forming the blow mold cavity, transferring the blown article to the stripping station, stripping the blown article with cooling the core rod.
Dependencies are inferred from the claim text.