Glass forming blowing

FEM is the only practical tool to handle the problem. Not surprisingly, this method was first applied to membranes or thin shells in the field of structural analysis, a field where, in fact, FEM was pioneered, with a much later penetration to fluid mechanics and polymer processing. Indeed, Oden and Sato (81) were the first to apply FEM to examine the three-dimensional membrane inflation problem. Two other engineering fields that apply a similar FEM approach are metal sheet forming and glass bottle blowing (82). 

At the gob feeder, the forming operation begias. The gob feeder deUvers a glass gob shaped such that it enters the blank mold without excessive mold contact, distortion, or reshaping of the glass. Shears cut off a gob of glass. The gob is fed to either a blow and blow, press and blow, or press-only forming operation to produce a container. 

Poly(ethylene terephthalate) (PET) bottles have been used for some time as an alternative to glass and aluminum. At first one-way bottles ia different sizes were used returnable PET-botfles of reasonable quaUty have been marketed. In the future, returnable PET-botfles will be used. The first examples of total production lines have been exhibited, ie, blow-form-fill-seal ia an extra superblock constmction. 

Production molds are usually made from steel for pressure molding that requires heating or cooling channels, strength to resist the forming forces, and/or wear resistance to withstand the wear due to plastic melts, particularly that which has glass and other abrasive fillers. However most blow molds are cast or machined from aluminum, beryllium copper, zinc, or Kirksite due to their fast heat transfer characteristics. But where they require extra performances steel is used. 

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