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Matthew R. Hyre, Virginia Military Institute, Lexington, VA
Gob formation at the feeder
Industrial glass container forming is a complex sequence of unit processes
that leads up to the actual forming process in an individual section machine.
The forming process can be roughly divided into several steps that begin
with the formation of a glass gob at the feeder, followed by the transfer
and loading of the gob into a blank mold. The shape of the glass gob and
its orientation before it falls are important components of the manufacturing
process of many glass products. Large deviations from the ideal gob shape
and trajectory can have severe consequences on the penetration of the
glass into the transfer equipment and molds, and asymmetric loading of
the gob into the blank molds can cause uneven temperature and wear patterns
on the mold interiors. Traditionally, gob shape control has been conducted
by trial and error based on past experience and operator knowledge, but
recent advances in numerical techniques and computer capabilities have
made the numerical modeling of the gob forming processes feasible.
A numerical study was performed recently using POLYFLOW to investigate
the importance of the initial gob formation and transfer on the formation
of glass bottles. The simulation modeled the formation of the gob at the
feeder, and the transfer of the gob to the blank mold. Techniques such
as thermo-mechanical coupling, mesh-to-mesh interpolation, and mesh superposition
of the plungers on the glass were employed. Remeshing techniques were
used that allowed a continuation of the calculations despite very severe
mesh deformations. By evaluating the extent to which feeder plunger motion
and gob transfer equipment affect gob shape and weight, a systematic methodology
to control these parameters can be developed.
Gob transfer to a blank mold
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