Hot Plate Welding
Hot plate plastic welding is generally
used to weld large and irregular shaped plastic parts with
difficult contours and joint lines. Hot plate welding uses
a heated platen to radiate heat through close proximity and
melt the joining surfaces. After the part interfaces have
been melted, the parts are brought together to form a molecular,
permanent, and in many cases a hermetic seal. Hot plate welders
are commonly available to join parts in either a vertical
or horizontal plane.
This method of welding uses thermal energy to
melt the welding zone through heat conduction. Even though
it is a time consuming process with a typical cycle time being
10 to 60 seconds, it is a cost effective process which generates
large batch sizes. As a result the strong bond that can bear
heavy mechanical loads. The molten polymer is exposed to air
during the process, which may reduce the weld strength due
to oxidation of the polymer.
In the Hot Plate Welding procedure, the
parts are held and aligned by holding fixtures. A heating platen
is then inserted between the holding fixtures. The parts are
pressed against the heating platen to melt the edges. Once the
edges are melted, the Heating platen is then withdrawn. The
parts are compressed together so the edges fuse together as
plastic cools. After cooling the holding fixtures open, leaving
the welding part in lower fixture.
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