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Mandrels:
The
mandrel is the tool positioned inside the tube and firmly anchored to
the back of the machine with a stretch resistant rod during bending. The
shank or body of the mandrel is the portion over which the tube is drawn
and initially determines the quality and shape of the outside of the
bend. On bends in tube likely to collapse due to a high relationship
between the tube O/D to wall thickness it will be necessary to extend
the support beyond the tangent point by use of ball segments mounted to
the shank. The number of balls required is relative to the bend radius,
the O/D to wall thickness ratio and the bend angle. The function of the
balls is to internally support the shape of the tube and prevent
flatting occurring after leaving the tangent point. If flatting is
permitted to occur or if the support is inadequate, wrinkles will
probably result on the inside of the bend.
There
should be a
mandrel retraction unit fitted to your machine,
this will
retract the mandrel balls from inside the tube at or just
before
the end of the bending cycle
usually 2-5 degrees depending on the type of mandrel in use and
lubricant.
this is
sometimes referred
to as
anticipated mandrel retraction.
Knowing this
we have manufactured a lubricant that has been proven to reduce friction
and lengthen tool life better than no other lube on the market. To find
out more about this lubricant for your application contact us.
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