What is Mandrel
Bending?
Mandrel bending is a widely misunderstood
bending term. Many customers and even some bending companies refer to
the bending dies as mandrels or shoes. Technically the mandrel is a part
of the tooling set but does not exist in most bending applications.
The mandrel actually goes inside the tube
and is held by a mandrel rod to support the tube at the tangent point
of the bend. The mandrel is then extracted after the bend is complete
or within the last few degrees of bending. This requires a machine with
a bed longer than the tube being bent and strong enough to support the
forces against the mandrel.
Common mandrels configurations include
the plug, ball, disc or multi-ball or disc design. The type of mandrel
required varies depending on the wall thickness of the tube, radius required,
and type of material being bent.
Mandrel bending can create a bend much tighter than empty bending as well
as improve the appearance of bend. Radii as tight as one times the diameter
of the tube (1D) are possible, whereas with empty bending (bends without
an internal mandrel) acceptable radii are usually two to three times the
diameter (2-3D). This is especially useful for automotive exhaust applications
or when a fluid or gas is being flowed through a tube. Most chassis or
frame tube bending applications do not require a mandrel and even though
the bend may appear stronger the outer wall of the tube is actually stretched
thinner by the mandrel bending process. For more questions regarding bending
applications please call or email the bending experts at Van Sant Enterprises.
Van
Sant Enterprises, Inc.
80 Truman Road | Pella, IA 50219
877-VAN-SANT | Phone 641-628-3860 | Fax 641-628-2614 | E-mail sales@vansantent.com
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