Focusing on the function of the tubes to be reshaped, and not on the
forming method, can lead you to select an end forming method that optimizes
the part cost, particularly if the opportunity involves a new part. The ways
to form the tube end boil down to a few basic methods, so understanding
their capabilities and limitations is critical to selecting the best process
for a particular part. Thinking about creative ways to employ the process
can help to improve product performance and reduce process cost.
The basic end forming methods are segmented tool sizing, ram forming,
rotary forming, roll forming, and spinning. The latter three have specific
advantages in working around the circumference of a tube, especially where
sharp angles and radical diameter changes require working the tube more
gradually. The first two work the whole circumference at one time. While
they provide a quicker forming cycle, they are limited in their range of
This article focuses on applications for which segmented tool sizing and
ram forming are the optimal methods, typically high-volume production for
basic tube end forms.
Fabricators who need to do end forming frequently ask many of the same
questions, whether the project is a part or an assembly of parts. What does
the formed tube need to do? Are all of the part's features necessary? Does
the current design already assume a specific forming method? Can we make
changes to mating parts? Can I achieve the same result with fewer parts?
The tube alloy and production process are important factors regarding the
part design and the forming method. Can the material accommodate the
necessary amount of deformation? If so, what is the best way to work the
material to achieve the end form? Is the tube seamless, or does it have a
weld seam? What are the tolerances and the cosmetic requirements according
to the print?