Manufacturing
mettle
The
FELSS processes of metal forming are proven technologies that offer
economic advantages for manufacturing complex workpieces
ROTAFORM,
a division of the FELSS group, supplies components ready for installation.
With a wide range of manufacturing processes and types of machines readily
available, it is able to establish an optimum balance between the demands
of the processes, costs and quantities for volume production. The processes
include various methods of cold forming, turning, grinding and stamping.
ROTARY
SWAGING
Rotary Swaging is a cold forming process for reducing cross sections
on metal bar and tube, using dies made up of two or more segments. The
workpiece on which the cross section is to be reduced is moved into
or placed between the segments. The dies are rotated around the workpiece
and apply radial forces in rapid succession. These movements with controlled
kinematics result in high specific forming forces being applied on the
workpiece.
Basically
there are two types of swaging – Infeed Swaging – in which the cross
section of the workpiece is reduced over a long distance, with a shallow
transition angle, and Recess Swaging – for localised reductions in cross
section (to form necks or other types of recesses) or for forming steep
transition angles.
For
Recess Swaging, an additional opening and closing movement is superimposed
on the reciprocating motion of the swaging system.
In
addition to all the normal advantages of cold forming such as short
cycle times, advantageous grain structure, close tolerances and good
surface quality, the process offers great potential for material and
weight saving. Since the volume of material remains constant, reducing
the outside diameter of solid bar results in an increase in length of
the workpiece.
As
a result, for example, a solid drive shaft for a passenger car formed
by Rotary Swaging, can be produced from a plank weighing approximately
20 per cent less as compared with a similar shaft produced by metal
cutting. In the case of tubing, the material flow is more complex. The
length and wall thickness will be increased and the inside diameter
reduced by varying amounts depending on the properties of the material
and the geometry of the workpiece.
It is also possible to achieve a controlled reduction in wall thickness
by using a support mandrel. Maximum advantages from the process for
reducing weight can be achieved if it is possible to change to the starting
material in the form of a tube in place of the solid bar. A special
benefit is the ability of the process to allow the forming of recesses
in the middle zone. If workpieces are produced from tubing by turning,
the cutting of such recesses is either not possible at all or only with
an unacceptable weakening of the cross section.
Compared
with other manufacturing techniques, Rotary Swaging allows higher degrees
of deformation (without the need for intermediate annealing) and a wider
range of shapes that can be formed. In addition to shapes with symmetry
of rotation, parallel flats, triangular, square and hexagonal profiles
can be swaged. On tubing, high precision complex internal contours such
as internal hexagons and internal gear forms or flutes can be formed
by using appropriately designed mandrels. This is also possible for
workpieces with blind holes or holes with reduced diameter beyond the
zone to be formed.
The
process can also be used as a reliable method of fixing parts together.
For example, two parts assembled by swaging to form a rigid assembly
for force transmission.
Tube
ends can be closed up to form solid bearing ends or provide a pressure
tight seal. Almost all metals and metal alloys can be formed by Rotary
Swaging, provided the available elongation at failure (DIN EN 10002)
is not less than 8 per cent.
Steel
ranging from basic mild steel to building steel and steel suitable for
turning on automatic lathes and even tool steel can be formed. Examples
of non-ferrous materials suitable for swaging are alloys based on aluminium,
brass, copper, bronze, magnesium and also nickel, tungsten and titanium.
In many cases,....
.......CONTD
