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Well known and used for years on automatic lathes this technique
is now widely used on CNC lathes and transfer machines. The
broaching operation works in 1° inclined position allowing
symmetrical profiles and forms to be manufactured in the same
setup on the machine. These forms can be hexagonal, square or
other special forms. No other second operation is needed, such as
punching on a press, or the much more expensive sinking
spark-erosion.
The final profile broach is held in a free rotating hub, which is
mounted on ball or needle bearings all on a 1° inclined rotating
axis. The broach has to be centered and coupled to a pre-bored
hole 1.5x deeper than the profile length in order to accommodate
the chips. The profile is formed in one continuous push. Coupled
to the work piece, edges of the broach cut only a part of the
profile at a time depending on the chosen feed per revolution.
This reduces considerably the need to thrust, compared to a
straight push on a press. Almost all free cutting materials can be
broached up to 850 N/mm2 tensile length, with a good tool life.
In medical or dental field, broaching operation is used for
implants, special screws, orthopedic accessories and medical
devices. In these cases, materials are mainly stainless steel or
titanium and requested profiles can be: hexagon, square, double
hexagon, double square, triple square, Torx, etc - sizes from 0,9
mm to 7 mm.
PCM
WILLEN SA is one of the
world leader in high quality & precision tooling for
machine-tools.
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