T A I W A N b u s i n e s s l machining l machines and tools
INOVATED COLLET CHUCK
CNC lathes with larger spindle passages, e.g. of 42,
52 and 65 mm diameters, may have a problem
with machining small parts of smaller diameters,
especially when machining radial holes or radial
milling by means of driven tools.
The driving tool head does not allow
drilling or milling closely at the chuck
face. The parts have to be extracted
from the chuck, which results in undesirable vibrations during machining (insufficient rigid clamping). The
new solution eliminates this problem,
as a result of two new parts in the
chuck - a reduced bayonet and a reduced collet housing. Both parts allow the driven tools to get closer to
the clamp face.
The reduced collet housing has a
clamping cone moved up to the front
wall of the inner bore in the reduced
bayonet. The clamping force thus extends to the face of the extended
clamp and ensures perfect clamping of
small diameter parts. The reduced bayonet has a 25 mm smaller diameter
at the front to allow the chuck holder
to move closer to the clamping axis
(the axis of the part).
Reduced clamps are produced for
standard 18SE collars reducing them
to 173E collars. The reduced clamps
for the 173E collars are then reduced
to the 163E collars.
The new solution replaces the socalled nose collars that allow better
access for the driven tools to the material, but the clamping force is concentrated under the cone of the collet in the clamp, while reducing
significantly at the extended part of
the clamp (i.e. in the nose). The rigidity of the clamping then fails to meet the requirement while transverse
drilling, radial milling or cutting.
Photo/Text: Petr Růžička