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CATEGORY: BEST WORKHOLDING/WORKHANDLING EQUIPMENT
One of the Matrix drawers
is open to allow access to
product in a specific bin.
Note how the others
remain closed to
prevent additional
tooling being taken.
Iscar morphs tangential inserts to fit cutter bodies as small as 8 mm
diameter, and the extra rigidity enables rampdown milling
Dedicated to
productivity
CARBIDE and cutting tool manufacturer Iscar, has
considerably widened the application range of milling
cutters that have their inserts clamped tangentially,
rather than radially. Central to the company’s new,
patented design is a change to the geometry of its T290
tangential inserts, leaving room for a thicker, more
torsion-resistant core and a larger number of inserts to
be clamped peripherally on the Sumomill tool body.
MACH 2008 marks the debut of this new cutting
98 MWP april 2008
system. For any cutter size, the width of the body core
ie the section not machined to accommodate the
inserts, is 65% larger than if radially-mounted
(laydown) inserts were used. The tool is thus much
stronger and can withstand higher impact loads,
minimising risk of fracture.
The advantages of mounting inserts tangentially are
well known. Principally, as forces generated during
machining are transmitted directly to the cutter body,
without applying undue stress on the tightening screw,
higher metal removal rates are attainable. During
recent trials, Sumomill T290 achieved significant
metal removal rates relative to cutter diameter; figures
as high as 60 cm 3/min were recorded using a 12mm
diameter end mill for full slotting operations, with
feed rates of 0.1mm per tooth.
More rigid tangential mounting of the inserts, and
clamping them using a larger tightening screw, greatly
decreases the risk of plastic deformation of the insert
pocket and improves the surface finish on the
machined component. The overall loading that the tool
can withstand is higher, leading to increased metal
removal rates. It is noteworthy that, due to its extreme
rigidity, Sumomill T290 is the only tool on the market
with tangential indexable inserts capable of ramping,
even into hardened steels.
Until now, such productivity benefits were available
only to users of bigger diameter mills, as the relatively
large tangential inserts would not fit smaller tool
bodies. It restricted widespread use of the technology,
as most milling applications use small diameter cutters.
Iscar solved the problem by redesigning its
tangentially-mounted, indexable carbide inserts, which
have two helical cutting edges and a highly positive
rake normally associated with solid carbide cutters. The
company has curved the insert into a convex shape and
achieved a tangential angle that is significantly larger
than is possible on tools with conventional laydown
inserts. This lowers cutting forces and improves tool
stability. The design also reduces heat generated at the
interface between cutting edge and workpiece during
machining, prolonging tool life and further
promoting high quality surface finish.
The convex shaped, tangential T290 insert has
enabled the development of end mills as small as 8mm
diameter, rising in increments to 80mm diameter.
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