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DR-100
has a high CBN content, 99%, and is supplied as solid I.S.O format
indexable inserts for top clamp
tool
holders. PCBN cutting tools machine hardened steels with apparent
ease because, using relatively high
surface
speeds, heat is generated at the point of cutting so the PCBN tool
cuts locally softened material.
Using negative
rake tool geometries to provide a strong edge, the heat
is carried away from the work piece
by the chip, which rapidly air
cools to provide a brittle and harmless
swarf, and the DR-100 insert, which
has a very high thermal conductivity.
This leaves the component cool, with its
hardness unaffected.
Cutting
forces are similar to those experienced by hard metal cutting tools
machining soft steel.
DR-100
should be used as a roughing or semi-finishing tool for hardened
steel. Where a light depth of cut (less
than
0.50 mm) is required, DR-50 should be used. DR-100 machines
fully Pearlitic cast iron, rough and finish,
where the
solid insert format allows. Although DR-100 is tough,
vibration or deflection will result in poor
tool life.
Coolant
can be used to; drive the swarf away from the shear zone where it
might interfere with the cutting edge and;
keep the temperature of the part stable
When
machining hardened materials, coolant must not be used where interrupted
cutting occurs,
as this
will thermally shock
the DR-100 insert as it comes out of cut, resulting in catastrophic
failure of the tool. Coolant can be used
for interrupted cutting cast iron that has not been heat treated.
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