Sandvik Coromant Heat resistant super alloys - Manual (Page 67)

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The cutter diameter is more or less
selected by the operation and the machine
capability. The choice of ceramic insert, car-
bide inserts or solid carbide is determined
by productivity calculations, surface require-
ments and process limitations (machine,
fixturing etc). The
k
r
/insert style (round,
45º, or 90º) and number of teeth selected
will have a dramatic effect on the machining
strategy and ultimately on the tool life and
Q. Therefore the feature type and machining
strategy will influence which concept style
should be selected.
Milling direction
During a milling operation, the workpiece is
fed either with or against the direction of
rotation and this affects the nature of the
start and finish of cut.
• In up milling (also called conventional
milling) – the chip thickness starts at
zero and increases to the end of the cut.
There are high cutting forces which tend
to push the cutter and workpiece away
from each other. The insert is forced
into cut, creating a rubbing or burnishing
effect work-hardening the surface.
• In down milling (also called climb mill-
ing) – the insert starts its cut with a large
chip thickness. This avoids the burnishing
effect with less heat and minimal work-
hardening tendencies.
Always use down milling for machining of
HRSA materials with carbide inserts.
Milling process
Down milling Up milling