Die & Mould Making - CNC - Computer Numerical Control

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ap/ae ≤ 0,2 mm
When using inserted ball nose end mills,
for instance, it is favourable to use tools
with shanks made of heavy metal (big bending
stiffness). Especially if the ratio overhang/diameter
is large.
Another application parameter of importance
is to try to use down milling tool
paths as much as possible. It is, nearly
always, more favourable to do down milling
than up milling. When the cutting edge goes
into cut in down milling the chip thickness
has its maximum value. And in up milling,
it has its minimum value. The tool life is
generally shorter in up milling than in
down-milling due to the fact that there is
considerably more heat generated in up-,
than in down milling. When the chip thickness
in up milling increases from zero to
maximum the excessive heat is generated
as the cutting edge is exposed to a higher
friction than in down milling. The radial
forces are also considerably higher in up
milling, which affects the spindle bearings
negatively.
In down milling the cutting edge is mainly
exposed to compressive stresses, which are
much more favourable for the properties
of cemented or solid carbide compared with
the tensile stresses developed in up milling.
D U
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D U
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