Using an abrasive cutting wheel on a
cut-off machine with an improper, worn
or damaged spindle bearing can lead to
axial and radial run-out.
Excessive radial run-out (A) overloads
individual diamond segments and
causes them to overheat. This can lead
to stress cracking in the wheel core or to
softening of individual segments. The
result can be broken segments that
increase the risk of personal injury.
Axial run-out or spindle wobble (B) also
results in higher thermal stresses and
wider cuts.
Undercut
Undercutting is a wearing away of the
steel core of the wheel at or just below
the diamond segments. When cutting
road surfaces, do not cut through into
the more abrasive ballast (gravel,
crushed rock) below the paved surface,
TS 440
as indicated by a light colored dust.
Doing so can cause undercutting. If
undercutting can be detected upon
visual inspection, replace the wheel.
WARNING
Undercutting can result in wheel
breakage and/or thrown segments,
which can lead to severe personal injury
or death to the operator or bystanders.
Immediately replace a diamond cutting
wheel if undercutting is visible.
Built-up edges, dressing
Built-up edges are identified by a pale
grey deposit on the top of the diamond
segments that clogs and blunts the
segments.
Built-up edges can form:
–
when cutting extremely hard
material, such as granite,
–
as a result of incorrect handling,
such as applying excessive feed
force.
Built-up edges increase vibration,
reduce cutting performance and cause
sparking.
Diamond cutting wheels must be
"dressed" at the first sign of built-up
edges. To dress a diamond cutting
wheel, briefly cut a more abrasive
material, such as sandstone, aerated
concrete or asphalt.
Wet cutting helps prevent the formation
of built-up edges.
Blunt segments
If you continue to use a diamond cutting
wheel with blunt segments, the
segments may soften as a result of
excessive heat build-up. The wheel core
will also overheat and lose its
mechanical strength or tensioning. This
can lead to stress cracks in the wheel or
its segments and/or wheel wobble.
WARNING
Diamond cutting wheels that wobble or
have built-up edges or blunt segments
may break apart, throw off segments
during use or lead to significant reactive
forces, causing serious or fatal injury.
Replace them immediately.
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