Cutting tool nomenclature:-
·
Cutting
tool nomenclature means
systematic naming of the various
parts and angles of a cutting tool. The surfaces
on the point of a tool bear definite relationship to each other that are defined by angles.
·
The complete nomenclatures of the various
parts of a single point tool are: shank,
face, flank, heel, nose, base,
back rake, side
rake, side clearance, end cutting edge, wide cutting edge and
lip angle. These
elements define the shape of the tool.
·
The shank is that portion of the tool
bit which is not ground to form cutting edges and is rectangular in cross - section.
·
The face of the cutting
tool is that
surface against which the chip sides upward.
·
The flank of a cutting
tool is that surface which faces the workpiece.
·
The heel of a single
point tool is the lowest
portion of the side cutting
edges.
·
The
nose of a tool is the conjunction of the side and end cutting edges.
A nose radius increases the tool life and improves surface
finish.
·
The base of a tool is the underside of the shank.
·
The
rake is the slope of the top away from the cutting
edge. Back rake
indicates that the plane which forms the face or top of a tool has been ground
back at an angle
sloping from the nose.
·
Side rake indicates
that the plane that forms the face or top of a tool has been
ground back at an angel sloping from the side cutting edge.
·
Side rack is more important than back
rake in turning operation
·
The side clearance or side relief
indicates that the plane that
forms the flank
or side of a tool has been ground
back at an angel sloping
down form the side cutting
edge.
·
The end clearance or end relief
indicates that the nose or end of a tool has been ground back at an angle sloping
down from the end cutting
edges.
·
The end cutting edge angle indicates
that the plane which forms the end of a tool
has been ground back at an angle sloping form the nose to the side of t e
shank.
·
The
side cutting edge
angle indicates that
the plane which
forms the flank
or side for a
tool has been ground back at an angle to the side of the shank. In the main, chips
are removed by this cutting
edge.
·
The
lip or cutting angle is the included
angle when the tool has been ground
wedge shaped.
·
The tool signature is a sequence
of numbers listing
the various angles,
in degrees and size of the nose radius. This numerical method of identification has been
standardized by the American Standard
Association.
·
The seven elements
that comprise the signature of a single
point cutting tools are
always stated in the following
order: back rake angle and nose radius.
Thus a tool with a shape specified
as
8 - 14
- 6 - 6 - 6 - 15 – 4
·
8o is back rake, 14o
side rake, 6o end relief, 6o side relief, 6o
end cutting edge and 15o side cutting
edge angles, and 4 mm nose radius.
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