2. Objective of ppt
You will get to know signature of cutting tool.
Effect of various angle on machining.
Why there is need to learn signature of cutting tool.
Different system on which It is base
3. 3Tool Geometry
Both material and geometry of the cutting tools play very
important roles on their performances in achieving
effectiveness, efficiency and overall economy of machining
4. Why SIGNATURE ???
The numerical code that describes all the key angles of a given cutting tool . A
tool signature may be used for HSS or carbide inserts
Convenient way to specify tool angles by use of a standardized abbreviated
system is known as tool signature or tool nomenclature.
It indicates the angle that a tool utilizes during the cut.
It specifies the active angles of the tool normal to the cutting edge.
This will always be true as long as the tool shank is mounted at right angles to
the W/P axis.
5. 5
Tool Designation
1. ASA System (American Standard Association)
2. ORS System (Orthogonal Rake System)
3. NRS System (Normal Rake System)
6. ASA (American Standard Association)
It is pure geometrical in nature i.e no calculation as of mechanics.
The ASA specify the tool geometry with three intersecting orthogonal plane i.e
one plane parallel to and other plane perpendicular to the cutting tool n both of
the them orthogonal to base of tool
1. P(b)-Base plane ; plane perpendicular to velocity vector or parallel to the
base of tool.
2. P(l)- Machine longitudinal plane ; plane orthogonal to the base plane n
taken in direction of assumed longitudinal feed.
3. P(t)- machine transverse plane; plane perpendicular to both Base plane
and Longitudinal plane
It uses rectangular coordinate system but actual cutting plane of cutting tool.
7. Various tool angle specified in ASA
system
Back rake angle
Side rake angle
End relief angle
Side relief angle
End cutting edge
Side cutting edge
9. ORS (Orthogonal Rake System )
ORS also called as old ISO system.
The actual cutting plane is utilized and all the angles are measured in a plane corresponding to cutting
tool.
The cutting plane is defined as the plane where the base of cutting tool is present
The cutting plane is defined as the plane normal to base plane and passing through the principal
cutting edge
Base plane P(b):-Plane perpendicular to the cutting velocity vector
Cutting plane P(c):-Plane perpendicular to P(b).and taken along principle cutting edge.
Orthogonal plane P(o):-Plane perpendicular to bot P(b) & P(c) and the axes.
10. Various tool angle specifies in ORS
system
Inclination angle (i)
Orthogonal rake angle ()
Orthogonal clearance of principal flank angle
Auxiliary orthogonal clearance angle
Principal cutting edge angle
Auxiliary cutting angle
Nose radius
12. ISO System or NORMAL RAKE system
(NRS)
The major problem with ORS system are these:
1.The true geometry of the cutting tool is not revealed when the cutting edges are inclined
from the base plane. 2.Also,
tool grinding in ORS required additional calculation for setting of angles in the cutter
grinder .
To overcome this problem NRS was introduced
In this system the rake angle is visualized in the normal plane in plce of orthogonal plane in ORS
In this system the base and cutting plane are same as ORS , but the third plane is perpendicular to
cutting edge of tool it is called the normal plane .
In this system, the side rake angle is defined as the angle between the base plane of tool and the rake
face of the tool measured in a plane normal to side cutting edge.
Generatrix (G) – Cutting motion (CM) – Work (W)
Directrix (D) – Feed motion (FM) – Tool (T)
3. Tool-work motions and G & D in form milling
4.In drilling machines, for making holes both the cutting motion and the feed motion are imparted on the cutting tool i.e. drill bit whereas the workpiece remains stationary