It is useful to III Year JNTUA MECHANICAL ENGINEERING STUDENTS.

1. MACHINABILITY DATA SYSTEMS
Prepared by
B.VenuM.Tech(CAD/CAM)
ASSISTANT PROFESSOR, MeRITS

2. MACHINABILITY DATA SYSTEMS
•The problem reduces to one of determining
the proper speed and feed combination.
Machinability data systems are basically
intended to solve this problem.

3. • Definition of the problem: stated precisely, the
objective of a machinability data system is to
select cutting speed and feed rate given that the
following characteristics of the operation have
been defined:
1. Type of machining operation
2. machine tool
3. Cutting tool
4. Work part
5. Operating parameters other than feed and
speed

4. • Type of machining operation:
1. Process type- T,F,D,M,B,G,etc.
• Machine tool parameters:
1. Size and rigidity
2. Horse power
3. Spindle speed and feed rate levels
4. Conventional or NC
5. Accuracy and precision capabilities
6. Operating time data
• Cutting tool parameters:
1. Tool material type( high-speed steel, cemented carbide, ceramic, etc.)
2. Physical and mechanical properties ( hardness, wear resistance, etc.)
3. Type of tool ( single point, drill, milling, cutter, etc.)
4. Geometry (Nose radius, rake angles, relief angles, number of teeth, etc.)
5. Tool cost data

5. • Workpart characterstics:
1. Material – basic type and specific grade
2. Hardness and strength of work material
3. Geometric size and shape
4. Tolerances
5. Surface finish
6. Initial surface condition of work piece
• Operating parameters other than feed and
speed:
1. Depth of cut
2. Cutting fluid, if any
3. Work piece rigidity
4. Fixtures and jigs used

6. The methods of solving the speed/feed selection
problem are:
1. Experience and judgment of process planner,
foreman, or machine operator
2. Hand book Recommendations
3. Computerized machinability data systems:
• Data base systems
• Mathematical model systems

7. • DATA BASE SYSTEMMS:
These systems require the collection and storage of large
quantities of data from laboratory experiments and shop experience. The
data base is maintained on a computerized storage file that can be
accessed either by a remote terminal or in a batch mode for a more
permanent print out of cutting recommendations.
Mathematical model systems:
These systems go one step beyond the data base systems. Instead
of simply retrieving cost information on operations that have already been
performed, the mathematical model systems attempt to predict the
optimum cutting conditions for an operation. The prediction is generally
limited to optimum cutting speed, given a certain feed rate.
The definition of optimal is based on either the
objective of minimizing cost or maximizing production rate.