fundamental of machining or metal cutting part -1

Fundamentals of Machining /Metal Cutting ©engineeringmasters

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Introduction to Metal Cutting:

The Process of analyzing the machining operation for determining the forces in machining

operation, power consumption, temperature induced in machining, tool life etc.is called as

metal cutting. By analyzing the machining operations we can determine the above Parameters.

1. By knowing the forces in machining operation we can estimate about the rigidity

requirement of a machine tool.

2. By knowing the power consumption the required capacity of prime mover can be

estimated.

3. By knowing the temperature induced in the machining it is easy to select the machine

tool material

4. By knowing the tool life, the process parameters during machining will be adjusted such

that the tool life must be Greater than or equal to the tool changing time.

Types of Tools: Following are the types of Cutting tools

(A) Point Cutting Tool

(B) Multiple Point Cutting Tool

(A) Single Point Cutting Tool: if Cutting tool is only have one cutting edge to remove

the material than it is known as single Point Cutting Tool.

Example: Turning Tool, Shaping Tool, Planning Tool etc.

(B) Multiple Point Cutting Tool: If Cutting tool is having more than one cutting edge

to remove the material than it is known as Multiple Point cutting tool.

Example: Milling Cutter, Drill, Grinding, Broaching etc,

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Factors affecting/influencing machining operations: Following are the

factors which affects the machining operations

1. Properties of Work piece material:

Force required will be higher for hard work piece

With increase in hardness of work piece force required for machining also increases

which may cause to increase power consumption and reducing the tool life

With increase in ductility the forces required in machining reduces which leads to

reduce power consumption and increase the tool life.

2. Tool Geometry: The Geometric Properties of single point cutting tool like back rake

Angle, side rake angle, relief angle, cutting edge angle, nose radius etc will

Influence the machining conditions during machining.

3. Cutting Fluids: With the use of cutting fluids Power consumption during machining is always

decreases which lead to increase the tool life.

Why Machining is Important

• Variety of work materials can be machined 1. A Variety of Working Material can be machined machining mostly applied to metals

2. Variety of part shapes such as Screw threads, Accurate round holes and very straight

edges and surfaces can be formed by machining

3. Good dimensional accuracy and finishing can be achieved by machining

Disadvantages with Machining Wastage of Material: Chips Generated in machining are wasted material at least in the unit

operation Time Consuming: A machining operation generally takes more time to shape a given part the

alternative shaping process, such as casting, power metallurgy, or forming

Cutting Conditions in Machining There are three dimensions in Machining Process: Cutting Speed (v) –Primary Motion Feed (f) –Secondary motion Depth of Cut (d) – Penetration of tool below original work surface

For certain operations, material removal rate can be found as

MRR = vfd ( v = cutting speed ,f=feed rate , d= depth of cut)
