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Module 1: Introduction and Importance of Machining

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Introduction and Importance of Machining – Lesson Summary

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Importance of Machining 

One of the primary concepts in manufacturing 
Manufacturing plays a very major role in any country's GDP
Majority of the pillars of historical monuments such as temples are developed based on machined components

What is Manufacturing?
In simple terms,  manufacturing is the conversion of raw material into a finished product using some energy. Manufacturing is one of the value addition process by which raw materials of low utility and value due to inadequate material properties and poor, or irregular size shape finish are converted into high utility and valued products with definite dimensions forms and finish imparting some functional ability.
Approaches to Manufacturing 

Top Down (Subtractive Manufacturing) 
Bottom Up (Additive Manufacturing) 

Machining 
Machining is the process of removal of excess material in the form of chips or otherwise to give desired shape, size, surface roughness and the tolerance on the workpiece obtained from primary manufacturing process.
Importance of Cutting fluids in Manufacturing
1) Primary function of cutting fluid is lubrication to reduce friction between contact surfaces.2) Cooling the cutting zones.3) Flushing chips away from the cutting zone.4) Corrosion protection of the machined surface.5) Longer Tool Life.6) Reduce Thermal Deformation of Workpiece.7) Better Surface Finish (in some applications).8) Enabling part handling by cooling the hot surface.9) Ease of Chip handling.
Classification of Manufacturing Processes
Type I 
1)Casting
2)Forging
3)Moulding
4)Forming
 
Type II
 

1)Machining
2)Finishing

 
Type III
 

1) Welding
2) Brazing
3) Riveting
 

 
Type IV
 

1)Painting
2)Electroplating
3)3D printing
 
Multi-Point Cutting Tool Processes
The following are the overview of various multi-point Cutting tool processes: 



Drilling Process


Reaming Process


Tapping Process


Milling Process


Broaching Process


Grinding Process


Honing Process

Finishing Or Polishing Process

Machining of Brittle Materials
I. The chip separation ts effected by brittle fracture requiring lesser energy of chip formation
II. Shorter chips causing lesser frictional force and heating at the rake surface
III. No Built-up edge (BUE)formation
 
Machining of Ductile Materials
 
Smooth and continuous cutting (Continuous chip formation) in ductile materials produce better surface finish but BUE formation may worsen the surface finish. 
 
Shear Zones
 
There are three (3) main shear zones in metal cutting namely
 

I. Primary shear zone: Present between work piece and chip region
II. Secondary shear zone: Present between chip and tool region
III. Tertiary shear zone: Present between tool and work piece region
 
Types of Chips 
 


Continuous Chips 

Continuous Chips with BUE 


Serrated or Segmented Chips



Discontinuous Chips