Metal cutting or machining is the process of producing workpiece by removing unwanted material from a block of metal, in the form of chips. This process is most important because almost all products get their final shape and size directly or indirectly by machining. Its major drawback is that in this process there is lot of material lost in the form of chips.

1. TOPIC : CHIP FORMATION
GOVERNMENT ENGINEERING COLLEGE BHARUCH
SUBJECT:PRODUCTION TECHNOLOGY(2161909)
DIV : MECHANICAL B (6th SEM)
GUIDED BY: A.P.Shah
PREPARED BY :
Raval Krunal N. (160140119096)
Sakhiwala Mahir H. (160140119098)
Shardhara Kishankumar A. (160140119099)
Shah Vraj M.(160140119101)
Shaikh Mohammad Saklen M.(160140119102)

2. CONTENTS
• Introduction
• Mechanism of chip formation
• Factors of chip types
• Types of chips
• Chip breakers

3. INTRODUCTION
• Metal cutting or machining is the process of producing workpiece by
removing unwanted material from a block of metal, in the form of
chips.
• This process is most important because almost all products get their
final shape and size directly or indirectly by machining.
• Its major drawback is that in this process there is lot of material lost
in the form of chips.

4. MECHANICS OF CHIP FORMATION
• A wedge shaped tool is made to move relative to the workpiece.
• As the tool makes contact with the workpiece it exerts pressure on it
resulting in compression of the metal near the tool tip.
• This induces shear-type deformation within the metal and it starts
moving upward along the face of the tool.
• As the tool advances this process of shearing goes on increasing and
material is removed.

5. MECHANICS OF CHIP FORMATION

6. CHIP FORMATION IN DUCTILE MATERIAL
• As the tool makes contact with the workpiece it results in exerting
pressure on the material in front of it.

7. CHIP FORMATION IN BRITTLE MATERIAL
• Cracks develops in the workpiece near the tool tip.
• This crack result in stress concentration.
• Hence, crack propagation intensity increases and the chip detaches
itself from the base material.
• This results in discontinuous, irregular shape and sized chip.

8. CHIP FORMATION IN BRITTLE MATERIAL

9. FACTORS FOR CHIP TYPES
• Nature of workpiece
• Nature of tool
• Dimension of tool
• Feed rate
• Cutting speed
• Cutting environment like temperature, friction etc.
• Friction between tool and workpiece

10. TYPES OF CHIPS
• Continuous chip
• Discontinuous chip
• Continuous chip with built up edge (BUE)
• Segmented chip

11. CONTINUOUS CHIP
• A long continuous chip will result when
1. Work material is ductile
2. Cutting speed is high
3. Small feed and depth of cut
4. A sharp cutting edge
5. Low tool chip formation
• Good surface finish result when this type of chip is formed

12. CONTINUOUS CHIP

13. DISCONTINUOUS CHIP
• A discontinuous chip result when
1. Brittle work material
2. Low cutting speeds
3. Large feed and depth of cut
4. High tool chip formation
• Form into separate segments as shown in fig.
• Impart an irregular texture to the machined surface

14. DISCONTINUOUS CHIP

15. CONTINUOUS CHIP WITH BUILT UP EDGE
• A continuous chip with built up edge results when
1. Ductile material
2. Low to medium cutting speed
3. Tool chip friction causes Portion of chips to adhere to rake face near
the cutting edge.
4. BUE forms, then breaks off, cyclically
• Much of the detached BUE is carried away with the chip, sometimes
taking portion of the rake face with it, which reduce life of tool.
• This causes the surface to become rough.

16. CONTINUOUS CHIP WITH BUILT UP EDGE

17. SEGMENTED CHIP
• This chips are semi-continuous in the sense that they posses a saw
tooth appearance that is produced by cyclic chip formation of
alternating high shear strain follwed by low shear strain.
• This chips are associated with difficult to machine metal when they
are machined at higher cutting speed e.g.
1. Titanium alloy
2. Nickelbase super alloys
3. Austenitic stainless steel
4. Steel

18. SEGMENTED CHIP

19. CHIP BREAKERS
• Continuous chip produced while machining ductile material often
causes difficulties of handling because they occupy considerable
space and have sharp edges
• They may also be hot.
• They also get entangled and start rotating with the job.
• Hence this is desirable to break this chips into short convenient length
for their Proper disposal. This operation is done by chip breaker.
• Chip breakers are classified as:
1. Groove type
2. Obstruction type

20. CHIP BREAKERS
1. Groove type chip breaker
• A small groove is provided
behind the leading cutting edge
of the tool insert on the rake
face.
• The geometry of grooves
determines the radius of the
chip curvature.

21. CHIP BREAKERS
2. Obstruction type chip breaker
• Obstruction type either integral
or attached to the cutting tool.
• Attached chio breaker can be
made adjustable to the different
cutting condition.
• One of the advantage of
obstruction type chip breaker is
that it cause less wear on tool
face than groove type chip
breaker.