This document discusses the effects of cutting parameters on surface roughness and tool wear. It defines surface roughness and lists factors that affect it such as feed rate, depth of cut, and cutting speed. Higher feed rates and depth of cuts increase surface roughness. The document also describes different types of tool wear including abrasive, chipping, thermal cracking, and fracture wear and discusses how to reduce each type of wear.

1. EFFECT OF CUTTING PARAMETERS ON SURFACE
ROUGHNESS AND TOOL WEAR
PRESENTED BY:
 2020-ME-73
 2020-ME-89
 2020-ME-64
SUBMITTED TO:
Waqas Rafique
MTM LAB OEL

2. SURFACE ROUGHNESS
 Surface roughness/roughness is defined as the
irregularities which are inherent in the production
process.(e.g. cutting tool or abrasive grit). Roughness It is
quantified by the deviations in the direction of the normal
vector of a real surface from its ideal form. If these
deviations are large, the surface is rough; if they are small,
the surface is smooth.

3. ADVANTAGES OF A GOOD SURFACE
FINISH
• Incredibly important for corrosion and chemical resistant effects.
• It offers a specific visual appeal to the product.
• Helps with the adhesion of coatings and paints.
• Eliminates surface defects.
• Improves conductivity and adds surface electrical conductions.
• Increases product’s strength against wear while minimizing friction effects.

4. METHODS OF MEASURING SURFACE
ROUGHNESS
• Direct measurement methods
• Non-contact methods
• Comparison methods
• In-process methods
• Stylus method

5. APPLICATIONS OF SURFACE FINISH

6. SURFACE ROUGHNESS CHART

7. FACTORS AFFECTING SURFACE
ROUGHNESS
• Feeds and speeds
• Machine tool condition
• Toolpath parameters
• Cut width (stepover)
• Tool deflection
• Cut depth
• Vibration
• Coolant

8. SURFACE ROUGHNESS vs FEED
 The effect of feed rate is very high on the surface
roughness and very clearly observed on the roughness
profile as well as the Fourier spectra. Increase in
roughness is generally considered to be a function of
square of the feed rate. But here it appears to be a
direct function due to the effect of swelling and side
flow. At low feed rate the micro roughness is more
seen in the presence of several frequencies. Chip
thickness and coil radius increase with increase in feed
rate.

9. SURFACE ROUGHNESS VS FEED

10. SURFACE ROUGHNESS VS DEPTH OF
CUT
 Surface roughness increases with
increase of feed rate and depth of cut.
Decreasing trends of surface
roughness are noticed with increase of
cutting speed and depth of cut.

11. PERFORMANCE OF EXPERIMENT ON Al
6061
 We have performed turning operation on CNC
lathe machine to investigate the effects of
different cutting parameters on surface
roughness

12. PICTURES OF TURNING OPERATION


13. PICTURES OF TURNING OPERATION

14. Parameters
S. No. Cutting Speed(m/min) Vc Feed rate(mm/rev)
F
Depth of Cut(mm)
D
1 308 0.05 1
2 369 0.1 1.5
3 429 0.15 2

15. RESULT OF SURFACE ROUGHNESS TEST
S.
No.
Spindle
speed
(rpm)
Feed Rate
(in/min)
Depth of
Cut (in)
Cutting
Speed
(ft/min)
RMR
(ft.in2/min)
PC (hp) FC (lb)
1 800 0.02 0.039 2000 3 6.37 105.2
2 1200 0.015 0.059 2000 2.25 4.78 78.9
3 1600 0.01 0.078 2000 1.5 3.1 52.6

16. 52.6
78.9
105.2
0
20
40
60
80
100
120
0.01 0.015 0.02
CUTTING
FORCE
FEED RATE
FEED RATE VS CUTTING FORCE

17. 2000
2300
2600
0
500
1000
1500
2000
2500
3000
52.6 78.9 105.2
CUTTING
SPEED
CUTTING FORCE
CUTTING SPEED VS CUTTING FORCE

18. 52.6
78.9
105.2
0
20
40
60
80
100
120
0.039 0.059 0.078
CUTTING
FORCE
DOC
DOC VS CUTTING FORCE

19. CONCLUSION FROM ROUGHNESS TEST
 Theoretically measured the cutting force and power
 Surface Roughness was also measured theoretically which depends upon the
feed that was constant throughout
 From the graph it is clearly visible that as the value of feed increases the cutting
force increases. This was due to increase in chip load per tool edge.
 The value of Fc decreases with decrease in depth of cut and increase with increase
in depth of cut.
 The graph shows that cutting force stabilizes at high cutting speeds and the
cutting force hardly varies with increase in cutting speed at low feed rates.

20. TOOL WEAR & FACTORS
 Cutting tools are subjected to an extremely severe rubbing
process. They are in metal-to-metal contact between the
chip and work piece, under high stress and temperature.
According to Australian standard, the tool wear can be
defined as “The change of shape of the tool from its
original shape, during cutting, resulting from the gradual
loss of tool material”.
Factors:
 Mechanical wear
 Cutting heat
 Chemical wear

21. TYPES OF TOOL WEAR
 Abrasive wear
 Chipping
 Thermal cracking
 Fracture

22. ABRASIVE WEAR AND HOW TO AVOID
 Abrasive wear
 The wear zone is a mode of uniform wear on the tool cutting edge, which is
caused by the mechanical wear of the workpiece. This will make the cutting edge
of the tool blunt, and even change the size. If severe thermal stress occurs at a
higher speed, it will even change the size of the knife edge, especially if the
appropriate tool coating is not used.
 How to avoid
 If the wear area becomes too large or the tool is damaged prematurely, reducing
the cutting speed and optimizing the amount of coolant used will help. This
prevents localized wear and extends tool life by using the entire available cutting
edge.

23. CHIPPING AND HOW TO AVOID
 Chipping
 Fragmentation is caused by many different reasons, such as excessive impact,
thermal cracking or wear during operation. Think of it as a series of chips or
spalling bits on a cutting tool. If not corrected in time, this wear usually results in
poor surface finish and may even lead to serious tool failure.
 How to avoid
 Cracking is usually caused by excessive loads and shock loads during operation,
but it can also be caused by thermal cracking (another type of tool wear). There
are several steps to check whether your cutting tool has cracked. First, you need to
make sure that the machine does not vibrate or chatter. Then adjust the speed and
feed rate accordingly, increase the speed and reduce the feed rate.

24. THERMAL CRACKING AND HOW TO AVOID
 Thermal cracking
 Thermal cracks are caused by temperature fluctuations during milling.
They are identified as a series of cracks on the tool surface perpendicular
to the cutting edge. The rate of crack formation is slow, but it can lead to
cracking and premature tool failure.
 How to avoid
 Hot cracks are usually identified by tool cracks perpendicular to the
cutting edge. One of the best ways to transfer thermal cracks is to add an
appropriate heat-resistant coating to the end.

25. FRACTURE AND HOW TO AVOID
 Fracture
 As the name suggests, fracture refers to the sudden break of the tool
during machine operation. Fracture is the complete loss of tool usage due
to sudden fracture, which is usually caused by improper speed and feed,
incorrect coating or improper cutting depth.
 How to avoid
 Adjusting the speed, feed and depth of cut and checking the rigidity of
the setting will help reduce cracking. Optimizing the use of coolant also
helps avoid hot spots in the material, which can dull the cutting edge and
cause fracture. The HEM toolpath prevents fracture by providing a more
consistent load on the tool.