Tool wear
Content
MME 2122
MANUFACTURING LAB 2
EXPERIMENT # 1
TOOL WEAR MEASUREMENT AND TOOL LIFE
PREPARED BY:
MOHD KHAIRUL RIDHWAN ADHHA
0535251
GROUP 2
PREPARED FOR:
DR. ERRY Y.T ADESTA
DATE OF EXPERIMENT:
11TH SEPTEMBER 2008
1
CONTENT
1.0
Objectives / Aim Of The Experiments
2.0
Introduction
3.0
Apparatus Required
4.0
Method And Procedures
5.0
Result
6.0
Data Analysis And Discussion
7.0
Recommendations / Suggestions
8.0
Conclusions
9.0
References
2
1.0
OBJECTIVES
To observe the flank wear and crater wear on a High Speed Steel (HSS) cutting
To observe the relationship between the cutting time and the HSS tool wear
To be familiar on how to create a tool life by using the step given.
To practice on handling the turning machine.
2.0
INTRODUCTION
Theory of tool life:
Tool wear describes the gradual failure of cutting tools due to regular operation. It is a
term often associated with tipped tools, tool bits, or drill bits that are used with machine tools.
Tool wear is generally a gradual process, much like the wear of the tip of an ordinary
pencil. The rate of tool wear depend on tool and work piece material, tool shape, cutting fluids,
process parameter and machine tool characteristic.
During any cutting operation the cutting tool is subjected to high localize stresses, high
temperatures, sliding of chips along rake angle, and sliding of the tool flank along the freshly cut
surface. Aside from breakage, cutting tools wear in many different ways, including: 1) Edge wear
And Flank wear, 2) Crater or Top wear, 3) Chipping, 4) Built-Up Edge Deformation and 5)
Thermal Cracking.
In this experiment we are observing only flank wear and crater wear. Flank wear occurs on
the relief face of the tool and is generally attributed to:
1. Rubbing of the tool along the machine surface, thus causing adhesive and/or abrasive wear
2. High temperatures, thus affecting tool-material properties as well as the work piece surface.
Crater wears which contact with chips erodes the rake face. This is somewhat normal
for tool wear, and does not seriously degrade the use of a tool until it becomes serious enough to
cause a cutting edge failure.
3
Crater wear occurs on the rake face of the tool and changes the chip-tool interface
geometry, thus affecting the cutting process. The significant actors influencing crater wear are
temperature at the tool-chip interface and the chemical affinity between the tool and the work
piece materials. Additionally, the factors influencing flank wear also influence crater wear. Crater
wear is the movement of atoms across the tool-chip interface. Since diffusion rate increase with
increasing temperature, crater wear increase the temperature increase.
The allowable wear land for HSS in a turning operation is 1.5 mm. The following
approximation relationship has been established based on the experiments on machining steels.
T ≈ C7V-7d-1f4
V is the cutting speed (mm/min)
T is the time in minutes that is takes to develop a flank wear land
C is the cutting speed at which the tool life is 1 minute
D is the depth of cut (mm)
F is the feed rate of revolution in turning (mm/rev)
Cutting Tool:
Principles of Cutting tools:
A Cutting Tool is used to remove metal in the form of small chips. The process is termed
as machining and is perhaps the most versatile manufacturing process. The machine that
provides the necessary relative motions between the work and the cutting tool is commonly
known as the machine tool.
Cutting tools are design to sharp edges to minimize rubbing contact between tool surface and
the work piece. Variation in shape of cutting tools influence:
a) Tool life.
b) Surface finish of the work surface.
4
c) The amount of force required for cutting operation.
Cutting tools can be divided into two categories: single-point tools and multiple-cuttingedge tools. Single-point tools are used in turning, boring, shaping, and planning. Multiplecutting-edge tools are used in drilling, reaming, tapping, milling, broaching and sawing3. In this
experiment we are focusing on single-point cutting tool. Tool signature as – 10, 20, 7, 6, 8,
15,1/32. The basic tool angels and its functions as below:
Back rake angle, b: It affects the direction of chip flow. If it increase, tool life increase slightly
and cutting force decrease.
Side rake angle, s: It affects the direction of chip flow. If it increases, cutting force reduced,
tool life increased and surface finish improved.
End relief angle (ERA): Reduce rubbing between end flank and workpiece. It reduced cutting
force but excess angle weaken the tool.
Side relief angle (SRA): Reduce cutting force and as large as to allow for the feed helix.
End cutting edge angle (ECEA): Reducing rubbing of the surface and should e as minimum as
possible.
Side cutting edge angle (SCEA): It influences chip flow and widen the thin chip, increase the
tool life and minor improvement in surface finish.
Nose radius (NR): It increases tool life, surface finish and reduce force if the radius forms arc.
5
3.0
APPARATUS REQUIRED
35 cm mild steel work piece
HSS cutting tool
Lathe machine
Bench Grinder
4.0
METHOD AND PROCEDURES
A mild steel work piece is selected which is the length of approximately 35 cm.
The oxide layer is removed from the work piece by using a lathe machine with other
cutting tool.
High Speed Steel (HSS) Cutting tool is made using grinder. After finish making cutting tool, it is
measured by using profile projector before been used.
The lathe machine is set with a cutting speed of 100 m/min, depth of cut of 0.4 mm and
feed rate of 0.1 mm/rev and the work piece is cut with a new HSS cutting tool.
With an interval of every 2.5 minutes, the cutting operation is stopped
6
The profile projector in a measurement room is used in order to measure the changes in
measurement of the wear on the HSS cutting tool.
The operation is continued until 30 minutes of cutting time.
The operation is considered as success if it can run until first 15 minutes of cutting time.
The graph of TOOL WEAR types (in mm) versus TIME (in minutes) is plotted.
6.0
DATA ANALYSIS AND DISCUSSION
In this experiment, we had to test the tool bit wear. The time need to be set and the machine need
to be control. After 2.5 minute, the machine was stopped and the tool bit was brought to the
profile projector to measure the tool wear. After taken the reading, the experiment was continued
until 30 minutes.
Calculation
From the following approximate relationship, we can find C:
T = C 7 V -7 d -1 f 4
C 7 = T V 7 d1 f -4
C 7 = (30) (1007) (0.21) (0.1-4)
C 7 = 6 x 10 18
C = 481.496
7
Observation
In making the cutting tool, there are three flat surfaces to be gained by grinding which
have specific angels for every surface. The first surface with End Cutting Edge Angle, 8˚ and
End Relief Angel, 60˚. The second surface with Side Cutting Edge Angel, 15˚ and Side Relief
Angle, 6˚. The last surface with Back Rake Angle, 10˚ and Side Rake Angle, 20˚. These angels
need to be mark correctly in order to get the right geometry. During grinding process to get the
flat surfaces, the work must be done carefully. Eventually, during the process because of too
much concentration in getting flat surfaces, the angels have been miss cut and getting a bit larger
and smaller than it suppose to be.
In the process of cutting metals, the tool is worn as a result of friction of the chip o the tool
face and of the tool flanks on the work. Tool wear involves abrasion and the removal of micro
particles of the surfaces, as well as microscopic chipping of the cutting edge. Friction and the
resulting wear in cutting metals differ somewhat from the general friction of the surfaces of
machine parts. The difference is that here friction occurs between renovated surfaces that are
continuously being formed and at high temperature, high pressures on comparatively small area
of contact.
Problems occur during metal cutting and tool wear measurement:
The tool vibrates - The vibration occurs due to the changing cutting force and cutting
tool was not tightening enough. It also may caused by the work piece not put tightly with
the machine.
Built-up-edge (BUE) – because of the existence of BUE at the tip of cutting tool, error
occurs in the value of Y-axis and X-axis of the measurement.
Coolant – because of no use of coolant the tool wear much faster.
7.0
Recommendations / Suggestions
Mark the tool angels correctly and accurately.
Cut the HSS carefully to get the right geometry. More practice will make it better.
Choose the suitable cutting parameter (cutting speed, feed rate, and depth of cut).
Use the coolant to reduce the tool wear.
Take the reading many times and takes the average.
8
8.0
CONCLUSION
1. The geometry of the cutting tool determines the wear rate.
2. The tool life is largely depends on the cutting parameters and tool geometry.
3. Condition of the tool surface, the use of coolant, hardness of the tool material and the
hardness of the work material.
10.0 REFERRENCE
1. http://en.wikipedia.org/wiki/Tool_wear, 5 September 2008
2. MME 2122, Manufacturing Engineering Lab II Manual, Department of Manufacturing and
Materials Engineering.
3. Mikell P. Groover (3rd edition), 2007. Fundamental of Modern Manufacturing. Asia. John
Wiley and Sons (Asia) Pte. Ltd
4. www.sme.org, Cutting Tool Materials.pdf, 5 September 2008
5. Woodrow D. Miner, 2005. A Tool Wear Comparative Study In Turning Versus Computer
Simulation In 1018 Steel (thesis), Brigham Young University
9
MANUFACTURING LAB 2
EXPERIMENT # 1
TOOL WEAR MEASUREMENT AND TOOL LIFE
PREPARED BY:
MOHD KHAIRUL RIDHWAN ADHHA
0535251
GROUP 2
PREPARED FOR:
DR. ERRY Y.T ADESTA
DATE OF EXPERIMENT:
11TH SEPTEMBER 2008
1
CONTENT
1.0
Objectives / Aim Of The Experiments
2.0
Introduction
3.0
Apparatus Required
4.0
Method And Procedures
5.0
Result
6.0
Data Analysis And Discussion
7.0
Recommendations / Suggestions
8.0
Conclusions
9.0
References
2
1.0
OBJECTIVES
To observe the flank wear and crater wear on a High Speed Steel (HSS) cutting
To observe the relationship between the cutting time and the HSS tool wear
To be familiar on how to create a tool life by using the step given.
To practice on handling the turning machine.
2.0
INTRODUCTION
Theory of tool life:
Tool wear describes the gradual failure of cutting tools due to regular operation. It is a
term often associated with tipped tools, tool bits, or drill bits that are used with machine tools.
Tool wear is generally a gradual process, much like the wear of the tip of an ordinary
pencil. The rate of tool wear depend on tool and work piece material, tool shape, cutting fluids,
process parameter and machine tool characteristic.
During any cutting operation the cutting tool is subjected to high localize stresses, high
temperatures, sliding of chips along rake angle, and sliding of the tool flank along the freshly cut
surface. Aside from breakage, cutting tools wear in many different ways, including: 1) Edge wear
And Flank wear, 2) Crater or Top wear, 3) Chipping, 4) Built-Up Edge Deformation and 5)
Thermal Cracking.
In this experiment we are observing only flank wear and crater wear. Flank wear occurs on
the relief face of the tool and is generally attributed to:
1. Rubbing of the tool along the machine surface, thus causing adhesive and/or abrasive wear
2. High temperatures, thus affecting tool-material properties as well as the work piece surface.
Crater wears which contact with chips erodes the rake face. This is somewhat normal
for tool wear, and does not seriously degrade the use of a tool until it becomes serious enough to
cause a cutting edge failure.
3
Crater wear occurs on the rake face of the tool and changes the chip-tool interface
geometry, thus affecting the cutting process. The significant actors influencing crater wear are
temperature at the tool-chip interface and the chemical affinity between the tool and the work
piece materials. Additionally, the factors influencing flank wear also influence crater wear. Crater
wear is the movement of atoms across the tool-chip interface. Since diffusion rate increase with
increasing temperature, crater wear increase the temperature increase.
The allowable wear land for HSS in a turning operation is 1.5 mm. The following
approximation relationship has been established based on the experiments on machining steels.
T ≈ C7V-7d-1f4
V is the cutting speed (mm/min)
T is the time in minutes that is takes to develop a flank wear land
C is the cutting speed at which the tool life is 1 minute
D is the depth of cut (mm)
F is the feed rate of revolution in turning (mm/rev)
Cutting Tool:
Principles of Cutting tools:
A Cutting Tool is used to remove metal in the form of small chips. The process is termed
as machining and is perhaps the most versatile manufacturing process. The machine that
provides the necessary relative motions between the work and the cutting tool is commonly
known as the machine tool.
Cutting tools are design to sharp edges to minimize rubbing contact between tool surface and
the work piece. Variation in shape of cutting tools influence:
a) Tool life.
b) Surface finish of the work surface.
4
c) The amount of force required for cutting operation.
Cutting tools can be divided into two categories: single-point tools and multiple-cuttingedge tools. Single-point tools are used in turning, boring, shaping, and planning. Multiplecutting-edge tools are used in drilling, reaming, tapping, milling, broaching and sawing3. In this
experiment we are focusing on single-point cutting tool. Tool signature as – 10, 20, 7, 6, 8,
15,1/32. The basic tool angels and its functions as below:
Back rake angle, b: It affects the direction of chip flow. If it increase, tool life increase slightly
and cutting force decrease.
Side rake angle, s: It affects the direction of chip flow. If it increases, cutting force reduced,
tool life increased and surface finish improved.
End relief angle (ERA): Reduce rubbing between end flank and workpiece. It reduced cutting
force but excess angle weaken the tool.
Side relief angle (SRA): Reduce cutting force and as large as to allow for the feed helix.
End cutting edge angle (ECEA): Reducing rubbing of the surface and should e as minimum as
possible.
Side cutting edge angle (SCEA): It influences chip flow and widen the thin chip, increase the
tool life and minor improvement in surface finish.
Nose radius (NR): It increases tool life, surface finish and reduce force if the radius forms arc.
5
3.0
APPARATUS REQUIRED
35 cm mild steel work piece
HSS cutting tool
Lathe machine
Bench Grinder
4.0
METHOD AND PROCEDURES
A mild steel work piece is selected which is the length of approximately 35 cm.
The oxide layer is removed from the work piece by using a lathe machine with other
cutting tool.
High Speed Steel (HSS) Cutting tool is made using grinder. After finish making cutting tool, it is
measured by using profile projector before been used.
The lathe machine is set with a cutting speed of 100 m/min, depth of cut of 0.4 mm and
feed rate of 0.1 mm/rev and the work piece is cut with a new HSS cutting tool.
With an interval of every 2.5 minutes, the cutting operation is stopped
6
The profile projector in a measurement room is used in order to measure the changes in
measurement of the wear on the HSS cutting tool.
The operation is continued until 30 minutes of cutting time.
The operation is considered as success if it can run until first 15 minutes of cutting time.
The graph of TOOL WEAR types (in mm) versus TIME (in minutes) is plotted.
6.0
DATA ANALYSIS AND DISCUSSION
In this experiment, we had to test the tool bit wear. The time need to be set and the machine need
to be control. After 2.5 minute, the machine was stopped and the tool bit was brought to the
profile projector to measure the tool wear. After taken the reading, the experiment was continued
until 30 minutes.
Calculation
From the following approximate relationship, we can find C:
T = C 7 V -7 d -1 f 4
C 7 = T V 7 d1 f -4
C 7 = (30) (1007) (0.21) (0.1-4)
C 7 = 6 x 10 18
C = 481.496
7
Observation
In making the cutting tool, there are three flat surfaces to be gained by grinding which
have specific angels for every surface. The first surface with End Cutting Edge Angle, 8˚ and
End Relief Angel, 60˚. The second surface with Side Cutting Edge Angel, 15˚ and Side Relief
Angle, 6˚. The last surface with Back Rake Angle, 10˚ and Side Rake Angle, 20˚. These angels
need to be mark correctly in order to get the right geometry. During grinding process to get the
flat surfaces, the work must be done carefully. Eventually, during the process because of too
much concentration in getting flat surfaces, the angels have been miss cut and getting a bit larger
and smaller than it suppose to be.
In the process of cutting metals, the tool is worn as a result of friction of the chip o the tool
face and of the tool flanks on the work. Tool wear involves abrasion and the removal of micro
particles of the surfaces, as well as microscopic chipping of the cutting edge. Friction and the
resulting wear in cutting metals differ somewhat from the general friction of the surfaces of
machine parts. The difference is that here friction occurs between renovated surfaces that are
continuously being formed and at high temperature, high pressures on comparatively small area
of contact.
Problems occur during metal cutting and tool wear measurement:
The tool vibrates - The vibration occurs due to the changing cutting force and cutting
tool was not tightening enough. It also may caused by the work piece not put tightly with
the machine.
Built-up-edge (BUE) – because of the existence of BUE at the tip of cutting tool, error
occurs in the value of Y-axis and X-axis of the measurement.
Coolant – because of no use of coolant the tool wear much faster.
7.0
Recommendations / Suggestions
Mark the tool angels correctly and accurately.
Cut the HSS carefully to get the right geometry. More practice will make it better.
Choose the suitable cutting parameter (cutting speed, feed rate, and depth of cut).
Use the coolant to reduce the tool wear.
Take the reading many times and takes the average.
8
8.0
CONCLUSION
1. The geometry of the cutting tool determines the wear rate.
2. The tool life is largely depends on the cutting parameters and tool geometry.
3. Condition of the tool surface, the use of coolant, hardness of the tool material and the
hardness of the work material.
10.0 REFERRENCE
1. http://en.wikipedia.org/wiki/Tool_wear, 5 September 2008
2. MME 2122, Manufacturing Engineering Lab II Manual, Department of Manufacturing and
Materials Engineering.
3. Mikell P. Groover (3rd edition), 2007. Fundamental of Modern Manufacturing. Asia. John
Wiley and Sons (Asia) Pte. Ltd
4. www.sme.org, Cutting Tool Materials.pdf, 5 September 2008
5. Woodrow D. Miner, 2005. A Tool Wear Comparative Study In Turning Versus Computer
Simulation In 1018 Steel (thesis), Brigham Young University
9
