The chip formation does not flow effortlessly

The temperature of the cutting operation is important,
particularly when its high, it helps both the tool and the work being output. A
large section of heat is taken away by the excess chips. This is not a major
concern as the chips are not used. The possible effects of high cutting
temperatures are that the tool will be likely to wear out much faster.  There will be some sort of flaking and on the
cutting edge because of the thermal shocks. The elevated temperatures will also
cause build up formation. The cutting tool during the procedure of machining is
a great concern since cutting metals are related with elevated temperatures in
the cutting zone. Having a high temperature
of the cutting tool causes hardness change, metallurgical transformation, or
even chemical composition change due to work done in deforming and in
overcoming sliding friction between tool, workpiece, and chip. Henceforth,
they have reflective consequences on the tool life, dimensional and form
accuracy, and surface finish of the product. The cutting temperature on the
tool is particularly crucial since a lot of heat is being produced. The rise of
the heat temperature and cooling of the tool at work are linked with
considerable temperature differences in cutting edges. Moreover, the heat generated
during chip formation does not flow effortlessly through the workpiece and
chip.

Tool materials

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

Tool
materials play a huge role in material cutting and tool wear. The progression
of high speed steels to carbide and moving further onto ceramics and other
durable material. From the 1960’s the
development of the use of coatings, particularly titanium nitride, allows
high-speed steel tools to cut faster and last longer. titanium nitride provides
a high surface hardness, resists corrosion, and it minimizes friction.
In the industries, carbide tools have substituted high-speed steels in most
applications. These tools cut around 3/5 times quicker than high-speed steels.
A great percentage of cobalt binder increases the tool strength, on the other
hand it lowers the wear resistance. Carbide is used in cylindrical tools. Many manufacturers
of carbide tools create a variety for certain applications. The correct choice of
the tool can increase the life or improve the cutting speed of the same tool. The
tools that are Shockproof those types are used for interrupted cutting. The stronger
tools are chemically-stable types which are essential for high speed finishing
a material like steel. The heat-resistant tools are required for machining the alloys,
like Inconel and Hastelloy.

 

 

 

 

Work
material

When the material reaches its maximum the followings
occurs, if the work material is brittle, a crack will appear in from of the cutting
edge, later it results in fracture. If the work material is ductile, a visible
crack will not be observed because of healing. The cutting tool material must
be stronger than the work material which is to be cut, moreover, the tool must
be able to resist the heat produced in process without any problems. Moreover,
the tool must have a precise geometry, with clearance angles designed so that
the cutting edge can co-operate with the workpiece without the rest of the tool
holding on the workpiece surface. The work material is a pre-shaped material
that is secured to the fixture, which itself is attached to a platform inside machine
so the cutting procedure can be carried out. The cutting tool that has sharp
teeth is also fixed in the machine and turns at high speeds.

Contact stresses

 

The contact stresses involve physical processes on the
surfaces and the contact of the cutting tool when the chip has been removed so
it can be investigated.  The contact
layers depend on the length of elastic, parts of this layer are on the normal
and shear stresses contact zone. A natural white layer is produced in the cutting
process which plays a protective role and results in the reduction rate of tool
wear. As the metal is cutting, a force acts through a small section of the rake
face, which Is in contact with the chip and is further known as the tool chip
interface. The contact of the tool chip interface the correct procedures should
be analysed such as, the contact pressures between the stresses (normal/shear),
the temperature distribution between the tool and the material, and finally the
parameters of relative motion. Experimental techniques have been done to
understand the stresses which include split tool, dynamometer and photo elastic
tools. The transparent tool is used to gain a direct observation of the tool chip
interface. The stress starts increases when the cutting speed rises. The mean contact stress is found to be a function
and a characteristic of the state of stress in the contact zone. Moreover, the
shear contact stress determines to a significant extent temperature at the tool
chip contact, it can be stated that this temperature is solely a function of the
cutting speed and the work material.

 

 

 

Cutting
conditions

 

When the cutting conditions are correct the work can
be done swiftly. Various decisions must be made regarding the cutting tool and
the cutting conditions. These include surface finish, geometry, speed of the
machine, the depth of the cut and the cutting fluid that needs to be applied
for the correct material.  The cutting
tool wear must be monitored to prevent the tool from breakage also a rough
finish to the workpiece. The cutting-edge angle affects the
cutting process by, giving a feed and cutting depth, it defines the uncut thickness,
width of cut, and the tool life. As the width increase, on the other hand the
active part of the cutting-edge increases. This results in improved heat
removal from the tool and hence tool life increases. For example, if the tool
life of a high-speed steel (HSS) face milling tool having or = 60° is taken to
be 100% then when or = 30° its tool life is 190%, and when or = 10° its tool
life is 650%.

 

Fluids

 

The cutting fluids in the machining process and used
for several reasons which have a significant impact on the tool. The fluids
help by improving the tool life by cooling down the temperature, the fluid also
reduces the thermal deformation on the work piece, it also helps by giving a
smooth finish and flushes away the excess chip from the cutting zone. The
fluids also help as applies a corrosion protection over the machined surface.

There are generally three types of liquids used during
cutting procedures: These are mineral,
semi-synthetic, and synthetic. Semi-synthetic and synthetic cutting fluids
represent attempts to combine the best properties of oil with the best
properties of water by suspending emulsified oil in a water base. These
properties for the fluids are rust prevention, tolerance between an extensive
range of water hardness, work with various metals, restrict thermal breakdown,
and are environmentally safe.

Even though
the fluids help cooling, they also help with the cutting process by lubricating
the interface between the tools cutting edge and the chip. This procedure prevents
friction at this interface, some of the heat produced is prevented. This also
helps to prevent the excess chips from being welded onto the tool or the work piece.

 

 

Cutting tool shapes

Below the there is an explanation of the various tools
used for cutting:

Facing

The
facing tool is used as the first operation on the machines. The metal is cut
from the end to make it fit in the correct angle of the axis to remove marks
and blemishes.

Tapering

This
tool is used to cut the metal into a cone shape with the aid of compound slide.

Parallel Turning

The
parallel turning tool is used to cut the metal parallel to the axis. This procedure
is done to decrease the diameter of the metal

Parting

This
procedure is used slowly and carefully to perform the operation, this is due to
getting a perfect outcome and avoid any damage to the tool or work piece. To
make a deeper curt with this tool, it is removed out and transferred to the side,
so it can cut and to avoid the tool from breaking.

Cutting
tools come in various shapes and sizes, all of them have different angles and geometries.
Each of the tool has its own operation and are used for a specific purpose in
metal cutting. The main machining goal is to attain the most effective separation
of chips from the work piece. To gain the correct outcome, the cutting tool geometry
is vital also these following aspects are needed to be taken in account:

·        
Workpiece material

·        
Cutting tool material

·        
Power and speed

·        
Cutting conditions such as heat & vibration

The temperature of the cutting operation is important,
particularly when its high, it helps both the tool and the work being output. A
large section of heat is taken away by the excess chips. This is not a major
concern as the chips are not used. The possible effects of high cutting
temperatures are that the tool will be likely to wear out much faster.  There will be some sort of flaking and on the
cutting edge because of the thermal shocks. The elevated temperatures will also
cause build up formation. The cutting tool during the procedure of machining is
a great concern since cutting metals are related with elevated temperatures in
the cutting zone. Having a high temperature
of the cutting tool causes hardness change, metallurgical transformation, or
even chemical composition change due to work done in deforming and in
overcoming sliding friction between tool, workpiece, and chip. Henceforth,
they have reflective consequences on the tool life, dimensional and form
accuracy, and surface finish of the product. The cutting temperature on the
tool is particularly crucial since a lot of heat is being produced. The rise of
the heat temperature and cooling of the tool at work are linked with
considerable temperature differences in cutting edges. Moreover, the heat generated
during chip formation does not flow effortlessly through the workpiece and
chip.

Tool materials

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

Tool
materials play a huge role in material cutting and tool wear. The progression
of high speed steels to carbide and moving further onto ceramics and other
durable material. From the 1960’s the
development of the use of coatings, particularly titanium nitride, allows
high-speed steel tools to cut faster and last longer. titanium nitride provides
a high surface hardness, resists corrosion, and it minimizes friction.
In the industries, carbide tools have substituted high-speed steels in most
applications. These tools cut around 3/5 times quicker than high-speed steels.
A great percentage of cobalt binder increases the tool strength, on the other
hand it lowers the wear resistance. Carbide is used in cylindrical tools. Many manufacturers
of carbide tools create a variety for certain applications. The correct choice of
the tool can increase the life or improve the cutting speed of the same tool. The
tools that are Shockproof those types are used for interrupted cutting. The stronger
tools are chemically-stable types which are essential for high speed finishing
a material like steel. The heat-resistant tools are required for machining the alloys,
like Inconel and Hastelloy.

 

 

 

 

Work
material

When the material reaches its maximum the followings
occurs, if the work material is brittle, a crack will appear in from of the cutting
edge, later it results in fracture. If the work material is ductile, a visible
crack will not be observed because of healing. The cutting tool material must
be stronger than the work material which is to be cut, moreover, the tool must
be able to resist the heat produced in process without any problems. Moreover,
the tool must have a precise geometry, with clearance angles designed so that
the cutting edge can co-operate with the workpiece without the rest of the tool
holding on the workpiece surface. The work material is a pre-shaped material
that is secured to the fixture, which itself is attached to a platform inside machine
so the cutting procedure can be carried out. The cutting tool that has sharp
teeth is also fixed in the machine and turns at high speeds.

Contact stresses

 

The contact stresses involve physical processes on the
surfaces and the contact of the cutting tool when the chip has been removed so
it can be investigated.  The contact
layers depend on the length of elastic, parts of this layer are on the normal
and shear stresses contact zone. A natural white layer is produced in the cutting
process which plays a protective role and results in the reduction rate of tool
wear. As the metal is cutting, a force acts through a small section of the rake
face, which Is in contact with the chip and is further known as the tool chip
interface. The contact of the tool chip interface the correct procedures should
be analysed such as, the contact pressures between the stresses (normal/shear),
the temperature distribution between the tool and the material, and finally the
parameters of relative motion. Experimental techniques have been done to
understand the stresses which include split tool, dynamometer and photo elastic
tools. The transparent tool is used to gain a direct observation of the tool chip
interface. The stress starts increases when the cutting speed rises. The mean contact stress is found to be a function
and a characteristic of the state of stress in the contact zone. Moreover, the
shear contact stress determines to a significant extent temperature at the tool
chip contact, it can be stated that this temperature is solely a function of the
cutting speed and the work material.

 

 

 

Cutting
conditions

 

When the cutting conditions are correct the work can
be done swiftly. Various decisions must be made regarding the cutting tool and
the cutting conditions. These include surface finish, geometry, speed of the
machine, the depth of the cut and the cutting fluid that needs to be applied
for the correct material.  The cutting
tool wear must be monitored to prevent the tool from breakage also a rough
finish to the workpiece. The cutting-edge angle affects the
cutting process by, giving a feed and cutting depth, it defines the uncut thickness,
width of cut, and the tool life. As the width increase, on the other hand the
active part of the cutting-edge increases. This results in improved heat
removal from the tool and hence tool life increases. For example, if the tool
life of a high-speed steel (HSS) face milling tool having or = 60° is taken to
be 100% then when or = 30° its tool life is 190%, and when or = 10° its tool
life is 650%.

 

Fluids

 

The cutting fluids in the machining process and used
for several reasons which have a significant impact on the tool. The fluids
help by improving the tool life by cooling down the temperature, the fluid also
reduces the thermal deformation on the work piece, it also helps by giving a
smooth finish and flushes away the excess chip from the cutting zone. The
fluids also help as applies a corrosion protection over the machined surface.

There are generally three types of liquids used during
cutting procedures: These are mineral,
semi-synthetic, and synthetic. Semi-synthetic and synthetic cutting fluids
represent attempts to combine the best properties of oil with the best
properties of water by suspending emulsified oil in a water base. These
properties for the fluids are rust prevention, tolerance between an extensive
range of water hardness, work with various metals, restrict thermal breakdown,
and are environmentally safe.

Even though
the fluids help cooling, they also help with the cutting process by lubricating
the interface between the tools cutting edge and the chip. This procedure prevents
friction at this interface, some of the heat produced is prevented. This also
helps to prevent the excess chips from being welded onto the tool or the work piece.

 

 

Cutting tool shapes

Below the there is an explanation of the various tools
used for cutting:

Facing

The
facing tool is used as the first operation on the machines. The metal is cut
from the end to make it fit in the correct angle of the axis to remove marks
and blemishes.

Tapering

This
tool is used to cut the metal into a cone shape with the aid of compound slide.

Parallel Turning

The
parallel turning tool is used to cut the metal parallel to the axis. This procedure
is done to decrease the diameter of the metal

Parting

This
procedure is used slowly and carefully to perform the operation, this is due to
getting a perfect outcome and avoid any damage to the tool or work piece. To
make a deeper curt with this tool, it is removed out and transferred to the side,
so it can cut and to avoid the tool from breaking.

Cutting
tools come in various shapes and sizes, all of them have different angles and geometries.
Each of the tool has its own operation and are used for a specific purpose in
metal cutting. The main machining goal is to attain the most effective separation
of chips from the work piece. To gain the correct outcome, the cutting tool geometry
is vital also these following aspects are needed to be taken in account:

·        
Workpiece material

·        
Cutting tool material

·        
Power and speed

·        
Cutting conditions such as heat & vibration

x

Hi!
I'm Mary!

Would you like to get a custom essay? How about receiving a customized one?

Check it out