This chapter is discussed about the project background, the problem of
the project, the objective of the project and project scope.
The challenge of modern machining industries is mainly focused on the
achievement of high quality, in term of workpiece dimensional accuracy, surface
finish, high production rate, less wear on the cutting tools, economy of
machining in terms of cost saving and increase of the performance of the
product with reduced environmental impact. Turning process is a very commonly
used machining process in industry. The ability to control the process for
better quality of the final product is paramount importance.
manufacturing industries, the quality and productivity of the product was the
main focused for manufacturers. The level of performance of the process can be
represented by the geometrical and metallurgical characteristics of the chips. The
computer numerically machine tools have been implemented during the past
decades to increase the productivity of the product. For the rigorous demands
in industries, the quality of cutting tools has been improved continuously to
obtain better cutting techniques to get a better finish.
case of turning operation, unbroken chips pose a major obstacle for maintaining
accurate machining processes 1.
Effective chip control is needed for automatic production system because any
misstep in chip control can cause the lowering in productivity and worsening in
operation due to frequent stop.
numerous chips are being produced in less time by these methods which require
better control of long continuous chip which is one of the most important
factor regarding performance of the workpiece. When the chips are out of
control, it may lead to machine failure which directly alter productivity.
conduct an experiment to see the formation of chip for cutting tool that have
chip breaker require special setup like CCD camera.
To investigate the chip formation produced by
the turning process using finite element analysis.
To investigate the effect of cutting force from
the turning operation on cutting tool.
To achieve the project objectives, 3D model need to be
create using CAD software which in my case the Solidwork is selected. For the
analysis base on differences cutting speed, depth of cut and feed rate, the
software of finite element analysis select is the ABAQUS/Explicit software. The
simulation of turning process create using this software and analyse and
results compare base on cutting speed, feed rate and depth of cut. The material
for workpiece is mild steel and carbide for the cutting tool.
For the conclusion, this chapter explain about the project
background, problem statement, objectives and project scope.
This chapter will explain the theory of machining, tool
wear and surface roughness. All of the literature by referring article from
journals and books. These helps to understand the problem rise up and also
contribute of knowledge in this study. These sections discuss generally on the
previous studies and research related to experimental study.
Machining and turning operation
There are a variety of machine tools accessible in the
market, each designed for a specific use for industrial application. For
instance, for making slots for die cavities and producing curved shapes for
gears, milling machine tools are used. Grinding machine tools are used to get
high finish dimensional accuracy and quality, but with relatively low
productivity when compared with milling operations. Of all the machine tools,
the most popular are lathes machine. In general, a lathe is a machine tool that
rotates the work material while cutting is achieved by moving a single-point
cutting tool against the workpiece. However, in some lathe, the cutting tool
may rotate while the workpiece remains stationary during machining.
The history of the lathes can be traced back to the
screw-cutting engine lathes that are considered as most important of machine
tools and the oldest machine tools 2. Back to 1740s in
France, the earliest record of a screw cutting lathe dated. However, it was not
until late 1700s that the first practical screw-cutting lathe was built and the
first lathe was slow and clumsy. But its invention had started the history of
modern machinery. As a result form that lathe became known as the “King of
All Tools” 3.
For the revolutionary developments in the machine tool
industry, it have been marked by the development of the Computer Numerically
Control (CNC) machines. There are several advantages offer by CNC machining such
as improving the uniformity in manufactured products, facilitating contour
machining, and adding flexibility to milling and drilling operations 4. Despite the
composure of CNC machines, the vibration during machining still became a major
issue. In fact of it, the tool vibration control becomes more critical in productivity
and quality improvement when using NC machines.
In a machining process, the dimensional accuracy of a
manufactured part is known that it depends on the deflection of the spindle as
well as on the accuracy of the relative position between the workpiece and the
tool. As a result, the finish quality and the accuracy that a machine can
achieve depend on many factors such as the rigidity of the machine tool, the
material of the workpiece and the type of cutting tools.
The turning machines are, of course, every kind of
lathes. Lathes used in manufacturing can be classified as engine, turret,
automatics, and numerical control etc. They are heavy duty machine tools and
have power drive for all tool movements. They commonly range size from 12 to 24
inches swing and from 24 to 48 inches center distance, but swing up to 50
inches and center distance up to 12 feet are not common. Many engine lathes are
equipped with chip pans and built-in coolant circulation system.
In a turret lathe, a longitudinally feed-able, hexagon
turret replaces the tailstock. The turret, on which six tools can be mounted,
can be rotated about a vertical axis to bring each tool into operating
position, and the entire unit can be moved longitudinally, either annually or
by power, to provide feed for the tools. When the turret assembly is backed
away from the spindle by means of a capstan wheel; the turret indexes
automatically at the end of its movement, thus, bring each of the six tools
into operating position. The square turret on the cross slide can be rotated
manually about a vertical axis to bring each of the four tools into operating
position. On most machines, the turret can be moved transversely, either
manually or by power, by means of the cross slide, and longitudinally through
power or manual operation of the carriage. In most cased, a fixed tool holder
also is added to the back end of the cross slide; this often carries a parting
these basic features on a turret lathe, a number of tools can be set on the
machine and then quickly be brought successively into working position so that
a complete part can be machined without the necessity for further adjusting,
changing tools, or making measurements 5.
Single-spindle Automatic Screw Machines
are two common types of single-spindle screw machines. One, an American
development and commonly called turret type (Brown & Sharp), is shown in
the following figure. The other is of Swiss origin and is referred to as the
Swiss type. The Brown & Sharp screw machine is essentially a small
automatic turret lathe, designed for bar stock, with the main turret mounted on
the cross slide. All motions of the turret, crow slide, spindle, chuck, and
stock-feed mechanism are controlled by cams 6. The turret cam is
essentially a program that defines the movement of the turret during a cycle.
These machines usually are equipped with an automatic rod feeding magazine that
feeds anew length of bar stock into the collect as soon as one rod is
more and more Computer Numerical Controlled (CNC) machine are being used in
every kind of manufacturing processes. In a CNC machine, functions like program
storage, tool offset and tool compensation, program-editing capability, various
degree of computation, and the ability to send and receive data from a variety
of sources, including remote locations can be realized through on board
computer 7. The computer can
store multiple-part programs, recalling them as needed for different part.
Cutting tool materials
The classes of cutting tool materials currently in use
for machining operation are high-speed tool steel, cobalt-base alloy, cemented
carbides, ceramic, polycrystalline cubic boron nitride and polycrystalline
diamond. Different machining application require different cutting tool
materials. The ideal cutting tool material should have all of the following
Harder than the work it is cutting
High temperature stability
Resists wear and thermal shock
Chemically inert to the work material and
To effectively select tools for machining, a machinist or
engineer must have specific information about:
The starting and finished part shape
The work piece hardness
The material’s tensile strength
The material’s abrasiveness
The type of chip generated
The work holding setup
The power and speed capacity of the machine tool
Carbon steels have
been used since the 1880s for cutting tools. However carbon steels start to
soften at a temperature of about 180?C. This limitation means that such tools
are rarely used for metal cutting operation. High Carbon Steel contain carbon
between 0.8% to 1.3% carbon and tools made of these steels can be hardened. For
the tool like chisel, only the working part which is the edge of the chisel was