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Assignment No- 01
SELECTION OF MANUFACTURING METHOD FOR MACHINE ELEMENT
Introduction:-
The manufacturing processes selected must be an economical balance of material manpower, product design, tooling cost and equipment, plant space and many other factors influencing cost. The process must b e selected in such a way that the produced product will be acceptable to the consumer functionally, economically and appearance-wise.
FUNDAMENTAL RULES FOR THE SELECTION AND PLANNING OF A MANUFACTURING PROCESS:
1 The process must assure a product that meets all desig requirements of quality , function and reliability
2 Daily production requirements must be meet 3 Full capacity of machine and its tooling should be utilized 4 Idle operator and idle machine time must be reduced process 5 The process must provide the maximum utilization of the minimum amount of
material 6 The process should be flexible enough to accommodate
reasonable changes in design7 The process should be designed to eliminate any unnecessary operations
and combine as many operations as are physically and economically practical 8 Capital expenditure that must be amortized over short periods must be kept
as low as possible.
A manufacturing method is a process of shaping, joining or a finishing a material. Sand casting, injection molding, fusion welding, and electro-polishing are all process; there are hundreds of them. It is important to choose the right process- route at an early stage in the decision before the cost- panalty of making changes becomes large. The choise,for a given component,depends on the materialof which it is to be made, on its size, shape and precision, and on how many are to be made- in short, on the decision requirements. A change in decision requirements may demand a change in process route.
FIG- METHOD SELECTION DEPEND UPON MATERIAL AND SHAPE
CLASSIFICATION OF MANUFACTURING PROCESS
Manufacturing process are classified broadly as follows
A) Shaping B) Joining C) Finishing
And these are further classified as
1) Casting process 2) Metal forming process3) Plastic processing4) Joining processes5) Sheet metal working
FIG- CLASSES OF MANUFACTURING PROCESS
1) CASTING PROCESSES
The Casting or the Founding Processes is the processes of forming object by pouring molten metal in moulds and letting it solidify.
Casting is one of the oldest manufacturing processes dating back to more than six thousand years.
The products of the process known as castings are used extensively in engines, machine tools, automobiles, aeroplanes, household appliances and many other fields.
In fact, all metals are cast at some stage of their production. Wrought materials are produced from ingots which are cast in ingot
moulds.
2) METAL FORMING PROCESSES Mechanical working of a metal is a simply plastic deformation
performed to change the dimensions, properties and surface conditions with the help of mechanical pressure
Depending upon the temperature and strain rate, mechanical working may be either hot working or cold working, such that recovery processes takes place simultaneously with the deformation
The plastic deformation of metal takes place due to two factors i.e deformations by slip and deformation by twin formation
During deformation the metal is said to flow, which is called as plastic flow of the metal and grain shapes are changed
If the deformation is carried out at higher temperatures, then the new grains starts growing at the location of internal stresses.
3) PLASTIC PROCESSING The processing of plastic involves operations similar to those used to
form an shape the metals. Plastics can be moulded, cast, formed, machined, joined and
processed in to different shapes with ease and in few operations on it As the plastic melt at relatively low temperatures, they are easy to
handling and require less energy to process The properties of plastic components are largely affected by the
method of manufacturing and by the processing parameters hence it is necessary to control these conditions.
Generally plastic are shipped to manufacturing lands as pellets. Or powder and they are melted just before shaping process
4) JOINING PROCESSES Joining processes are used for joining metal parts and in general
fabrication work. The commonly used joining prosesses are as follows:
1 Welding2 soldering3 brazing4 Athesive bonding
5) SHEET METAL WORKING Sheet metal working is generally associated with pressed machines and press
working Press working is a chipless manufacturing process by which various components
are produced from sheet metal Press components are used in automobile industry, aircrafts, telephones and
radio industry, electrical goods manufacturing, etc. All the press operations are done at the room tempersture