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