Manufactuing Processes:

Introduction:

Manufacturing involves turning raw material to finished products, to be used for various purposes. There are a large number of processes available. These processes can be broadly classified into four categories.

1: Casting processes

2: Forming processes

3: Fabrication processes

4: Material removal processes

Casting Processes

These processes only processes where the liquid metal is used. Casting is also the oldest known manufacturing process.

Basically it consists of inducing the molten metal into a cavity of mould of the required form and allowing the metal to solidify.The object after solidification removed from the mould. Casting processes are universally used to manufacture a wide variety of products. Casting is the most flexible and cheapest method and given high strength of rigidity to the parts which are difficult to produce by other manufacturing processes.

The principle process among these sand casting where sand is used as the raw material. The process is equally suitable for the production of a small batch as well as on a large scale.Some of the other classified casting processes for specialized need are

· Shell mould casting

· Precision mould casting

· Plaster mould casting

· Permanent mould casting

· Die casting

· Centrifugal casting

Forming Processes:

These are solid state manufacturing processes involve minimum amount of material wastage. In forming process metal may be heated to temperature which is slightly below. This solidify temperature and large force is applied such the material flows and act in desired shape. The desire shape is controlled by means of a set of tool ties and dies, which may be closed during manufacturing.

These processes are normally used for large scale production rates. These are generally economical and in many cases improve the mechanical properties. These are some of the metal forming processes.

· Rolling forging

· Drop forging

· Press forging

· Upset forging

· Extrusion forging

· Wire forging

· Sheet metal operation

Fabrication Processes

These are secondary manufacturing processes where the starting raw materials are produced by any one of the previous manufacturing processes desired. Its assembly involve joining pieces either temporary or permanent. So that they would be perform the necessary function. The joining can be achieved by either or both of heat and pressure joining materials.

Many of the steel structure construction, we see are first rolled and then joined together by a fabrication process are

· Gas welding

· Electric arc welding

· Electrical resistance welding

· Thermo welding

· Brazing welding

· Soldering welding

· Cold welding

Material removal processes:

These are also a secondary removal manufacturing process, where the additional unwanted material is removed in the form of chips from the blank material by a hard tools so as to obtained the final desired shape.

Material removal is normally a most expensive manufacturing process. Because more energy is consumed and also a lot of waste material is generated in this process. still this process is widely used because it deliver very good dimensional accuracy and good surface finished. Material removal process are also called machining processes. Various processes in this category are

· Turning

· Drilling

· Shaping and planning

· Milling

· Grinding

· Broaching

· Sawing

· Trimming