The manufacturing of any system involves a series of mechanical process. Each part is manufactured using a different mechanical process such as casting, machining, drawing, joining etc. After the parts are manufactured, they must be sent for various hardening process annealing, carbonizing etc. depending on the material used.
Various mechanical processes involved
Casting
- In this process the new part is formed from the melting of the metal, and then it is subjected to flow into the mold cavity where it takes the required shape and is allowed to solidify.
- Parts such as vanes, casing and shafts in the draft fans are manufactured by this process.
- The metal formed in this process is usually of the uniform characteristics.
- The metal grains are uniformly distributed in the metal.
Machining
- In this type the already existed part of a system or a part that is taken from the casting process is used in order to make a new part.
- Machining process uses various machine tools such as lathe, planer, shaper, milling machine etc. and they require electric power.
- The ends and corners of the draft system are to be chambered in order to prevent any cuts to the human.
- Some parts of the system such as vanes of the fan are machined in order to maintain or remove the excess material on the vanes.
Joining
- This process is of two types permanent joining or temporary joining.
- Temporary joining involves nuts and bolt fitting whereas permanent joining includes riveted joints, weld joints etc.
- In draft system bolt and nut joints are seen in removable or frequent replaceable parts. For foundation support of the system, we use eye bolt.
- Welds are used for permanent joining. Parts which are broken or very big in size are welded together to get a single unit.
- Riveted joints serve the same purpose as the welded joints. But in riveted joints a piece of the metal is used which combines the two distant pieces in a single shape by the application of pressure. This is done with casing when it comes in two different parts.
Metal hardening process
- There are many metal hardening processes such as annealing, carbonizing etc. The final outputs of the casting process may not have good strength so these processes will provide the necessary hardening support to the parts.
- We use different hardening processes with different metals.
- Parts of the draft system which are made of steels under go annealing process.
- The parts such as casing are made of steel which are to be annealed
The manufacturing process of the parts is important because the use of an accurate process will make it easy for understanding which type of repair is appropriate for the given part of the system.