Mild steel tubes of different thicknesses and diameters are carried into the factory. At first, they are being cut along lengths, as an example, the upper frame of tubular chair consists of minimum 05 different lengths of tube. A Numerical control or computer controlled tube bending machine is used to bend according to the required shapes and angles. Normally, 14-16 curves of different radiuses required to be shaped for a chair frame. Next, the MIG welders join the chair frame components according to the design templates with MIG (Metal Inert Gas) welding machine. After that, the grinders grind on welded surfaces of the chair structure with Angle Grinders to get smooth surface.
Next, the chair frame is brought to the buffing section (Polishing Section) for the preparation of Electroplating (Nickel Chrome Plating). Electroplating is a process of applying coating of other metal on steel objects. There are a lot of varieties of electroplating such as Nickel plating, Chrome plating, Nickel-Chrome plating, Zinc plating etc. Electroplating takes a huge number of specialized devices & equipments and furthermore is subject to strict environmental constraints.
During electroplating, (Nickel Chrome Plating), following operations are performed:
- At first, buffing or polishing operation is done. Steel chair structure or parts are polished well to remove rust and surface roughness. After polishing, it looks like a mirror. Buffing or polishing operation is fully accomplished by hand.
- After that, chair structure or chair parts are thoroughly cleaned (degreased and re-rusted) by using NaOH (Basic Chemical) & HCl/Sulfuric Acid and rinsed in hot water.
- Next, well cleaned chair structure or parts are put into the Nickel plating tank for a certain period (period depends on required thickness of coating) to apply coat of Nickel metal.
- After Nickel coating, chair parts or structure are put into the Chrome plating tank for getting a thin coat of chrome metal.
- Finally, clean again with hot water and dry in the hot air. Thus, Nickel-Chrome plating (Electroplating) is accomplished.
In this way, Nickel Chrome plated Tubular Chair structure is made.