It consists of inspecting and checking all purchased raw materials and supplied parts before they are taken into stock or used in actual manufacturing. Inspection may take place at the supplier's end or at the manufacturer's door. If the quantity of incoming materials is large and involves large transportation costs, it is economical to inspect them at the vendor or supplier's premises.
Control of the production process
Inspection work is done while the production process is going on simultaneously. Inspection is done at various work centers and critical production points of men and machines. This had the advantage of preventing wastage of time and money on defective units and avoiding delays in assembly.
Inspection of finished products
This is the final stage where the finished goods are inspected and carried out before marketing to see if low quality product can be rejected or sold at a low price.