This current research represents an application for the scheduling optimization of various types of manufacturing factory in Bangladesh as well as all over the world. A case study is presented for scheduling of jobs when parts are treated on machines on the basis of availability in the factory. Set up time and operation time are measured through time and motion study. This paperwork is concerned about the minimization of the make span. By using Johnson’s algorithm for two machines problems and Extension of Johnson’s algorithm for three machines problems the idle time for the machines in a flow shop-scheduling environment is established. Time-in and time-out strategy for two machines as well as for three-machine problem is focused in this article. The work proposes to find the optimal sequence in scheduling and sequencing which help to increase productivity, effective utilization of machines and maximize the profit of industries.