Assembly line balancing using Rank positional weight (RPW)
- 1. Rank Positional weight (RPW) for assembly line balancing HEURISTIC METHOD
- 2. Rank positional weight It is a heuristic algorithm used to solve the assembly line balancing problem. This methods depends on the processing times for all tasks and their followers.
- 3. RPW Example The below figure shows the tasks, times and precedence relation for each element used in cashew machine assembly. Tas Time (min) Description Predecessor 1 20 Frame assembly - 2 20 Cutter assembly 1 3 45 Motor assembly 2 4 10 Crank assembly 3 5 7 Pickup assembly 2 6 5 Belt cover assembly 5 7 8 Cup assembly 5 8 20 Bucket and disk assembly with shaft 5 9 15 Feed motor and belt assembly 5 10 5 Circuit assembly 5 11 4 Hopper assembly 6,7,8,9,10 12 45 Connect wires 11,4 13 6 Outer cover assembly 12
- 5. RPW solution method 1-draw precedence diagram. 2- for each task find the transitive followers (followers of followers till you reach the end of the graph). 3- calculate the RPW for each task (i). (RPW(i)= time of the task (i)+ summation of times of tasks in the transitive followers (i) 4-re-arrange tasks according to their RPW in descending order 5-open a work station and assign the feasible tasks till the cycle time is reached or no more assignable tasks in the station. 6- Repeat step 5 till all tasksare added to work stations.
- 6. RPW Task RPW 1 210 2 190 3 106 4 61 5 115 6 60 7 63 8 75 9 70 10 60 11 55 12 51 13 6
- 7. RPW in descending order Task RPW 1 210 2 190 5 106 3 61 8 115 9 60 7 63 4 75 6 70 10 60 11 55 12 51 13 6
- 8. Assign to work stations Station task time Sum of station time 1 1 20 20 2 20 40 5 7 47 7 8 55 2 3 45 45 4 10 55 3 8 20 20 9 15 35 6 5 40 10 5 45 11 4 49 4 12 45 45 13 6 51
- 9. RPW software The RPW software available can be purchased by 10$ only Contact me for more information Shadymagdy@windowslive.com