Manajemen Produksi dan Operasi Schedulling – Johnson rules M-12
2006 Jurusan Teknik Industri UNISSULA Andre Sugiyono Johnson’s Rule Used to sequence N jobs through 2 machines in the same order © 1995 Corel Corp. Saw Drill Job A Job B Job C Jobs (N = 3)
Sequencing Jobs through Two Work Centers – Johnson’s Rule Johnson’s Rule – a technique for minimizing makespan in a two-stage process Step 1 – List the jobs and the processing time for each activity Step 2 – Find the shortest activity processing time among the jobs If the shortest processing time is for a 1st activity, schedule that job first If the shortest processing time is for 2nd activity, schedule that job last Step 3 – Find the shortest activity processing time among the remaining jobs and schedule as in step 2 above. Repeat until all jobs are scheduled.
Johnson’s Rule Example: Tysna’s office cleaners does the annual major cleaning of STIKOM buildings. The job requires mopping (1st activity) and waxing (2nd activity) of each building. Tysna’s wants to minimize the time it takes her crews to finish cleaning (minimize makespan) the five buildings. He needs to finish in 20 days. Activity 1 (Mopping) days Activity 2 (Waxing) days A. R. Auditorium 1 2 B. R. Serbaguna 3 5 C. Ruang Dosen 4 D. R. Perpustakaan E. R. Expo
Johnson’s Rule Sequence Activity 1 (Mopping) days Activity 2 (Waxing) days A. R. Auditorium 1 2 C. Ruang Dosen 4 B. R. Serbaguna 3 5 D. R. Perpustakaan E. R. Expo
Penjadwalan kapasitas Terbatas (finite capacity schedule) Bottleneck Penjadwalan produksi berulang (mass production)