The Sequencing Conundrum: Optimizing Assignment Grading - Part A and Part B

Two expert woodworkers at Craft Wood Furniture, a mid-sized production house that employs approximately 50 people, work on the company’s furniture products in the finishing stages of the production cycles: sanding, primer polishing, and applying final coats of paint. Their expertise is critical to ensure that each furniture item meets the company’s high standards of durability and aesthetics. However, each furniture item differed in terms of size, type of material used, and level of complexity, which means that the total completion time also differs for each item. Craft Wood Furniture wants to determine the optimal scheduling sequence for the most time-effective and smoothest workflow. How should the various tasks be arranged for a seamless flow between the two workers without unnecessary delays?

This exercise note is suited for an introductory operations management course. It can also be used in a core course in production and operation management at the graduate level, preferably during sequencing and scheduling modules. Both parts of the exercise note can be ideally discussed in a session of 75 to 90 minutes. The exercise note focuses on the idea and implementation of Johnson’s rule for sequencing of n jobs (or tasks) and two processors (or woodworkers, in this case). Johnson’s rule is a commonly used heuristic to determine the most optimal sequence in situations where the required time to complete each job on each processor, as well as the order of processors, is known. Students learn about what methods the processors (or woodworkers) can use to equilibrate the workload and avoid unnecessary delays due to waiting for completion of other assigned tasks. The exercise note proposes a practical solution by using Johnson’s rule. It provides students with a foundation for quantitative decision-making processes, with a holistic view of factors such as job sequencing. After completion of this exercise note, students will be able to <ul><li>Understand the role and importance of correct sequencing.</li><li>Use Johnson’s rule for sequencing n jobs through two processors (see Part A of this exercise note).</li><li>Use the modified Johnson’s rule for sequencing n jobs through three processors (see Part B of this exercise note).</li><li>Identify and minimize idle time to make optimal use of resources.</li><li>Become familiar with total slack or idle time issues and optimal use of resource utilization issues mentioned above.</li></ul>

• Sequencing
• Scheduling
• Johnson Rule
• Optimize