Maximizing Throughput: The Value of Dispatching Rules

Andrew Brown, Lyndia Stacey, Filzah Nasir and Hossein Abouee-Mehrizi
Case revision date: 
5 pages
Manufacturing is an important part of Canada's economy, representing 11% of its Gross Domestic Product (GDP) as of August 2014. Due to globalization, many Canadian manufacturing industries face new challenges and, to remain globally competitive, they need to become more efficient. Industry Partner A was seeking efficiency gains by implementing Operations Research (OR) methods in their job-shops, particularly for their production scheduling. A job-shop is a type of manufacturing process in which small batches of a variety of custom products are made. As in many production models, it has a number of machines or resources on which the production work is processed. In job-shop scheduling, each job consist of several operations, each completed using a specific machine or resource for a set amount of time. The flow diagram in Figure 1 illustrates a hypothetical example of a job-shop. Each job has a due date by which time the job is ideally completed. At each machine, there are queued jobs waiting to be processed and a dispatching rule is implemented as a scheduling method to determine which queued job should be ‘dispatched’ for processing.
Andrew Brown, a graduate student at the University of Waterloo, was asked by Industry Partner A1 to analyze various dispatching rules and propose a method that reduced the number of late jobs as part of his Masters dissertation under the supervision of Dr. Stan Dimitrov. Hossein Abouee-Mehrizi, an Assistant Professor, ensured the content of this case complemented his course on scheduling theory.
Learning objectives: 

The main objective of this case study is to provide a real world scenario so that students can apply dispatching rules to operations within a real context using scaled and relevant data. The students will practice applying dispatching rules to job-shops and understand the benefits and disadvantages of selecting certain rules as well as analyze these options in order to make an appropriate selection.

Key words: 
Job shop, dispatching rules, key performance indicators
CEAB attributes: 
Problem Analysis; Investigation; Use of Engineering Tools
Module 01 - Case Study
Module 02 - Dispatching Rules Analysis
Module TN - Teaching Note
WCDE-00336 Production Data (Excel File)

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