The Distinctive and Common Qualitiesof Job Shops and Flow Shops
ABSTRACT
The purpose of this paper is to clarify the similarities and differences between job shops and flow shops as well as advise with regard to facility layout. The selection of a job shop or flow shop layout should be made based upon the properties and characteristics the manufacturers desire to have in place for producing their products. These considerations will ultimately result in cost-saving measures as well as increases in overall efficiency. I. Explanation of the Defining Attributes
Elements of Job Shops
A production environment in which similar operations and equipment are organized by function is typically referred to as a job shop. Job shops are a unique form of manufacturing in which the jobs pass through functional departments and lots. Within each lot may, a variety of different operational routing may exist. Several internal constraints on jobs and machines present themselves in this layout: No precedence constraints abide among tasks of different jobs; interruptions of tasks are not allowed; and each job can be performed only on machine at a time (1).
A particularly distinguishing feature of the job shop is its functional design. Design by process is a feature that commonly contributes to the higher customization of products. Such diverse products include space vehicles, aircraft, machine tools, and specialized tools and equipment. Due to the wide range of services provided, equipment that can perform a broader range of tasks is required and workers must have high skill levels to perform the assigned tasks. The layout tends to be less capital intensive and more reliant upon higher workforce wages (2).
Machines are grouped according the type of manufacturing process. The lathes, drill presses, and machines capable of plastic molding are grouped separately throughout the facility. Route sheets are used as the production control device to define the path of the material through the manufacturing system. Materials tend to
The purpose of this paper is to clarify the similarities and differences between job shops and flow shops as well as advise with regard to facility layout. The selection of a job shop or flow shop layout should be made based upon the properties and characteristics the manufacturers desire to have in place for producing their products. These considerations will ultimately result in cost-saving measures as well as increases in overall efficiency. I. Explanation of the Defining Attributes
Elements of Job Shops
A production environment in which similar operations and equipment are organized by function is typically referred to as a job shop. Job shops are a unique form of manufacturing in which the jobs pass through functional departments and lots. Within each lot may, a variety of different operational routing may exist. Several internal constraints on jobs and machines present themselves in this layout: No precedence constraints abide among tasks of different jobs; interruptions of tasks are not allowed; and each job can be performed only on machine at a time (1).
A particularly distinguishing feature of the job shop is its functional design. Design by process is a feature that commonly contributes to the higher customization of products. Such diverse products include space vehicles, aircraft, machine tools, and specialized tools and equipment. Due to the wide range of services provided, equipment that can perform a broader range of tasks is required and workers must have high skill levels to perform the assigned tasks. The layout tends to be less capital intensive and more reliant upon higher workforce wages (2).
Machines are grouped according the type of manufacturing process. The lathes, drill presses, and machines capable of plastic molding are grouped separately throughout the facility. Route sheets are used as the production control device to define the path of the material through the manufacturing system. Materials tend to
Cited: European Journal of Operations Research 93 (1996): 1-33. 2. Morton, Thomas E., David Pentico. Heuristic Scheduling Systems. New York: John Wiley & Sons, 1993. (1982): 173-184. 4. Parker, Gary R. Determining Scheduling Theory. London: Chapman & Hall, 1995. 5. Pinedo, Michael. Scheduling: Theory, algorithms, and systems. New Jersey: Prentice Hall, 2002. (2003): 215-229. Production Economics. 40 (1995): 185-195. Economics 99 (2006) 4-15. 10. Bertolissi, Edy. "Heuristic algorithm for scheduling in the no-wait flow-shop." Journal of Materials Processing Technology 107 (2000): 459-465. 11. Lee, Chung Yee. "Performance comparison of some classes of flow shops and job shops." International Journal of Flexible Manufacturing Systems 10 (1998): 379-405. 12. Guinet, Alan. "Efficiency of reduction of job-shop to flow-shop problems." European Journal of Operational Research 129 (2000): 469-485. 14. Cheng, T. "Analysis of material flow in a job shop with assembly operations." International Journal of Production Economics 28.7 (1990): 1369-1383. 15. Tsubone, Hitoshi, M. Horikawa. "A comparison between machine flexibility and routing flexibility." International Journal of Flexible Manufacturing Systems 11 (1999): 83. 16. Sen, Alper. Engin Topaloglu, Omer Benli. "Optimal streaming of a single job in a two-stage flow shop." European Journal of Operational Research 110 (1998): 42-62.