Flexible Manufacturing

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Flexible Manufacturing

Business firms generally choose to compete within one or two areas of strength. These areas of strength are often referred to as distinctive competencies, core competencies, or competitive priorities. Among the options for competition are price (cost), quality, delivery, service, and flexibility. An ever-increasing number of firms are choosing to compete in the area of flexibility. Generally, this has meant that the firm's major strength is flexibility of product (able to easily make changes in the product) or flexibility of volume (able to easily absorb large shifts in demand). Firms that are able to do this are said to have flexible capacitythe ability to operate manufacturing equipment at different production rates by varying staffing levels and operating hours, or starting and stopping at will. Specifically, manufacturing flexibility consists of three components: (1) the flexibility to produce a variety of products using the same machines and produce the same products on different machines; (2) the flexibility to produce new products on existing machines; and (3) the flexibility of machines to accommodate changes in the design of products.

FLEXIBLE MANUFACTURING SYSTEMS

A flexible manufacturing system (FMS) is a group of numerically-controlled machine tools, interconnected by a central control system. The various machining cells are interconnected, via loading and unloading stations, by an automated transport system. Operational flexibility is enhanced by the ability to execute all manufacturing tasks on numerous product designs in small quantities and with faster delivery. It has been described as an automated job shop and as a miniature automated factory. Simply stated, it is an automated production system that produces one or more families of parts in a flexible manner. Today, this prospect of automation and flexibility presents the possibility of producing nonstandard parts to create a competitive advantage.

The concept of flexible manufacturing systems evolved during the 1960s when robots, programmable controllers, and computerized numerical controls brought a controlled environment to the factory floor in the form of numerically-controlled and direct-numerically-controlled machines.

FMS is generally limited to firms involved in batch production or job shop environments. Normally, batch producers have two kinds of equipment from which to choose: dedicated machinery or non-automated, general-purpose tools. Dedicated machines save cost but lack flexibility. More flexible general purpose machines such as lathes, milling machines, or drill presses are all costly, and may not reach full capacity. Flexible manufacturing systems provide the batch manufacturer with another optionone that can make batch manufacturing just as efficient and productive as mass production.

OBJECTIVES OF FMS

The general objectives of an FMS are to approach the efficiencies and economies of scale normally associated with mass production, and to maintain the flexibility required for small- and medium-lot-size production of a variety of parts. Two kinds of manufacturing systems fall within the FMS spectrum. These are assembly systems, which assemble components into final products, and forming systems, which actually form components or final products. A generic FMS is said to consist of the following components:

  1. A set of work stations containing machine tools that do not require significant set-up time or change-over between successive jobs. Typically, these machines perform milling, boring, drilling, tapping, reaming, turning, and grooving operations.
  2. A material-handling system that is automated and flexible in that it permits jobs to move between any pair of machines so that any job routing can be followed.
  3. A network of supervisory computers and microprocessors that perform some or all of the following tasks: (1) directs the routing of jobs through the system; (2) tracks the status of all jobs in progress so it is known where each job is to go next; (3) passes the instructions for the processing of each operation to each station and ensures that the right tools are available for the job; and (4) provides essential monitoring of the correct performance of operations and signals problems requiring attention.
  4. Storage, locally at the work stations, and/or centrally at the system level.
  5. The jobs to be processed by the system. In operating an FMS, the worker enters the job to be run at the supervisory computer, which then downloads the part programs to the cell control or NC controller.

BENEFITS OF FMS

The potential benefits from the implementation and utilization of a flexible manufacturing system have been detailed by numerous researchers on the subject. A review of the literature reveals many tangible and intangible benefits that FMS users extol. These benefits include:

  • Less waste
  • Fewer workstations
  • Quicker changes of tools, dies, and stamping machinery
  • Reduced downtime
  • Better control over quality
  • Reduced labor
  • More efficient use of machinery
  • Work-in-process inventory reduced
  • Increased capacity
  • Increased production flexibility

LIMITATIONS OF FMS

Despite these benefits, FMS does have certain limitations. In particular, this type of system can only handle a relatively-narrow range of part varieties, so it must be used for similar parts (family of parts) that require similar processing. Due to increased complexity and cost, an FMS also requires a longer planning and development period than traditional manufacturing equipment.

Equipment utilization for the FMS is not always as high as one would expect. Japanese firms tend to have a much higher equipment utilization rate than U.S. manufacturers utilizing FMS. This is probably a result of U.S. users' attempt to utilize FMS for high-volume production of a few parts rather than for a high-variety production of many parts at a low cost per unit. U.S. firms average ten types of parts per machine, compared to ninety-three types of parts per machine in Japan.

Other problems can result from a lack of technical literacy, management incompetence, and poor implementation of the FMS process. If the firm misidentifies its objectives and manufacturing mission, and does not maintain a manufacturing strategy that is consistent with the firm's overall strategy, problems are inevitable. It is crucial that a firm's technology acquisition decisions be consistent with its manufacturing strategy.

If a firm chooses to compete on the basis of flexibility rather than cost or quality, it may be a candidate for flexible manufacturing, especially if it is suited for low- to mid-volume production. This is particularly true if the firm is in an industry where products change rapidly, and the ability to introduce new products may be more important than minimizing cost. In this scenario, scale is no longer the main concern and size is no longer a barrier to entry.

However, an FMS may not be appropriate for some firms. Since new technology is costly and requires several years to install and become productive, it requires a supportive infrastructure and the allocation of scarce resources for implementation. Frankly, many firms do not possess the necessary resources. Economically justifying an FMS can be a difficult task, especially since cost accounting tends to be designed for mass production of a mature product, with known characteristics, and a stable technology. Therefore, it is difficult to give an accurate indication of whether flexible manufacturing is justified in many cases.

Rapidly-changing technology and shortened product life cycles can cause capital equipment to quickly become obsolete. Conversely, however, it is important to understand that when it is financially possible, flexible manufacturing is an option that creates synergy among existing machines, making it possible to create massive batches of products in a span of time previously thought impossible. With today's fast moving trends and constant inventory turnover on all marketplaces, flexibility is truly the key in manufacturing almost anything.

For other firms, their products may not require processes at the technological level of an FMS. IBM found that a redesigned printer was simple enough for high-quality manual assembly and that the manual assembly could be achieved at a lower cost than automated assembly. Potential FMS users should also consider that some of the costs traditionally incurred in manufacturing may actually be higher in a flexible automated system than in conventional manufacturing. Although the system is continually self-monitoring, maintenance costs are expected to be higher and energy costs are likely to be higher despite more efficient use of energy. Increased machine utilization can result in faster deterioration of equipment, providing a shorter than average economic life. Finally, personnel training costs may prove to be relatively high in comparison.

For some firms, worker resistance is a problem. Workers tend to perceive automation as an effort to replace them with a tireless piece of metal that does not eat, take breaks, or require benefits. To combat this perception, many firms stress that workers are upgraded as a result of FMS installation, and that no loss of jobs ensues.

Despite any problems, use of flexible manufacturing systems should continue to grow as more firms are forced to compete on a flexibility basis and as technology advances. It has shown many advantages in low- to mid-volume, high-mix production applications. Future systems will probably see lower and lower quantities per batch. FMS can somewhat shift emphasis in manufacturing from large-scale, repetitive production of standard products to highly-automated job shops featuring the manufacture of items in small batches for specific customers. The increased availability of flexible manufacturing technology will also give multi-product firms more choices of how to design production facilities, how to assign products to facilities, and how to share capacity among products.

BEYOND FLEXIBLE MANUFACTURING: AGILE MANUFACTURING

Fliedner and Vokurka, in their Production and Inventory Management Journal article on agile manufacturing, define

agile manufacturing as the ability to successfully market low-cost, high-quality products with short lead times (and in varying volumes) that provide enhanced customer value through customization. An agile firm manages change as a matter of routine. The difference between agility and flexibility is whether or not the change in market demand has been predicted. Flexibility refers to the capability of rapidly changing from one task to another when changing conditions are defined ahead of time. Agility refers to the ability to respond quickly to unanticipated marketplace changes. Fliedner and Vokurka present four key dimensions of agile competition:

  1. Enriching the customer: This requires a quick understanding of the unique requirements of individual customers and rapidly meeting those requirements.
  2. Cooperating to enhance competitiveness: This includes better intra-organizational cooperation and may extend to inter-organizational cooperation, such as supplier partnerships and virtual relationships.
  3. Organizing to master change and uncertainty: This involves utilizing new organizational structures provided by such techniques as concurrent engineering and cross-functional teams.
  4. Leveraging the impact of people and information: This places great emphasis on the development of employees through education, training, and empowerment.

IMPLEMENTING AGILE MANUFACTURING

Finally, the two authors prescribe a series of internal and external initiatives for successful implementation of agile manufacturing. The internal initiatives include the following:

  1. Business process reengineering: This is the rethinking and radical redesign of business processes so that dramatic improvements in critical areas can be achieved.
  2. Management planning and execution tools: This involves the use of such techniques as manufacturing resource planning, real-time manufacturing execution systems, production planning configurators, and real-time threaded scheduling.
  3. Design for manufacturability/assembly: The results include modular products that allow for future upgrades, fewer parts for enhanced reliability, and recycling.
  4. Reorganization processes: Process reorganization could include the use of flexible manufacturing systems or cellular manufacturing.
  5. Intraorganizational cooperation. This form of cooperation calls for the use of employee empowerment/involvement techniques and employee education and training.

External initiatives include:

  1. Interorganizational cooperation: This means early supplier involvement in product and process designs, training suppliers in such activities as vendor-managed inventories, and joint research efforts.
  2. Supply chain practices: The use of outsourcing, schedule sharing, and postponement of product design are included.
  3. Information technology: Some companies are using technology to improve supply chain efficiency. For example, the move from centralized mainframe computing to decentralized client and server computing.
  4. Point-of-sale data collection: Reductions in order entry time are being achieved with electronic data interchange (EDI), radio frequency communications tools, bar coding, and electronic commerce.

The authors propose that flexibility provided by agility may emerge as the most important competitive priority of the early twenty-first century, as competition is expected to ensure that manufacturers will increasingly need to adapt readily to market shifts.

SEE ALSO Cellular Manufacturing; Economies of Scale and Economies of Scope; Lean Manufacturing and Just-in-Time Production

BIBLIOGRAPHY

Anderson, Dr. David. Design for Manufacturability & Concurrent Engineering; How to: Design for Low Cost, Design for High Quality, Design for Lean Production, and Design Quickly for Fast Production. California: CIM Press, 2008.

Chandra, Charu, Mark Everson, and Janis Grabis. Evaluation of Enterprise-Level Benefits of Manufacturing Flexibility. Omega 33, no. 1 (2005): 1731.

Fliedner, Gene, and Robert J. Vokurka. Agility: Competitive Weapon of the 1990s and Beyond. Production and Inventory Management Journal 38, no. 3 (1997): 1924.

Ford Furthers Flexible Manufacturing Effort. Manufacturing Engineering 133, no. 1 (2004): 27.

Popely, Rick. Ford Upgrades Chicago Plant to Meet Need for Flexible Manufacturing.' Knight Ridder Tribune Business News 9 June 2004.

Schonfeld, Erick. The Customized, Digitized, Have-It-Your-Way Economy. Fortune 28 September 1998, 114124.

Truett, Richard. Ford's Flexibility Reaps Rich Reward. Automotive News 78, no. 6106 (2004): 17.

Tseng, Mei-Chiun. Strategic Choice of Flexible Manufacturing Technologies. International Journal of Production Economics 91, no. 3 (2004): 223227.