Managing High-Mix, Low-Volume Asmbly
As model mix increas and production volume decreas, asmblers are discovering that tried and true manufacturing strategies no longer apply.
开水冲鸡蛋的正确做法
In describing U.S. consumers on his 1972 comedy recording, Class Clown, George Carlin was almost prophetic about the state of U.S. manufacturing today. The typical consumer, he noted, does not merely want an inhaler with a nasal decongestant. He wants an inhaler for his left nostril imprinted with his state's motto.
Carlin may have been riffing on crass commercialism at the time, but his gibe goes to the heart of an issue facing a growing number of asmbly plants today: Manufacturing is shifting away from high-volume, low-mix production to high-mix, low-volume production.
According to ASSEMBLY's annual Capital Equipment Spending Survey, there's little doubt that fewer manufacturers are performing high-volume asmbly today than there were 8 ye
ars ago. In 1996, 25 percent of plants produced more than 1 million asmblies annually. In 2004, only 19 percent did so. At the same time, the number of low-volume manufacturers is increasing. In 1996, 24 percent of plants produced less than 1,000 asmblies annually. In 2004, 35 percent did so.
As production volumes have decread, production variety has incread. U.S. manufacturers are asmbling a greater mix of products than ever before. In 1996, 16 percent of plants asmbled more than 10 different product types annually. In 2004, 23 percent did so.
The main reason for this shift, as Carlin alluded to, is that consumers increasingly want products tailored to their particular needs. Consider the humble refrigerator. It has one job: keep food cold. Yet Whirlpool Corp. (Benton Harbor, MI) offers no less than 57 models of refrigerator, differentiated by configuration, features, finish, height, width and, of cour, price.
"Customers are looking for more variety. They don't want the same old thing," explains K
evin Duggan, president of Duggan & Associates (West Warwick, RI), a consulting firm specializing in lean manufacturing.
Outsourcing also shares the blame for the increa in high-mix, low-volume production. High-volume production has largely been taken over by foreign manufacturers, while low-volume production has remained in the United States.
"You can't get the turnaround time from offshore manufacturers. They're just not geared for that," says Wes Price, CEO of BCP Trilogy (Placentia, CA), an electronics manufacturing rvice (EMS) provider. "Offshore manufacturers like to t up and run. They have quite an investment in capital equipment, and they don't like to take their machines down, becau they have to amortize that cost. As a matter of fact, we often subcontract low-volume jobs for a Latin American contract manufacturer."
Another reason for the shift to high-mix, low-volume production is business volatility. Manufacturers, especially tho that supply OEMs, can no longer afford to be tied to one major customer or industry.
"The trick is to supply a lot of different parts to a lot of different customers, rather than a lot of one part to one customer," says Duggan, author of the book Creating Mixed Model Value Streams: Practical Lean Techniques for Building on Demand (Productivity Press, New York, 2002). "I know one machine shop that supplies a high-volume product to a large aerospace conglomerate. Every time that big company hiccupped, the machine shop would stall and almost go out of business."意识形态化
According to Duggan, the machine shop would be better off with a larger, more diver customer ba. By learning to reduce tup times and build a combination of products at the same time, the shop will find that it needs less lead time to produce an order. When lead times shrink, capacity opens up and there's less chance for things to go wrong.
"High-mix, low-volume asmbly gives you the ability to react to changes in the marketplace," says Duggan. "When you build in big batches, you don't have that ability."
That's the good news. The bad news is that product variety and fast respon times can increa the costs associated with material handling, tup, test and other process. To 非主流的歌
木兰辞全文excel at high-mix, low-volume asmbly, manufacturers must be adroit at scheduling, inventory management, mistake-proofing and process control.
刘邦的故事
Different Paradigms
老师与学生The strategies for high-mix, low-volume asmbly are often opposite from tho for high-volume, low-mix production. For example, high-volume manufacturers win business bad primarily on the cost and quality of their products, says R. Michael Mahoney, president of Manufacturing Decision Analysis LLC (Loveland, CO). On-time delivery and customer responsiveness are qualifiers for business, but they're not the most important considerations.
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