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vc304.qxd 8/2/2004 1:00 PM Page 24 SPOTLIGHT Quality Cones From AsiaYen Lung By Jimmy Ying and Rob Baum This month’s profile is part of Voice Coil’s series on Chinese cone manufacturers. With so much of the speaker assembly business moving to China, European and American speaker designers need to know more about Chinese soft part vendors. It is likely that the frames and magnetic structures were already sourced from China when the speaker was assembled in the US or Europe, but the cones were sourced from American factories. Now, with Chinese assembly, it is expedient to source as much local content as possible. A number of the Chinese cone vendors are seeking US marketing and sales partners who already have a customer base, tooling, paper beating technology, and the pulp formulations European and American customers prefer. One Chinese cone vendor that fits this description is Yen Lung (which means “develop continually, run perpetually”). JY-304-1 FIGURE 1: Santoprene versus other surrounds(red = NBr, Blue = Butyl, green = Santoprene). Precision Econowind, Inc. PO YUN ENTERPRISE OFFERING THE BEST QUALITY, BEST PRICED VOICE COILS AVAILABLE TO THE SPEAKER INDUSTRY TODAY. TINSEL TO COIL ATTACHMENT AVAILABILITY VARIETY OF WIRE TYPES AND ADHESIVE TYPES AVAILABLE ROUNDWIRE, FLAT WIRE, EDGEWOUND, INSIDE/ OUTSIDE area of interest MANY COIL CONFIGURATIONS AVAILABLE WE PROVIDE HIGH QUALITY IMPORTED OR DOMESTIC COILS OVER 50 YEARS COMBINED EXPERIENCE IN USA, ASIA, EUROPE, ALSO AVAILABLE: CANADA FORM MATERIAL, COLLAR MATERIAL, CUT FORMERS AND COLLARS For samples and quotes please contact Jon Van Rhee. JY-304-2 FIGURE 2: Surround detail. 24 VOICE COIL 8940 North Fork Drive • Fort Myers, FL 33903 • Tel: (239) 997-3860 Fax: (239) 997-3243 • Email: [email protected] vc304.qxd 2/9/2004 8:15 AM Page 25 Established in 1983, Yen Lung (Photo 1) was one of the leading cone paper producers in Taiwan. In 1995, with manufacturing costs rising in Taiwan and their customer base moving to China, they shifted to southern China to follow both their customers and lower production costs. The Taiwan factory continues the production of high-value and upscale cones. A workforce of 800 produces 6.5 million cones per month. Yen Lung supplies brand names including Sharp, Sony, JBL, Sansui, Infinity, Pioneer, Onkyo, Blaupunkt, and Kenwood. Most of Yen Lung’s exports are to Europe; only a small percentage of their output ends up in the US, and now they would like to expand their exports there. The factory in Dongguan in southern China contains 11580m2 of usable factory space, with 1700m2 of warehouse space for materials and 600m2 of space for finished goods; the total land area is 17,333m2. Yen Lung is 100% Taiwanese, and owns the land and buildings. They passed QS9000 inspection in September 2001. There are a dozen cone factories in south China alone. From afar, it would be easy to lump all these factories together. But once you begin working with them, you find thatlike in the USnot just dedicated, but also interesting, characters run them. Perhaps Yen Lung’s Michael Lin (Photo 2) “takes the cake.” Michael started out with formal training in pre-med, initially making his living doing autopsies in a coroner’s office. Then he became a high school math teacher (his wife is still a teacher). This did not seem to agree with him, and eventually he founded Yen Lung in Taiwan. Lin’s favorite activity is racing around the neighborhood on his motorcycle. Since Yen Lung is a major factory in the town, If you don't think there is anybody in Asia that can handle your project, try Bring us your challenges, and we will turn them into products... Hendrik Huebscher [email protected] Bill Kindel [email protected] MEILOON USA CORP. 1434 W. Taft Ave., Orange, CA, 92865 T 714-282-7561 F 714-282-7081 Turnkey Solutions Audiophile cables Die cast baskets Digital Analog Converter All in one coaxial connector Class D Subwoofer amplifier Custom design film capacitors PHOTO 1: Yen Lung building. 739-6788 Vance Dickason Consulting -Loudspeaker and Transducer EvaluationComputer Optimized System Design for: 2 Channel/Home Theater (including THX Certification)/Car Audio/Multi MediaComplete Design Team available for: -System Design-Rapid Prototyping-Industrial Design-CNC Capability-Powered Servo Subwoofer Design-Custom Transducer Engineering- PHOTO 2: Michael Lin. Phone: 503-557-0427 • Fax: 503-557-0442 • E-mail [email protected] MARCH 2004 25 vc304.qxd 2/9/2004 8:15 AM Page 26 the mayor and local police chief are afraid of losing a key employer in a motorcycle accident. So whenever Michael speeds off on his bike, the police chase him down and give him a ride back home in a police car. Aside from motorcycle racing down city streets, a morning exercise run is part of his routine. Michael Lin and his associates at Yen Lung (General Manager of Dongguan Yenlung, Edward Lin, and General Manager of Suzhou Yenlung, Yu Tian Lin) are a committed, decent, and honest group of men who work hard to make a good product and try their best to satisfy their customers. Products Yen Lung offers a wide variety of materials: paper (including pressed, semi-pressed, and non-pressed); various grades of polypropylene (including premium grades from Nike); and premium cone materials such as carbon fiber and Kevlar. Surrounds include foam (and water-resistant foam), rubber, and fabric. IMSS Surrounds Yen Lung, working with Advanced Elastomer Systems (a subsidiary of ExxonMobil Chemical) implemented and commercialized the Injection Molded Santoprene Surround (IMSS) process. While many speaker cone manufacturers thermoform Santoprene rubber sheets for surrounds, the IMSS process is unique, with significant benefits (Figures 1 and 2). Menlo Scientific first explored Santoprene rubber when Monsanto developed it in the 1980s. While Santoprene rubber is stable and essentially immune to flex fatigue and environmental effects, it is difficult to glue, and edge resonance is sometimes an issue. It seemed that Santoprene rubber needed to be a bit lossier to reduce the edge resonance notch in the response, so in the case of autosound, subwoofers, and outdoor speakers, the robustness outweighed the slight increase in the edge response notch. When a few high-end manufacturers began using Santoprene rubber for soft dust caps and achieved superb results, we should have realized the problem was not in the (lack of) lossiness or damping of Santoprene rubber. Instead, in a thermoformed Santoprene rubber edge, the typically hard adhesive joint between the cone and surround (primer plus an epoxy or CA) results in a mechanical impedance mismatch, causing a reflection of mechanical energy back down the cone. Also, the uniform thickness of the surround edge of a thermoformed sheet of Santoprene rubber is a less than optimal crosssectional profile. Injection-molded surrounds permit design freedom and precise control of the cross-sectional profile. Yen Lung researched IMSS and devised an optimum crosssection surround profile. To everyone’s surprise the injection molded Santoprene rubber edge significantly outperformed the response of modified butyl rubber and foam surrounds. Not only was the edge notch gone, but also the general response shape was smoother. The IMSS displayed a slightly better frequency response than rubber or foam, and a weight far less than rubber and only slightly greater than foam. The cost increase for this overmolded/shuttle molded surround feature is less than ten cents per cone. At the beginning of 2003, Yen Lung joined the Engineered Fibers Technology (EFT) program. EFT is a US26 VOICE COIL vc304.qxd 2/9/2004 8:15 AM Page 27 based paper science consulting firm based in Connecticut. They analyze pulp and paper processes, instruct regarding additives, and provide paper characteristic testing services. See www.eftfibers.com/ for details. New HorizonsThe Shanghai Factory Just as US cone companies watch with dismay as their business drains to the East, Yen Lung has seen its business shift first to the south China coast, and now to the midnorthern coast, to the region just west of Shanghai. Demand has surged from Japanese, local customers, and all the Taiwan transplants from Dongguan moving into the Shanghai area. So, to supply them all, in November of 2002 Yen Lung built a new factory in eastern China, in Suzhou, 80km northwest of Shanghai. The “5S” Approach to Manufacturing Yen Lung is also gradually promoting the “5S” approach, which is arguably more important than their recent ISO 9002 certificationnice as that is. The term “5S” came about because the original Japanese names of each of the five principles began with the letter S. Lest we forgetin our mad rush to send all our business to China in search of a better priceit is the Japanese who are truly the masters of heavy industrial manufacturing, Toyota Motor Corp being the gold standard. Rob Baum visited Toyota factories in the Nagoya/Toyota City area of Japan (while obtaining his MBA), as the guest of a Japanese industrial firm. He was truly impressed, not just with what he saw, but what he didn’t see: waste. “5S” is essentially a highly organized, common sense approach to manufacturing; an area-based system of control and improvement, as opposed to a project or product based system. The concept of “5S” refers to the five basic elements of organizational effectiveness. They are simple principles designed to ensure that processes and equipment perform predictably, minimizing waste. The ideas behind the “5S” principles are generally lost in translation, but here they are anyway: • • • • Seiri = tidiness (clearing up/separating/sorting), Seiton = orderliness (organizing/simplifying/coordinating), Seiso = cleanliness (cleaning/sanitizing/sweeping), Seiketsu = neatness (standardizing/systems/standards/ continuing), • Shitsuke = discipline (training and discipline/standardizing/self monitoring/cooperating). This is important for Yen Lung and all manufacturing companies that wish to improve themselves, since waste has many formsand most waste is invisible. Material, time spent not adding value, idle equipment, and excess inventory are examples. Most companies waste substantial amounts of their available resources. Attention to “5S” also goes along with a key tenet of the legendary Toyota Production System: all work processes must be controlled and scientific experiments constantly modified and improved by the people who actually do the work. That Yen Lung is paying attention to such ideas is indeed a good sign for their future as a quality cone supplier. Production Facility Paper making machine: 34 sets Forming machine: 22 sets Cutting machine: 30 sets Attachment machine: 15 sets Coating machine: 6 sets Neck enforcement machine: 26 sets Pad printing machine: 1 set Power generator 330kva: 2 sets Air-compressor: 4 sets Lathe: 5 sets CNC: 1 set Milling machine: 1 set Drilling machine: 4 sets Testing Equipment Temp and humidity chamber: 2 sets Heater: 2 sets F0 testing machine: 2 sets Height gauge: 5 sets Vernier caliper: 55 pcs Thickness gauge: 16 pcs Electronic scale: 17 sets Tensile strength test gauge: 7 sets pH value tester: 3 pcs Dissolve tester: 1 set Foam hardness tester: 2 pcs Rubber hardness tester: 2 pcs Density gauge: 10 pcs Test of glue consistency gauge: 1 set Reposition gauge: 2 sets Administration Director: Mr. Michael Lin (Contact for US and European customers) General Manager of Suzhou Yenlung: Mr. Yu Tian Lin General Manager of Dongguan Yenlung: Mr. Edward Lin Contact Information Songmushan Area, Dalong Town, Dongguan City, Guangdong Province, China e-mail: [email protected] (Attention: Michael Lin) +86 769 3101715 FAX +86 769 3319303 e-mail: [email protected] website: http://www.yenlung.com 7, Alley 68, Lane 206, Nan Feng ST. Taoyuan, Taiwan, R.O.C Santoprene rubber is a trademark of Advanced Elastomer Systems. See www.santoprene.com for details. Michael Klasco is the President of Menlo Scientific, Ltd. in Richmond, Calif., a consulting firm . to the loudspeaker industry. Jimmy Ying is an associate of Menlo Scientific. All rights reserved. This article cannot be reprinted or translated in whole or in part without permission of the publisher. MARCH 2004 27