EHV-Weidmann fills niche for transformer board: specialty paperboard manufacturer focuses on quality improvement.

As New England paper mills go, the BHV-Weidmann Industries mill in St. Johnsbury, Vermont, USA, has barely passed Adolescence. It was incorporated in 1969 as EHV Industries Inc., and shipped its first order for electrical insulating board, or transformer board, in 1970. Before then, the domestic suppliers of insulating board included mainly the Rogers Corp. in Rogers, Connecticut, and the Spaulding Fibre Co. in North Rochester; New Hampshire.

In the 1960s and 1970s, the United States saw significant increases in electrical power distribution facilities. To meet this demand, transformer manufacturers such as Westinghouse and Allis-Chalmers were asking suppliers of electrical insulating board to produce much larger shoots to avoid having to work with spliced sheets, which exhibited lower strength capabilities. Both Spaulding and Rogers declined to develop such a product.

Robert C. Fuehrer and Gordon Mills, two employees of Spaulding, saw an opportunity to form their own company in the mid-1960s to produce transformer board in larger sheets. They eventually selected a site in Vermont because, of its readily accessible water, energy, and transportation, and because of attractive state and local financial backing and tax considerations. In 1969, Fuehrer aim Mills became cofounders of EHV (lot extra high voltage) Industries Inc. Throughout this process, Mills developed a working relationship with Weidmann AG in Switzerland, Weidmann infused capital and manufacturing technology into EHV and became a one third owner in the early 1970s. To reflect this ownership, EHV Industries was renamed EHV Weidmann Industries Inc. Today, the company is wholly owned by Weidmann AG and is part of WICOR Americas Inc., a privately owned organization. It is the sole North American producer of transformer board.

TRANSFORMER BOARD PRODUCTION

EHV's mill has two cylinder board machines, referred to as BM 1 and BM2. BM 1 was part of the initial St. Johnsbury operation, while BM 2 was started up in June 1975. BM 1 produces a slightly larger sheet than BM 2, 150-inch trimmed width by 260-inch length, versus 126-inch by 248-inch on BM 2. The grades on BM 2 however, have a higher density range than those from BM 1, 1.10 to 1.25 g/[c.sup.3] (grams per cubic centimeter) versus 0.85 to 1.10 g/[c.sup.3]. The mill achieves higher densities using a proprietary hot press.

Furnish for each machine consists of purchased unbleached soft-wood kraft and recycled transformer board, or "off-cut." The stock preparation system consists of a kraft and broke line that serves both board machines. Kraft and broke flows are then metered into the appropriate machine chest (each machine has its own). Following the machine chest, each machine has its own pre-headbox system, comprised of refining, cleaning, and screening. Sandy Hill supplied the board machines. However, the headbox on BM 2 (a double-cylinder configuration) now employs a pressurized unit supplied by Voith Sulzer while BM 1, with a single cylinder, has the original dry vat system. The pressurized headbox allows for greater uniformity in cross-directional properties.

Each machine has a "making roll" which, after several revolutions, develops a very thick sheet (0.095 in to 1.250 in). An air operated knife slices the sheet from the making roll and the sheet is transferred to the drying stage. BM 1 has a conventional high velocity dryer while BM 2 has a proprietary hot press. This press will accommodate up to 12 sheets at one time and operates at pressures of tip to 200 bars or 2940 psi (pounds per square inch).

The dried sheets are first trimmed and cut to various widths on a saw table, and then sent either to fabrication or to the laminating area. Laminating uses a resin curtain-type coater followed by another pressing stage. Depending on the desired thickness of the final product, as many as 50 sheets at a 0.118-in thickness are laminated together to a final product thickness of up to 6 in. Board sheet thicknesses are more typically in the range of 0.030 in to 0.315 in.

OVERCOMING PRODUCTION PROBLEMS

Variations in the degree of resin penetration into the sheet, caused by minute quantities of impurities in the white water system, used to be a major concern. The complete separation of process white waters from all other waters has effectively minimized that problem. Chest overflows and all cleanup waters are now entirely handled by the mill's effluent treatment system.

Another major improvement has been the addition of a pulper specifically designed to handle the extremely difficult off-cut or board broke material. The company installed a Beloit Barracuda pulper equipped with a 500-horsepowei motor and deflaking plates in 1999. Before then, off-cut was blended with the purchased kraft in the mill's other pulper. That limited the amount of off-cut that could be recycled. It was also difficult to achieve good uniformity in fiber development with a single pulper operation as often too much energy was being expended on the broke portion of the furnish. Thus, the new pulper gives the mill the ability to effectively use more off-cut material and to produce a more uniform product.

EHV recently equipped both board machines with a DCS system developed by mill personnel. "This has been a useful tool in determining the root cause of operating problems and in maintaining product quality and uniformity," says Brian Trask, board processing manager. Operators, supervisors, and engineers use this system daily to improve the operation. Recent problems with a finished product were directly related to the way the pulp fiber was refined. DCS trending graphs showed that an excessive amount of energy was being imparted to the fiber. Without the DCS trending capability, the cause would have been much more difficult to pinpoint.

QUALITY CONTROL

The mill also recently relocated chemical, mechanical, and electrical labs to a new building. The electrical lab--including low voltage and high voltage testing areas--is unique. In the low voltage lab, technicians test board for dielectric constant, resistivity, and dissipation factor. In the high voltage lab, the company tests board for failure under constant and impulse conditions. Constant voltage conditions can be up to 200,000 volts while impulse conditions of up to 800,000 volts are possible. Product failure occurs when the applied voltage causes penetration.

EHV uses "six-sigma" methodologies to improve processes and product quality. This statistical procedure has improved product uniformity. Using six-sigma analysis, and with today's computer capabilities, operators can vary several parameters at once and optimize the interdependence or relationship between variables.

To meet the quality demands of the international marketplace, EHV is ISO 9001 certified and maintains IEC 641 certification. The company also meets the quality requirements of the Japanese market. As part of their ISO 9001 program, all of the company's procedures for both board manufacturing and product fabrication are now on an internal computer network, reports Rick Daniell, manager of research and development.

EHV-WEIDMANN TODAY

Today, the St. Johnsbury mill has two cylinder machines and a 140,000 [ft.sup.2] fabricating plant that converts transformer board into a wide variety of made-to-order sizes and shapes. The facility uses the latest computer numerically controlled (CNC) machines, which are used for milling, punching, sheet cutting, and cylinder winding.

A product design group works with EHV customers to continually develop new designs and to investigate the use of non-cellulosic materials. One such non-cellulosic fiber is Nomex (a Dupont registered product). EHV, in partnership with Dupont, manufactures an electrical insulating pressboard from this material that exhibits higher temperature capabilities than those made from cellulose.

In addition to the facilities in St. Johnsbury, EHV has fabricating plants in Rockford, Tennessee and Saltillo, Mexico. A separate marketing organization, Weidmann Systems International, has several sales offices in the North America, Mexico, and Brazil.

IN THIS ARTICLE, YOU WILL LEARN:

* EHV Weidmann produces electrical insulating (transformer) board for transformer manufacturers.

* The company operates two cylinder board machines, referred to as BM 1 and BM2, which are able to Impart highly specific properties.

* EHV recently equipped both board machines with an internally developed DCS system that has helped them salve operating problems.

* The company uses "six-sigma" methodologies to improve processes, product quality, and uniformity.

FURTHER RESOURCES;

* EHV Weidmann industries, St Johnsbury, Vermont, USA, Phone [phone], Fax: [phone]

* www.vmec.org/success/ehv.html (Case study an EHV Weidmann Y2K remediation project)

GOOD COMMUNICATIONS PRODUCES PRODUCTIVITY GAINS

Chris Robbins is a true New Englander, having grown up in the fishing town of Stonington, Maine, USA. Upon graduating from the University of Maine with a degree in electrical engineering, he worked for Allis-Chalmers doing development engineering on circuit breakers and transformers. Four years later he joined Permali Inc., a Pennsylvania-based producer of electrical insulation. A desire to return to New England was partially responsible for his considering a position with EHV Weidmann Industries in St. Johnsbury, Vermont. In 1976, he accepted an offer from EHV in technical sales.

Robbins rose through the sales management ranks, serving as president of Weidmann Systems International, a sister company, from 1985 to 1993. He became president of EHV-Weidmann in 1995.

When you meet Robbins, you realize he is a "people person," and an excellent communicator. He believes in involving all employees in the company's success, and was instrumental in refining the employee bonus plan to be totally inclusive. He conducts "town meetings" on a tri-semester basis for all shifts at the St. Johnsbury operations, and at the plants in Rockford, Tennessee, USA, and Saltillo, Mexico.

He feels his greatest accomplishment has been in the area of productivity. At one time, the culture at EHV tended to be "stodgy," Robbins recalled. "Supervisors were very territorial. Communication had to go from the top of one department to the top of another department and then down to the desired person or group, It was a silo-type environment."

To break down those barriers, Robbins brought in a facilitator to conduct on-site and off-site sessions with salaried and hourly staff. Gradually, the company developed a new mission statement and a new sense of collaboration. Today, communications are very open and individuals readily shift from slower areas to those that are short-handed. "You've got to be flexible to be successful in today's highly competitive marketplace," Robbins said. "This flexibility in the use of our people is the main reason we have enjoyed a 40% increase in productivity in recent years." Thus, despite virtually no price increases in several years, EHV Weidmann remains a profitable operation.

Art Boniface is a freelance writer. He can be contacted at 1 Dartmouth Lane, Woodstock, VT 05091 1279, or by e-mail at: [e-mail]