Heil 'Automated Job Shop' Produces Custom Trailers on Assembly Lines

IT'S UNUSUAL for a manufacturing facility the size of the 200,000-sq-ft Heil Trailer International plant in Athens, Tennessee, to be considered a job shop. Yet that is exactly what management has designed-a place where individual trailers are built on an assembly-line basis.

The Athens location produces three different product lines-petroleum tanks, dry bulk trailers, and intermodal containers. The products are specialized and so is the market. The average order that goes through the plant is for 1.3 trailers.

"Even when we get orders for multiple trailers, the trailers normally aren't the same," says Steve Slaughter, general manager. "We have had to develop a plant that lets us give the customer exactly what he wants but one that improves our efficiency."

To address these issues, Heil has expanded its engineering operation and its production.

"We have cut the cycle time in half," says Bob Foster, president. "We can build an entire trailer in less than a week."

Advanced Engineering An advanced engineering department, established in 1995, now handles special projects for production in one of the seven plants Heil operates worldwide.

"In the last two years, this group has built 20 new products electronically-products that we have never offered before," Slaughter says. "With the engineering completed and tested, these designs become something that we can manufacture at our plants in Argentina, the United Kingdom, Thailand, or here in the United States-whichever plant is closest to the customer."

A staff of four handles the work of the advanced engineering department, including trailer design and testing. All design work is done using Pro Engineer, software that offers three-dimensional modeling that can generate a realistic rendition of how the trailer or container will appear.

Once the concept is approved for manufacturing, production drawings are generated using AutoCAD Version 14. To reduce machine tool setup time, Heil uses AutoCAM software to program its CNC equipment based on the existing AutoCAD drawings.

Getting It Built The Athens plant has a variety of CNC equipment, including two plasma-cutting tables and Whitney 647 punch plasma machines that the AutoCAM software can program.

Heil acquired one of the plasma-cutting tables and one of the punch plasmas when the company added 100,000 square feet to the Athens plant in 1995.

"We doubled the size of the plant, but we more than doubled its capacity," Slaughter says. "That's because of a lot of small changes we made to the plant layout, along with the efficiency of the plant equipment we bought. As a result, we have increased capacity from 90 trailers per month to 200."

The plasma tables get extensive use. "Approximately 85% of the metal that comes into this plant as raw material goes across one of these two cutting tables," Slaughter says.

The 20 feet by 42 feet tables are produced by MG Systems and are equipped with Allen-Bradley controllers. As the plasma cutters produce the parts, smoke from the operation is pulled beneath the cutting table and is piped to a filter immediately outside the building. Filtered air is returned to plant-along with the warm air generated by the plant heaters in the winter time.

In addition to the second punch-plasma and cutting table, Heil equipped its expanded plant with another plate roll, automated seam welder, and a 12-ft shear.

"The new equipment is a duplication of machines we already had," Slaughter says.

Material Flow The basic layout of the Athens plant is a "U" shape. Raw material enters through one end of the plant and immediately is fed through the fabrication department.

Components flow to one of three parallel assembly lines for tanks, dry bulk trailers, and bulk containers.

"Our tanks have the same basic elliptical design," Slaughter says. "The shape of the tank itself doesn't really change that much. But with all the different weight laws and customer preferences, it's unusual to see two identical trailers going down the same assembly line."

The base capacity for a Heil tank trailer is 9,200 gallons, but the company offers capacities up to 13,000 gallons. Lengths vary, as do the number of axles, the type of operating equipment installed on the tank, the number of compartments, and general specifications that typically vary geographically.

The plant fabricates its own heads. A full complement of dies enables the head press to produce the six standard-size heads the company offers.

"Being able to produce our own heads is a real advantage for us," Slaughter says. "We are not subject to the deliveries of an outside supplier. When we need a head, our press can fabricate one in two minutes or less."

Each of the assembly lines is fully fixtured. The fixtures are sufficiently flexible to accommodate the variety of configurations each line produces while at the same time ensuring tight fit-up. The fixtures allow the weldments to rotate to maximize the amount of welding in the flat position.

ISO Certified Heil's plant in Athens earned ISO 9001 certification in April 1996.

"Because we changed agencies, we went through the qualification process twice," Slaughter says. "We went through it once and then changed to Bureau Veritas and were certified again. We went with Bureau Veritas because of our international operations."

Heil has branched out internationally in recent years. Most recently the company opened a tank plant in Canuelas, Argentina. The plant began production in November. Full production is expected in the first quarter of 1999. The company also acquired Thompson Carmichael Ltd, a British tank manufacturer located near Birmingham, England. A tank plant in Thailand has been in operation since February 1996.

Industry Challenges In addition to his position as president of Heil Trailer International, Bob Foster is serving this year as chairman of the Truck Trailer Manufacturers Association.

"Our industry faces a wide range of concerns," he says. "As always, we face regulatory challenges. Underride continues to be a concern, along with size and weight regulations. Other nations are going to longer and wider equipment, and the U S needs more productive equipment.

"We also are concerned about what is happening with the trucking industry. Having a sufficient number of qualified drivers is a huge concern for this industry."

The Y2K computer bug is another challenge. "We are testing our systems now to make sure that we have no business or employment interruptions," Foster says.

Despite his role as TTMA chairman, however, Foster continues to devote plenty of time and attention to the expanded plant in Athens.

"It really is a tremendous plant," he says. "We have used the kaizen concept to rethink the way we produce tank trailers. We do a lot of brainstorming along with common sense analysis of what we do and why we do it. We constantly are evaluating our quality, ergonomics, and plant safety. The people who work there have uncovered gold mines of ways to do things better. They make this operation the largest and most modern tank trailer facility in the world."

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