May 15, 2001, about 9:30 a.m.: A small fire breaks out in a dryer at the Ansonia, Conn., plant of Latex Foam International (LFI), a maker of premium latex mattress and pillow components. LFI management calls the local fire department.
About 10:30 a.m.: The flames in the dryer are extinguished. LFI executives order pizzas for employees and the fire crew, and head for the back side of the building to thank the fire chief. They swing open the plant’s multiple, large bay doors to let the smoke clear from the facility. It is a windy day.
The wind swirls through the plant, quickly clearing the smoke. But it also apparently contributes to reigniting the flames in the dryer, which then spread rapidly to some nearby mattress cores and beyond. The fire crew, who have already rolled up their hoses, are unable to reengage in time to stop the now escalating blaze. Thankfully, none of the company’s 240 employees are harmed in the ensuing inferno. But the 258,000 square foot facility—LFI’s only plant—is totally destroyed by the fire. With it go all of the company’s inventory, records and equipment.
That’s the way that John Coffey, LFI executive vice president and chief information officer, remembers that devastating day in May for the privately held firm, founded in 1975. But what happened next provides an example of how Yankee perseverance, combined with the latest in factory automation, was able to turn adversity into advantage.
LFI is the only North American manufacturer of latex foam using what is called the Talalay process—a method that produces a high quality, highly resilient and breathable material used in premium latex mattresses and pillows. At the time of the fire, the company held the dominant U.S. market share for this material, against European and Asian imports. And despite the shock of losing the plant, LFI wasted no time in taking steps to protect that position.
“There was a big show going on in Germany, where all the latex manufacturers were,” Coffey recalls. “In fact, we had a booth over there, and in less than 48 hours after the fire, we were on the ground in Germany buying up all of the excess capacity we could get our hands on to keep our customers going.”
That bought time for LFI executives to consider their options. One was to shut down operations and liquidate the company. “But we basically kept going forward with the intention of rebuilding,” Coffey relates. “We were insured, and we knew we had a great product and terrific employees.”
Among other things, LFI seriously considered relocating to Chattanooga, Tenn., where labor costs would be lower, and where city fathers offered some enticing financial incentives. In the end though, the people factor swung the decision to stay in Connecticut, Coffey says. “Technical expertise is a key part of our process, and our trained staff was here,” he notes.
LFI acquired a building in nearby Shelton, Conn., that previously housed a rivet manufacturer, and set about planning to rebuild its process. Given relatively high Northeastern U.S. labor rates, one thing was clear. “We knew that we’d have to automate significantly to be able to survive and stay competitive in a worldwide market using Connecticut labor,” Coffey says.
For help with the automation design, LFI worked with NIC Systems Corp., a Plantsville, Conn., systems integrator that had done automation work for LFI at the previous plant. “We had been working with them since about 1995, so we knew their process pretty well,” says Bob Godard, NIC Systems president.
With NIC’s help, LFI had been automating the old plant prior to the fire on a step-by-step basis as funds became available. That approach had produced improvements, but resulted in what Coffey and Godard alike refer to as “islands of automation.” Individual programmable logic controllers (PLCs) controlled various operations, such as the presses where the latex mattress cores are formed. Each PLC had to be programmed separately. Many operations were manual, and systems were not networked together. So at the Shelton plant, with the opportunity to install a new automation system from scratch, LFI wanted a highly integrated solution that would enable optimum plant-wide process control and efficiency, says Coffey.
LFI considered proposals from various automation suppliers. But LFI executives eventually selected a system to be supplied by Siemens Energy & Automation Inc., based in Alpharetta, Ga., with NIC Systems to be the integrator. “Everything was pretty well fast-tracked. One of their main goals was to make sure that they could get their production running quickly and reliably, to gain back any lost market share,” says John Lanzoni, account manager in Siemens’ Wilbraham, Mass., office. “So I think it was critical that our solution was not only totally integrated, but also completely redundant. We were able to demonstrate that with our solution, they would virtually never have downtime because of a PLC problem.”
The decision to go with the Siemens solution was made in mid-January 2002, says Lanzoni. And by May 15, 2002, exactly one year after the fire, LFI was able to hold an open house at the new Shelton plant, which by then, was partially operational. The plant hit full production in September that year. Coffey credits NIC Systems’ experience among the reasons for the relatively quick start-up. “NIC had done a fair amount of integration with us before, so they knew our process, and they were way along on the learning curve.”
In LFI’s Talalay manufacturing process, liquid latex foam material is compounded in stainless steel tanks and poured into the base of aluminum, clam-shell-style molds, or presses, containing thousands of pins that create aeration in the finished mattress cores. Once the material is evenly distributed, the press closes, a vacuum is pulled to completely fill the mold cavity with the foam, and the material is put through steps including freezing, carbon dioxide injection and heating to solidify and cure the latex foam. When the press opens, the mattress core is removed and conveyed through washing, drying and quality testing steps prior to fabrication, where the core is cut and constructed to appropriate sizes.
Unlike the old plant, in which separate PLCs controlled individual presses and different process steps, all of processes in the new plant are controlled centrally by two redundant Simatic S7-400H PLCs from Siemens. They are linked by a redundant Profibus network to redundant WinCC supervisory control and data acquisition (SCADA) servers. The S7-400Hs control the compounding and press room portions of the plant directly, says Coffey. An additional half dozen Simatic S7-300 PLCs control washers, dryers and material handling systems, and are linked to the S7-400Hs via Profibus or Ethernet, as appropriate, he adds.
One cost-saving feature of the system, according to Siemens’ Lanzoni, is the use of an option called Web Navigator, by which the WinCC systems are connected via thin-client technology to 56 Siemens MP370 human-machine interface (HMI) panels used by operators throughout the plant. “With the thin-client technology, we eliminated the need for a PC (personal computer) at every machine and the software license to run each PC client, which is typical with most other SCADA/HMI packages,” Lanzoni contends. The savings is about $3,000 per station, he estimates, or a total of $168,000.
Of the 56 operator stations, 48 are located at each of the Shelton plant’s 48 molds, or presses, which are organized as four cells of 12 presses each. Unlike the old plant, where operators manually controlled the pouring of the liquid latex into the presses, the new plant relies on four ABB IRB 2400 robots—one per cell—to uniformly inject the latex into the presses. The result, according to Coffey, is both labor savings and improved quality, due to the consistency and repeatability with which the robots pour the latex compound. “The quality control is really a factor of the ability to evenly spread the latex in the mold,” he says. Compared to the previous manual method, he says, “our uniformity is better now than it was before the fire.”
Coffey says a major benefit of the plant-wide automation system is the ability to gather data both for real-time decision-making and corporate level reporting. “We monitor the process with the WinCC and we dump a tremendous amount of data to a SQL database,” he notes, “and from there, all that data is available on the intranet for analysis and reporting.”
The system pays plant floor-level dividends as well. “The tag logging operation within the Siemens system is one of the best features for us,” Coffey says. “It monitors every press and every cycle, and should something go wrong, a supervisor can walk right up to that press and see the entire fingerprint of the process, with all the variables, and he can very rapidly diagnose and repair the problem.”
LFI also makes good use of the system’s alarm system to head off press room snafus, Coffey observes. If alarms indicate a problem with temperature control, for example, or with the carbon dioxide coming to the press room, operators can hold up the presses until the problem is fixed, he explains. “If you don’t do that, you get a gooey mess that’s very difficult to clean up, and it causes significant down time.” If the mold curing process is performed incorrectly, each press can require up to one hour to clean, Coffey relates.
One of the most valuable uses of the system came shortly after the Shelton plant start up, says Coffey, when LFI discovered that it had undersized the refrigeration system for the new plant. The Siemens system allowed the company to do two things, he notes. “First, it allowed us to come up with a load balancing algorithm that would maximize our production, given the amount of refrigeration resources that we had,” says Coffey. “And it also helped us quantify exactly how much more refrigeration we needed, so that when we did design the new system, we were able to design it to the right size.”
In the end, says Coffey, the automation system has enabled LFI to not only boost its quality, but also its output, which is 20 percent higher today than it was at the old plant prior to the fire. And the company has done that with fewer employees—currently about 165, compared to 240 before—and with a smaller plant size. LFI’s 208,000 square foot facility in Shelton is almost 20 percent smaller than the former Ansonia plant.
Since the Shelton plant came on line, LFI has been able to regain most of the market share lost during the time that it was meeting customer requirements through outsourced import production, Coffey says. And demand for the company’s product lately has been so strong that LFI is planning to add more production capacity, with four more presses this year and an additional four presses in 2005, he adds.
Having the automation system in place will simplify the expansion, Coffey says. “Since the code in each one of our individual manufacturing cells is the same, we’ll be able to take a lot of that same functionality and design, and port it right over to the new cell.”
LFI’s current use of the automation system is still focused on keeping up with expanding production demands, Coffey says. But he foresees additional benefits down the road. “We’re really just beginning to scratch the surface of what we think this system can do for us,” he points out, “in terms of potential for cycle time reduction, cost reduction, and of course, quality improvement.”