Scattered throughout the production floor are flat screen monitors that provide real-time reporting on manufacturing performance and shift-by-shift comparisons of run and reject rates. Some shifts occasionally beat the target of 96 percent throughput and a 1 percent reject rate. The monitors were put in place a few months ago, and Plant Manager Richard Tommy says they already have provoked friendly competition between the shifts.

As many as 30 programmers were onsite during the equipment installation phase, though Black and one other electrical engineer integrated the multiple automation systems themselves. Almost 600 IP addresses are on the network, including 60 Allen-Bradley PLCs. NEMA 4 enclosures protect both the electronics and the workers. If any flour dust were to get into the enclosures, the potential for explosion would exist, so keeping the dust out is just as important from a safety standpoint as it is from an electronics standpoint. Discreet air conditioning units serve the panels.

For security purposes, no VPN keys are provided to non-Northeast personnel; isolation of the plant network from the corporate information system provides a physical firewall. A separate network ties together the plant’s 50 cameras. Hacking into the Ethernet network would not provide access to the video network.

Activities on the floor trigger recording by a DVR, allowing managers to review what transpired prior to an event. The system is a valuable tool for correcting improper procedures, notes Tommy. By reviewing the tape, “I learn, I teach, I move on,” he says.

A library of almost 100 verbal alarms was built to direct mechanics and other personnel to areas requiring attention. “You can get too granular with voice alarms,” allows Black, and the objective is to get the right personnel to an area requiring attention, then “let them figure out the problem and the solution.” The system also helps identify problems that are chronic or repetitive, triggering corrective action.

Flour dust is an unavoidable byproduct of volume baking, and multiple strategies are used to control it. One of the most striking is the extensive use of suspension rods to lift conveyors and other equipment off the floor. A collateral dead load capacity of 15 lbs. per square foot (psf) is typical for warehouse buildings. Clayton’s roof trusses were designed to support a 25 psf load, with additional capacity in some areas to support hanging conveyors.

At A M King’s recommendation, high-density cement was poured in all dry areas of the production floor. The composite added about $1 per square foot but eliminated the need for a urethane or epoxy topcoat. Colliton wanted to avoid the delamination and spider-webbing problems that plague resin flooring over time. The high-density cement is backed by a five-year warranty that guarantees it will accomplish that. The floor also has a polished veneer that makes it difficult for flour dust to cling to the surface. The cement mix only requires one expansion joint per 15,000 sq. ft. of poured surface, compared to one joint per 1,000 sq. ft. in a typical installation.

The cement would not be appropriate in a washdown environment, but management’s aversion to wet cleaning ensures floors will be kept dry. “If Dennis had his way, there wouldn’t be any drains,” one engineer laughs, but limiting floor drains to the proofer and the mixing area isn’t just about protecting the concrete. Managers also want to protect the machinery and electronics, and a drain is an open invitation to water use. Once a drain is installed, the thinking goes, a hose caddie soon will follow. Mixing water and flour in sanitary lines results in high BOD loads, another incentive to minimize water consumption.

Half the municipal water coming into the plant ends up in the product, and the rooftop cooling towers consume a big chunk of the balance. Northeast invested in meters that quantify the gallons of water that actually go down the drain. After validating metering accuracy, municipal authorities agreed to base sewer surcharges on the actual amount of water sent to the treatment plant, not the amount of incoming water.

“We wanted to go farther in water management,” adds Colliton, and two water systems were installed, one for process water, the other for housekeeping purposes. Both systems rely on rooftop solar panels to preheat hot water to 120°F. Process water is heated another 20° by an on-demand water heater, while a 115-gal. conventional tank stores and distributes housekeeping’s hot water. “It’s a pure solar preheat system,” says Colliton. “There’s no auxiliary heating until needed.” Compared to other Northeast Foods facilities, the solar system is expected to save more than 53 million Btus a year, or the equivalent of about 15,500 kWh.

Fifteen rooftop air handling units deliver 400,000 cubic feet a minute of filtered air to the production area, enough to provide eight air exchanges every hour. A beefy HVAC system was essential to removing heat from cooling buns and airborne flour dust.

Good housekeeping is essential for dust mitigation. Sanitation crews wage a continuous mitigation effort. “You’re fighting a dusty environment, and that can be difficult,” says Tommy. When production is down, the 10-person sanitation crew wipes down every horizontal surface on the floor, he adds. Portable vacuums are replacing other methods of dust removal, and managers are working with vendors to develop equipment refinements to reduce flour dust.

In addition, extensive use is made of natural lighting, with skylights outfitted with refraction lenses bathing the production area with sunlight. Light harvesting, coupled with induction lighting that consumes half as much energy as metal halide, helped lower electrical consumption to about a third of what would be needed for a comparably sized facility. Induction lamps also use a high-frequency generator to excite the bulb’s gas, doing away with fluorescent lamps’ electrodes, which are wear parts. Consequently, the fixtures deliver up to 100,000 hours of service life.

Total team approach

At a time when almost every greenfield project is labeled “fast track,” the Clayton facility distinguished itself by wedging design, permitting and construction into an exceptionally tight framework. Some of the credit goes to local authorities, who committed staff to the interim permitting process to keep construction on track.

A bigger factor was the collaborative approach between engineers at Northeast and A M King. Colliton took a small leap of faith by scrapping the company’s usual construction methodology. Instead of retaining an architect and then bidding the job to a general contractor, he opted for a design-build approach after meeting with professionals from A M King, which had not previously worked with Northeast. The A/E firm’s fee was established upfront, resulting in greater flexibility to specify upgrades and improvements as the project progressed.

“There were no egos in the room, no preconceptions about how the project should proceed,” says King. “Northeast’s engineers made us feel we were a valued part of the team.”

Specifications are often omitted when a manufacturer works with an architect, resulting in change orders and project costs that spiral “out of control,” adds Colliton. “This was a complete collaboration with both King and the equipment vendors. Now I’m convinced design-build is the way to go.” From groundbreaking to production startup, less than 10 months elapsed.

Despite the plant’s high level of automation, the team was careful to build in flexibility to accommodate the art as well as the science of baking. “I’m a big fan of letting the baker make fractional adjustments,” says Black. Some elements of production simply are not conducive to a lights-out approach. “There are still things where you must have people involved, and that’s coming from an automation guy,” he says.

A side benefit of automation is relieving plant personnel from mundane tasks, allowing them to add more value in terms of product quality and production flexibility. All operators are cross-trained in four different positions, and they have an enhanced understanding of the plant’s objectives and improved-performance efforts. Tommy instituted a well-received open-door policy for all manufacturing meetings. “There are no secrets,” he emphasizes. “We’re all working on one team.”

“Skilled operators become a valuable asset to the organization and are part of the success of the company,” adds Colliton. Reduced labor is always the cost justification for automation investments, but the soft return of increased staff member effectiveness is expected to pay big dividends in the years to come.

The lights may remain on in this plant, but automation is shining a brighter light on the science of baking. 
 

For more information:

Brian King, A M King Construction Co., 704-365-3160, bking@amkingconstruction.com

Ken Mentch, Workhorse Automation Inc., 717-581-6636, kmentch@workhorseautomation.com

SIDEBAR