Orchestrating assembly for the perfect timer

Not every plastics processor can count eating a chicken dinner among its regular QC procedures. But because food safety is the most important facet of the business, no turkey that enters the plant is left untasted at Volk Enterprises Inc. (Turlock, CA). The molder takes food safety very seriously and has built a niche that the company believes it has mastered.

     Founded in 1960 by Tony Volk Sr., Volk Enterprises is now owned by his four sons: Steve, Don, Dan, and Tony Jr. After opening a poultry plant in Turlock for a company in the Midwest, Volk Sr. noticed problems containing the turkeys'legs within their bags prior to vacuum forming. His invention, the first wireformed trussing device, became the basis for starting the company.

     Today, all but one of the molder's customers use Volk's plastic trussing devices, but this original wire product spawned a slew of other poultry-related molded items that the company produces captively. Volk holds the exclusive rights to manufacture one in particular, the patented Pop-Up Timer (see Figure 1). The timer is typically shipped inserted into the turkey or chicken meat. When the meat reaches the proper temperature, the inner pin rises out of the timer base, signaling that the food is fully cooked.

Cooking Requirements
It sounds simple, but there is a critical combination of factors that must be carefully measured and tested to ensure proper timing. First, Volk manufactures 12 different versions of the Pop-Up Timer, each corresponding to a type of meat, including duck, lamb, beef, and pork. Activation temperature for each varies slightly, and the pin is molded in six different colors: white, orange, green, blue, yellow, and red. Second, the timer must be placed in the proper location, for example, not near the bone or in a thin part of the bird. Finally, the alloy in the timer must release at just the right temperature.

     This last element is the key to the product, and Rick Gregg, molding operations manager, says the R&D invested in the timer has been significant. "It's taken 25 years of research to get the perfect timer," he says. "Our timers pop with ±1 deg F accuracy. That's taken us a long time to perfect."

     Like most of Volk's products, the Pop-Up Timer is molded from virgin nylon 6/6 in a hot runner tool. Volk standardized its hot runner systems and new press purchases by using Husky as its sole supplier for both. The company added the first of its five Husky machines to the six existing Van Dorn Demags when it expanded into stack machines. "We wanted to keep everything in one package, and deal with one company for everything," explains Gregg. "At the time Van Dorn wasn't offering a stack machine."

     The mold, a 96-cavity hot runner tool, spits out the barrel of the timer in a 9-second cycle. The stem, which is inserted into the barrel, is colored at the press and runs on a 96-cavity mold in an 8-second cycle. (Volk uses Fairway Molds in Walnut, CA for most of its toolmaking.) The nylon 6/6 is conditioned in Mastui dryers and fed from above.

Timer Assembly
Once the two components are molded, automation takes over in the assembly room next door. Twelve custom-made assembly machines designed by Volk drop the barrel on a turntable, where the firing agent, a metal alloy that looks like a short piece of pencil lead, is inserted. Next, a spring is dropped into the barrel, and finally the stem, which must click past a locking device inside the barrel to hold it in place. At this point the stem is not fully inserted.

     The partially assembled parts travel about 15 ft along a hot conveyor, called a cooker, which melts the alloy. Mirrors at the base of the cookers allow for visual inspection. At the end of the conveyor, a machine with vertically moving rods pushes the stems into the now-soft alloy, and a cooling trough then hardens the alloy (see Figure 2). The next time the stem releases is when dinner's ready.

What Makes It Pop
Although the secret ingredient, the firing agent, is an FDA-approved substance, Volk has begun to use other organic replacement materials. Gregg hints that the complete elimination of metal alloys in its product is not far off. "We've had to add another step in our process," he concedes, "but it's OK because the assembly machine will put out more than we can assemble at one time."

     A number of forces have prompted the switch. First is the variation in pricing in a component of the alloy. "Very rarely do we raise our price on our timers," says Gregg. In addition, the organic ingredient would expand the available temperature range and provide further patent protection on the timer.

Testing
Timers are tested both in water baths and in meat samples. A gas oven and an electric convection oven ensure that both cooking methods are taken into account. Customers such as Perdue Farms (Salisbury, MD), Wampler Foods (Broadway, VA), and Foster Farms (Turlock) send Volk a number of birds for cooking tests, and in return Volk experts help them write cooking instructions that coincide with each timer.

     With an arsenal of patented products under its belt, Volk is ready to take on custom molding, says Gregg. Extra space in the wireforming area and three acres behind the plant give the company plenty of room to grow. When asked about some unfinished office space in the front of the three-year-old, award-winning facility, Gregg just smiles. "We're in the process of looking at other things, so you never know."