“We had been putting the sausage links into bags that were then vacuum-packed and shrunk on a rotary chamber machine,” says president Michael Kiolbassa. “This worked well, but placing that many links in a bag could be difficult, and as we increased production, the labor requirements became prohibitive. We had been using a chamber machine, and Multivac approached us about installing one of their FormShrink machines.”
The proprietary Multivac FormShrink packaging process uses special high-shrink thermoforming films that shrink tightly when passed through a heating tunnel. This results in an attractive package with a second-skin appearance around the contours of the product. The process minimizes excess packaging and the “dog ears” often associated with shrink-bag packaging.
“We didn’t want to sacrifice the look we achieved with the bags, but the FormShrink uses printed film that is synchronized top and bottom, and the finished packages look just like the bags,” says Kiolbassa. “We ran the numbers, and it looked like the rollstock machine would save us a lot of money, so we decided to go ahead with it.” Kiolbassa installed the Multivac Model R-250 FormShrink machine in April of this year.
The R-250 uses two rolls of Form-Tite film to form the package. Both rolls have similar nylon and EVOH construction, but the bottom roll, which forms the cavity for the product, is 100-microns thick, while the top roll, which is sealed across the tops of the packages, is 50-microns thick. The two rolls of film, both of which are flexo printed in eight colors, are registered during the operation to produce the final package.
To produce the finished package, the intermittent-motion FormShrink machine incorporates a series of steps that start with a bottom-forming station and finish with the package discharge. To start with, a chain with grippers pulls film from the bottom roll mounted on the front of the machine. This chain maintains control of the film through the length of machine.
The film enters the forming section where a combination of air blowing down from above and vacuum from below pulls it into cavities to form the packages. This is a two lane machine that runs three rows of 20-oz packages or two rows of 40-oz packages on each cycle, so each cycle produces six 20-oz packages or four 40-oz packages. The machine runs about 10 cycles/min.
Top and bottom film registration
Each roll of film is printed with each image slightly shorter than required and the film is stretched for each package to achieve exact registration of the webs. The amount of stretch required, which is determined by the result of the stretching on the previous package, is regulated by the controls on the machine.
The packages, which are still connected together by the top film, next enter the form cutter, where knives cut the packages apart. Because the packages are rectangular, there is no extra film between them, but the excess edge trim is cut off and wound onto an overhead roll. The packages then travel through a hot-water bath (which is not part of the FormShrink machine), where the film is shrunk tightly around them.
Machine has been phenomenal
“The FormShrink machine has been phenomenal,” says Kiolbassa. “Our output has doubled, and we’ve cut our labor costs by 35 percent. It wasn’t easy at first. We had a steep learning curve for the first 90 days. The bag machine runs the same for everything; you just change the bags for different products.
“With the FormShrink machine, you have to change the film for each product and change the cavities for each package size, so we had to revise our production schedules to have longer runs of each product and package. Bu Multivac had people here to help us, and the system is working really well now.”
Plant manger Ismail Jaber concurs. “We’re thrilled with the FormShrink machine,” he says. “It has surpassed our expectations. Both Multivac and Curwood had a crew here for several weeks, and they gave our people really intensive training. This is our busy season, so we’re running the machine 12 hr/day, six days/week, and we’ve had no problems.”