In today’s market, changeover plays an increasingly important role for food processors, partly because of pressure from mass-market retailers to reduce the size and increase the frequency of shipments.
Retailers are lowering costs by reducing their inventory levels, with a just-in-time approach to consumer demand. Therefore, “All their vendors need to have a better reaction time to their needs. It means shorter leads on orders, and it means more frequent, smaller orders,” says Nils Gustafson, vice president of operations with Ubiquity Brands at the company’s Lincoln Snacks (www.lincolnsnacks.com
) operation in Lincoln, Neb.
Retailers “don’t want to carry 10 days of inventory at their distribution center — they want to carry less than two days. So either I carry that inventory, which I don’t want to do, or I get more efficient at changing over,” says Gustafson. “The best way I can keep my carrying costs down is to have more changeovers and get much, much better at them.” Lincoln Snacks processes and packages the snacks Screaming Yellow Zonkers, Poppycock and Fiddle Faddle.The three ‘ups’
Improving changeover efficiency starts with defining when changeover starts and when it concludes. “I break changeover into the three ‘ups’: clean-up, set-up and start-up,” says John Henry, CPP, president of Changeover.com (www.changeover.com
), a changeover consulting firm in Fajardo, Puerto Rico.
Clean-up includes removing residual product, left over from the previous production run, from the equipment. It may require disassembling, washing and/or sterilizing the machinery. Set-up, which is more synonymous with changeover, refers to the physical adjustment or changing of parts on a machine to run the next product or package. Start-up is the time it takes to restart the equipment and get it back to full production speed.
|KHS's Innoket roll-fed labeler uses a linear design for simple handling and quick changeover.
If equipment adjustments are not performed to meet the specific demands of the new production run, addressing variables such as package size, container, label and/or closure, the start-up phase can extend to hours. In the worst-case scenario, the line does not achieve full production speed before it’s time to change the line over again.
Equipment modifications can make a big difference in reducing the start-up period. Lincoln Snacks recently modified the horizontal form/fill/seal machine it uses to fill stand-up pouches, gaining a very satisfying reduction in start-up time. The modifications focused on improving control over pouch forming and filling.
“We used to fight the changeover on that line” because it was difficult to control the film as it fed through the machine, Gustafson recalls. “The mechanic would spend a significant number of hours lining out that machine just right. But with the forming and bag-control improvements, our ramp-up time was reduced more than 40 percent. It’s a night-and-day difference. Now the operators basically load in the film and push a button.”Cutting changeover time
Typically, plant mangers have an idea of where changeover times could be improved. But putting an improvement plan into action can be daunting. Henry suggests a three-step approach: eliminate, externalize and simplify.
He explains that the first step is to eliminate any processes that are unnecessary or that produce a layer of complexity without adding value. A processor could eliminate a labeler changeover when switching case sizes by changing from “relative” positioning of the label — in the center of the case, for example — to “absolute” positioning, in which the label is applied to the same corner of every case.
The second step, externalization, refers to taking as many changeover tasks as possible off-line. For example, rather than powering down the line, then taking 10 minutes to round up the appropriate change parts, tools, supplies and packaging materials, the operator or mechanic should gather and stage all items needed for changeover while the line is finishing up the previous production run.
The third step, simplification, focuses on making changeover adjustments as quick and easy as possible. In this step, the food processor reduces reliance on tools to make adjustments. Another way to simplify is take some of the thinking out of changeover tasks.
With this in mind, some processors use color-coded change parts and attachments. “With color coding, it’s easier to put the right part in the right place,” says Alok Tiku, a research analyst with Frost & Sullivan (www.frost.com
) in San Antonio, Texas, who specializes in food processing equipment.
In addition, equipment can be purchased with or modified to include quick-change components such as hand knobs and clamps, or with electronic aids such as digital indicators and programmable controllers. Turning a knob or entering a keystroke combination is much simpler and faster than replacing a nut and bolt.
Although every food processing plant is unique, they all share a common challenge: How to make packaging line changeover as efficient as possible. Every minute the line is down because of a change in packaging size or materials, or just a label change, represents lost profitability.