Quick: What’s a quick changeover? The term is relative, according to John Henry of Changeover Inc. “Some lines may take 16 to 20 hours, but if you can get it down to 10 hours, that’s a quick changeover,” he says.
Changeover expert Jerry Claunch takes a different view. “The changeover time must be reduced 75 to 80% in order to qualify as quick change.
“In addition, the start-up after a changeover should be immediate, without tweaking or delays, and the first product is usable without any rework. As far as time is concerned, changeovers under 10 minutes should be the goal.”
Claunch’s methodology, which he claims makes Claunch & Associates the world’s leader in reliable and rapid changeovers, has provided results for the past 18 years at production plants such as OSRAM Sylvania (see sidebar below).
By the way, what is a changeover? Henry describes it as the total process of changing from one product to another. He breaks a changeover down into three segments he calls Ups:
1. CLEANUP: The time it takes to remove the old material from the line.
2. SETUP: The time it takes to do any physical adjustment.
3. START-UP: The time it takes to get back to production speed.
Henry underscores the importance of an encompassing definition: “If you conduct a fast, but sloppy setup, that will increase your start-up time. If you don’t include all three, you’re not going to successfully reduce your changeover time.”
Growing in popularity
Henry says there’s more awareness about changeovers now than ever before. It may be because there are more of them.
“If you think back to the early 1960s, a Coke manager oversaw one changeover in his career—when the plant was built. Now there are hundreds of versions of Coke in different flavors and sizes,” Henry says.
Another factor is cost; Henry estimates that the cost of a changeover on a modern packaging line is $10ꯠ to $20ꯠ per hour. “Not only are people becoming more aware of the magnitude of the costs, the company is getting hammered by its customers to provide a quicker response time,” Henry adds.
Claunch adds that intangible costs must also be factored in, such as customer disappointment and lost business.
What can be done? Henry identifies four routes to faster changeovers:
• Install new machinery.
• Add change parts or modify current machinery.
• Provide proper training.
• Develop documentation.
Today, adding new machinery generally means servodrive motors and other electronics that are tailor-made for fast, precise, and repeatable changes. Claunch estimates that a move to electronic equipment can reduce changeover time by 15%. Our two experts reveal some downsides to electronics in light of so-called “push button changeovers” (see sidebar above).
The people factor
“Organizational aspects are everything that’s not nuts and bolts,” Henry explains. That includes people. In fact, Henry feels they are more important than machinery.
“Make sure people know what they’re supposed to be doing, and that there’s good documentation on how a changeover is supposed to be done,” Henry says. “People should be properly trained, and carts and materials should be available so they don’t waste time looking for parts.”
One opportunity to improve changeovers is at the very beginning—when workers are hired.
“Do you have warm bodies to run the line, or do you have people with some skills that can be trained for efficient changeovers?” Henry asks.
He also mentions that product design is another aspect that’s often overlooked; products can be designed so that their changeover and the associated packaging change can be conducted in an efficient manner.
Free—and economical!—tips
We asked our two experts to provide their best tips that can be done quickly and for under $1ꯠ—and can make a difference. Interestingly, both were in complete synch with their advice:
Eliminate threads—do away with nuts, bolts, and other threaded fixtures and connections. “It’s so simple that it’s almost embarrassing, but you’d be surprised at how many people haven’t done this already,” offers Henry.
Add handstops and fixed positions for package size changes. “This is usually done by eyeballing the adjustment and then tweaking during start-up,” says Claunch. “Fixed positions allow them to go right to a set point.”
It also makes the changeover more machine dependent, rather than solely operator dependent.
For those looking to improve their changeover times, Henry says an important motivator is to make a quick fix. “We can come up with all sorts of wonderful ideas, but if they are not implemented for a year or so, people can lose all of their initial enthusiasm. Do something quickly without a lot of rigamarole.”
When is it time for faster changeovers? There’s no time like the present.
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Click here to see sidebar 2.
