This month, more than 40 NASCAR drivers will descend on central Florida for the 48th annual Daytona 500 motor race. Whoever wins the famous event will probably credit his success to one or more well-orchestrated pit stops, where mechanics quickly change tires, gasoline, body panels and other components.
In the fast-paced world of packaging lines, success or failure also depends on the ability to make quick changes. Like death and taxes, changeover is inevitable, and the need for speed has never been more crucial to the consumer goods industry.
Changeover is the process of converting a machine or line from running one product to another. To switch between product sizes or package configurations, engineers often must shut down the entire line. As a result, changeover is a notorious source of waste with cartoners, case packers, fillers, palletizers, shrink wrappers and other types of packaging equipment.
“Quick changeover reduces equipment setup time, thus enabling more frequent setups,” says Don Penkala, president of Granite Bay Consulting Inc. (Granite Bay, CA). “This improves manufacturing flexibility and lead times by reducing lot sizes.
“As more and more companies compete on speed, the ability to respond quickly and profitably to changing customer needs and production schedules is today’s competitive advantage,” adds Penkala. “In addition, faster changeovers require less equipment and less floor space, improving return on net assets.”
Large retailers, such as club stores, national chains and super stores, are demanding a greater variety of product sizes and packages today. For instance, they often dictate how many cartons are contained in a case or on a pallet, or how many items appear in blister packs. At the same time, manufacturers are on a continual quest to improve product shelf-appeal in highly fragmented retail markets.
“It is no longer the large that eat the small, but the quick that eat the slow,” notes Tony Barr, product marketing manager for modular conveyor systems at Bosch Rexroth Corp. (Buchanan, MI). “This is an increasingly meaningful axiom in business, particularly in the packaging industry.
“The velocity of change in market trends, such as mass customization, and marketing priorities continually drives demand for a wide range of packaging sizes, formats and media,” continues Barr. “In addition, mega retailers and club stores have been uniquely instrumental in shaping consumer preferences for novel packaging formats, such as multipacks and mixed packs. As a result, manufacturers tend to warehouse less, favoring, instead, frequent flavor and pack-pattern changes.”
“[Those] shifts to alternative package designs, sizes, materials and configurations are having an effect on machinery demand,” adds Chuck Yuska, president of the Packaging Machinery Manufacturers Institute (Arlington, VA). “The trend toward multiple sizes and quantities of product in all segments is resulting in orders for new machines because of limitations in the capabilities of existing units.” More and more manufacturers are looking for flexible equipment that is easy and quick to change over.
“The need for greater flexibility to handle the dissimilarities, as well as to speed changeovers, is growing rapidly,” notes Yuska. In fact, he claims that changeover-related factors influence at least 50 percent of all packaging equipment decisions today.
“Changeover is so important [today] because product lifecycles are shorter,” says Craig Friesen, product manager at SWF Cos. (Elk Grove Village, IL). “Building a packaging machine for just one product or package is going by the wayside. Consumer goods producers need packaging machines capable of handling multiple products or packages, or systems that can be easily modified to keep up with the changing marketplace.”
Product ProliferationManufacturers of batteries, hardware, lightbulbs, pens, razors, toothbrushes and other consumer products are operating an increasing number of packaging runs because of the proliferation of product varieties, sizes and configurations.
According to Barr, contemporary packaging plays a dual role. “Fundamentally, it protects contents for delivery to the consumer,” he explains. “But, it is also an important strategic tool that helps companies establish and maintain differentiation from competitors, and even carve out new market segments. A capacity for quick changeover means operational agility, creating competitive advantage by optimizing process flexibility, speed-to-market, and product and service quality.”
A good example of product proliferation in today’s marketplace is the Coca-Cola Co. (Atlanta). Up until the mid-1960s, the company’s popular soft drink came in only one flavor in a simple 6-ounce glass bottle. Now, it’s available in more than 100 different combinations of flavors and containers.
“We, as consumers, are demanding mass-customized products,” says John Henry, president of Changeover.com, a consulting firm based in Fajardo, Puerto Rico. “This means that the Coke bottler who used to do a product changeover maybe every 30 years, now may need to do two or three changeovers per day.”
According to Henry, changeover costs include tangible expenses, such as direct labor, lost production time and lost capacity. Indirect costs include increased customer response time and extra stress on equipment and operators.
Henry says an inability to change over quickly can result in lost business because production cannot respond fast enough to meet unexpected increases in demand. “Changeover can take a significant amount of time,” he explains. “Four to 8 hours is not unusual. That is time when the line is not running and no product is being produced.
“Cost of changeover is typically $10,000 to $20,000 per hour for packaged consumer goods,” claims Henry. “That is a lot of money if you do it daily. It is tremendously expensive and wasteful. And, much of it is unnecessary.”
Common MisperceptionsTo get a realistic handle on cost, changeover time should be measured from good part to good part. “A good part is a saleable part or package that meets all the customer requirements and parameters,” says Rick Harris, president of Harris Lean Systems Inc. (Murrells Inlet, SC). “The physical changeover may take 20 minutes, but the good-part-to-good-part time may be 2 hours. So, in that instance, therealchangeover time would be 2 hours instead of the 20 minutes that most people think about.”
Two factors should be included when measuring and monitoring changeover speed: the mean and the variation of the changeover speed, measured from the last good part of one run to the first good part of the next run. “There are several reasons for this,” notes Jamie Flinchbaugh, a principal at the Lean Learning Center (Novi, MI). “If I measure the trend of the mean, it will tell me if I’m getting better. However, one of the major problems in changeover is lack of standardization, and the variation will tell me that.
“We want to see that variation moving closer and closer to zero,” adds Flinchbaugh. “It is also important, for the sake of making improvements, to measure the time spent in different elements of the process, because it will tell if you have to work on coordination issues, technical issues or communication issues.”
Unfortunately, there’s a common misperception in most organizations that changeover is inexpensive. Many people think changeover costs hundreds of dollars per shift. In reality, it often wastes thousands of dollars per hour.<$> “It is absolutely imperative to get a good number from accounting of the true cost of changeover,” warns Henry.
“Another myth is that the only people who need to be concerned with it are plant floor people,” Henry points out. “But, everyone in the company has a role to play.”
According to Quarterman Lee, president of Strategos Inc. (Kansas City, MO), the ability to do quick changeover requires a cultural change within an organization. “Accounting systems may have to change and marketing strategies should change, in many cases, to take advantage of new capabilities,” he explains.
Bosch Rexroth’s Barr believes changeover must be viewed as a strategic business opportunity. “Changeover is rich in potential for competitive advantage, depending upon the vision and skill with which it is approached,” he explains. “Intelligent, anticipatory, 360-degree planning is the key to designing and implementing flexible packaging lines. The challenge is best met--and the attendant risks most effectively identified and managed--with a systematic, close working alliance among multiple-discipline teams comprising the marketing, packaging design and operations functions, as well as suppliers of packaging equipment.”
Is 'Flexible' a Myth?Fortunately, most packaging machines today are flexible. They feature modular configurations and layouts to maximize application flexibility and minimize reconfiguration time. That enables manufacturers to change package formats faster to meet market requirements. In addition, more and more packaging machines use servo motion control.
Downtime is the most important factor in making decisions about changeover. To shorten downtime, the key is to change over equipment as fast as possible.
Stanley Johnson, executive vice president of Schneider Packaging Equipment Co. (Brewerton, NY), says he frequently hears people ask, “How long does it take to change over your machine?” He suggests a typical goal of 15 minutes or less.
“Depending on how many people are making the line changes, and if the changes have to be done in series or can be done in parallel, the time to change over a line can be the sum of all changeover times,” explains Johnson. “If you can cut the time required in half to change over just one machine, the total sum can be reduced, saving money and improving profits.”
Some vendors promise “changeover in as little as 2 minutes” without qualifying the number of sizes, the number of people required, the complexity involved in the changeover, or the cost associated with this claim.
“While two-minute changeover may be possible on equipment where the change between product sizes is small, you have to take into consideration the complexity and the number of sizes the machine must change for,” warns Johnson, “as well as the amount of distance between the maximum and minimum size that the machine must adjust through.
“For rough initial estimates, I like to use the ‘factors of two’ rule: for each change or increase in size, multiply the time required by two,” explains Johnson. “This gives an aggregate time to work against, and helps identify the type of change mechanism that will be required to reduce changeover time.
“Often, this can be done without a lot of parts or tools,” adds Johnson. “Toolless changeover replaces common tools, such as a wrench, with handles, knobs, scales and indicators to quickly reposition portions of the equipment to accommodate another predefined size.”
Changes between sizes may often be accomplished with a handwheel adjustment or a simple slide adjustment using pointers and scales or a digital readout. However, more complex changes may require change parts or even servo adjustments.
“You reach a point where incremental improvements in the time to change over results in very expensive increases to the machinery costs, so the cost-benefit balance must be reviewed,” notes Johnson.
On a case packer, for example, changing the case depth may require a simple handwheel adjustment where changes in length or width may require that parts be changed. Several areas are not always easily adjusted, like a pusher plate on a load arm.
In this application, Johnson says it may be easier and less expensive to offer a set of change parts where pusher plates are exchanged based on the product selection. However, one problem with this concept is that people lose parts. Johnson recommends looking for designs that include a method for storing and coding the spare change parts so that they are readily available and easy to differentiate.
One concern with toolless changeover is that operators will fiddle with things. “Sometimes, during normal running, operators will see that they can make an easy adjustment using a handle instead of a tool, and will end up putting the equipment out of adjustment,” says Johnson. “To prevent this from occurring, it is important to train your operators and to document the positions of the changes required for each product size change. If the operators follow these documents when changing over the equipment, the changeover will be successful, and machine downtime will be reduced.”
Some experts believe that the tension between flexibility and efficiency needlessly intimidates many packaging professionals. “The two imperatives are not mutually exclusive, nor even necessarily inconsistent,” says Bosch Rexroth’s Barr. “Changeover need not be complex. The most effective changeover methods are elegantly simple, focusing on the few critical process attributes that make or break efficiency.
“Consider conveyor guide rails, for example,” notes Barr. “Multiaxis adjustability and quick-release levers set to match preprogrammed product ‘recipes’ minimize time and tools required for changeover while ensuring repeatability.”
Barr says engineers should remember that they don’t have to be left alone trying to address the challenges and opportunities presented by changeover. “The cost and complexity of packaging innovation provides strong incentive for packaging machinery manufacturers and their customers to establish strong relationships in the development process,” he points out. “Special handling characteristics associated with new container shapes, for example, can--and should--be discussed with packaging process technology suppliers early in the development cycle.”
Package Design ConsiderationOne of the biggest challenges to implementing flexible packaging lines is package design. “Designers keep coming up with packages that can’t easily be run on existing lines,” says Henry. For instance, he recalls one manufacturer that had its marketing department design a tapered bottle. The company made a large quantity of bottles and then shipped them to be run on the packaging line.
“It would not run on existing equipment,” says Henry. “They wound up doing it almost manually.”
In another case, a design engineer decided to use two different glass vials. “Instead of choosing two the same diameter, one is 0.063-millimeter smaller than the other,” laments Henry. “A 5-minute height changeover is now a 90-minute full dimensional changeover.”
While glass and plastic containers pose unique challenges, Henry says anything with paper is always difficult, especially corrugated material. “This is because it can vary so much in size, stiffness and other characteristics,” he points out.
Product designs can also create havoc when it comes time to change over a packaging line. “Typical of such problems are those presented by different height packages with different footprint dimensions, such as base diameter,” says Barr. “While adding very little--if any--value to the consumer, differences in diameter transform a simple height changeover into a complex, multiaxis changeover.”
Barr urges consumer goods manufacturers to follow “best practices in smart packaging design to facilitate quick adaptability of packaging equipment to changes in product mix, process flow or marketing priorities.”