Your customers tell you that short production runs are becoming the norm in their businesses. They explain that these short runs necessitate quick machine configuration changeovers. They tell you that while factories once manufactured many thousands of a single item in one production run, now they make hundreds, and some production "runs" now consist of only a few items.
Lastly, they tell you a one-hour changeover once every week or two might have been acceptable ion the past, but those days are over. Anything more frequent is simply too costly and would be absolutely ruinous to customer productivity.
That's what they tell you. How do you respond?
Well, it's clear that one of the better ways to increase manufacturing output is to reduce the time required to changeover from one product to another. One of the main tools industrial OEM machine, skid, and robot builders can use to reduce changeover time is automation.
New Environment, New Rules
In this new operating environment, quick changeover from one product to the next is an absolute necessity, and an unbending requirement of industrial OEM customers. "Printers need to cut makeready,the transitioning from one print job to another,because it represents a big percentage of the time it takes to produce a product," says Frank Andaloro, president of E.R. Smith. E.R. Smith is a system integrator specializing in remanufactured printing machinery. "The printing industry is looking for fast makeready and short runs. A long run of 50,000 signatures, the term for packets of pages, could take 15 minutes to makeready, which is acceptable. But when that is broken into 10 runs of 5,000, that's 10 makereadys, each still 15 minutes long, so makeready becomes a huge factor relative to total job cost."
Automation suppliers are seeing the same flexibility requirements being demanded of other machine builders. "Production runs are becoming shorter and the ability to quickly changeover from one package size to another is becoming more important as packagers target smaller niche markets with higher margins," observes Mike Nager, industry marketing manager for Phoenix Contact (www.phoenixcon.com).
Many industries have similar quick changeover needs, and this is driving machine builders to incorporate high levels of automation into their designs.
At Your Servo
A key technique to reduce changeover time involves replacing line-shaft-driven machines with multiple servo motors. ATR of Altoona, Pa., remanufactures envelope-producing machinery, and a recent project replaced a single motor drive/line shaft with 12 synchronized servo motors. This eliminated about a dozen line-shaft connections, five gearboxes and two Positive Infinity Variable (PIV) drives.
"A changeover from one product to another often required maintenance to physically change a half dozen gears to a different tooth count," recalls Marty Karduck, general manager of ATR. "This procedure would typically take about two or three hours.
The servo motors and the automation systems eliminated manual gear changes and now allow operators to change from one product to the next through a recipe manager. The recipe manager transfers product recipe settings to establish the gearing relationship within the machine.
According to Karduck, the norm in the industry has been to physically change gears to make a product change. "So, to assist the operator, the new HMI screens are configured so maintenance personnel can 'pick the gear' that they normally would have installed in the old electromechanical system," adds Karduck.
PIV adjustment required the machine to be running and, therefore, producing scrap during a tuning and setup phase. "The automation and servo system eliminates the PIVs and the setup phase and provides major advantages for end users that require frequent product changeovers," concludes Karduck.
System integrator JL Souser (www.jlsouser.com), York, Pa., worked with ATR on the project, and president Craig Souser explains the control system architecture. "Operator interface is through a Rockwell RSView HMI (http://www.rockwellautomation.com) linked to a ControlLogix PLC and a Bosch Rexroth (http://www.boschrexroth-us.com) motion controller. The Bosch controller is linked to the 12 servos via a SERCOS fiberoptic communications bus."
JL Souser specializes in printing machinery automation, and newer versions of its printer controls incorporate a single Bosch Rexroth controller for both logic and motion. "Our preferred control engine is a Bosch Rexroth PPC because it can handle 32 axis in tight synchronization," adds Souser.
Triangle Package Machinery (http://www.trianglepackage.com) is a Chicago-based OEM of packaging machinery and equipment. Its newest machine, the Triangle/FlexCell, is a bag-in-box cartoner designed to run 90-100 cartons/min. with minimal changeover time and a small footprint (Figure 1).
Figure 1: Quick Change Cartoner
To meet customer requirements for a bag-in-box cartoner that
could run 90-100 cartons/min., the machine was designed with
minimal changeover time as servos replaced manual adjustments
made with handles and indicating scales. Optional components