The drive to servo-centric packaging machines

The need for more flexibility is driving pharmaceutical manufacturers to servo-centric packaging machines, but concerns remain about validation and the blue screen of death with PC-based controls.

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Servo-centric Packaging MachinesBy Alan Brown, Contributing Editor, Pharmaceutical Manufacturing

 

MOST PHARMACEUTICAL manufacturers keep quiet about their new equipment purchases, and they usually expect their machine suppliers to do the same. What we do know is that servo-powered packaging systems are claiming space on those factory floors. These flexible machines have become a mainstay among consumer products companies. However, regulatory requirements still present formidable barriers to their use in the pharmaceuticals sector.

“The pharmaceutical industry is just realizing the benefits of servo technology—the easy changeovers that make it economical to do short runs and small lots,” says Jeff Jackson, product management director at Bosch Packaging Technology pharmaceutical division in Minneapolis, which has built many servo-driven machines for drugmakers. “Instead of taking several hours to change cams and mechanical machine setups, you simply recall a predetermined recipe for the machine, load up a different type or size of vial, and get back up and running in minutes.”

The perceived problem for drug manufacturers is that servo systems typically rely on PC-based control systems. They present many more validation issues than the PLC controls and mechanical linkages of conventional shaft-driven packaging systems.

Despite these apparent drawbacks, many pharmaceutical firms are willing to do what’s needed to put servo-centric machines on the floor, especially as they commercialize more specialty drugs with varied packing options. “With cost pressures from competitors, insurers, and large buyers, pharma companies are looking for machines that give them more flexibility,” adds Jackson. “An electronic system can do this far better than a mechanical system. Pharmaceutical companies are more open now to accepting and implementing servo technology in place of the mechanical solutions of the past because they know servos can give them this greater flexibility, which they need to meet varied production requirements.”

Servos’ Advantages
Economic pressures aside, an OEM who builds servo-based equipment gives users advantages over shaft-driven equipment, says Mike Wagner, business development manager at Rockwell Automation. “Before servos, packaging machines had an AC motor running at a fixed speed,” he says. “Mechanical linkages off the main shaft translated shaft motion from one speed to another or from rotational to linear motion. For each revolution of the main shaft, you had one product coming out the other end. Every time you wanted to go from vials to bottles or change the size or shape of the package, you had to reconstruct the machine.”

Servos change this game. Instead of mechanical linkages to a main shaft, each servo system, which includes motor, gearhead and software, operates independently.

“Everything—pressure, velocity, position—can be modified,” says Wagner. “Before, it would take seven hours to make those changes, so you didn’t want to do it unless you had a large enough lot to run effectively. Now you can make the changeover in three to five minutes. It’s like loading a recipe.”

 

     FIGURE 1: SERVOS' BENEFITS CAN'T BE IGNORED
  Bosch Packaging Technologies
 

The pharmaceutical industry is beginning to see the benefits of servo-centric machines, particularly the easy changeovers that make it economical to do short runs and small lots. Bosch Packaging Technology has built many servo-driven machines for drug makers.

Freeing the servo-based functions from the drive shaft lets the machine controls adjust independently to each event during the packaging process. “Imagine a simple, low-to-moderate-speed bottling line,” says Bob Hartwig, vice president of Pester USA, an Allendale, N.J.-based subsidiary of a German packaging equipment firm. “It’s made up of a host of simple machines, all of them interdependent, and working in concert. As the system collects data, the servos on the line can adjust independently to any production problem as it occurs.”

Servos simply offer an entirely new level of speed and precision, adds John Kowal, global marketing manager for Elau Inc., a subsidiary of Schneider Electric. He says a conservative estimate is that 70-80% of the stretch banders, overwrappers, case packers and palletizers now sold to pharmaceutical companies already use servos.

“One of the great things about servo control is its closed-loop feedback,” he says. “Our servo-based capper controls torque to ±0.02% versus 20% for a standard clutch-drive capper. We know exactly what the values are. We can store the torque value for each cap, so if there’s a recall, the manufacturer might only have to recall a thousand bottles instead of a million bottles.” The same data can be analyzed for trends that indicate wear or a need for maintenance.

Also, since servos consist of much smaller motors, maintenance is rare. “Servos have a mean time between failures (MTBF) of 200,000 hours,” contends Wagner.

21st Century Manufacturing
Beside their technical advantages, servos are more affordable than in the past, which is breaking down another barrier to their adoption. “Five or six years ago, servos cost about $10,000 a pop,” says Hartwig. “Nowadays, they cost less than $5,000 each, and prices are still falling.”

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