Rotary servo drive technology and its similar linear motor technology may or may not enter the packaging machinery industry, depending on who you're discussing the issue with. A few packaging machine manufacturers are focusing on the high flexibility linear motors offer for industrial applications, a crucial characteristic in packaging machine design to ensure the integrity of packaged products. Claude Chirignan, a senior applications engineer at Anorad in Sherry, New York, revealed that his parent company, Rockwell Automation, is in discussions with a leading European packaging equipment manufacturer. He believes that engineers in the packaging machinery industry shouldn't be obsessed with the high precision or smoothness of linear motors—these two features only help meet the specific specifications of semiconductor process equipment and machine tools. Instead, they should focus on another capability of linear motors: their ability to reliably extend precision to almost any conceivable stroke length. This is clearly different from ball screw drives, Chirignan added, noting that ball screws are prone to shaft twisting, breakage, and other problems at longer stroke lengths. A Unique Motion Pattern: Jacobs Automation LLC's linear motor system differs from traditional systems in that its power unit, propulsion unit, and mover reciprocate in a straight line. Furthermore, its trajectory control method is unique, allowing for individual control of each mover. However, George Gulalo, president of Motion Tech Trends, an industrial analysis and market research firm specializing in motors and motion control technology, believes that linear motors are too powerful for most packaging machines. The motion generated by packaging machinery is fundamentally relatively "clumsy," and traditional cylinders and pneumatic motors are more suitable for handling such movements. New Motors Enter the Fray At least one established packaging company is still outlining the potential applications of linear motors. Kevin Jacobs of Jacobs Automation LLC has been keenly observing vertical and horizontal forming, filling, and sealing machinery, considering all the opportunities he can perceive in order to apply his newly patented linear motor design. Unlike traditional linear motor systems, Jacobs' new system features a power unit, propulsion unit, and mover that reciprocate along a straight line, much like a toy car moving along the two straight sides and two rotating sides of an elliptical track. PackTrak's unusual capability is the simultaneous operation of multiple movers, each of which can be controlled independently. Jacobs believes that this layout allows PackTrak to replace the rotary servo and the two opposing track drives on the rotary servo motor, which are connected to the linkage drive of the opposing sealing head frame of the forming, filling, and sealing machine. As required, the pair of opposing movers always move synchronously with the movement of the packaging bag. As long as the heat-sealing head remains hot, it can maintain close contact with both sides of the film for the necessary duration to complete the fusion process, thus eliminating the time limit for sealing the packaging machine's work cycle. This technological innovation in linear motors also helps manufacturers meet the growing demand for flexibility. Jacobs recalls a cookie manufacturer 20 years ago that could only offer two packaging sizes for the same product; now, that company can offer 40 different packaging sizes for the same cookie. Replacing the fixed-pitch chain conveyor currently used in flow packaging machines with linear motor guideways allows engineers to easily handle constantly changing packaging sizes, switching between sizes simply by changing panel functions. Flexibility is crucial for packaging equipment engineers, a view shared by Gary Schultze, a senior electrical engineer at California Linear Devices in Carlsbad. He believes that a packaging machine might operate in the same set position for 50% or even 70% of a product's output. Linear drives, consisting of rotary servo motors and ball screws, would repeatedly start and stop in the same position countless times, eventually leading to wear points. Linear motors, however, have limited mechanical contact, at most between the support shaft and the bushing, and therefore do not experience wear after repeated operation. This means extended service life and increased productivity, which he believes will help convince engineers of the practical value of linear motors. He stated that his company's cylindrical linear motors have already entered several packaging applications that heavily rely on high acceleration, citing numerous examples of applications they have developed or are currently focusing on, such as mesh brakes, separators, fast return conveyors, carton gluing machines, and bottle filling machines. However, John Kowal, Global Marketing Manager at packaging automation company Elau, believes that 50% of the linear motor market still belongs to the semiconductor industry, calling it a "very ideal" application for handling relatively light and consistent loads. Demand for larger linear motors mostly comes from the machine tool industry. Several years ago, the linear motor industry anticipated that the packaging sector would be the next big opportunity, but this has not yet materialized. After all, linear motors are still much more expensive than rotary motors with gear transmissions, he explained. He even believes that the high acceleration capabilities of linear motors, measured in Gs, are unnecessary for packaging substances like milk, adding that a fifth-order polynomial control strategy is sufficient to easily handle the deceleration required to prevent spills. He believes that even the next generation of fully servo-driven machines in the packaging industry may not be able to widely adopt linear motors, as their application will always be limited to specific situations requiring high speed and short strokes. New Characteristics of Linear Motors A Glimpse into the Latest Developments in Linear Motor Technology: ■ A novel linear motor system from Jacobs Automation LLC differs from traditional linear motor systems in that its output device, propulsion device, and mover reciprocate along a straight line, much like an electric toy car that can move back and forth along the two straight sides and two rotating sides of an elliptical track. Another unusual feature of PackTrak is its ability to operate multiple movers simultaneously and control the trajectory of each mover individually. These "passive" movers are entirely controlled by coils fixed in the track, requiring no external connections, and thus can move freely along the track without being entangled or restrained by ropes, cables, or drag chains.