Among the most sophisticated bag converting equipment made by CMD Corp. is the PDI Medical Combination Pouch System. It turns flat rollstock into a complete range of premade header bags and shaped pouches in a chevron or shaped-seal configuration. Pouch sealing can be done in single or multiple lanes across the width of the machine at speeds to 200 seals/min.
Increasingly stringent medical regulatory requirements demand not only quality pouches but also complete specification and sealing data for documenting processes. Each seal has to be virtually perfect. In addition, to stay ahead of the competition, CMD needs to offer unique advantages: real-time process monitoring, complete data management, and tight control of sealing parameters such as temperature, pressure, and dwell time.
Machine control is based on actual data points, not just filtered or averaged data. Users are able to optimize seal parameters whenever needed. Instant analysis of high-volume data was a must because machine operators need to know immediately if platen heat is uneven or dwell times a split-second too short, thus requiring processes to be changed or shut down. High levels of accuracy and precision have to be maintained consistently across thousands of seals. CMD customers also need minimal changeover times between jobs as production demands.
Meeting these requirements meant the new-generation PDI pouch converting systems needed to be designed with exceptional controls finesse. That’s where machine components distributor CMA/Flodyne/Hydradyne came in. CMAFH’s knowledge and their familiarity with Bosch Rexroth drive and control components made them the perfect partner that CMD needed.
Data is interpreted instantly and converted into a set of sealing parameters called a “recipe” for creating the seal. Recipe-based programming at the operator panel ensures precise control of customer-specific converting requirements each time a job is changed. The control and quality assurance of recipe-based operating parameters is required for the demanding medical pouch industry because the difference between a good seal and a rejected one can be measured in microseconds.
“The operator can flag out-of-spec seals and make adjustments on the spot,” says CMD Intermittent Motion Product Line Manager Scott Fuller. “That can mean the difference between throwing away a few pouches and losing an entire truckload.”
Rexroth software makes changeovers between jobs easy. Instead of adjusting cams and other mechanical components, changes are made at the HMI terminal. To transform better data into optimum control, the machine’s hardware was upgraded as well. Rexroth’s IndraDrive Mi integrated servo motor/drive platform and IndraDrive C converters, which blend inverter and power supply in a single unit, are good examples. These were combined with Rexroth IndraDyn MSK servo motors, allowing comprehensive and responsive control in a compact space with less cabling. And by combining IndraControl VEP 40 HMI, L40 MLC motion logic control, and servo technology, CMAFH realized a large performance upgrade without increased machine size.
Because the compact, scalable IndraDrive Mi has the drive mounted in the motor casing, control cabinet space requirements are reduced significantly. Its power and communication output run via a single cable that’s daisy-chained to each integrated drive. A Rexroth KCU compact adaptation box allows a common coupling to be used for all connections to the IndraDrive Mi units.
For motion synchronization in three axes for cutting, sealing, and pouching, CMD relies on Rexroth’s IndraMotion MLC L40 motion logic controller with Flex Profile functionality. Flex Profile precisely controls all synchronous and time-based converting steps. The IndraMotion MLC controls platform provides the flexible functionality to help CMD reduce material waste, increase throughput, and simplify operations.
Along with machine control, Rexroth also supplied pneumatics for cross cooler actuation along with runner blocks and profiled rail for key machine functions such as supporting cutting and sealing operations and stacking pouches. Rexroth anodized aluminum structural framing was used to create the stacking table and support a protective light curtain.
Tests of the new system show that it can deliver sealing strikes, each with thousands of pounds of force, within a +/- 1.5% tolerance, the sealing industry’s tightest control. Dwell time, force, and temperature can be adjusted almost instantly. Pouch width, the number of rolls of material involved, and the type of material can all be altered simply by keying in the appropriate recipe. Real-time data also tracks how thoroughly the machine controls the sealing process, proving compliance with strict regulations.
Finally, troubleshooting is facilitated by an Ethernet hub that allows remote dial-in for machine diagnostics.
“It’s a high-performance machine at a competitive price,” says Fuller.
