More than any other single industry, general-purpose motion control is focused on packaging machinery. Servos have revolutionized packaging equipment in the past 20 years and there is a continuing trend toward higher numbers of servos in new machines. But now, suppliers of automation control solutions are also targeting two key areas to improve their offerings: application-specific software solutions and hardware solutions to help enable modular packaging machine designs.
Modularity is the Goal
“The key trend for motion control in packaging automation is modularity,” says Tom Jensen, engineering manager for ELAU Inc. “For the past 10 years, machine builders have been placing an emphasis on modular machine design but the technology hasn't provided robust solutions until now.”
One area Jensen says will take modular design to the next level is the emergence of integrated drive-motor solutions. With these newer products, the amplifier and motor are together in one unit, and system interconnections can be reduced to a single cable back to the motion controller.
ELAU has recently announced its new intelligent servo module, and other new products in this area include the IndraDrive Mi from Bosch Rexroth and offerings from AMK Drives, Animatics and Intelligent Motion Systems.
Jensen says designing modular machines using this hardware, and with software options ready to go, can create plug-and-play operation for OEMs. Servo options can be written into the machine on the front end and, if a customer wants to add motors to the machine, he says that “you turn that virtual code into real code driving a real motor.”
That's where the drive-motors come in, since they provide a way to add servo functionality to the machine without expanding the electrical enclosure. With the control structure and software already in place, the customer can use networking technology and specific automation protocols to communicate with drive-motors as they are added to the machine.
The lure of integrated drive-motors is the potential to reduce controls overhead in machines, plus cabling and electrical enclosure costs, by housing only the motion controller and power supply in the control cabinet. One ELAU customer also believes they will be able to reduce the height and footprint of their machines based on this technology.
Software Solutions for Packaging
A second area where modular solutions are impacting packaging machines is in the area of application-specific software solutions. More and more suppliers are providing an integrated set of hardware and software for specific applications such as pouching machines, cartoners, filling machines and other vertical machinery markets within packaging.
The approach is to provide software libraries, function blocks and/or software objects that address the software control needs of specific applications. Many suppliers offer solutions based on IEC 61131-3 and offer function block libraries that can be easily used in projects and configured for specific machine implementations.
“Using standard libraries reduces the programming load for customers,” says Jensen. “We have packages for specific types of machines such as form-fill-seal where 80 percent of the programming is done. All the engineer needs to do is parameterize the function blocks and focus software development toward how to differentiate the machine from others.”
In the pages that follow, you'll see a variety of motion control solutions for packaging equipment. Control suppliers are working not only to provide products but also integrated system-level solutions with a focus on the needs and requirements of modern packaging equipment.
SOLUTION FOR FILLING APPLICATIONS
Pre-programmed function blocks and basis projects developed by Pilz Motion Control simplify the process of developing filling machines. Programming is written as a ladder diagram for the Soft PLC in the system.
The system is used for filling liquid and paste-like products, many in creamery applications, with up to 60 dosages per minute. Quantity of product can be changed depending on the size of the can, and movement of cans is optimized by following defined maps. All motions are precisely controlled to eliminate jerk to avoid damage and spillage.
Coordinated motion is achieved using a “virtual main axis,” which provides a master velocity reference for the four decentralized servomotors. An internal motion generator allows the system to adapt curves to any product at any time even with the smallest product variations. All parameters are stored to simplify changeover. All settings can be saved in the PLC to allow the change of parameters by pressing just one button. Automatic optimization of weight is achieved by weighing and correcting the quantity of the product.
Required system hardware includes one PMCprimo 16+ motion controller and four PMCtendo DD4 servo drives, which get target and actual values for position and current for control and diagnosis via CANopen (update time of 1 msec).
BAG SEALING AND STRIPPING SOLUTION
Baumüller has developed a software solution and matching drive system for continuous vertical bag forming, filling and sealing machines. The solution provides a software template that offers users a view of the functions in the individual machine modules.
No motion control expertise is necessary for the implementation of the foil take-up and transport, vertical synchronization, sealing and dosing functions. Instead, the process is controlled by means of software modules. The modularity of the template makes it easy to adapt the default hardware and software architecture to the machine concept.
The system uses a single b maXX-drivePLC controller for functions including motion, logic and HMI. The ability of the drive-based controller to access the drive quickly and synchronously results in a machine that runs continuously on the basis of an electronic line shaft. Integration of a PLC in the drive saves space and the IEC 61131 multi-tasking real-time operating system is able to respond to events quickly.
Baumüller also extended the standard movement sequences of the cross-sealer carriage to include a stripping function that removes any product residue from the area of the foil that is about to be sealed.
INTEGRATED SOLUTION FOR CARTONERS
A hardware/software solution from Allen-Bradley focuses on effective cartoner design and adapting machine performance to changing product mix, smaller products in smaller bags, different material in different shapes and running at faster speeds.
Key features of the system include the ability to track product attributes using shift registers, and utilizing position-driven outputs for functions such as glue and reject control. The design approach replaces mechanically linked assemblies with an electronic line shaft, providing coordinated control for multiple mechanical assemblies that each add work to the product.
The Rockwell Automation solution offers a number of key benefits. Servo indexing moves the conveyor to a fine positioning point quickly and repeatedly, while electronic gearing ensures date stamps are applied or coupons are inserted into the packages at an optimum, programmable ratio. Output cams provide a simple programming interface to schedule position-based output triggering. These cams also can be enabled by other inputs or events. Absolute feedback enables the cartoner to maintain position even when power is interrupted, eliminating homing routines.
Application processes can also be distributed or consolidated among multiple processors. Managing the trade-off among speed, memory, cost, packaging and connectivity options allows for modularity of machine design and implementation.
ZIPPED FOOD POUCHES
A five-axis motion control system from Baldor is at the heart of a continuous “cross-web” zipper applicator for continuous vertical form-fill-seal and horizontal flow-wrapping equipment. New machinery for manufacturing resealable pouches, developed by Line Equipment for inserting Supreme Plastics' narrow zippers, is expected to achieve throughputs of more than 80 pouches per minute.
The motion system uses a panel-mounted Baldor NextMove BX motion controller to manage the zipper applicator and linear motor axes, and a Flex+Drive to control the zip feed and cut axis. Both link to an HMI using a CANopen which allows the operator to define zip length, pouch size and other application parameters.
Application-level software in the form of keywords in Baldor's Mint language contributed significantly to fast software creation. FLY is a high-level command which synchronizes the movement of two axes while controlling the position of one, and provides a solution for the continuous zip attachment process. Mint software also provides a method for correlating the zip-attach and linear motor heating element axes to the web material, so the applicator automatically tracks web speed. This command operates virtually, allowing the machine to be set up without wasting material.
INTEGRATING ROBOTS INTO PACKAGING PROCESSES
The PacDrive™ automation controller and robotic software library from ELAU provides a solution for integrating robots into packaging machines.
ELAU's software development environment provides a preconfigured program structure or template that enables modular software design. Using the template, multiple robotic modules can be integrated into an overall project just like any other machine module. Programming is simplified by a library of pre-tested, reusable, IEC-conforming function blocks including the PLCopen motion function blocks.
Programmers can parameterize rather than write original code for hundreds of functions including robotics, which results in consistent and highly maintainable code. Access to all variables simplifies machine engineering and diagnostics.
The modular, reusable nature of the robotic software library provides an ability to change robot arm dimensions, move profiles, belt height and picking distances without additional programming. Adding robotic cells is easy because each robot is a task, and can be added or removed from the PacDrive controller's program. Variables are simply input to determine the robot's parameters.
A robot's trajectory can be easily specified as points in the range of movement. The conversion of Cartesian coordinates into positions for the individual robot axes is performed automatically and in real time by the PacDrive software.
RANDOM INFEED CONVEYOR FUNCTION BLOCK
A Random Infeed application function block from ORMEC Systems Corp. makes it easy to implement random infeed conveyor applications with a minimum of programming effort.
Random infeed or SmartBelt conveyors take products randomly spaced on an infeed conveyor, and evenly space the them on an outfeed conveyor. In many applications there is an additional conveyor with lugs, between which the products must be placed.
An encoder on the outfeed conveyor provides a method for synchronization and ability to measure the amount of spacing correction required. Sensors at the intersection of each belt detect the exact position of products. The user's application program uses one instance of the function block for each phasing belt.
Inputs to the function block provide a way to specify product length, spacing of products and the position on the outfeed conveyor relative to the sensor where the leading edge of the product should be placed.
Outputs include a “correction distance,” or amount of phase correction required and “master distance,” the line distance available to make the correction.
REMOTE SYNCHRONIZATION SOFTWARE LIBRARY
To streamline controls' design for dynamic machine control applications such as those found in packaging applications, Beckhoff Automation has introduced a new TwinCAT Remote Synchronization Library.
This new software library provides function blocks that makes it easier for users to synchronize several multi-axis machines that have TwinCAT control systems. This solution is ideal for synchronizing systems that control dozens of axes or small axis count machines.
In applications where more than one PC controller is required for multiple machines in a line, the Remote Synchronization Library allows for general time synchronization. Information for distributed control can be used to coordinate multiple machines by calculating offsets to compensate for differences in execution time and CPU clock frequencies. In addition, the library includes special techniques for synchronizing NC axes (“distributed axes”) and electronic gearing of axes on separate controllers.
SINGLE-AXIS AC DRIVE TARGETS PACKAGING
The new Sinamics S120 ac drive from Siemens is targeting high-performance, single-axis packaging applications. The drive expands the Sinamics S120 system into an integrated modular drives system for both single-axis and multi-axis applications with the capability of running high-performance servo and vector modes.
The drive features a modular concept that separates power and intelligence. Power and controller sections are selectable to increase flexibility and scalability, and choices allow users to select the right controller for their current needs but protect their drive investments if the application ever changes.
The drives are designed to handle positioning tasks such as those found in automatic assembly machines, material handling and applications such as packaging, printing, plastics, textiles, converting and hoisting.
The drives are available in single phase 230V in the power range 0.25 to 1 HP, and three phase 460V in the power range 0.5 to 400 HP. The power modules are available in block construction or as chassis units.
PiCPro SOFTWARE/CONTROLS FOR PACKAGING
Danaher Motion's latest PiCPro software supports up to 64 axes of high-performance motion control and standard functions for automating machinery found in typical printing, packaging and converting applications.
Designed to simplify system integration, the PiCPro software is used to program the MMC-D64 Machine and Motion Controller and provides connectivity to MMC Smart Drives and AKM servo motors.
PiCPro combines IEC61131 ladder logic or structured text programming with 100 MHz Ethernet motion control. A complete instruction set is optimized for continuous motion applications including functions for gearing, camming and automatic registration correction.
The MMC-D64 motion controller provides real-time data to the application program over the digital motion control network, one-click download of firmware or parameters to all the drives on the network and connectivity options for interacting with third-party devices for data transfer and sharing, plus significant I/O expansion capabilities.
The controllers conveniently interface with MMC Smart Drives that are available in 230 and 460V packages ranging from 500W to 65 kW continuous output power, AKM rotary motors, DDR and Cartridge DDR direct-drive motors.