Evolution in Packaging Controls

Robotics and software solutions deliver impact in OEM packaging machinery

Since electronic servo motion control emerged as an automation solution 25 years ago, packaging machinery has been a primary target for innovation. These high-speed, line-oriented machines were often originally designed with a main lineshaft to synchronize complex mechanical motion. Packaging machines were a perfect fit for multi-axis coordinated motion, electronic gearing and camming, large axis count controllers and the fundamental strengths of servo technology.

The pace of innovation hasn't slowed, and with high-speed networking and integration of logic and HMI control, changes in controls have become an even more complex and multifaceted evolutionary process. Suppliers are now looking to use processing power and software advances to implement kinematics for robotics and find ways to simplify and speedup the software development process. This report surveys the latest trends and how packaging controls are evolving to power the newest generation of machines.

PackXpert Generates Robotics Code for Packaging

A consistent theme in the evolution of packaging controls is the implementation of new tools for creating application software more easily and quickly, along with the integration of robotic handling capabilities into a wide range of OEM packaging machines.

An example is PackXpert, a recently introduced software technology from Adept Robotics. This software is designed to take the company's expertise in robotics for packaging and make it available to customers in a simple, easy-to-use product that is useable right out of the box.

"We decided to take our expertise in vision-guided, conveyor-tracking robots and create motion application programs that provide a solid level of software, and make it available to users as soon as they install the product," says Travis Armstrong, a systems' engineer for Adept.

Armstrong says robotic motions are similar for a wide range of product handling applications. The PackXpert application software walks the user through configuring the application and setting up process-specific items such as whether there are one or four conveyor belts, or the application requires vision. The idea is to allow the user to configure the system using point-and-click software. Then PackXpert builds all the underlying programs required for the application.

"All the user needs to do is configure the system, teach the locations and what the part looks like, and we create the underlying programs that do most of the work," says Armstrong. "One of our main goals is shortening development time. Instead of finding time to write programs for error recovery, handling multiple products and changing over from Product A to the next-generation product, we wanted to minimize the amount of time it takes to develop an application."

"Being Green," Sustainability Puts Focus on Efficiency

This year's PackExpo, held in Chicago in November, confirmed for some that the strong focuses on "being green" and sustainability issues are increasingly becoming important for packaging machinery builders. For more and more OEMs, there is a goal to reduce packaging material usage by producing more accurate machines that reduce the waste of packaging films and other materials. But according to Rick Rey, a packaging industry business development manager for Bosch Rexroth, this focus is rippling into controls, as well.

"As a supplier, we look at how machines can be ‘green' for the (manufacturing) plant in terms of more efficient energy and air usage. With both electric drives/controls and pneumatic products, there is an emphasis on driving greater levels of efficiency," Rey says.

One example he cites is that servomotors can routinely utilize bus sharing, so when motors are decelerating they are in a regenerative mode and provide bus voltage to other motors that are accelerating. Capacitor modules can also be designed into systems and used to store dc energy which can be reused.

One example of how the focus on energy efficiency is shaping the thinking of OEMs is an application for pallet loading beverages. When the pallet is lowered, because it is a heavy load, the motor is regenerating a significant amount of electricity.

"What happens is the system's dc voltage can only go so high and once you saturate the level of the bus voltage, most systems bleed off that additional energy into a resistor and it becomes wasted energy and heat," Rey says. But since a regenerative power supply can serve as an inverter and convert that additional energy back to ac energy, it can be put onto the three-phase line. Average power consumed by the machine is greatly reduced and is something end user plants can look at as a long-term strategy for reducing energy usage.

Application Software Tools Speed Packaging Development

A key to the evolution of packaging control is the pace of change in consumer products which is affecting the size and configuration of packaging, and requiring more flexible machinery and higher production rates. According to Travis Holley, a packaging industry consultant for Siemens, there is a strong demand for higher performance and the ability to handle this broad range of products.

"For product handling applications including orienting products, loading of trays, multi-pack loading into cartons and palletizing, we see a demand for automation and motion solutions that can handle more modular machine concepts. OEMs are looking for control architectures, both hardware and software, that can handle modular designs," Holley says.

There is also a primary focus on software solutions that expedite the development for the OEM. Machine builders don't want to be creating 100 percent of the machine code for every machine they are shipping.

"We have developed application tools and libraries for key machine types in the packaging industry," Holley says. "Libraries are available for vertical form-fill-seal, horizontal flow wrapping, smart belt feed systems and robotic handling to name a few."

A hot technology area is robotic handling, where the number of machine configurations demand differing kinematic solutions to execute the paths and motions required for those machine types. Each kinematic solution needs to be flexible to handle a range of products.

Siemens has introduced a top-loading application for robotic handling that allows users to simply configure their solution without worrying about developing the fixed order polynomial equations to create the path for a specific application. The libraries allow users to define restricted areas or interference points in the path and integrate safety solutions. The software helps the OEM execute the motions required, protect the machine with restricted area configuration and protect operators using integrated safety functionality.

Single, Scalable Architecture and Multi-Discipline Control

With packaging OEMs challenged to be more productive, efficient and flexible, there is a strong move in controls toward a single architecture for the machine that also integrates software tools to simplify and shorten the process. According to Axel Rodriguez, product manager for Rockwell Automation's CompactLogix programmable automation controllers, these issues, along with sustainability, are shaping the future for packaging machinery builders.

"Important factors for OEMs are the ability to utilize a single, scalable architecture that can be deployed for small and large machines," he says. "The same controls should be able to be used for different disciplines within the machine or production line. And there needs to be a set of tools and features built into products and architectures to reduce development times for OEMs."

In the past, he says, many packaging applications would have a separate controller for motion and line control, but now, modern architectures combine those disciplines into a single control. The controllers can go up-front in the line or at the back of the line, for processing and/or material handling applications.

"The idea of scalable control is OEMs offering different levels of machines, from small machines without a lot of features and functions to a scalable architecture that can cover a wide variety of machine types," says Leo Petrokonis, a packaging business development manager for Rockwell.

A reduction in development times can be accomplished by utilizing modular control concepts. Machines use the same basic functions such as jogging or homing servos, which don't change from machine to machine. Modular control makes it possible to modularize, label, execute and deploy these functions to reduce development time for new machine types.

An example is how Rockwell can use an "add-on instruction" to identify a group of code, name it and make it available for use in other applications. Users can also redeploy the same technology over existing controllers because the hardware is software-upgradeable.

Robotic Case Packer Uses Mechatronic Design

A key part of the evolution of packaging controls is an ability to weave robotics into the systems. More robotic mechanisms are available off-the-shelf, but software integration has become the important issue.

"Packaging machine controls are now more commonly adding function block solutions for robotics," says Tom Jensen, engineering manager for Schneider Electric's ELAU Packaging Solutions. "Major packaging innovations are happening at the software level and with integrating robots into machines."

He says the mechanical game of packaging machines has changed. Everything used to be custom. Now there are many more off-the-shelf components being utilized. The challenge is how to integrate these components from a motion control perspective and simply programming the application.

Jensen says there is a need to hide the software complexity inside the machine, especially in the American market. Servos simplify the mechanics of the machines, but the software needs to contend with more variables. A typical packaging machine in the US has seven to eight axes of control, so the programs can get long and complex. Most users love the operation of the servo-driven machines but need to simplify their approach to programming the machine.

A success story is the Edson RPd 270 robotic case packer, which utilizes a compact, modular two-axis delta mechatronic design. This new delta robot differs visibly from most case packers with its sleek, uncluttered work envelope. To optimize performance, Edson has combined ELAU's robotic, automation and servo module technologies with a complete electrical panel and HMI. The two-axis delta concept offers unique reach, payload and efficiency needed for case packing, compared to articulated robots or three-axis delta pick-and-place robots.

"The core of the Edson machine is its ability to control the XY space," says Jensen. "The robot has a large 30-lb payload and can offer cycle rates ranging up to 60-70 picks a minute depending on the weight of the objects."

"The concept of the Edson robot is simple but the calculations for robotics control, camming and synchronization, are advanced. The mechanics of the system are simple but the integration piece is more difficult. If, as the technology supplier, we didn't simplify the approach so one function block could be used with both the robot and other servos, the system would have been much more complicated," Jensen says.

Source: http://www.designnews.com/