Tech Update: Packaging Machine Controls
If you were an auto manufacturer 25 years ago trying to automate an assembly line, you were faced with several automation and robotics systems that simply didn’t talk to one another, notably referred to as “islands of automation.” Today, if you’re planning a completely automated packaging line, you’ll find the process a lot smoother—though not perfect—due to 25 years of experience that machine builders, system integrators, controls and robot manufacturers and component suppliers have chalked up.
Some rules never hurt
While MAP (Manufacturers Automation Protocol) tried to set hardware and communications networking standards for automation equipment in the auto industry, it met with limited success because most users weren’t willing to invest $3,000 per network node for hardware and software. MAP didn’t catch on that well, but with the ubiquity of Ethernet today, networking is relatively inexpensive—at least at the hardware/communications level.
“There certainly is something familiar about the old ‘islands of automation’ and today’s challenges on packaging lines,” says David Kaley, Mitsubishi Electric industry market manager. He explains there is, however, one very significant difference: In the ’80s, open networks still had to be created, and vendors were reluctant to adopt open standards without trying to put their own twist on them. Today’s engineers don’t have to create the network; they have Ethernet. Their task is to define blocks of data that can be transferred from one machine to the next.
It’s at this application level where a challenge still exists in getting packaging machine, robot and line controllers to speak the same language. Each machine has its own unique addresses for I/O and equipment functions, so a common language is needed to get machines and application-level software programs communicating.
PackML is a mark-up language in plain English dedicated to removing the “bits and bytes” of machine configuration for systems designers. The primary objective of PackML is to bring a common “look and feel” and operational consistency to all machines that make up a packaging line. PackML provides:
• Standard defined machine states and operational flow
• Overall equipment effectiveness (OEE) data
• Root cause analysis (RCA) data, and
• Flexible recipe schemes and common SCADA or MES inputs.
“We’re still struggling with the adoption of PackML,” says Leo Petrokonis, Rockwell Automation business development manager for the packaging industry. “I think one of the reasons is that the standard costs money to be compliant, but there are some machine builders who have fully invested in PackML.” Machine builders that have adopted PackML find real savings in startup costs because all their machines are compliant and communicative. Engineers find it easy to reuse code, creating PackML macros that are easily editable in English.
“There are benefits for machine builders,” says Brian Deal, Schneider Electric market segment manager, packaging. “By implementing PackML, OEMs can improve and shorten their machine development cycles.” PackML lets machine builders choose the automation platform best suited for their machine, reduce creation of customized code and improve their delivery times to processors.
“The OMAC Packaging Workgroup (OPW) has been reenergized with the leadership from Bryan Griffin of Nestlé,” says Jorge Izquierdo, PMMI vice president. “Among the latest developments, OPW has continued to update the PackML standard, which continues to gain traction in the end-user community.” Izquierdo reports that OPW sees continued support for PackML from all participants in the supply chain—food processors, OEMs and control suppliers. Does PackML matter to processors? The short answer is yes, because communications with both legacy and new equipment will mean processors have the data they need to continuously improve their operations.
The data you need to improve
Processors want data they can turn into KPIs and OEE, and they want it as a plug-and-play system. “OMAC is actively continuing to drive out standards for OEE and S88.5 (batch control),” says Martino Caranti, GE Intelligent Platforms global segment leader for advanced packaging and assembly. “We see these standards as a method of reducing cost by simplifying line integration for both OEMs and end-users. Food and beverage end-user adoption of OMAC standards will drive more open communication requirements, pushing OEMs to supply this functionality going forward. Driving the OMAC standards back into the OEMs will enable end-users to ‘plug-and-play’ their multi-vendor production equipment more easily, allowing reduced costs and better asset utilization.”
Integrating horizontally, machine-to-machine, is not the chore it used to be. The platforms are open and no longer proprietary, thus enabling systems to communicate. “Some plants are taking this integration to the next level by layering MES and ERP systems,” says Mitch Vanover, Hixson Architecture & Engineering manager, automation. “This not only integrates equipment horizontally, but also vertically as well by tying the factory floor to upper-level enterprise zones for better coordination of people and resources, while improving quality.”
While data collection and reporting systems obviously help the processor, they still need a fair degree of improvement. “It’s a huge task for machine builders to develop data collection/efficiency/reporting systems,” says Khalid Ikram, Evergreen Packaging engineering controls manager. “It would be beneficial if someone in the industry could provide already developed systems that can be easily interfaced with any machine.”
The vertical integration to MES and ERP is a work in progress, and tools are available to make it happen. Processors need to download information from the MES layer to machines for setup and product management. Machine builders need to aggregate the machine data to the MES layer for analysis of production runs, product quality and capacity utilization. “This entails increased LAN or WAN connectivity, ERP connectivity, local and I/O motion connectivity, and some programming with powerful integration tools,” says Caranti.
Improving machine performance
As packaging lines collect more data, new challenges occur and are being met by machine developers. “[Processors] are asking for more diagnostics and access to more performance data,” says Kim Magon, Triangle Package Machinery Co. marketing manager. “As a result, programs are getting very large, slowing down processor speeds. We need to see faster processors to be able to provide better diagnostics while at the same time, controlling our machine devices.”
One way to offload PLC processors of heavy data I/O transactions is to dedicate a module to communicate directly to an external database. However, it’s important that machine builders make sure these modules can talk to all PLCs in the system and use any database protocol that is used in the MES and/or ERP systems, according to Kaley.
Faster processors are not the only way to improve performance. “Faster sensors are allowing us to get data measurement instantly and make quicker changes to the machine,” adds Magon. For example, Triangle Package Machinery’s bagger can make automatic adjustments as necessary. If the jaw closes on a frozen chicken nugget, the sensor will detect a product is in the way, and the jaw will open automatically, preventing possible damage to the jaw that could lead to significant downtime.
Machine builders are also taking advantage of I/O devices like sensors and drives that can be mounted directly on the machine, avoiding long cable runs and potential signal loss. With many of the high-performance sensor buses available, wiring is also simplified on the machine as sensors and other devices can be daisy chained together.
Flexibility and changeovers
While machine performance/throughput is important, changeover time can have a major impact on production costs if the packaging machine isn’t flexible enough to adapt to various package sizes and shapes. Ideally, all an operator would have to do is key in a new SKU and select it when changeover is required. The way Evergreen accomplishes efficient and quick SKU-based changeover is through the use of servo technology, which allows running various motion profiles without any mechanical changes.
For machine builders, the use of soft PLCs (IEC 61131-3) and motion controllers that provide graphical cam and gearing design lets them design machines for quick changeovers, according to Andy Hansbrough, Kollmorgen vertical market manager, packaging.
System designers can run into performance limitations with traditional PLCs. Many PLC suppliers offer combined motion and PLC systems in the same box, and in many cases, programmable automation controllers may be PC-based—so the trend is to provide integrated motion systems regardless of what label is attached to the box.
With hardware, the use of servo motors provides the flexibility of a machine to make quick changeovers between products. “The latest developments in servo-based motion and position control are being used to automate guide rail position and other changeover settings, not only reducing the changeover time but also improving the reliability of the adjustment,” says Doug Ferguson, Hixson manager, manufacturing engineering.
According to Petrokonis, machine builders are trying to phase out pneumatics wherever possible because pneumatic devices typically are inefficient. While electrical equivalents have been prohibitively expensive in the past, their costs are coming down, and machine builders, with the aid of powerful design tools, are no longer specifying oversized components (such as a 2hp servo when a 1hp device is sufficient) to make sure the machine can handle the job.
Closed-loop pneumatic positioning control systems go a long way in extending the overall potential of pneumatic systems. “These systems combine an internal or external position sensor—calibrated to the cylinder’s stroke length—that provides a continuous feedback signal to a pneumatic ‘valve bank’ that increases or decreases the pneumatic flow to extend or retract the cylinder position,” says Tom Wood, Bimba Manufacturing marketing manager. “These systems are easily programmable to allow position flexibility and accuracy, allowing a single machine to service different packaging applications.”
Electric actuators have become a more attractive solution. “These actuators, with either a ball or lead screw in combination with a servo or stepper motor, provide greater accuracy and speed than pneumatic systems,” adds Wood. Although electrical drive systems have been historically higher in price than pneumatics, recent technology advances have made electrical systems more affordable to use in packaging machines, also increasing packaging machinery flexibility. Responding to line variations might have been the operator’s responsibility some time ago—e.g., to shut down the packaging machine gracefully when there were no products to be packaged. Under servo-based control and with connection to fillers, conveyors and robots on the line, this is no longer true. “We are now able to improve machine flexibility by providing an option that can automatically change the speed of our bagger based on upstream or downstream signals without operator intervention,” says Steve Bergholt, Triangle control system development manager. In other words, the bagger can speed up or slow down without stopping, which improves efficiency and reduces rejects.
Tools for machine builders and processors
Many automation suppliers offer simulation software products that speed packaging machine design. “Built-in machine simulators allow designers and users a low-risk way to iterate machine designs quickly and easily as machine and motion elements are developed to meet production requirements,” says Hansbrough.
This iterating or tuning can be used to size the servos and all the motion and position components based on loads, inertias, etc. Rockwell worked with SolidWorks to create a system called Motion Analyzer, which not only can tune the system but also suggest changes in structural design and create prints and bills-of-material as well. In addition, these tools prevent the gross over-specifying of equipment that wastes energy and also makes sure equipment is only energized when it needs to move or work.
Processors benefit from these tools indirectly; they also benefit from improvements to HMIs. Like some infamous Windows error messages that needed translation into plain English to be useful, packaging machine error messages like “AXIS 1 SERVO FAULT” are becoming a thing of the past. Operators may not know what an axis is, what number one refers to and just what is at fault. “Why not,” suggests Petrokonis, “tell them ‘The pusher arm is jammed?’”
Machine designers are responding through the use of pictures, graphics and international symbols that transcend an operator’s native language. Operators often have a selection of half a dozen languages, and there are often pictures, canned videos and PDF files to help them fix a problem—much like today’s office copy machine that explains where and how to fix a jam, says Deal.
“In 2012, we’ll be introducing a new feature that allows us to include a PDF parts manual as well as the operations and maintenance manual right on the HMI screen,” says Triangle’s Bergholt. Processors already have the option of bilingual displays and enhanced graphics and videos to show and explain proper procedures, he adds.
Control suppliers like Rockwell Automation have been partnering with robotics and motion manufacturers to try to consolidate various control screens from different components on the machine to a single interface, with the goal of combining as many as possible machine control screens on a single packaging line interface, according to Petrokonis. “We’re trying to make that integration a lot easier and cleaner,” he explains.
Touch screen technology with integrated safety, smarter menus driven by a bigger screen and the ability to host multiple software interfaces as a single interface are ways to provide operators with a single, unified system, says Caranti. This will simplify the experience for operators, improve productivity and reduce the chance of human error.
Stoppages and machine safety
Integrated safety systems are becoming a more important part of machine control. With many older machines, if an operator needs to take a break, the only way to do that is to hit the combined E-stop/off switch, says Petrokonis. This raises several issues: Did the machine shut down without jamming? What happens to OEE data if it’s being recorded? Are any food safety issues involved with an idle machine? These issues and others also apply to whether a jam occurs in the machine: Does the whole machine need to be stopped? Does the machine have to be cleaned before it’s placed back in operation?
As more safety systems get designed into the control of a packaging machine, it may not have to be shut down when a small door is opened to remove a jam, says Petrokonis. Rather, the machine can be slowed down safely to prevent injury and avoid a complete stoppage, which might result in a total clean-up. Machine builders are beginning to get some standards with which to design safety systems, and automation suppliers are providing the tools to integrate safety and machine control.
Continuing advancements in operational productivity require tight integration with machine safety, thus requiring machine designers to keep abreast of international machine safety requirements and regulations, according to Hansbrough. “PMMI has been instrumental in including international requirements and regulations while developing the new ANSI/PMMI B155.1-2011 Safety Requirements for Packaging Machinery and Packaging Related Converting Machinery standard, which became effective in September 2011. The B155.1 standard provides design safety guidelines for industrial and commercial machinery and contains several control design options. The standard is available to purchase from the American National Standards Institute (ANSI).”
Machine builders have a lot on their plate as they create new generations of smart packaging machines, which make a processor’s job a lot easier. The brains they build into the controls will provide more throughput, efficiency and safety, giving operators new tools to monitor quality and performance.
For more information
Leo Petrokonis, Rockwell Automation,
Brian Deal, Schneider Electric,
Jorge Izquierdo, PMMI,
David Kaley, Mitsubishi Electric,
Martino Caranti, GE Intelligent Platforms,
39 02 4888001, email@example.com
Khalid Ikram, Evergreen Packaging Inc.,
Mitch Vanover, Hixson Architecture & Engineering,
Doug Ferguson, Hixson Architecture & Engineering,
Kim Magon, Triangle Package Machinery Co.,
Andy Hansbrough, Kollmorgen,
Tom Wood, Bimba Manufacturing,
Steve Bergholt, Triangle Package Machinery Co.,