ROBOTS: A matter of control
Canadian PlasticsPlastics Processes Plastics: Auxiliary Equipment
Underperformance is a drag. Ever go to the movies and watch an actor clearly phoning in his lines, or to a concert and listen as the singer just goes through the motions? Irritating, right? Now imagine that you’re a plastics part molder,...
Underperformance is a drag. Ever go to the movies and watch an actor clearly phoning in his lines, or to a concert and listen as the singer just goes through the motions? Irritating, right? Now imagine that you’re a plastics part molder, with your business hanging in the balance, and your equipment is going through the motions. That’s more than irritating – it’s serious stuff.
Unfortunately it happens too often. Maybe even to you. Take your automation. Most molders know that robots can offer savings by removing labor from the gate. But just because you have robots operating in your plant, don’t assume that puts you ahead of increasing domestic and global competition. What was top performance yesterday might be uncompetitive today.
Having the right controls and programming software tools can be the key. “Many processors have the proper equipment on the floor, but don’t fully understand the controls and therefore don’t maximize their automation,” said Stephane Bourdages, vice president of Automatisation S.A.B. Inc., which represents Harmo. “They think their robots are performing effective pick-and-place operations, but in reality they have wasted cycle time in the mold area and a robot waiting over the mold when it could be adding value by trimming, boxing, inspecting, or assembling parts.”
The good news? New control and programming software tools are being implemented continuously by suppliers, and they can help simplify control, enhance performance and flexibility, improve communication, and reduce maintenance.
THE RIGHT ROBOT
One of the problems of in an underperforming robots and automation situation is rooted in the machines themselves. In keeping with that old adage about the silk purse and sow’s ear, robot controls can’t make an out-of-date robot better.
“A few years back, molders used to brag of having robots that were well-maintained and lasted 12, 14, 16 years or more,” said Joe Varone, regional sales manager for robots at Wittmann Battenfeld Inc.”But because of the rapid change in robot technology, a robot more than seven to 10 years old is more likely making the molder less competitive by not optimizing the possible cost benefits. Even though those older robots have been through the accounting cycle and are paid for, they should be replaced if maximum performance and output are important to you.”
Newer linear and multiple-axis robots are faster, have less downtime through improved reliability and communication capability (messaging and networking), offer better communication to the operator (user graphics and interface simplification), and can perform 3D motions that conserve energy while reducing cycle time. In some cases, the robot can optimize 3D work paths automatically, a new leap in technology. The caveat, though, is that some of these capabilities can only be fully realized if the control units are fully integrated, and if the operator knows how to properly work the controls.
THE JOY OF INTEGRATION
“Integrating the control units gives the user even more options for optimising the interplay between the injection molding machine and the robot,” said Johannes Brandstotter, head of sales with Engel Automation. “The integrated robot can access all of the machine parameters and start to take off parts before the mold is fully open, thus reducing cycle time. We refer to this kind of communication as zero time communication because no time is lost for transmitting information via interfaces; instead the information is processed by a single CPU.”
The integration is almost always easier to accomplish if the molding machine and the automation technology have been purchased from a single source, Brandstotter added, since it lessens the amount of data management work.
As with the robot and automation units themselves, it helps if the controllers are current generation. “A lot of the controllers that processors are using are showing their age, and don’t have the required flexibility without having someone else program it for the processor,” said Rod Charlton, president of ODG Automation Inc.
There’s no doubt, electronic controls technology is advancing rapidly and allowing performance and functionality such as vision guided robots and significant advances in messaging and networking. “Tracking information and communicating it throughout the organization is easily achieved and an added benefit of some of the recent advances being made,” Charlton continued. “It’s even possible for the manufacturer of your automation equipment to have electronic remote access and provide analysis and troubleshooting support to your maintenance staff even when a technician can’t be dispatched immediately. Vision systems in automation and on robots can do more than inspecting and measuring your parts; vision is increasingly being used to guide robots so that they can locate parts for pick-and-place or to guide a robot for the assembly of components.”
KEEP IT SIMPLE
Today’s generation control systems definitely aren’t kids’ toys, but most are noticeably simpler to master than their predecessors. “To allow for simple and fast programming and control of the robot, despite the complexity of the overall system, Engel’s RC 200 robot control unit offers the users different user levels, from a simple view, to a fully object-oriented visualization of the sequence,” said Johannes Brandstotter. “In other words, the control unit speaks same language as the machine operator, the fitter, and the programmer. Machine operators can now handle many tasks themselves that previously required programmers to be called in.”
These new control systems are almost sci-fi movie smart. “Yushin’s E Compact and E Touch II controllers feature so-called ‘artificial intelligence’ for the speed and timer control, with the robot monitoring an injection molding machine’s cycle time and mold open time to automatically adjust the speed and timers to match it,” said Brad Lemieux, sales manager with Yushin representative En-Plas Inc. “Also, when the processor adjusts the injection molding machine’s cycle, the robot will intuitively and automatically adjust itself to match the changes, making the robot operator’s life a little easier.”
And they’re fast, too, and with a lot more to offer than just de-molding. “Sepro’s new Visual 3 control operates at 20-millisec speeds, which is five times faster than its predecessor,” said Jim Healy, vice president, sales and marketing, with Sepro America LLC. “It also has a path tracking feature that allows our S5 line of three-axis servo robots to be programmed to move a part through a complex pattern inside or outside of the mold space, making it possible to remove large complex parts from tight mold openings, or perform motions outside the molding area that might otherwise require an articulated-arm robot.”
Here’s something to keep in mind: “Going forward, most of the advances in robot technology will be in the controls,” said Joe Varone. In other words, without the right control and programming software tools integrated into the right robots and automation, your production work cells run the risk of just going through the motions – and costing you your competitive edge.