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Automating the Factory

 

New robots, controls, and conveyors help keep factories humming

 

 

By Patrick Waurzyniak
Senior Editor 

 

 

Automation equipment fuels the factory. From robotics and automation controls to the latest in conveyor technology, today's manufacturers need the best tools to automate their plants in order to stay ahead of the competition.

Robotics technologies play key roles in automating factories, working as material-handling systems and applying vision-guided robots in many newer applications. Along with vision systems, more intelligent robots and improved robotic controllers lead the way in automating today's factories.

Intelligent robots and vision add capabilities to robotics, making possible applications that didn't exist some time ago. "There are two trends I'm encouraged by, and one of them is making possible new applications," notes Dick Johnson, general manager, material handling, Fanuc Robotics America Inc. (Rochester Hills, MI). "If you take a look at our intelligent line of products with force sensing and all six degrees of freedom, and also our 3-D vision product that uses structured light and gray-scale, all of a sudden new things are possible that were not possible without those features."

With robot sales on an upswing in 2004, cost factors contributed to a recent surge in robotics applications, Johnson adds. "Another area is cost reducing existing applications from a system level, and 2-D vision has certainly been very strong. If you had a robotic system in the past, you typically had to present the products to be conveyed or transferred to the robot extremely accurately, so the robot was repeatable, it could go to the same fixture, the same location, pick the part, load the machine tool, or convey or transfer the part. With the 2-D vision, all of a sudden all you need is a belt conveyor, and if that part is put somewhere near the robot, the vision system can see it, it can pass the information to the robot, the robot can then pick it."

Such robotic systems can make the costs of adding a second robot to existing applications much lower, Johnson says. While many of Fanuc's customers are automotive OEMs and Tier suppliers, the company now is attempting to spread its reach into general industries. "Automotive has been pretty much where robotics was founded, and remains a large portion of our business, with paint-shop and arc-welding applications," says Johnson, adding that material handling allows stretching into different businesses including palletizing assembly and nonautomotive parts.

Vision-based systems pave the way for many robotics applications, with Fanuc gaining about 25% annual cumulative growth in vision, Johnson notes. "The key is, back in the '80s a vision system might be $80,000 and then the application engineering to tailor it to your application was another $80,000. Today, we have vision systems that list for $5995. Now that's the software, you still have to buy a PC and a camera, but it gives you the idea."

At IMTS 2004, Fanuc Robotics demonstrated several systems including intelligent robots and vision-based systems, as well as introducing its new heavy-duty, 3-D vision-guided six-axis M-900iA series robots, which are available in 350 and 600-kg payload models designed to tackle heavy-part transfer duties such as automotive powertrain applications. The new robot boosts Fanuc's top payload from the previous maximum of 450 kg.

"We also greatly increased the moment of inertia, because when you're moving a big part, you can assume that it's going to be at some distance from the face plate," adds Johnson. "That's where the robot sees the counteraction of the moment, and when it moves it, it sees the massive inertia."

Robot controllers typically are proprietary rather than open controls with full Windows compatibility, but with its new NX100 robot control, Motoman Inc. (West Carrollton, OH) is offering customers a control with Windows CE and a separate real-time operating system, according to Eric Nieves, Motoman manager, technical advancement. "From a motion-control perspective, it's not really that different from the previous generation, in terms of number of robots, number of axes--but of course, it's a new controller so the architecture's faster, the processor's faster, the interpolations are faster, better."

With the NX100 control, Moto-man offers customers the ability to control multiple robots, as did its predecessor, the XRC control, but the robot supplier previously hadn't offered a nonproprietary control. Using VX Works, the NX100 features a real-time operating kernel for motion control that functions separately from the Windows OS.

"The big issue is probably the architecture from the controls perspective," Nieves says. "It is a two-operating-systems control. That's fairly novel. We've been doing proprietary operating systems since we started, but the reason we did this is we get a lot of requests for PC functionality on a robot controller. People want the ease of use, the familiarity, of Windows, but on the other hand, you've got a sophisticated control that you don't want anybody messing with. So we use VX Works, which is commercially available. Two of the most famous mission-critical applications using it are [NASA's] Endeavor and the Mars landing craft.

With Windows CE, the system offers boot-up times of under a minute, Nieves adds, and it also features an integrated soft PLC with increased I/O, faster scan time, and support for larger ladder programs (up to 10,000 steps), and a graphical ladder editor that runs on the NX100's teach pendant. "For years, the controls engineers have hooked it up to the laptop and viewed it in structured rungs," he adds, "and we applied that same GUI to our concurrent I/O. It's a big advantage to controls engineers and to the maintenance man to program on the robot pendant or on a PC, and send it to the controller."

Multiple robot control can help manufacturers cut the cost and footprint required in robotic cells for multiple controls on cells with more than one robot, adds Nieves. The new control's cabinet is about 350-mm wide, while the previous controls for two robots required about two linear meters. "We're giving them back floor space, which dovetails into what we're trying to do with Six Sigma," says Nieves. "Instead, you could put in some inspection equipment so you could do in-process inspection in that area."

Ease-of-use in programming for automation applications can pose problems for manufacturers seeking robotic solutions. "We've seen a reluctance in the past for manufacturers to apply automation because of the complexity of it," says Keith Bailey, director, product development, Adept Technology Inc. (Livermore, CA). "Machine-tool users are more comfortable with CNC-type programming. Most robots don't program in a CNC environment, but something like a teach pendant is very close to that and they're comfortable with it.

"As the cost of robots declines and the capability tends to accelerate, we find there are new barriers," he adds. "Cost used to be a barrier, now the next barrier is complexity."

Another factor is that manufacturing operations, like most businesses these days, are trying to do much more with less. "They're reducing their people and they're doing the same job now with half the people," Bailey notes. "Where they used to send their people for training, now they don't train. People don't want to be trained. They want a product that they can use."

To make robots more intuitive and easy to program, Adept recently used PLC programming familiar to controls engineers in its Cobra PLC line of SCARA robots, Bailey notes. "There is a large base of engineers that know how to program using the Rockwell approach," says Bailey, adding that Adept's PLC Server interface has recently been adopted by Rockwell's third-party programs. "They have a whole array of broad PLCs that they sell, all programmed with the RSLogix software. One direction we're heading in is more toward coming out with products and interfaces that are familiar to people.

"We're also working on ease-of-use in terms of point-and-click environments," Bailey adds. "The robots we have today are pretty easy to use, but when you go into vision-guided applications, which are pretty common today, the level of complexity rises dramatically. Ten years ago, you had to be a vision expert just to get it to recognize a part."

Robots can now run parts through an object finder to locate parts, and the systems are much closer to the point where users can point-and-click in order to see the object, says Bailey. "It's down to what we call a single-instant training session," he says. "We've been moving our vision toward the PC platform, where our upcoming iVision product will be our first for robot guidance specifically on a PC-based platform."

Demand for robots has been strong this year for Rixan Associates Inc. (Dayton, OH), exclusive supplier of Mitsubishi robots in North America, notes Stephen Harris, Rixan president, particularly for the company's specialties of assembly, pick-and-place, and machine tool load/unload.

"Consumer confidence is up and we've seen a big improvement," Harris says. "We're seeing a lot more price sensitivity than we used to. Controllers getting smaller and far more capable, and reliability is going up."

Automating manufacturing also requires enabling automation equipment to share information seamlessly across the enterprise. Newer CNC controls and drives are making it easier for plant management systems to send information from automation equipment up to the factory enterprise, according to Rick Rey, product manager, Bosch Rexroth Corp. (Hoffman Estates, IL), Electric Drives and Controls.

"Being able to monitor production by monitoring good and bad parts can easily be dynamically tracked during production," notes Rey. With the new Rexroth IndraMotion MTX control's Ethernet connectivity via the industrial PC and Ethernet interface integrated with the CNC hardware, the control's Ethernet connection allows production information from the CNC to be passed up to the factory enterprise.

"The monitoring of a machine's system diagnostics and error reporting is a crucial trend in automated factories," Rey notes. "Being able to detect a problem when it occurs is essential; the factory maintenance can react immediately to problems. Likewise, using information from the control and drives to detect when there is a potential problem, maintenance personnel can rectify a potential problem before a breakdown."

With its predictive maintenance feature, which can be used to monitor the amount of stiffness and play in an axis, the IndraDrive can send an alarm when the tolerance of amount of stiffness or play in the axis is being exceeded, Rey notes. "By receiving this alarm, the maintenance personnel can check the axis before potential damage to the machine occurs that would cause greater downtime," Rey adds. "As you know, in factory automation, time is money. If the machine is not producing parts, that's money lost."

Factory efficiencies can be greatly aided by implementing Six Sigma and Overall Equipment Effectiveness (OEE) programs, notes Jim Spearman, manager, Machine Tool Solutions, GE Fanuc Automation Americas Inc. (Charlottesville, VA).

"One of the most critical elements to a successful OEE improvement program is a robust shop-floor data collection and plant-intelligence software system," says Spearman. "A good system will provide network connectivity to machine tools and other assets and provide drill-down intelligence at the machine line or cell level. These systems can improve your asset utilization by helping you understand shop floor dynamics, minimize downtime with predictive maintenance, determine causes of machine downtime and idleness, and provide baseline measurements and detailed reporting on OEE. The system also provides the needed information to aid in developing an effective control plan to ensure process improvement sticks."

Automated conveyor equipment like Bosch Rexroth's new VarioFlow flexible chain conveyor system introduced at IMTS 2004 also can help manufacturers increase factory flexibility with improvements in line speed and reductions of line bottlenecks on assembly lines.

With the VarioFlow, manufacturers can link assembly operations with functions such as parts feeding and packaging on either side of the assembly process. VarioFlow consists of two profile widths, 65 mm and 90 mm, with chains of 62 mm and 87 mm, respectively. The system offers an integrated variable-speed drive option with transport speeds (up to 60 m/min) and stronger chain than other single-strand chain conveyors.

 

This article was first published in the February 2005 edition of Manfacturing Engineering magazine. 


Published Date : 2/1/2005

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