Linear axis-mounted robots, spindle pick-up automation and robotic hybrid palletizer systems help boost production efficiencies
By Patrick Waurzyniak
Automation systems are much more than just using robots to weld, cut or finish components. Today’s part-handling automation choices are expanding, with new or enhanced robotic and non-robotic material-handling solutions that can improve cycle times, optimize factory floor space and help lower overall manufacturing costs.
Linear motion automation systems greatly expand the robotic work envelope and help manufacturers maximize factory-floor layouts. Using track-mounted or overhead gantry robots offers manufacturers better options to create production lines best suited to their manufacturing operations. Among non-robotic material handling, newer spindle pick-up automation and linear pallet-handling systems offer manufacturers more choices in small-parts manufacturing for high-volume applications like automotive gears and engine components.
“Machine tending and machine loading are about 42% of the robot market. It’s significant, and it’s for everything from die-cast machines, to injection molding, to machine tools and all manner of machines,” said Joe Campbell, vice president, sales and marketing, Güdel Inc. (Ann Arbor, MI, and Langenthal, Switzerland). “Right now, because of linear motion technology you have an unprecedented array of choices for how to load and unload your machine tools.”
Those choices include using a robot at each machine tool, putting the robot on a floor track to serve multiple machine tools, or employing overhead gantry-mounted robots to service multiple machines. “The cost-effectiveness and reliability of linear motion robotic automation makes all of these choices viable,” Campbell said.
Expanding the Robot’s Reach
Automation specialist Güdel builds linear-motion automation systems for mounting multiaxis robots on track systems using universal plates that can fit any OEM robot brand. In January 2014, the company announced that it had transitioned all manufacturing of its third-generation robot tracks from Switzerland to its US headquarters in Ann Arbor, MI.
The Güdel next-generation robotic track systems include a newly launched overhead rail, the Trackmotion Overhead (TMO) system, that mounts robots on overhead gantries in either an inverted orientation, on the side of the rail or on top of the rail. The overhead tracks are somewhat unusual for the market, said Campbell, with FANUC offering its own gantry robot tracks while other robotic OEMs do not. “A lot of people use floor tracks rather than overhead gantries based on outdated perceptions of what is easier,” he added.
Rail-mounted six-axis robot models are popular because of their flexibility for multiple applications. “The operative word is multiaxis. The robot controller can manage the linear track motion as a seventh axis, making the robot and track operate as an integrated, highly flexible device,” Campbell said. “Furthermore, these systems can be reapplied and used in other applications.”
Using highly reprogrammable robots makes them an ideal flexible manufacturing choice for automating factories. “We configure linear motion tracks for an application, but we’re configuring them with the same building blocks that we may use for a completely different industry or a different segment, and they can be redeployed,” Campbell said. “We’re doing a number of jobs right now in automotive powertrain parts manufacturing where we’re relocating, reconfiguring, reprogramming and adding onto old gantry robots that we’ve installed over the years.”
More Robust Construction
In high-speed sheetmetal press automation, powertrain machine load and unload, and tire manufacturing, Güdel acts as an integrator. “We use our standard modules configured specifically for an application such as powertrain. In both tire and sheetmetal, we have standard products designed for those applications,” Campbell said.
The traditional approach has been to build very light, open-truss-designed gantry robots, he added. “You’ve got two X tracks in parallel, then the beam that goes across them is an open truss, like the truss you’d find in a steel building,” he said. “From that design standpoint, the way you get speed and performance is to keep taking weight out—you want as light a weight as possible. We think we’ve got a better alternative for the increased demands for higher throughput in the packing area.”
Güdel takes a different design approach, he said. “We built our gantry mechanisms with welded box-beam construction and steel tube, not an aluminum truss. Our philosophy is to build the mechanism as stiff as possible, with a rack-and-pinion drive instead of the belt drive, and take that stiff mechanism and push a tremendous amount of power into it through the motors and the gearboxes—that’s how we get speed.”
The new generation of Trackmotion adds improved performance and reliability. The frame is now a closed, gusseted weldment that delivers increased stiffness with a smaller footprint. The enclosed frame design also prevents debris buildup in the center of the track. The track’s improved stiffness means less deflection over the travel length, with repeatability of ±0.02 mm, the ability to operate at higher speeds and acceleration of up to 180 m/min, while requiring less floor space.
“The previous generation was kind of brute force, they would lay down two C channels and weld a bunch of cross beams, like railroad ties, across them,” Campbell said. “You still see people offering this, which is big and heavy. If you look at the new Trackmotion systems we’re doing, it has a welded, closed-profile design with gussets—it’s like a unibody in a car.” The welded frames give the system much more stiffness with less mass while taking up much less space. “The robot guys want the best ratio of usable work envelope to footprint—they want the smallest dead space around the base of the robot, and the biggest work envelope.”
Testing for a worst-case scenario is critical to ensure reliability. Where many buyers make a mistake is to just add the weight of the robot and the payload together, Campbell noted. “If the robot weighs 1000 pounds, with a payload capacity of 100 pounds, and I build my track and the bearing structure to support 1100 pounds, that’s guaranteed to fail,” he said. “The worst case is the robot with a full payload, and the full payload is at a certain distance from the toolplate on the robot, then you put the robot at full extension and at 90° to the track so it’s stretched out over the side, move it at full speed and then hit the emergency stop. That is when you need your track to perform.”
Adding Robotic Flexibility to Palletizers
For more flexible palletizing systems, automation and robotics integrator Intelligrated (Mason, OH) has been adding robots to its traditional palletizing systems used in process industries, packaging systems and warehouse applications. “We’re seeing an increased need for flexibility in our solutions,” said Matt Wicks, Intelligrated vice president, product development, manufacturing. “Many of the demands placed on our customers require them to be agile with their solutions. Robotic applications are at the forefront of this trend.”
Intelligrated’s solutions for manufacturers include case packing, palletizing, warehousing and order-fulfillment. “Many manufacturers’ automation solutions focus on the process of manufacturing the product, but when it comes to packing, palletizing and warehousing, this is where their automation systems stop,” Wicks said. “We offer automation solutions to streamline manufacturers’ processes downstream of their manufacturing.” The company’s automation systems include robotic case packing and palletizing, conveyance and sortation, automated storage and retrieval systems (AS/RS) and shuttle technology, inventory management, warehouse management systems software capabilities and order-picking solutions.
Many requirements should be considered when investing in an automation system, Wicks said, including system capacity, return on investment and reliability. “When considering solutions to automate manufacturing order fulfillment, integration with the manufacturing systems is critical,” he said. “The tight relationship between what is being manufactured, what is in inventory and what is required to fulfill orders must be balanced to maintain efficiency of all the systems.”
Several new products recently launched that lend support to order fulfillment needs of manufacturers, Wicks said, including the Alvey 750 robotic hybrid palletizers, several new product offerings from Intelligrated’s Knighted subsidiary and the OLS (one-level shuttle) system for case storage and retrieval.
“Integration of robotics into our automation solutions have been increasing over time. A good example of this is how we have been integrating robotics into our conventional palletizers,” Wicks added. “Traditionally, automated palletizing has been done with a custom machine suited to the needs of the manufacturer that are unique to the manufacturer’s products. If those products change over time, physical changes may be required to support the new product types. By integrating robotics into a conventional machine, this provides more flexibility into the palletizing patterns being formed and reduces the need for physical changes when packaging changes. As robotics become more advanced, the opportunities for their integration have followed suit.”
Spindle Pick-Up Automation
For smaller parts manufacturing, the VL-Series turning machines from EMAG LLC (Farmington Hills, MI) use the machine working spindle not only to machine workpieces, but also to load and unload them from automation. The VL-Series vertical pick-up turning machine models include the VL 2, VL 4, VL 6 and VL 8 lathes aimed at small-part manufacturing applications in automotive and nonautomotive medium-to-large-scale part production.
With EMAG’s patented spindle pick-up technology, the workpiece is transported into the machine using a lateral conveyor system in an “O” design included as standard equipment. The “O”-automation is a workpiece transport system which is fitted to the left side of the machines. “The parts travel on the conveyor to a pick-up station,” said Marius Mazur, product manager for the VL of turning machines. “In the pick-up station, the parts on the conveyor belt are positioned exactly in the center using the NC program. A gimbal-mounted pressure plate pushes the part safely to the clamping jaws and workpiece clamping system, irrespective of burrs or casting projections. For us, this automation is an integral part of the machine, where one operator can operate up multiple machines at a time.”
The VL-Series vertical turning machine’s advantages include a small footprint and the automation’s ability to lower cycle times and optimize machine uptime. The pick-up spindle takes the raw parts from the universal workpiece prism and after machining places finished parts back on the prism.
Workpieces handled by the VL-Series lathes are mostly cylindrical; however, asymmetrical or position-oriented workpieces can be put on specially designed pallets and simply inserted in the drag frames, Mazur said. Workpiece sizes range from 100-mm diam and 150-mm length for the VL 2 lathe, ranging up to 400-mm diam by 300-mm lengths on the largest VL 8 machine. The systems offer users attractive Overall Equipment Effectiveness (OEE) levels with high machine uptime. Cycle times are improved dramatically with the system, Mazur said. “Pick-up working spindle moves in the X and Y axes with minimum response times and the tool turret guarantees short swiveling times,” Mazur said. “The machine is working constantly.”
High-Efficiency Pallet Changers
Another non-robotic solution, the Rotary Loading System (RLS) comes from automation developer Liebherr Automation (Saline, MI), a subsidiary of Liebherr-Versahntechnik GmbH (Kempten, Germany). The RLS offers a smaller footprint and it’s aimed more at job-shop-type applications, noted Kevin Heise, vice president, Automation Systems, Liebherr Automation.
The RLS is ideal for smaller operations that don’t need and cannot afford larger linear automation systems like Liebherr’s PHS pallet-changing linear automation systems. The RLS is a cost-effective way to automate high-efficiency production on one or two machine tools, Heise said.
“The linear gantry is the backbone of our portfolio,” Heise said. “It was basically one of the whole enablers, once manufacturing switched from transfer lines.” The systems help manufacturers maximize production, he said, for high-volume lines in automotive that build crankshafts, cams, heads, blocks, and transmission parts.
Medical components are another area targeted by Liebherr with the RLS automation, which comes in two sizes, the RLS 800 and RLS 1500 systems capable of transporting workpiece weights of 800 and 1500 kg, respectively. “The Rotary Loading System is kind of like the little brother of the PHS,” Heise said. “For smaller footprint applications, it’s ideal and you might load one or two machine tools with it.”
Liebherr’s RLS automation helps keep machines running constantly, Heise said, with machine uptime averaging up to 90–95%. For a job-shop owner, this allows the operation to free skilled operators for more advanced work in toolsetting, gaging or other areas, he added.
The RLS features rack columns that are modular designs, with up to 24 storage locations in a minimal footprint. The optional Rotary Storage Tower (RST) can be added later, with the tower offering space for up to 18 additional storage locations in a slightly larger minimum space requirement. The systems include the Soflex Cell Controller for simple operation with an intuitive user interface for the Soflex-PCS cell control system software. ME
This article was first published in the June 2014 edition of Manufacturing Engineering magazine. Click here for PDF.
Published Date : 6/1/2014