by Bennett Brumson , Contributing Editor
Robotic Industries Association
Robotics have the speed, strength, and precision to accomplish an ever-widening range of tasks in the manufacturing and packaging of consumer goods, appliances and more. But, without a suitable end-of-arm tooling (EOAT), an industrial or service robot can’t manipulate a product. “End-of-arm tooling enables the robot to add value to the end-user’s process. Without an EOAT, the robot can do very little,” says, Tim DeRosett, Director of Marketing at the Motoman Robotics Division of Yaskawa America Inc. (Miamisburg, Ohio).
The Basics of Tooling
Power in Hand
End-effectors are actuated electrically, hydraulically, mechanically or pneumatically, and are available in a variety of styles, including angular and parallel. Selecting the proper EOAT for an application is usually based on end-user’s needs and the familiarity of the robot integrator. As EOAT, robots and their controllers become more powerful and capable, random bin picking is emerging as a mainstream application.
“Advantages and disadvantages of each type of end-effector vary relative to power consumption, size, complexity, weight and requirements. Pneumatic end-effectors accommodate most applications in the packaging industry due to their weight-to-power ratio,” says Samir Patel, Director of Sales and Engineering at Kawasaki Robotics (USA) Inc. (Wixom, Michigan). “When compared to electrical end-effectors, installation of pneumatic end-effectors is relatively simple and components are easy to find.”
Pneumatic EOATs are well understood and have been available for many years, making them the majority of tooling, says Walter Hessler, Vice President of Sales with PHD Inc. (Fort Wayne, Indiana). “In the past and the near future, the majority of EOATs are pneumatic. Pneumatic EOATs are readily available and can apply significant forces at high speeds in a small package. Pneumatic EOATs are an effective medium for generating force and motion.”
Hessler goes on to talk about the drawbacks of pneumatic EOATs. “Pneumatic end-effectors provide for less control over grip forces and are less flexible than electric EOATs. Until recently, manufacturers considered pressurized air to be free of cost. Everyone is now looking at the costs of air compressors.” Compressed air is no longer “free as air,” as once was the conventional wisdom in manufacturing.
Hydraulic EOATs are able to generate very high clamping forces and to actuate quickly. “Hydraulics are fast and precise,” says Chris Blanchette, National Distribution Sales Account Manager with FANUC Robotics America Corp. (Rochester Hills, Michigan). “Broken hydraulic lines can be extremely messy and can destroy tooling or parts. Hydraulic EOATs are expensive because of the need for large compressors to run the fluid.”
In conjunction with the source of an EOAT’s power, end-users and integrators also must decide which style of tooling best suits the needs of a particular application.
“Integrators select end-effectors to deal with a high mix of consumer products that might change frequently by adding fingers capable of adapting to different products. Two or three articulated fingers encompassing a product has enough contact points to form a stable grip,” says, Samuel Bouchard, President of Robotic Gripper Co. (St-Nicholas, Quebec, Canada). Adaptive grippers facilitate consumer goods production and packaging due to the fact that these EOATs automatically adjusts when manipulating a high mix of products, says Bouchard.
Parallel EOATs work well when wielding well-defined non-compliant products says William Townsend, President and Chief Executive Officer of Barrett Technology Inc. (Cambridge, Massachusetts). “Parallel jaw grippers with two or three fingers do a good job of handling well defined objects. These grippers work well if parts are organized upstream before entering the robot’s workspace.” If the product is susceptible to changing shape, the end-user should consider an EOAT with more flexibility, says Townsend. “With delicate objects, the gripper needs to sense the forces, so as to not damage the component.”
Angular tooling is compact, says Blanchette. “Angular grippers are very fast and small which is an advantage for end-users. The disadvantages of angular grippers is the relatively limited part mix they can pick because of the angle they run in.”
Hand in Hand
The robotics market is trending towards hybrid tooling, where an end-effector has several tools to perform a wider range of tasks. “Robotic layer grippers for de-palletizing in supermarkets and warehouse distribution centers deal with thousands of stock keeping units. One technology cannot handle that variety so end-users need an EOAT with a combination of technologies. Designers of EOATs are becoming more comfortable with hybrids, combining different technologies,” says Dr. Volker Schmitz, President of Schmalz Inc. (Raleigh, North Carolina). Engineers are no longer wedded to one tooling technology when designing a solution to meet end-users’ needs.
Motoman Robotics’ Software and Controls Technology Leader, Greg Garman, concurs. “The robot is able to pick multiple parts with the same gripper. End-effectors might have a parallel jaw gripper on one side, an angular gripper on another, and have suction cups on another side. Each tool can pick up different parts.”
Many consumer items and appliances, among others, require a light touch during the manufacturing or packaging process. “Vacuum is not an invasive grip and the strength of vacuum cups is well beyond their physical size. The air pressure of pneumatic grippers can be adjusted to dial-down the force of the grip,” says Robert Dalton, General Manager of SAS Automation LLC (Xenia, Ohio). Coating a gripper’s jaws with polyurethane or silicone is another way to deal with delicate parts without causing deformation.
Like Dalton, Tom Herdon, General Manager at FIPA Inc. (Cary, North Carolina), advocates operating vacuum tooling at a lower power level. “Turning down the vacuum or using different materials such as a soft rubber enables end-users to handle sensitive products. Rather than grabbing a product, surrounding and handling it from the outside works better,” Herdon says.
Obtaining information about delicate parts goes a long way in alleviating end-users’ reluctance to accept robotics in the production process says Brandon Schmutlzer, Design Engineer at the Vaccon Company Inc. (Medway, Massachusetts). “We get samples of the part from the end-user. If the end-user worries about lightweight glass cracking, we design our system around that concern by using adjustable pumps so not to pull too high of a vacuum on the part.”
Manufacturers are increasingly making use of radio frequency identification (RFID). Herdon says, “Integrators put RFID tags on the EOAT and the product being manufactured to ensure the correct tool is used for that product.”
Random bin picking is the ability of vision-guided robots with appropriate tooling to pick haphazardly arrayed parts or components from a bin and place them for the next step in the manufacturing process. It is seen by many integrators and robot end-users as the ultimate application, not only in consumer goods and appliance manufacturing, but other industries as well.
Adil Shafi, President of ADVENOVATION Inc. (Houghton, Michigan) says, “Bin picking has come a long way. Random bin picking was difficult to implement in the past but has become easier to implement. I predict that by 2020, a number synonymous with perfect vision, bin picking will be mainstream in manufacturing.”
Shafi says some engineers define bin picking as simply removing parts arranged in one layer a form of bin picking, while others believe a robot is not bin picking unless parts are entangled together. “Bin picking is not a monolithic application but has many subclasses,” says Shafi. For more information about bin picking applications, view past Robotics Online feature articles on the topic (How to Implement Bin Picking… and The Pervasive Relevance of Bin Picking…).
Shafi will lead a webinar, The Basics of Robot End-Effectors, on Thursday, February 16, 12:00 PM through 1:00 PM EST. “I will cover the basics of each type of gripper and focus on compliant gripping,” previews Shafi.
To successfully execute random bin picking or combining more than one application in a single robotic work cell, integrators of the EOAT should consider how the entire production process is organized. “A good integrator should ask where the part came from before entering the work cell. If the part has a known orientation, a good integrator will try to prevent loosing that known orientation,” says Tom Sipple, Material Handling Technology Leader at Motoman Robotics.
The container from which parts are picked could also pose a challenge to integrators of bin picking applications, says Rick Bobzener, Engineering Manager at Tech-Con Automation Inc. (Burlington, Ontario, Canada). In one example, Bobzener says, “The design of the actual container was a challenge. Our robots could find [the parts], their angle, and interface the tool…to pick it up. The biggest problem was overhanging lips, deformed bins, and other features that created interference when bringing the part out of the bin.”
Pure random bin picking is still a “holy grail” of robotics and is not 100 percent yet, concludes Bobzener.
Robotic tooling covers a wide range of consumer goods and other products and processes. “Applied Robotics (Glenville, New York) has looked at grippers for everything from cups of gold nuggets to bundt cake pans to robotic bartenders,” says Gerry Morris, Application Engineer at Applied Robotics. “Design and implementation comes down to an object’s material, shape and required motion, as driven by a combination of the robot and end-effector.”
More Tools, More Apps Throughout All Industries
As tooling becomes more sophisticated and capable, new applications will open for robotics. “Because a greater variety of end-effectors are available now, robots are used in a wider range of applications, such as packaging and food processing and other wash-down applications,” says Hessler. “In the past five years, robots have been used in a wider range of applications than ever before because end-effectors can now function better in those environments.” Look to see this trend of robotics equipped with tooling of greater sophistication continuing and expanding, not only in the manufacturing of consumer goods and appliances, but throughout all industries.