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Jun 26, 2023

Collaborative Robot Do’s and Don’ts

Collaborative robots enable humans to work in close proximity to machines without traditional safety barriers and cages. Photo courtesy Universal Robots USA Inc. Collaborative robots are an important

Collaborative robots enable humans to work in close proximity to machines without traditional safety barriers and cages. Photo courtesy Universal Robots USA Inc.

Collaborative robots are an important element of Industry 4.0 and smart manufacturing initiatives. The next-generation machines can control force and work safely next to people on assembly lines without traditional safety guarding.

Since cobots first burst onto the scene more than a decade ago, they have transformed many factory floors and made automation more accessible to smaller manufacturers. The technology has also enabled numerous companies to reshore production to the United States and implement low-volume, high-mix production strategies.

On the outside, many cobots look similar to traditional SCARA and six-axis robots, but they’re actually much different. They are typically lighter and slower, and they have smaller payload capacities. Their mass and momentum are effectively reduced. Most machines are designed to stop if they come in contact with a person or object.

Advanced sensors enable cobots to stop or reverse direction if they come into proximity with a human. The technology combines the use of several safety checks; perceptive and predictive systems that allow robots and humans to work side by side.

Technically, there are four modes of collaboration: hand guiding, power and force limited, speed and separation monitoring, and safety-rated stop. The first two modes require specialized robots with force sensing, rounded edges, redundant controls and software. However, speed and separation monitoring and safety-rated stop can be accomplished with traditional six-axis robots just as easily.

Collaborative robots offer many advantages over traditional industrial robots for certain applications. They’re safe to operate next to people without cages, so they can be utilized in highly manual production lines that have historically been off-limits to traditional robotic systems.

Most cobots are also significantly easier to program than other types of industrial robots. And, they’re extremely flexible, meaning they can be easily redeployed and repurposed quickly to work on different tasks in a facility.

In addition, because they require less physical infrastructure to operate, collaborative robots can fit more readily into workspaces designed for humans. This helps to maximize their return on investment, since manufacturers are able to utilize them across multiple assembly lines in a plant.

Above all, cobots are designed to work together with humans instead of replacing them. The goal behind the technology is to place control of factory automation back into the hands of operators and give them a tool to do their jobs more efficiently.

“Collaborative robots are opening the door to manufacturers that have been apprehensive to automate their assembly lines in the past,” says Chris Blanchette, executive director for global accounts at Fanuc America Corp., which offers a variety of cobot models. “It’s finally bringing a lot of companies on board to the value of automation.”

“A collaborative machine can be set up by operators after only a few hours of training, is light enough to be redeployed around a plant multiple times per day, and can be made to run without fencing and guarding,” adds Joe Campbell, a robotics industry veteran who recently retired as senior manager of strategic marketing and applications development at Universal Robots USA Inc., the company that pioneered the technology 15 years ago. “Functionally, every weakness or difficulty of a traditional robot is obviated by the change in focus.”

In the past, many people were intimidated by robots. Advanced technology now makes robots more accessible to everyone, especially small manufacturers. Collaborative machines are flexible, easy to use and safe to operate.

Collaborative robots can help companies in all industries boost quality, improve efficiency and reduce costs. However, as with any automation tool, their overall effectiveness depends on choosing the right application and planning ahead.

According to Grandview Market Research, the global market for collaborative robots will grow 32 percent annually between now and the end of the decade. This demand will be driven by shorter product lifecycles and the increasing prevalence of low-volume, high-mix manufacturing environments instead of high-volume, low-mix production.

Cobots can be utilized in highly manual production lines that have historically been off-limits to traditional robotic systems. Photo courtesy ABB Robotics

Most cobots are much easier to program than other types of industrial robots. Photo courtesy Universal Robots USA Inc.

Despite all the hype, cobots have pros and cons that manufacturing engineers must carefully consider. The technology is exciting, but it’s not ideal for some types of applications. For instance, limited payload capacity and slower operating speeds are two drawbacks.

“Cobots tend to have lower capacity than many other types of robots, but they make up for it when to comes to ease of use and deployment,” says Campbell. “Most cobots are articulated, six-axis machines, so they don’t give up anything in terms of reach or work envelope. They’re also just as repeatable and precise as traditional six-axis robots.

“But, speed is definitely slower than a traditional robot when operating in collaborative mode,” explains Campbell. “If you want to make lots of products at high speeds, cobot technology is probably not a good fit.

“However, if you value flexibility and have processes that you can’t solve completely with automation, cobots are often a good answer,” claims Campbell. “They’re especially good for applications that need to have a human operator working in the vicinity and engaged with the machine.”

Both collaborative and traditional six-axis robots allow high flexibility in motion and can do a wide variety of applications that require motion dexterity. Both have speed limitations vs. delta or SCARA robots, although traditional six-axis robots are generally much faster than collaborative robots.

For simple applications, cobots can be a better fit, due to the simplicity in creating the applications, thus allowing end users to develop solutions. However, as applications become more complex, the advanced tools, language features and integrated options available with traditional six-axis robots generally make them a better choice.

SCARA robots are all about speed and precision and are generally far superior to collaborative robots in both areas. If an assembly application requires speed, precision or some level of complexity, a SCARA robot will, in most cases, be the better choice.

“Cobots are an ideal fit for high-mix, low-volume production environments,” says Campbell. “Because they’re flexible, the machines can be easily redeployed quickly and move from one part to the next.”

Collaborative robots can be quickly set up on any workstation in a factory and redeployed based on production needs without the constraint of traditional safety barriers. That increases manufacturing flexibility and agility for more frequent changeovers.

“Approximately 80 percent of our shipments are installed without traditional safety barriers,” Campbell points out. “But, many manufacturers use area scanners when running cobots at higher speeds.

“It really depends on the plant philosophy about risk assessment and how they enforce safety standards,” explains Campbell. “Each facility often interprets published guidelines differently.

“Typically, the cost of a cobot will be comparable to a traditional six-axis machine,” says Campbell. “However, the difference is that the total installed cost is significantly less. There’s reduced cost for things such as programming time, training and safety barriers. When you add up those intangibles, the cost of a cobot can be anywhere from one-third to one-half the cost of a traditional robot.

“Ramp-to-production time is the amount of time from when a machine hits your factory floor until you’re actually producing or processing parts,” notes Campbell. “With cobots, that time is typically measured in hours vs. days or weeks.

“Our machines run on 120 volts, so there’s no need to do a power drop or tap a high bus bar,” adds Campbell. “It’s very easy to just plug a cobot into an outlet and start working.”

Smaller manufacturers require flexible automation that can easily and quickly be adapted to meet shifting demands. Photo courtesy Fanuc America Corp.

Small-to-medium-sized manufacturers are driving demand for collaborative robots today. They’re looking for production equipment that doesn’t include large-scale investment in fixed automation or large robotic arms. These include tasks like machine tending, light assembly, test and inspection, and quality control.

Smaller manufacturers require flexible automation that can easily and quickly be adapted to meet shifting demands. They need systems that can be programmed easily and quickly, and can support multiple types of automation tasks.

Manufacturers in all industries need more flexible automation to adapt with speed and efficiency to changing market conditions and labor supplies. Manufacturing is becoming more specialized and less predictable, which is harder to automate.

Collaborative automation allows people and robots to work together to make manufacturing more flexible while maintaining safety and productivity. It increases manufacturing flexibility by allowing people and robots to work on tasks together that previously would have required safety barriers and cages.

This has challenged previous conceptions about what types of assembly tasks can be automated. In the past, assembling large numbers of customized products often meant dull, delicate and repetitive work. With cobots, people are able to focus on more rewarding, cognitive tasks while the robot provides tireless precision and endurance.

“We see a huge demand for automation in the U.S. today, as companies look to address issues such as labor shortages, consumer demand for personalized product, and the growing pressure to operate sustainably,” says John Bubnikovich, president of ABB’s U.S. robotics division. “Businesses of all sizes, across all industries, must be able to quickly adapt their processes to succeed in this period of unprecedented uncertainty.

“Robotics OEMs are developing collaborative robots that respond to manufacturers’ demands for safe and easy-to-use automation solutions to help plug gaps in the availability of skilled labor,” explains Bubnikovich.

“Small manufacturers and first-time users are looking for collaborative robots that are easy to program and deploy, so they can adopt robotic automation without having to add robot-specific technicians to their staff,” Bubnikovich points out.

“Manufacturers of all sizes are also looking for more robust collaborative robots that have higher payloads and longer reaches, allowing the cobots to perform a wider range of industrial applications,” notes Bubnikovich.

This new cobot features a significantly longer reach. Photo courtesy ABB Robotics

“Increased speed and accuracy are also important in expanding the range of tasks cobots can perform,” claims Bubnikovich. “The latest cobots on the market are being used for automating more demanding tasks such as machine tending, welding, parts handling, polishing and assembly.”

“The labor shortage has become a reality in all industries and markets,” adds Jessica Juhasz, manager of application engineering in the general industry segment at Fanuc. “Manufacturers are looking to easily fill the gap with a robot, but they do not want the cost of a large industrial robot system.

“Being able to safely have a robot working next to people eliminates the need for costly fencing and sensors that take up a lot of real estate in their facilities,” says Juhasz. “Some manufacturers are looking to buy robots to replace [or supplement] manual labor, so there’s a big focus on ease of use and user friendly programming features.

“Manufacturers also look at mobility,” explains Juhasz. “Being able to easily move a collaborative robot mounted on a wheeled cart or an automated guided vehicle from one job to the next [is appealing]. That can eliminate the need for large and expensive rails that may be required for larger industrial robots.”

Collaborative robots are popping up in industries and applications that relied on manual assembly lines in the past.

“Many companies are trying to augment some of their lines with automation,” says Fanuc’s Blanchette. “They want to address some areas where they may be having ergonomic issues or problems with quality. They can add collaborative robots without changing the configuration of their assembly line.”

General part handling applications are ideal for collaborative robots. Tedious work, such as sorting parts or loading presses, is a good place to start.

“Any assembly task that requires three hands would also be appropriate, with the cobot acting as the human’s assistant,” explains Blanchette. “For instance, the machine could hold a heavier part while the person is joining the assembly together with a screwdriver.

“In applications where life cycles are short, collaborative robots enable manufacturers to change over to new products very quickly,” Blanchette points out. “We’re also seeing increased demand for cobots in companies with high turnover rates and areas experiencing severe labor shortages.”

The low barrier to entry appeals to many types of manufacturers, such as firms that specialize in contract electronics production. The flexibility of collaborative robots is especially popular with companies that want to redeploy the machines elsewhere in their facilities. They’re moving cobots around assembly lines to fill in whenever or wherever needed.

For instance, contract manufacturers that want to change over from one printed circuit board style or size to another simply deanchor a machine and roll it to the next assembly line. They are able to use the same robot on an assembly line, then easily reuse it on an inspection line later in the day, where the robot loads and unloads PCBs in an inspection machine.

“Labor cost and skilled worker shortages are the primary drivers behind increasing demand for cobots,” says Campbell. “Smart manufacturers are learning how to leverage their workforce. They deploy cobots to work on simple, repetitive parts while operators perform more complicated or value-added tasks.

“Today, cobots are used in every industry and every application segment,” claims Campbell. “The biggest trend is the growth of process applications, such as screwdriving and welding.”

Screwdriving is a perfect candidate for cobots, because they can provide flexibility and repeatability to a mundane tasks. Faced with severe labor shortages and reshoring initiatives, large and small manufacturers are investing in collaborative screwdriving systems that enable humans and robots to work in close proximity on assembly lines.

Screwdriving is a popular application for collaborative robots. Photo courtesy ABB Robotics

Operators can work side by side with cobots. Humans can focus on tasks that are easily accessible, while the machines work on things that are more difficult, such as inserting and driving screws in hard-to-reach areas or confined spaces where fasteners aren’t always visible.

“[Automated] screwdriving used to be a task that was complex, costly and took up a large footprint on the assembly line,” says Catherine Leclerc, product owner for the screwdriving applications at Robotiq Inc. “As such, it was reserved for use in vast plants with big automation budgets producing in high volumes.

“This type of custom project by an integrator could hardly meet the reality of small manufacturers that deal with [limited] assembly line space, tight budgets and [sparse] automation staff,” Leclerc points out. “Now, with cobots and screwdriving systems designed specifically for cobots, the technology has become accessible to any manufacturer.

“There are screwdriving systems that can be bought off the shelf, shipped within a few business days, easily installed and adapted to production changes,” claims Leclerc. “It’s a completely new era.”

“Screwdriving is a great application for cobots,” adds Campbell. “In fact, it’s one of our most popular applications.

“All of the programming is done through the UR teach pendant,” Campbell points out. “That has simplified things and removed a lot of risk, especially for smaller manufacturers that may have shied away from automation in the past.”

Collaborative screwdriving is used in many industries. However, engineers must perform a risk assessment and deploy proper safeguarding to ensure the safety of humans working around or with a cobot.

Welding is another popular application for collaborative robots. Cobots are especially popular with small companies and contract manufacturers, because they don’t require a big capital investment like traditional automated welding cells equipped with six-axis robots. The learning curve is much smaller, and manufacturers don’t need all of the traditional tooling and safeguarding that’s associated with welding.

“The welding profession is experiencing a labor crisis,” says Campbell. “The average age for skilled welders is 55, most are likely to retire within 10 years, and younger people aren’t entering the profession in sufficient numbers to sustain industry demand.

“There is an urgent need for collaborative welding systems that are safe to use around human beings and can be used to support expert human welders by taking over the tedious and unergonomic aspects of the welding process,” claims Campbell.

Long dismissed as too heavy-duty a task for cobots, welding is now the fastest growing application segment for UR. Its UR10e robot, which boasts a 51-inch reach and a 27-pound payload capacity, is popular for MIG and TIG welding.

“Cobots are ideal for anyone doing any type of metal fabrication,” explains Campbell. “They’re easy to learn, easy to deploy and redeploy, and cost effective. A ready-to-go cell can be deployed for about $85,000, which is less than paying the annual salary of a skilled welder.

“Welding is a great application for cobots, because it’s path oriented,” Campbell points out. “It also has significant process control requirements, which is where software comes into play. A variety of integrators have created easy-to-use interfaces.”

For instance, Hirebotics LLC has developed an app that enables welding cobots to be set up from a smartphone or a pad. Its Cobot Welder system features a 32-by-48-inch workstation mounted on a mobile cart. The robot controller and the welder are premounted inside the cart. The system features a UR10e robot paired with a Miller Invision 352 MPa pulsed welder and S74 feeder, plus a Tregaskiss MIG welding gun.

“Everything is wired and ready to go,” says Matt Bush, chief operating officer of Hirebotics. “The only thing the customer has to do is open the box and take it off the shipping pallet. Then, they just install the arm, the weld torch and cabling. That all takes less than one hour to accomplish. The only thing left to do is to plug in the cable and connect to the Internet, because everything is cloud-based.

“Most of our customers cannot hire enough bodies to fill the demand that they have today,” says Bush. “They’re not necessarily looking for lower cost or higher productivity. They are looking for something to fill the spot where they cannot put a human, because of the labor shortage.

“Collaborative welding involves a robot performing part of the task and a human performing the other half,” explains Bush. “It enables humans to do what they’re best at—tactile tasks that require dexterity. Robots are better at performing monotonous tasks that get boring fast. Cobots are ideal for low-volume, high-mix applications.

“We focus on giving welders a tool that they can use produce monotonous welds,” Bush points out. “Instead, they can use their expertise and skill to focus on complex parts.”

Despite numerous advantages, collaborative robots have traditionally been hindered by their limited payload capacity. However, that’s starting to change.

For instance, UR recently began shipping its much-anticipated UR20. The machine can handle 20-kilogram payloads and features a 1,750-millimeter reach.

“The UR20 is the most innovative cobot we have produced,” claims Campbell. “Benefits include faster cycle times, the ability to handle heavier loads and advanced software enhancements that enable unprecedented motion control capabilities.

“The joint architecture has been redesigned and we’ve eliminated about 50 percent of the components,” explains Campbell. “Anytime you reduce the part count of a mechanical assembly, you increase the reliability and the quality. It also means that more machine tending applications can be done with a double gripper, which improves cycle time.”

At the recent Automate show in Detroit, Fanuc also unveiled two cobots that feature high payload capacity.

New cobots can handle heavier payloads than in the past. Photo courtesy Universal Robots USA Inc.

“Our CRX cobot series can now handle products that weight up to 30 kilograms, while the CR cobot series can now handle up to 50 kilograms,” says Juhasz. “We now offer 11 model variations that can work in a variety of industrial applications including assembly, inspection, material handling, packaging, palletizing, sanding and welding.”

The CRX-25iA boasts a 30-kilogram payload capacity and a 1,889-millimeter reach. The CR-35iB is the industry’s strongest collaborative robot, featuring a 50-kilogram payload capacity, a large work envelope and a small installation footprint. A streamlined and lighter mechanical unit features Fanuc’s latest sensor technology for improved safety.

ABB also recently introduced the GoFa 10 and 12, two new variants of its collaborative robot portfolio that handle payloads up to 10 and 12 kilograms, respectively. Both machines are powered by ABB’s OmniCore controller.

“In addition to their enhanced payloads, the GoFa 10 and GoFa 12 cobots offer class-beating tool center point speeds of up to 2 meters per second with 0.02-millimeter repeatability, a two-fold improvement over comparable products,” claims Bubnikovich. “IP67-certified against moisture and dust ingress, they extend the benefits of fast and accurate collaborative robotics to new industrial applications.

“Setup is made easy with lead-through programming and Wizard easy programming software, allowing even nonspecialists to quickly automate their applications by manipulating simple graphical command blocks rather than writing complex programming code,” adds Bubnikovich.