Bigger isn’t always better. Articulated robot arms have grown to meet their needs, but manufacturers should also consider gantry robots for heavy or bulky payloads, noted a Gudel exec at Automate.
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CHICAGO — Despite corporate desires to keep costs in check by using articulated robots, there are times when they simply won’t do the job. The materials to handle might be too heavy or too large, Joe Campbell, vice president of sales and marketing at Gudel Inc., told an audience here at Automate 2017 yesterday. Or the end user may not have taken all process factors into account such as the speed of movement, angle, or weight at full extension. Gantry robots are an alternative worth considering, he said.
Manufacturers continue to build ever-larger articulated robots with increasing capabilities. KUKA’s Titan robot was at one time the largest on the market, weighing more than 4,700 kg (10,000 lb.) and with a payload of more than a ton (1,000 kg). It has already been surpassed twice, and still larger robots are in development.
- Articulated robots have grown ever larger, thanks to technical advances and demand from manufacturers in multiple industries.
- However, two-axis gantry robots might be better for moving heavy loads, said Gudel executive Joe Campbell at Automate 2017.
- Campbell outlined other considerations for companies that are evaluating different types of robots for their needs.
Articulated arms grow with advances, applications
The need for larger robots is dictated by evolving business conditions, said Campbell, who is also business unit manager for products at Gudel in Ann Arbor, Mich. Manufacturers of aerospace, agricultural, and oil field equipment are using robotics to produce ever-larger parts.
Advances in sensor technology, simulation, and offline programing are enabling advanced robotic applications, Campbell said. Robot-based automated storage and retrieval systems are increasingly being used in tire manufacturing, finished goods, and pharmaceutical applications.
Companies are also changing the types of robots that they are purchasing, Campbell explained. Some organizations have replaced traditional indexed automation with robots on two-axis tracks.
The automotive industry is using more robots with large part shuttles, while other industries are replacing traditional indexed automation and conveyors with robots and track systems.
The more a company can increase the utilization of a robot, the better it can cost-justify the investment, Campbell said. Ideally, companies want robots that can run multiple machines. But that isn’t always practical, depending on cycle times, he observed. If the cycle time is too short, multiple robots will be needed for multiple machines.
Going with gantry robots
Although articulated robots can handle an increasingly complex variety of welding, painting, and other applications, manufacturers and materials handling companies sometimes need another solution. Such companies should consider gantry robots, advised Campbell.
“If a commercial robot will do the job, use it; it will be a cheaper option. But if the item is too big or too heavy, use a gantry,” he said.
For example, Caterpillar Inc. uses a two-axis gantry robot to move 3,000 kg (6,600 lb.) cylinder blocks.
NSH Simmons is using a gantry with two robots, a 5 m X axis and a 1 m Z axis, to handle payloads up to 950 kg (2,094 lb.) for rail car wheel machining. Other gantries, featuring other designs, are used for other rail car applications, Campbell said.
In Europe, construction companies are using a system featuring a ZP-7 gantry on TM-72 floor tracks that includes all of the necessary engineering, materials, and design for prefabricated flooring, trusses and walls. This includes cutting, gluing, screwing, nailing of wood, Campbell said.
This gantry saves a tremendous amount of labor and associated costs while also greatly accelerating the production process for these construction materials, he observed. This type of robot has yet to catch on in the U.S., but its continued success in Europe could lead to deployments here, according to Campbell.
Selecting the right robot for your business
Businesses should consider several factors when evaluating gantry versus articulated robot systems, Campbell advised. Companies need to be as specific as possible when discussing their needs with robotics suppliers.
That means they need to work out multiple profiles for acceleration and deceleration. Campbell said he has seen robots be severely damaged because the users didn’t consider acceleration, deceleration, weight at full extension, and other factors.
Prospective end users should also look for support for the ANSI 15.06 programming environment, said Campbell. While robot controllers are good, PLC is better, and hybrids that combine robot controllers with PLC and CNC are best, he said.
When looking at the robot, Campbell said, a company should determine if its internal environment can handle it — is there ample existing power supply? If not, how easily and costly will it to be to add additional power? Will the current building floor and foundation support the robot’s weight? How heavy are the peripherals, and where will they need to be placed?
Once everything is installed, will there still be room to access the robot as well as other systems for maintenance and repairs? While dual robots might be nice to have, cycle times might leave a second robot sitting idle too often to justify the cost.
Companies typically want robots providing the fastest velocity, quickest acceleration, and the lowest cost, Campbell said. “Pick two. You will pay a lot more for all three,” he said.
Campbell also pointed out that companies need to look at various environmental guidelines as they consider which robotic option is best for them.