CHICAGO — Many companies are set in their ways and may take some convincing before automating processes that have traditionally been done by humans. Such was the case with Onken’s Inc., which lacks access to a large pool of skilled labor because it is located in tiny Easton, Ill. (population 321). In particular, the recycling equipment manufacturer needed welders, which are in short supply across the U.S., so it turned to welding robots.
Last year, the American Welding Society (AWS) updated its forecast to an estimated shortage of 372,000 welders by 2026. Job search site Indeed listed nearly 9,000 open welder positions as of March. This presents an opportunity for robotics, said Zane Michael, director of thermal business development at Yaskawa Motoman’s robotics division, at last week’s Automate 2017 trade show here.
“The typical feedback I heard during my travels in 2016 was: ‘We can’t find qualified welders; when we do, they are hard to keep. Today, we have a 50% no-show in our weld shop. Finding welders who produce quality welds is next to impossible,'” he said.
This shortage has led to lost business, longer delivery times, and reduced product quality, according to Michael.
Onken case study
Onken experienced the problems firsthand. The company makes tanks, trailers and bins to hold bulk grease from restaurant operations, as well as oil storage tanks for auto parts companies and the U.S. government to explore with Yaskawa Motoman the pros and cons of automating the task.
Welding robots offer several advantages in comparison with human welders, Michael said, including the following:
- Robots can weld faster than any manual welders.
- Welding robots can change critical welding parameters to accommodate changes in the weld joint during welding.
- The production efficiency of a robotic welder is approximately 4.5 times that of a manual welder.
“The best person to program a welding robot is your best welder,” Michael said. “While the unit is being programmed, it will move at the same speed as the welder and will follow what the welder does to a T. Robots have very repeatable actions.”
Onken selected a two-cell station with a Motoman extended-reach MH50-II20 robot. The cell features a wide work envelope with small interference zone so that it can be located close to workpieces and equipment, reducing floorspace requirements.
The welding robots have brakes on all axes and can be floor-, wall- or ceiling-mounted for layout flexibility.
The robot uses a dynamic DX200 controller that includes patented technology to easily handle multiple tasks and control up to eight robots (72 axes), I/O devices, and communication protocols.
The MH50 unit and other welding robots offer built-in adaptive control. They are able to change travel speed, the stick-out distance for gas metal arc welding (GMAW), and the torch and travel angles as needed. The robots can also adjust the amperage and voltage.
Two cells aren’t for everyone
With a two-cell station, the robot could work in one cell while a human worker could load and unload tanks of different sizes in the second cell. However, this is not the best set up for all companies, Michael cautioned.
A two-cell operation is more expensive than a one-cell operation. If the processes are properly designed, the two-cell operation will add production capacity that will more than pay for the extra expense.
In many production facilities, Michael noted, the load and unload operation is swift, or there is too little production to be done. A two-cell operation could result in too much idle time to be worth the additional expense. Even at Onken, the main challenge is programming time, he said.
A two-cell operation also takes up more floor space, which may not be available. Even if space is free, a two-cell operation could impinge on other operations and production, Michael cautioned.
“Consider your load and unload times,” he said. “If a one cell operation meets your production needs, use it.”
More on Automate and Welding Robots:
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- Gantry Robots Pose Alternative to Articulated Robots for Bigger Applications
- Sustainability, Like Automation, Is Good Business, Says Automate Panel
- Robotic Welding to Benefit From Updated Controls, Clearer Vision
- Is Robotic Welding ‘Inevitable’?
Welding robots require safety and ROI
Safety is another consideration in determining the number and the design of the work cells. Prior to 2012, regulations required that humans and operating robots be separated. But that has changed since the onset of collaborative robots, Michael pointed out.
Still, operations should include the necessary safety precautions. As of now, Motoman does not have welding robots working in close proximity to humans, he said.
There can be other challenges as well. At Onken, welds needed to ensure tight seals so that the tanks, bins, etc., didn’t leak. A servo-robot camera is used to identify the proper location and angle for each weld while also providing tracking just ahead of the weld torch. A laser provides guidance assistance to ensure the accuracy of each weld.
Since the installation of the Motoman robot, Onken has been able to double its output capacity while also being able to reassign a couple of its welders to other tasks, according to Michael.Read More