Automating the Finishing
Dave Scott of AFS Corporate Member Great Lakes Castings (Ludington, Michigan) is no stranger to the world of automatic and robotic grinding. Before working at Great Lakes Castings, Scott was part of a Grede facility that successfully worked toward fully automated grinding.
Great Lakes isn’t there just yet, but it’s on the way. And Scott is glad to be part of that journey.
“I’ve never talked to a foundry that regretted an investment in an auto processor,” Scott said. “It makes your facility more cost competitive, and a better place to work at after you make those investments. It’s easier to recruit people and it broadens your horizons as far as what types of employees you can attract. It’s good all the way around.
“It’s good for the customers, good for the shareholders, and good for the employees.”
Great Lakes, a green-sand iron caster, has a finishing facility that utilizes automated grinders and trim presses. It produces gray iron castings ranging in weight from 0.5-50 lbs. that range in volumes from low-moderate to high.
Scott and Great Lakes, however, are far from the only metalcasting facility that’s seeing the benefits of automation. AFS Corporate Member Lethbridge Iron Works (Lethbridge, Alberta, Canada) has had automated grinding for 15 years, and the company has also learned a few important lessons.
“The bigger and the heavier the castings, the greater the benefit,” Lethbridge’s Blair Lozza said. “The smaller castings that are in the single digits of pounds, maybe you’ve got employees that can grind really fast. A human might be able to do a couple hundred an hour. You’re at the limits of the robot that it might not actually be twice as productive as a human for something small and light, but the bigger and heavier castings you not only double what a human can do. With the bigger and heavier castings, the automated system can be multiple times more productive than a worker hand-grinding.”
That worker is just one of the people who benefits.
Good for the Staff
Performing manual grinding is not the most glamorous part of a metalcasting operation. The labor is difficult and involves plenty of heavy lifting, and worker injuries can occur. Because of the physical strength required, only a small percentage of the available workforce can do the job.
Automated grinding can help with those issues.
Tim Brown of AFS Corporate Member Benton Foundry (Benton, Pennsylvania) said he and his facility recognized the safety benefits. For one, Benton’s six robotic grinders are in enclosed units that are ventilated to a collector. The grinding is performed in a controlled environment with the operator not too close, limiting silica exposure.
Limiting silica isn’t the only way that automation is a plus. Operating a machine isn’t as taxing as lifting heavy casting after heavy casting. And not quite as dangerous.
“Now you don’t have the human grinding castings or taking castings and grinding them against a grindstone. There’s a safety improvement now because the worker is an operator,” Lozza said. “They’re just putting castings off and on a fixture. They’re not physically grinding them by themselves. Right away, they’re not going to be injured or have any type of repetitive injury. The job is a lot less physically demanding.”
Because of that, there are more potential employees on the job market.
With manual grinding, only very physically strong applicants were able to do the job. The heavy lifting and intense work meant that a large segment of the population wouldn’t have the physicality to complete the tasks.
That issue was also compounded by the lack of potential workers who would even want the positions to begin with.
Automated and robotic grinders open jobs for a bigger pool of candidates.
Brown said Benton could see a labor situation approaching where it would be harder and harder to find people to take on a career in grinding.
“With manipulators you’re able to not have to manhandle the castings. Anything above 20 pounds, if you want to pick it up with the manipulator you can, as opposed to manhandling it,” Brown said. “We say we don’t want you handling 50 pounds or greater. The manipulation allows not only to make the work easier physically, but now opens it up to more operators.
“Someone of a more diminutive stature is able to do it and do it well.”
Lozza was more direct about the appeal of operating an automatic grinder.
“We don’t have people turn it down,” he said.
Good for Business
The benefits of automatic grinding go beyond worker safety. They also can lead to better and more predictable products.
Lozza said Lethbridge will even remove draft for some customers so it makes their downstream process easier. If it needs to machine or drill some holes through faces with draft, the company can do that and make the customer’s process more consistent. The same goes if it needs to put a washer on a part-line surface, we can make that washer sit flat. That could mean a little more grinding cost for the customer, but still less than a machining process.
That ability makes the facility more flexible.
“It’s a huge selling point. We do like to mention the consistency, the repeatability,” Lozza said. “The castings are all going to look the same, versus if you had two different guys grinding them. Across several different shifts you could have a dozen different guys grinding your castings and they could all look different. The robot makes it repeatable and consistent and the customers do like to hear about that.”
Scott echoes that.
“The consistency and quality of a product coming off an autoprocessor instead of manually grinding definitely reduces customer complaints,” Scott said. “Really what it translates into is to automatically process a part is less costly than manually grinding. The direct labor content per part goes down significantly, which does allow us to win business that we typically would not win.”
Not only do grinders add consistency, they bring more efficiency. They are quicker than their human counterparts and don’t tire as days wear on. And that brings more profit and the incentive to bring more machines.
“For sure it makes you more efficient,” Lozza said. “As soon as we moved castings from hand-grinding to our first robot, our productivity rates on those castings almost doubled. Right away, we’re putting out twice as much product with the same staff. That would’ve been the reason to continually add machines.”
One key is to make sure the machines are being used and used efficiently. Though automatic grinders’ prices are coming down, they’re still big investments for foundries, and will do little good if not maximized.
Benton monitors tits grinders in real-time to make sure they’re delivering up to their potential. The metalcaster has a system that notifies a supervisor if a robot hasn’t been engaged for more than three minutes. There are many reasons the robot could stop—safety, equipment switches, opening of doors—and when any are violated the machine will stop running. Brown said Benton investigates when one machine might not be running as much as another, trying to find out why.
“It’s actually made us better foundry people from the standpoint that we’ll review the tooling and the corebox to look at things now, to see what we have as issues and can we eliminate them,” Brown said.
Click here to see this story as it appears in the January 2019 issue of Modern Casting