Grinding Halt

Kim Phelan

The hazards of grinding castings were adding up and taking a toll. Managing and mediating the work environment had proven insufficient––and in the end, the brass division of AFS Corporate Member Clow Valve’s foundry in Oskaloosa, Iowa, arrived at a radical conclusion: Eliminate risks by eliminating grinding.

Between 2014 and 2018, the Clow facility had seen 23 grinding operators injured at a cost of $7,385 for external medical treatment and $19,757 for internal nursing resources. As the company began closely assessing the nagging problem, the numerous risks involved with facing a grinding stone that’s rotating at 1,600 rotations per minute came into focus: strains, sprains, avulsions and musculoskeletal disorders (due to ergonomic issues); plus lacerations, contusions and abrasions (from touching the grinder); foreign bodies (from flying chips); and noise exposure. In addition, 122,960 lbs. of dust generated in a year created risks of silica exposure, and in the copper-based alloy operation, lead exposure.

The foundry used the Washington State Ergonomic Assessment tool to measure its quantitative risk factors, said Safety Engineer Tony Ingle, which included posture, repetition, vibration and force, as well as contact with a thermal surface. 

“Up until 2017, Clow had implemented engineering controls with baghouses and positive pressure air, administrative controls with human stretching and flexing, and PPE such as powered air purifying respirators, uniforms, eye protection, hearing protection, foot protection, gloves, aprons and welding sleeves,” Ingle said. “But that year, one of our foremen came up with a solution.” It was an idea that soon had the buy-in of the management team and a transforming effect on the foundry.

Two things drove the innovation: the desire to remove cost from processes, but more urgent still, said Brass Cleaning Supervisor Jeff Beuthien, the need to halt the occurrences of operators coming to management’s office with bloody knuckles. The concept was simply to remove the grinding process altogether where possible, and they tested their theory on a 2-in., two-edge stem (like a pipe with a collar), working closely with his internal operators and the company-owned machine shop. First, they developed a punch press that sheered the gate off the side of the casting; they improved on that slow process by just cutting the gate more closely and then sending the part to the machine shop. Without the group fully appreciating what they’d done, Clow Valve’s “cut, clean, ship” no-grind initiative was born.

“They already had a victory before we even started going down that road, Beuthien said. “So we thought, ‘Well, we’ve got 2 ½-, 3-, 4-, 6-, 8-, 10-, 12-and 16-inch stems [poured with two different alloys]––why can’t we do the same thing with those?’ The programmers at our machine shop already wrote the program for the 2-inch one, so we were like, ‘Let’s try our 6- and 8-inch bread and butter castings.’ We make thousands of those every month.”

As they continued the no-grind experiment on other castings, the change attracted attention. 

“Not only were the plant managers seeing it, the general manager was seeing it, and accountants were seeing this change taking effect on our expenses as we eliminated this grinding part,” Beuthien said.  “Everyone was saying, ‘This is a great project––let’s move forward with it.”

From there, it was a matter of replicating the mode of thinking and execution for all Clow’s other stem sizes, he said. A team comprising the foreman, the GM, plant managers, production supervisors, leads, the EHS department, the pattern shop and operators further developed the new initiative in 2018, which Ingle said resulted in a 60% reduction in overall grinding at the brass foundry and a complete elimination of grinding-related injuries. In a year’s time, Clow gained $50,000 of savings in grinding wheel costs, going from 108 wheels to a mere 10. The foundry took dust generation down 38% to 75,688 lbs. and shaved man hours per ton from 12.28 to 10.08 the first year––according to Ingle, it’s on track to hit 7.36 in 2020.

Documenting was done for each type of casting to ensure consistency and machining reproducibility; also, as the makeup of the team itself altered, processes would remain intact. 

“I give our team credit for recognizing the potential benefits of this program and putting forth the effort to pursue it,” Ingle said. “Even considering a process change on this level is a difficult proposition, and these team members make it a priority. I’m proud to work for a company that makes the safety and well-being of its team members as essential as every other aspect of our organization.”

Ingle and Beuthien emphasized the critical importance of the collaboration they experienced with Clow’s machine shop, which worked side-by-side with foundry personnel in a continuous effort to balance the amount of gate cutting required to successfully program machining for each sized casting. Having the machine shop located just down the street from the foundry made back-and-forth help and communication easier, they explained, than if they’d been more geographically separated. As programmers made suggestions about gate location and other tweaks, it was the dedication and cooperation of the two teams that ultimately achieved the no-grind company objective, the sources said. 

Dealing With Pushback

With major change comes the age-old crutch to which humans invariably revert: “But that’s how we’ve always done it.” As Clow pulled back on the volume of castings it was grinding, it ran into pushback from cutting operators who were suddenly asked to forget the directive to cut for speed and instead start cutting for accuracy.

Cutting operators were also historically incentivized in their pay rate to cut fast. Undoing the mindset with training and continuous reinforcement was achieved over about six weeks. Some personnel were concerned they weren’t going to make as much money, but Beuthien said showing operators the facts on paper got them to understand that cutting with precision wasn’t going to cut into their paychecks.  

Besides convincing operators to aim for a closer, more accurate cut––leaving 1/16th to 1/8th inch of gate material on the casting––another major training hurdle was consistency in cutting so the machine shop could manage things on the programming side. 

“Consistency is key, even if it’s consistently wrong or a larger gate or smaller gate––as long as it’s consistent, machine shops should be able to work with you,” said Beuthien. “Of course, the smaller the gate, the better.

“Everyone gets comfortable with what they have done for years,” he added, “and it can take time to get people out of that rut. In the end, you’re reducing the amount of work that they have to do, which is always a win. It takes more effort at first to monitor the work that has been done, but as long as you work with your operators they will work with you as well.”

Creating “Go/No-Go” gauges helped keep the manual cutting consistent. Clow staff measured how much gate the machine shop wanted removed for particular castings and machined a pipe to that exact size. If the piece being cut passes through the pipe, it’s a go. Experienced operators with keen eyes need only check one out of every 20 or 30 pieces just to recalibrate themselves. 

Today, cutting close and accurate is the norm, cost is taken out of the post-casting process, grinding operators can be reallocated to other needed areas, and no one’s worried about their wages anymore.  
Molding Magic

The human side of the no-grind project was reinforced with new molding technology Clow had invested in during early 2017, just as the “cut, clean, ship” concept was germinating. The company replaced a 40+ year-old 1620 matchplate with a DISA 2024 matchplate, enabling greater mold yield, as well as tighter tolerances and more consistent molding. 

The technological advances have been game-changing. Even some products that aren’t on its cut-clean-ship list don’t have to be ground because the DISA makes such a tight parting line, said company sources. And if a pattern doesn’t require a filter or core, the operator can simply push the go button and the molding just automatically runs.

One downside: With additional squeeze pressure produced by the new molding machine, the foundry observed a problem with patterns flexing, which could sometimes create an uneven parting line. To remedy the situation, staff modified the adapter plate, allowing older patterns to be properly supported on all sides. 

Clow had adapter plates created so it could run a smaller 16x20 plate dimension in the new 20x24 molding machine. Team members had used the original four-corner mounting holes, but this wasn’t enough support to keep the plate from bending. They added two more holes in the middle edge of the plate to help keep the plate from bending; they had success with 0.75 in. (20mm) plates, but use 1 – 1.25 in. (25mm – 30mm) plates for deeper pocket castings. 

The primary machine-related challenges that cropped up were shrink and oxide issues. Sometimes, a casting’s configuration made it hard to produce as a no-grind part. Attempts to relocate the gate would just occasionally not work, and the metalcasters learned there were times when they had to cut their losses, grind the parts, and move on.   

Looking back on the journey and what Clow was able to accomplish, Beuthien says pacing expectations was a big part of its success. Early mini-victories bolstered morale and became a springboard for ultimately eliminating the grinding process on 50 different casting parts the foundry makes––and they’re still looking at ways to do more. Equally important was ensuring universal internal adoption. 

“Because if you don’t have management support, you’ve got nothing,” he said. “And if you don’t have the wage employees’ input, you’ve got nothing. Everyone has to work together toward the end goal.”

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