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A view of the pouring and molding operation, from the melt deck at Watts Water Technologies’ new lead-free foundry. “We wanted to have good integration,” general manager Tyler Stone explained, describing the link between the pouring and molding controls.

Decisions Add Up to Solutions

Oct. 15, 2013
Speed to the market Design completed in 14 weeks 2,100°F lead-free bronze 80 to 120 molds/hour Fully enclosed sand prep Shakes out like malleable iron

Designers and machine builders like to claim they provide “solutions,” which is true in a sense. But, every solution starts as a problem to be solved, and the process of getting from the problem to the solution involves research and evaluations, and decisions. That’s why the new, 30,000-sq.ft. foundry started by Watts Water Technologies in April this year has been remarkable: it’s the result of numerous decisions involving various stakeholders, aiming to address multiple objectives.

All this was accomplished in less than two years, with “solutions” provided by multiple suppliers and equipment builders.

“A foundry is a building that works like a big, complex machine with many subsystems, all integrated together,” according to Watts Water Technologies’ general manager Tyler Stone, “and getting that machine to work together takes some shakedown time. I’m sure we’ll have some more of it, because now we are starting to work into our first planned maintenance cycles, and we’re evaluating how worn are things, how are things behaving, whether things are achieving the appropriate frequencies, performing vibration analysis, etc., things like that.

“But, overall, I think we are poised to do a pretty good job with our ‘speed to market’.” 

The speed to the market might have been a full stop if WWT had not made the decision to build the new foundry adjacent to its Franklin, NH, brass foundry. That sand foundry, in operation since 1970, produces a full range of castings used to produce a long list of products for residential and commercial water flow; water reuse and drainage; water quality products; and HVAC and connectors. These products are distributed worldwide under multiple brands.

The problem that set WWT on the course to a solution is the Reduction of Lead in Drinking Water Act, enacted in 2011 and taking full effect in January 2014, by which time all products used in handling or processing water that may be used for human consumption must be certifiably lead-free.

“We started thinking about what we should do with the implementation of the new legislation probably two or three years ago,” Stone said. While various alternatives were considered, the first critical decision was the one to build a new foundry at the Franklin site.

Note, however, that the operation needed to be entirely separate from the current production process, due to the lead-free standards established by the law. Because the Franklin campus also includes an extensive range of finishing, inspection, and assembly operations – the task of designing, building, and installing a coherent production process added another dimension of complexity.

Design and Engineering

“The Watts management came to us with a vision: they wanted to be able to meet the U.S. government's mandate on lead-free products at an early date, and to do it in separate, state-of-the-art facility,” recalled Ralph Perkul, president of Foundry Solutions & Design, the engineering and construction firm that earned the assignment as WWT's lead designer. “This would ensure that the leaded and lead-free products would be processed optimally, with little chance of cross-contamination.

“It was also being built to shorten the supply chain between the producer and its customer base, which meant bringing product from off-shore,” Perkul indicated. (Thus, another solution is revealed.)

“We took a lot of time thinking about what would be the right thing to do,” Stone recalled, “and Watts is a corporation, so there are a lot of stakeholders in that process. So we spent some time working with stakeholders, to make sure that the entire group was comfortable that we were making the right decision. So, we didn’t really get going on engineering until late March 2012 – that’s when we started seriously designing the foundry.

“We didn’t actually break ground until March 2012,” according to Stone, “Often in manufacturing the end-date never changes, and you just have to deal with it. So we did, and the team did a very nice job of bringing this thing home very quickly.”

The short schedule didn’t impede the progress, according to Perkul – the design concept was completed in 14 weeks -- though a reduction in the total size of the building did “presented a challenge,” he admitted.

That change was necessitated by the location of “wetland” at one corner of the property originally designated for construction. To avoid the complications to the permitting process, to the schedule, and to the production process, it was decided simply to scale down the building’s footprint.

“It definitely threw a wrench into the design process,” Stone said, “because they had something designed – there was a certain amount of square footage – and then when we looked at the permitting issues that could arise from it. It became clear that we could not go that way. It was not acceptable.”

“The limited available size of the property presented a challenge,” Perkul said. “Yet, the end-result was for an extremely efficient, yet compact design facility.”

Getting to that end-result involved many other decisions, for process technologies, equipment styles, and so forth.

Melting and Pouring

It’s difficult to conclude that singular function of foundry is the most important, but the melt deck might qualify for such a claim. Certainly for WWT, which developed the foundry to manage a high-volume stream of lead-free bronze products, the two Inductotherm Corp. furnaces selected to melt the metal to 2,100°F were critical selections. Melting and tapping are conducted from each furnace in alternating cycles. An auto-pour system is installed to receive the metal, remaining full at all times, with inert-gas pressurization to reduce any inconsistencies in the pouring process that may lead to solidification defects. 

“We chose Inductotherm equipment for the melting furnaces and the auto-pour system,” Tyler Stone explained, “and for several reasons. First, they are a good company. Second, we already operate Inductotherm equipment in the existing foundry, and we’re familiar with it, and had worked with the systems in the past.  After we looked at everyone, we decided to stick with Inductotherm for this new foundry.”

Noting that the WWT operators continue to work toward full capacity, the new furnaces have performed well during the first months of operation. That’s true for the auto-pour system too, the general manager said, and the selection of Inductotherm’s auto-pour system has been advantageous inasmuch as the coordination of melting and pouring is a critical interface for the entire operation.

“You know, building a foundry is a complex undertaking, and we were pressed for time,” Stone observed, “so it made good sense to stick with common equipment. We had to work out some wrinkles, but auto-pouring is doing well for us right now.”

Molding and Mold Handling

Sand molding, of course, is another essential task for a foundry, and for Watts Water Technologies the transfer from the auto-pour technology to the molding operation presented another critical interface. The molding system is comprised of are two XL2024 molding machines supplied by Hunter Foundry Machinery Corp. feeding a common HV-20 24 + 24 x 3 turntable mold handling system, also produced by Hunter.

Several objectives are accomplished with this selection, starting with production capacity. Hunter’s sales manager Dean Martin began by pointing out the selection of a single mold size, 20X24 in., meant that each machine will achieve an average mold production of 80 to 120 molds/hour. The multi-level rotary table provides a total of 96 positions for molds, which ensures a suitably timed cooling time for each mold after filling without disrupting the slowing the rate of production.

“We chose Hunter equipment, again, because it’s well designed and because we have a lot of experience with their products,” Stone said.  Those advantages outweighed any of the design features of any alternative molding options, he said.

“We wanted to have good integration,” he reiterated, specifically describing the communication between the pouring and molding controls.  “In today’s world, everything is electronic, so the integration of electronics and how smoothly that goes is an indicator of how smoothly the production process is going to run. We had to be very cognizant of how we would have these systems work together and interface them,” Stone stated.

Dean Martin added some further points to the list of advantages. “Feeding two molding machines with one turntable is possible because there is a common alloy,” and that supported the production volume goals while reducing initial capital costs for mold handling.

More important, “The turntable mold-handling system is entirely covered,” he noted, “and when connected to the dust- and fume-collection systems it does a very good job of keeping the foundry clean, with a minimal amount of air movement.”

Sand Handling and Environmental Controls

Just as important as molten metal and well-produced molds is the green sand used to form those molds. The raw material is prepared and stored not in some remote room, but in full view of the rest of the operation. It holds 130 tons of sand, which is released to a muller in batches via a bucket elevator. In the muller, the water and clay are added and mixed, so that each batch can be prepared and handled with precision.

“What is impressive to me is that the sand system interfaces with environmental controls, so that there isn’t any airborne sand,” according to Tyler Stone. “The sand preparation system is fully enclosed, but open to and in view to the entire foundry so that makes maintenance far, far easer.

All the green sand is captured and recycled, and Stone said there is some consideration of future recycling of core sand, too – part of some coremaking improvements that may be undertaken in the future. “There are lots of things this foundry was designed to have bolted on, to look at in the future.  So, we’ll be moving some core machines in our foundry, and looking to improve that technology. We’ll be looking to recycle our chips better, too. I’d love to get us to a ‘zero footprint’ kind of operation, environmentally.

For now, the environmental control system recycles air through the building in the winter to conserve heat, but it extracts and exhausts cleaned air during the summer months.

Shakeout and Knockout

Once a mold is cooled and exits the rotary table, a conveyor carries it to the shakeout stage. Shakeout is accomplished with a General Kinematics Corp. Vibradrum system, which dispatches the unmolded castings to an inline conveyor, for the core knockout stage, for which Rosler Metal Finishing supplied the machinery.

“We chose a General Kinematics system, and that has performed really well,” Stone explained. “We just recently replaced the lining in it, and that really helped us move our castings better and reduce noise significantly,” he said in September, “and we had some tuning to do, but they’ve been a pleasure to work with.”

General Kinematics developed the vibratory drum installation on a turnkey basis, and while the mechanical and electrical placement was a smooth effort, GK’s Bob Huffer said one detail that took a bit of extra attention was tuning the operation to treat the lead-free brass alloys— how to ensure the castings separate effectively from the sprues and the risers. “We discovered through some testing that this metallurgy acts a lot like malleable iron, and its much stronger than leaded brass alloys,” Huffer said, noting they were able to adapt the equipment to accommodate that discovery.

“Overall this was probably one of the better-run projects that we’ve had,” GK’s Dave Donahey reported. “Things went very smoothly, and the actual installation went much faster than we had anticipated.”

Whether the process was smooth or not, all the parties involved parties seem to agree that the completed foundry is a fitting result to a successful collaboration.

“Building things is always a big project,” Stone said. “You have to have some fortitude at the start to know what to expect. Our team has worked a lot of overtime. And I learned never to underestimate how complicated a foundry is, and to recognize the importance of the details.”