Meeting Customer Demands
The health of the metalcasting industry is built on casting success stories that keep customers returning to their foundry suppliers for more engineered cast components. Modern Casting shares three examples here.
Outdoor Lighting Stands Out
One of AFS Corporate Member Powercast’s long-term customers in the lighting industry developed a
concept for a fixture that would not only stand out with its elegant design, but also blend in perfectly with its surroundings and provide cutting-edge technology.
The cone-shaped fixture resembles a tree, and while its design stands out, it was not planned for manufacturability. The concept proved to be a challenging project for Powercast (St-Eustache,
Quebec, Canada), but by working closely with the customer, they kept the design intact while adapting it to the permanent mold process.
Powercast general manager Ravi Gupta said it was determined early that metalcasting would be the best process for the project, since assembling or welding several castings together would not have been feasible.
“Going with a permanent mold casting would provide the best value in terms of respecting the design as much as possible,” Gupta said. “The overall cost, ease of machining, ease of assembly and paint, surface finish and dimensional accuracy (were also factors).”
The design was created with an organic-looking lighting fixture in mind—one that would blend into
a typical urban setting. The concept was proposed and approved by the customer’s marketing department. It was then handed to the customer’s engineering team responsible for new products, with almost no room for design changes in order to keep the original concept intact.
The engineering team then turned to Powercast for assistance in discussing the production of this part, specifically as a casting. Many hours were spent in in-person and online meetings, discussing the intricacies of the component until the final casting drawing was finalized.
“The casting allowed the customer to replicate the required design as closely as possible,” Gupta
said.“Going with a one-piece casting also eliminated the options of welding different parts together, and replicated very closely the original concept, with its seamless design, graceful curves and
tree-like branches.”
It didn’t hurt that Powercast and the customer had a long standing relationship.
“Having worked closely on other complex designs before, we were asked to help with the casting design right at the start, which is the optimal timing to begin reviewing a potential casting,” Gupta said.
That doesn't mean the project was easy.
The shape of the component was challenging. The part has thin sections, undercut areas, and various precise features necessary for post-casting machining and assembly of LED components. The pouring height, how to pre-heat the tool and warpage were among the issues Powercast had to overcome through experimentation and trial and error.
“Ultimately all these challenges were addressed by our team as a group effort, through many brainstorming meetings, disagreements and agreements, and challenging each other’s
ideas,” Gupta said. “All of this led to a commonly agreed-upon consensus as per how to proceed. Every aspect of the process was discussed: how to design the tool, what materials to use, how the feeding/riser/ejector systems were going to function. How the operators were going to pour this
casting, how it was going to be cut, grinded, finished and packaged."
The customer provided various 3D-printed sections of the part and glued them together to create a life-sized model. After that, the customer required sample castings in aluminum. Powercast produced plaster molding casting samples, which replicated the eventual appearance.
Conversion to Ductile Iron Saves Over 30%
AFS Corporate Member converting a six-piece steel fabrication that incorporated two cast bolt-on attachments into an all-in-one ductile iron main frame casting for an agricultural customer.
The finished product was cast in ASTM A536 Grade 65-45-12, produced via horizontal green sand molding, robotically ground and CNC machined. It weighs 68 lbs., and connects all components (disk wheel, seed boot, depth adjuster, packer wheels) to the toolbar of an agricultural seeding disk/hoe opener.
The customer needed greater torsional strength from the component in order to reduce the flex that occurs when stresses are placed on the opener during cornering in the field. In addition to the part’s performance, there was a need to reduce the workload on the plasma laser cell that produced the fabrication’s components and a desire to reduce the bill of material required to make each part.
Ultimately, the customer wanted a better part at a reduced overall cost both internally and externally to the end user. Through collaboration with Lethbridge Iron, a design for castability, and also for economic manufacturability, addressed and overcame the challenge of redesigning the original part’s length to allow for a multi-impression pattern achieved a design that incorporated features previously achieved only by fastening separate castings to the fabrication.
The steel fabrication to casting conversion achieved an overall part cost savings of more than 30%, resulted in a capital expenditure savings from not having to purchase an additional laser cutter, reduced the bill of materials, reduced labor costs and the reliance on employee attendance for production.
“It was a tremendous win,” said Mark Mundell, Lethbridge Iron Works’ director of sales.
Robotics Make Difficult Casting Sustainable
The disc AFS Corporate Member Washburn Iron Works (Washburn, Wisconsin) casts for an agricultural client isn’t a new product for the had for decades, Washburn changed to a custom molding station with robotics. The manual process was so challenging physically that employees at Washburn
would asked to be transferred to another department, just to avoid working on this disc.
“We decided that’s not sustainable. It’s not good for any of our employees. It’s not good for our customers,”said Taylor Pearson, vice president of
sales and operations. “We embarked on a thought process and a design to automate the whole thing.”
In 2013, Taylor and his brother Cole Pearson, the vice president of manufacturing & processes, designed their own robotic grinding cell. The work
was done in-house, and Cole Pearson taught himself how to program the robot. With that in mind, Washburn was able to see what else robots could
do for them, and that’s what led them to the custom molding for the discs.
“That’s when we started putting pen to paper and coming up with ideas and bouncing designs off one another," Cole Pearson said. “We share an office,
which is really nice because we’d turn to each other and go ‘What about this?’ and someone says ‘Well, that’s a good idea, but what about that?’ It just
grows from there.”
The Pearsons have a whiteboard in their office and they would swap ideas and drawings. There might be a hang-up, but a few days later one would come up with a solution and move on to the next issue. The process of designing the robot took around 10 months, with six spent on planning and four months on building and
implementation. And somewhat to their pleasant surprise, things went smoothly once the robot was put to use last year. The robotic molding station uses two types of sand, fills the sand mold, can ram the mold both clockwise and counterclockwise depending on the cope and drag, and then strikes off the mold.
“We were pretty lucky or smart, probably pretty lucky, that our design worked right away,” Taylor Pearson said. “We haven’t had tweaks. We haven’t had a breakdown on it yet, knock on wood.”
The benefits to the robot are obvious.
“It’s kind of unique because not many people use the robot to make the mold,” Cole Pearson said. “They use robots to handle things. We’re using the robot to fill the cavities, ram them, strike them and do that over and over, and keeping the guys closing the molds over. It’s a pretty neat thing to see.”
The disc, which is produced in around 150 different formations, is now one of Washburn’s easier molding positions. Production is more repeatable and scrap rate has been reduced by 50%. Mold hardness has moved from 50-60 in the human manual process to 75-80, and the robotic molds are more uniform.
“Without the robot we wouldn’t have been able to maintain the pace, or we would have had to give a price increase,” Taylor Pearson said. “We try to provide solutions for customers, so rather than turn around to them and say we’ve got to double the price of this casting, we said how can we make this work and how
can we keep making this casting for them? That’s what leads us down the path.”