Complex Challenge, Rapid Response
Thanks to streamlined simulation, tooling, casting and machining capabilities, an intricate water passage went from purchase order to prototype in just 17 days.
Nicholas Leider, Associate Editor
(Click here to see the story as it appears in the March issue of Modern Casting.)
A 4-lb. aluminum water passage prototype produced by Tooling & Equipment International (TEI), Livonia, Mich., for Honda R&D Americas Inc., Raymond, Ohio, in 2013 was a complex project. The component integrated several parts into a single casting that featured six intricate cores. Varying wall thicknesses challenged design engineers to produce a solid casting that would pass demanding testing, while interior shapes needed to be simple enough for eventual high volume production.
Despite initial challenges, the water passage to be used in the carmaker’s development department went from a purchase order to a finalized, ready-to-use casting in 17 days. Early collaboration between the two engineering teams minimized difficulties later in the process, which allowed the component to quickly move through simulation, tooling, casting, machining and testing. Additionally, this casting also offers a glimpse at the relationship between supplier and customer. Working together on prototyping projects since 2010, TEI developed a relationship with Honda’s engineering and purchasing teams that allows for unusually early collaboration between the two companies.
“Honda brings us onboard very early in the process,” said Oliver Johnson, president, TEI. “We work together and consult from nearly the beginning, and they get a higher quality casting more quickly because of it. It’s a win-win for everyone, even though it’s a bit different than the standard process of quoting the part. You’re just picking a partner earlier in the process, and the water passage is a great example of our relationship.”
Locating a Source
At its 85,000-sq.-ft. facility outside Detroit, TEI’s prototyping department runs alongside an operation that produces a wide range of tooling for the metalcasting industry. TEI also offers prototype designing, engineering and casting support through its “Casting & Development Center,” which handled much of the water passage project.
“We manufacture our own tooling, we cast onsite and we machine in-house,” said Ted Kahaian, process manager, TEI. “Customers are shipping in trial parts or placing orders electronically, and we deliver finished parts that are ready to be bolted onto engines for testing.”
When Honda began looking for a prototyping source, the corporation settled on TEI for two major reasons. A dedication to confidentiality made TEI a perfect partner considering its ability to handle the majority of responsibilities, including design and engineering, tool manufacturing, casting, metrology, machining, assembly and testing, at a single site.
Additionally, TEI offers a low pressure nobake sand casting process, something that Japanese automotive manufacturers use for major engine parts such as cylinder heads, transmission housings and oil pans. Even if the eventual component will be produced via high pressure diecasting, the low pressure sand casting process can produce an appropriately high quality prototype.
“We regularly handle parts that are ultimately high pressure die castings, but tooling costs and lead times are major issues,” Johnson said. “For something like a transmission, for example, the tool could cost a million dollars and take six months. We can make a first casting in six weeks that will be representative in wall thickness and geometry.”
Planning for Action
While lead times for prototypes will vary from project to project, TEI’s design team has learned how early collaboration can streamline an already time-driven process. When Honda first approached TEI with the potential water passage casting, the two firms had worked on a number of projects together, allowing both engineering teams to build trust in one another. Design revisions and 3-D modeling took place in the preliminary stages of the project, while the purchasing department remained relatively hands-off.
“We started our dialogue with the engineering group, while keeping the purchasing people informed so there were no surprises,” Johnson said. “When we have agreed on a design and they are ready to deliver a 3-D model, that’s when the purchasing order comes out, so a lot of what takes place up to this point depends on a solid working relationship and trust.”
For the water passage, Kahaian began working with a Honda engineer who was less experienced with castings. The two went back and forth on a half-dozen design revisions, dealing primarily with the transitions between bulkier sections and walls as thin as 0.118 in. (3 mm).
Once TEI received the go-ahead to produce prototypes, finished castings were ready for delivery just 17 days later. The soft tooling was created via urethane board, and the cores were blown and assembled in a complex core package. While earlier simulations provided a great foundation for the water passage’s design, tweaks were necessary before final casting.
“I would say simulation got us 80 to 85% of the way there, but we had to dial in a bit with a different in-gate,” Kahaian said. “We had to add a few chills here and there. It took a few iterations, maybe three or four, until we produced a great, void-free casting.”
The water passage was cast in a nobake mold using a low pressure casting process with the understanding an eventual production part would most likely be cast in a semi-permanent mold. The aluminum casting then was machined with a five-axis CNC machine, before the addition of eight steel tubes and sealing caps. It then was leak checked to 30 psi. The testing for such prototypes in particular can prove to be challenging. A casting that fails in an automotive development application can lead to considerable setbacks in both time and cost, meaning prototypes must be delivered with all the necessary certification.
“These parts, because of where they’re headed, get extra special attention in terms of testing and checks when compared to a production part,” Johnson said.
Once prototypes were delivered, TEI remained in contact with its customer. With this water passage, the firm remained involved in its progression through to production.
“We follow projects from first contact all the way through to production,” Johnson said. “You learn so much about the casting and the process, you can help make the introduction to production much smoother. Very often, we will be involved directly with the production foundry. If there’s a Tier-1 supplier, they will be meeting with us to give us input on the production process.”
After casting a few hundred prototypes, TEI recently learned it has entered production in a tilt pour mold. Meanwhile, the TEI team has begun working on the next generation of the component.
“The industry has been changing,” Kahaian said. “What used to take a few months or a few weeks now takes a few days or a few hours. Really, when it comes to working with a customer, it’s about walking down that path and getting familiar with that part of the process. If we can successfully collaborate with one another, we can make quality castings much, much faster.”