When you’re the castings expert at a large manufacturer, many are the people and projects benefitting from your knowledge and input every day. Such is the case for Tony Lindert, materials engineer for Wisconsin-based Oshkosh Corp., which builds highly specialized vehicles and mobile machinery for customers including the Defense Department, fire fighters, and construction firms, to name a few—and, as of late, it’s embarking on the redesign and build of 50,000 vehicles for the United States Postal Service, half EV and half ICE. 

Lindert has been responsible for the materials and process engineering lab at Oshkosh for the last nine years. He serves as a castings consultant for all the company’s business units and often as a project liaison with the roughly 40 vetted, go-to foundries with which Oshkosh does business. Lindert said he gets involved in everything from the early stages of part design, to assisting with purchasing and performing quality audits at foundries—in other words, immersing in practically every facet of all casting projects. 

“It’s an interesting job,” he said, which is something of an understatement considering the Oshkosh portfolio comprises 12 different brands, each with multiple programs and countless castings. Modern Casting borrowed an hour with Lindert in between his meetings and design/quality intrigues to talk about how the sourcing of castings gets done at Oshkosh. 

Modern Casting: Since you’re involved in the early stages of new casting designs, at what point are you bringing the foundry into the discussion?
Lindert: I always believe in getting the foundry involved as early as possible. Typically, the earliest the foundry gets involved in our processes is with a tech review that we conduct for the part. At this point, the design of the casting is still open and we’re able to make changes. 

This happens shortly after the quotation process has gone through—we’ve usually down-selected to either one or two foundries that we’re narrowing in on, and then we’ll meet with that foundry on a Team’s meeting with me, as well as purchasing and engineering on the call. We’ll go through the technical requirements of the casting, discuss any questions, and listen to their input on whether there are any design-for-manufacturing issues or changes that the foundry recommends. Those are usually very productive meetings where the design really gets locked into place. 

MC: In your experience, what’s the most important value proposition the foundry brings to the table?
Lindert: I think a lot of designers doing the legwork on these parts, especially for our company, are somewhat newer—maybe three or four years out of college—and they come to us with very little knowledge of the foundry’s casting processes. Most have never visited a foundry and have a very abstract understanding of what a casting is, as well as the rules for designing around a casting, such as draft and cores. The foundry can help with a lot of that knowledge, and that’s part of my role, as well; to educate as much as possible. 

One thing that a foundry can do, which we’ve had some luck with in the past, is a Foundry 101 class or hosting those tech reviews onsite to get some of those design engineers to actually see the process. It’s one thing for me to explain what draft is; it’s another thing to see how a mold is pressed in the sand. That really helps educate our designers, and foundries are the best suited to do that. 

MC: How would you characterize product demand and sales this year at Oshkosh?
Lindert: It’s been a pretty busy year and, looking over quarterly financial results, I think everything’s looked good—we had a pretty big bounce back from 2021, and 2022 was a little bit slower with a lot of inflation concerns and supply chain challenges. 

Oshkosh is an interesting umbrella company over several segments. One of our largest is JLG, which is a construction company that makes the telehandlers and scissor-lifts you see on construction sites. I think they’ve had a really good year this year. And a big portion of our business is defense, which is mostly located in Oshkosh—it’s also been a pretty busy year for them. 

MC: What are the big projects occupying your time this year?
Lindert: We are redesigning postal vehicles for the USPS, so that’s had quite a number of challenges, because it’s a higher volume than we’re used to. I think they’re looking at 50,000 or so vehicles over a number of years.

There are a few castings on that platform that we have developed from the ground up, mostly aluminum, thin-walled castings, which are a little bit different than some of the castings we’ve normally made, especially for defense and construction—weight hasn’t been a big issue for defense in the past, and our telehandler products tend to have a lot of heavy, ductile iron castings. But all that has changed in recent years. We’ve really been pushing the envelope on some of our thin-walled castings, which has pushed us toward processes that we’re not as familiar with—moving from sand castings into more high-volume die castings. There are different quality concerns and design aspects to think about. So, it’s been a great learning experience with good challenges along the way. 

MC: It’s obviously critical to work with a foundry that specializes in the alloy and process best suited for the casting—tell me about the foundry vetting process at Oshkosh.
Lindert: Onboarding a new supplier is one of the key areas I try to get involved with as much as possible.  A new supplier, especially a foundry, has to go through a quality audit conducted by our quality engineers who specialize in this. We do have a specific quality audit that’s tailored toward foundries, and for different foundry types, such as aluminum or ductile iron, because there’s quite a bit of difference there. 

Those quality audits are essentially a spreadsheet with a day’s worth of questions and rankings. I like to be there to really get good eyes on their process and pick out some of the aspects that aren’t necessarily covered in a spreadsheet type of audit. I want to figure out the bread and butter for this foundry, what type of casting they specialize in, what wall thicknesses, what volumes—things that don’t always get communicated on an audit.  

MC: Can you elaborate on what the typical bidding/RFQ process look like?
Lindert: It varies segment to segment, but we have a good core list of foundries that we are comfortable with and work closely with. It’s a lot different than other commodities where you have some flexibility on where you’re going to get your little widget from. There’s a lot of partnership that goes with making a casting and any quality issues that come up afterwards. It can be a chaotic process in terms of missteps or things that can go wrong, and how you get over those is important. So, we toss a net that’s not too wide when it comes to sending out for quotes. For defense work, we’d probably see at least five foundries on that RFQ list, and I wouldn’t expect it to be over 10.

As far as the bidding process goes, there are strict timelines that come along with a lot of our projects, and we have to make sure that we have the right numbers in hand with the right people to talk to, which is always a challenge. That’s where that partnership comes in—our buyers have tight relationships with some of these foundries where they can reach out and say, “Hey, we have a part coming your way that you should take a look at; is it something that would fit well in your process? What do you think about it?” Those types of back and forth exchanges are very useful. 

MC: So, how many foundries are in the primary circle of Oshkosh preferred suppliers?
Lindert: It’s hard to give a definitive number, because some of the segments work more independently. I would guess there are probably about 20 ductile iron and iron foundries, maybe 15 or so aluminum foundries, and probably only about five or so for steel foundries—and that includes some of the investment casting foundries as well. The reason there are as many foundries as there are is because each segment has a much different need. On our government and defense side of things, volumes have been a few thousand parts per year. Now that we have postal vehicles, it’s going to be 10,000–20,000 parts per year. 

MC: At a high level, what are the testing certifications and abilities you require from foundries?   
Lindert: We rely heavily on radiographic inspection. So that would require an ASMT certification; there’s also an NAS 410 certification that some of the military parts use. Generally, the radiographic testing is more of an upfront part of our PPAP process. There are some castings that require ongoing testing, depending on the usage of the part. 

Some of our castings will use dye penetrant and magnetic particle inspection for surface analysis to detect cracks and surface defects. It really comes down to what alloy we’re buying. There can be hot tears with some of the steel parts, and some aluminum alloys have issues as well. So, we try to tailor our quality requirements around what the part is used for—what would be the impact of a failure and the risk level based on the alloy and process.

MC: What are the attributes you really want to have in a casting supplier? 
Lindert: One thing that I really look for when visiting a foundry is their level of automation. Not necessarily robots doing all the work, but how locked in are their processes? It always seems if there is a quality issue, we ask, “What changed between this lot and the previous lot? And they say, ‘Oh, nothing changed.’” The problem is, there’s thousands of variables that go into making a casting. So, anything a foundry can do to automate their process to reduce the level of variables, that is great to see. 

MC: What does your ideal foundry partner look like?
Lindert: I really appreciate the technical expertise from a foundry, and their willingness to collaborate on some design work. Some foundries will just respond to a quote with a number. Others will come back with design ideas and say, “Hey, you don’t necessarily need a core here; machining might be the better option and you’ll save money in the long run.” That type of thing. Those collaborative technical conversations are great. 

Sometimes this can happen well before a tech review, too. I might have a design engineer with an off-the-wall question on this part he’s trying to design—trying to really thin out a section and needing to know what the capabilities of the foundry are. It’s nice to be able to reach out to a technical expert at a foundry that I know and trust with 30 years of experience under his or her belt, and them being able to explain what their foundry can do. 

One good example of a collaboration is when our foundries are working with the same simulation software we have—we use simulations quite a bit for the design side of things over here. When the foundries have those same capabilities in house, we like to utilize their expertise and their process simulation as well to go over some of those challenges. It’s extremely useful before you’re cutting tooling and pouring the first part to know where the risk areas are—you’ve already mitigated some of that risk by employing what you’ve learned from that simulation software. There have been numerous instances where we’ve utilized simulation software, gone back and forth, and came up with great designs and great tooling.

MC: What new technology in metalcasting is making an impact at Oshkosh?
Lindert: 3D printed molds have been a huge help for us. One challenge that we have when we’re coming up with prototype vehicles and we’re bidding for, say, a defense contract, is that this process involves building a handful of prototype trucks at the beginning—somewhere between five and 20 trucks. And that’s before we’ve even been awarded the contract. It’s extremely difficult to get castings and forgings in those volumes for any economical cost. It’s easy to hog it out of billet, but you don’t want to do that because it’s not really representative of your end casting. So, the best way to get a representative casting when you only want a handful of them is 3D printing those sand molds—this has been extremely useful to reduce the lead times and reduce cost for a lot of those prototype trucks. We have quite a few success stories there.

MC: Is Oshkosh proactive about converting weldments to castings?
Lindert: We’re always looking to do it, for sure. It’s very good when the designers and project managers recognize it themselves and pursue it from the ground floor. Also, once a year, we do a complete tear down of one platform in at least one of our segments. We’ll go through every single part on that platform to figure out what ways we can save money and improve quality. And a lot of that is looking at weldments that, if the volumes look right, could potentially be turned into a casting. 

MC: Have you got a takeaway you’d like to leave about working with foundries?
Lindert: The main thing I push here at Oshkosh is that collaboration we talked about, and as early as possible. Throughout the company, we emphasize cost savings, and the best time to get that cost savings for a casting is during the design phase when you’re able to incorporate or remove a core or alter it to make it more manufacturable. Once the design is locked in, especially for defense, we can’t change that design without customer approval.