Making Parts Tough Enough for Off-Road Use

The world of rugged, off-road vehicles is unforgiving. Vehicles take hard hits from flying rocks, dirt potholes, and embedded boulders, and they’re expected to hold up at highway speeds!

Of course, because so much is expected of these buggies, jeeps and off-road chariots, there are parts and components specially designed to hold up to the abuse. One of the most maltreated components are the front and rear differentials, as they are often the closest exposed component to the dirt trail, aside from the tires.

Enter Tim Fulton and his company, Alien Machine Worx.

While Alien Machine Worx operates as a job shop, cutting production parts on various CNC machine tools, they also make customized components for off-roaders and hearty differential covers.

“We do parts for lots of people in lots of different industries. We do some off-roads parts for other people, some medical stuff for other people, we do some aftermarket parts for certain companies, and we make our own differential covers and shifter knobs,” explains Fulton.

He has had an interest in off-roading since he was just a kid. There are rumors that he started off-roading at 16 years-old with a 1970 Chevelle, but his official start was when he got his first Toyota truck at 17. The sport has long been his passion, but three years ago it also took hold of his career.

Lots of Engineering in a Simple Component

Differential covers, or diff covers, are not complicated parts. The only purpose they serve is to protect the precious gear mechanisms inside the differential, and OEMs often make simple versions out of sheet metal.

When you’re off-roading, sheet metal doesn’t hold up well to various sized rocks and debris. “OEM diff covers get holes in them pretty easily. If you roll over a rock it can get a hole punched in the side,” Fulton says. “The worst part about damaging a diff cover is that if you don’t have somebody behind you, you don’t even know you have a hole in there. You could still drive 100 miles; it’ll just go dry. Then you’ll burn up your whole differential before you even realize you put a hole in the cover. It’s a peace of mind thing when you’re doing off-roading.”

Alien Machine Worx diff covers are ¼” thick and have built-in ribs, called rock sliders, that not only add thickness but also provide deflection for the cover. There is a lot of design effort that goes into these diff covers, including stress testing and simulations in SOLIDWORKS.

“We’ve even taken them out and shot at them, and they haven’t cracked,” he explains. “The biggest thing is protection. People will spend X amount of dollars setting their gears up and all this stuff is inside the differential, and then they put a cheap cover. Then all of a sudden, you smash that whole gear set when you run into something.”

Alien Machine Worx also uses a specialized material for their diff covers: ductile iron. While it’s cast similar to cast iron, ductile iron is harder and less brittle, and you can weld on it. That means that it’s more versatile and more robust than cast iron.

“If somebody wants to get rid of nuclear waste, they use ductile iron. The thing about ductile iron is that you can put different formulated mixtures into it. I’m not going to give away the secret sauce, but my mixture has a bunch of different things in it to make it a lot stronger. You can mix ductile iron however you want, but with our mixture it’s stronger and designed for exactly what we are using it for.”

Because Fulton uses SOLIDWORKS for all his design work, as well as collaboration and manufacturing, he can input ductile iron as a material. While the program doesn’t know his exact formula of ductile iron, it’s close enough to provide accurate stress testing. He explains, “Basically, I can hold the two tires at the end of the axle, and I can drive force on the diff cover. With our diff cover, it shows the axle bending before the diff cover will give. And that’s straight on pressure—it’s not like real life where you have deflection, where you’ll hit the rock and bounce over it.”

“Testing in SOLIDWORKS gives me a really solid baseline, and then things are more forgiving out in the real world on the trails. In the simulation it’s something like 15,000 lbs of pressure pushing on that thing. You won’t encounter that in real life because the vehicle will just bounce over it at that point,” Fulton adds.

Custom Job Shop and Production Machining Business

While much of Alien Machine Worx’s focus is on their diff covers, Fulton also runs several production parts and one-off custom components for his clients. “We do a lot of production work for other companies. There are times we’ll have a machine dedicated to a customer for months, just working on their product line,” he says.

Because his company has become so well known in the off-road market for their diff covers, Fulton has taken on business building components for other companies in the space. “The diff covers are what has gotten our name out there. So, there are a lot of other companies with off road components that know we know what we’re doing in the off-road space, so we help them build their parts as well.”

“That’s kind of how Alien Machine Worx got its name… we did stuff that other people didn’t want to do. I tell people that if you can go to the store and buy what you need for $50 or $100, you don’t want to come to me. But if you really need something special or unique, then they would come to me and I would build whatever they wanted,” Fulton says.

He once had an off-road race team ask about carrying an extra alternator and starter on their buggy. While the path of least resistance would be to stick the parts in foam inside a toolbox, Fulton decided to go a different route.

“We mounted it on the roll cage so that it was easy to access. So, if their alternator went out as they were going across the desert, they could just jump out, unbolt two bolts on the roll cage, throw those two bolts on the engine compartment, and they were up and running again. We made it quick for them to move from point A to point B without those components flopping around and getting damaged in a toolbox,” he says.

Fulton thrives on doing customized work, which makes sense since the off-road market is all about unique methods of making things work.

Communication Becomes Key

Alien Machine Worx leverages a number of features in SOLIDWORKS, but really it’s about communication. “I had one person fabricate their own steering linkage and it rubbed on our diff cover after he installed it. Because of the way it was built in SOLIDWORKS, he was able to call me, we opened up the model and we did some measurements. Since he was a fabricator, he just took a grinder to the diff cover, and I was able to tell him exactly how much to grind off to make it work and still be safe,” Fulton says.

“SOLIDWORKS allows me to communicate with my customers easily. As a machine shop, I don’t think I’ve seen a blueprint in 10 years thanks to this system.”

Alien Machine Worx works with a variety of clients, both in and out of the off-road industry and some even in the medical space; oftentimes those clients don’t know much about manufacturing. “If somebody sends me their models, the hardest part more often than not is how am I going to fixture or hold them. Not everybody thinks about how they are going to machine a part when they are designing it.”

“Long before I build anything, I can share it with a customer. We’ll change things with a customer’s design to get it to an efficient manufacturability state. Then, we build all of our fixturing, all of our tooling, that’s all done inside SOLIDWORKS.”

Fulton continues to always look for ways to streamline his manufacturing practices, while also finding more efficient ways to design and improve client models.

“I lay in bed at night and come up with designs. Eventually, I need to get up and get them into CAD. I’m always thinking about ways to try and make my product better. That’s what keeps me up at night. What would people prefer to have over the competition. I live and breathe this stuff,” he says.

While Fulton figures that Alien Machine Worx will always have a job shop element to it, he’s sure that their presence in the off-road space is going to grow as well.

Learn about SOLIDWORKS in automotive racing with the whitepaper Giaffone Racing: Expanding Into New Racing Markets with Topology Optimization Tools.

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