What makes highly loaded gearboxes such an integral part of gear manufacturing?
The long and short of it is that a highly loaded gearbox is transferring a lot of energy from a turbine to places elsewhere. And those are things that can make reduced engine noise or increase fuel efficiency in an aircraft. But because they’re highly loaded, uniformity of the gear teeth in this instance is what matters the most.
Our system is important to that process because we’re able to do a surface finish on those gear teeth that is uniform to within 0.4 microns across the board. If your polishing process creates an uneven surface finish, you’re going to get uneven wear rates, and over time on a highly loaded gearbox, that’s just going to cause the gear teeth to get stripped and cause a failure down the road.
What breakthrough has OTEC made in super finishing highly loaded gears?
Our major breakthrough was just using our stream finishing technology on gear applications. The stream finisher allows us to take the container and rotate it while the part is fixtured, and the part is also rotating. That allows us to increase the amount of force on the part. Some of these other manufacturers will have things that are similar like a spindle finisher, but they just come straight over the side of the stationary bowl, and there’s not really too much opportunity to force media into areas that you want it to go. We’re able to adjust from being straight up at zero degrees all the way out to 35 degrees, and while we’re rotating the part and container, that just allows us to achieve much better surface finishes, and faster. If we’re talking about something along the lines of a vibratory, you’re looking at a machine that can go for 24 hours, and it may have some success in deburring, but the actual implication as far as the surface finish, is you’re not doing anything that’s necessarily going to get into the sub 1.0 microinch Ra type of finish. When we polish Indy car gears and bearings, they actually send us previously rem’d parts, which we improve.
The way we’re able to direct that flow of media is allowing us to have very consistent results, and it also allows us to hit different geometries. If somebody has something like a pinion gear that has teeth with curved edges and has a concave and a convex side, a customer can come to us and say, “We only want to finish the convex side.” We can adjust the flow of media and the rotation of the part to achieve that. Or, if they just said the concave side, we can do that as well. It just gives us a lot of different abilities. We can focus more on the gear face; we can focus on teeth, we can focus on edge breaks all depending on what a customer asks for. It gives us a lot of latitude to be able to direct the flow of media and finish it in ways that other people previously weren’t thinking about.
You can buy an OTEC stream finishing machine; you can automate it, place machines in multiple locations, and you can guarantee that those results are going to come out the same.
Describe some of the research that went into the development of this process.
This process with gears was someone came to us and looked at the stream finisher at a trade show and said, “Could you do that for gears?” We said, “Well, we hadn’t previously thought of it, but yeah, we could.” As we got further into the development of it, we just started developing larger machines to be able to handle all these different forms.
As customers have come to us with more things, then that’s what we do. It’s all process driven. All of our research comes as people come to us with new things. It’s exciting for us. People have problems. Once they have those problems, we’re excited to try and tackle them and find a solution to finish.
What makes the process environmentally friendly, and why has that become a most-sought-after demand for manufacturing gears?
Our systems are flow-through systems. You’re generally looking at 50 to 100 liters of water per hour that’s coming into the system. What we did to reduce people’s waste water disposal costs, is we started working with other manufacturers to develop centrifuges that work for our process. Now we’re running a centrifuge where you can run a closed loop on that system, and you’re only changing out that entire container of water once every three to six months. The waste that’s coming off during the process is all contained inside the dry waste container of the centrifuge.
What are aerospace OEMs and Tier 1 manufacturers taking away from this process as they look into using this method themselves?
They look at this and, just the thought that they can do this mechanically and have the consistency that we have, that’s their biggest takeaway. People hadn’t been looking at polishing and deburring solutions in aerospace gears before. They have complex geometries, and they thought it wasn’t possible. And now that they know it is possible, with the added benefit of automation, it’s really exciting for them to think what they can do.
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