Weather Guard Lightning Tech

CNC Onsite Cuts Repair Costs With Uptower Machining

Søren Kellenberger, CEO of CNC Onsite, joins to discuss uptower yaw gear repairs, flat tower flanges, and replacing 1,000 blade root bushings across 26 turbines.

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Allen Hall 2025: Soren, welcome back to the podcast.

Søren Kellenberger: Thank you, Allen, and, uh, nice doing it, uh, face-to-face- Yes, it’s great … and not as a team, uh, call. Right. That’s

Allen Hall 2025: true. Yeah. You’ve been doing a good bit of traveling, and you’re the new head of CNC Onsite.

Søren Kellenberger: I am, yes.

Allen Hall 2025: So congratulations on that.

Søren Kellenberger: Thank you very much.

Allen Hall 2025: And all the exciting new things that CNC Onsite [00:01:00] is doing, plus all the things you have developed and are now out in the field implementing, the, the list goes on and on and on.

I’m alwa- every time I talk to you, “Oh, we got a new-” Yeah … “machine to do something uptower.” So it’s all uptower, which is the, the beauty of CNC Onsite. You’re thinking about the operator and the cost to pull the blades off and do lifting the cell off and all those things. If we can do it uptower, we can save 30, 40, 50% of the cost of a repair.

Søren Kellenberger: Yeah.

Allen Hall 2025: That’s where CNC Onsite is just really killing it. You guys are doing great. Thank

Søren Kellenberger: you. Of course, we like what we do, but, uh, thank you.

Allen Hall 2025: Yeah. Yeah. Yeah, yeah. No, it’s good, it’s good. And, and so w- let’s talk about the things that I know about, and we’ll start there, and then we’ll go to all the new things you’re doing.

So the one that I see a lot of operators asking about is yaw tooth. Yeah.

Søren Kellenberger: Uh,

Allen Hall 2025: deformations, broken teeth on the yaw gear. That’s a big problem. And when I talk to [00:02:00] technicians, and I have them texting me about this, like, “Oh, well, I just weld on the gear back on, weld the tooth back on.” That’s a short-term solution.

That’s not gonna be long-term. The long-term solution is the CNC Onsite. Can you explain what you do to permanently fix these yaw gear problems?

Søren Kellenberger: Yeah. So what we do is actually we start by getting information about the, uh, original yaw ring, so the dimension of the teeth, and we get some load data. And, uh, then we start designing a replacement segment.

Uh, so what we ac- the process is actually that we bring a CNC controlled machine uptower, mount it on the yaw ring, and then we mill away that worn area, uh, creating a small pocket. And then those, uh, segments that we have designed, they are prefabricated. We bring them up and mount them in, in that, uh, pocket and bring the- The yaw ring back to where it’s, you can say, original design, uh, [00:03:00] that way.

Yeah

Allen Hall 2025: It’s better than the original design, ’cause you’re actually putting in better teeth than the, the manufacturer did originally.

Søren Kellenberger: True. Yeah, yeah.

Allen Hall 2025: So that happens, so you’re, you’re machining out those old teeth, broken teeth, putting the new set of teeth in th- and that all bolts in, and that’s it. That’s it.

But the, the difficulty is getting the machinery uptower to do that. That’s where a lot of your, your technology comes from, is getting this very accurate, uh, well-defined machine uptower and doing very controlled grinding and milling. Yes. So can you explain what that system looks like? If I’m gonna grind off those yaw, broken yaw teeth, how big is that kit?

Søren Kellenberger: It… Obviously, it depends a little bit on the turbine size. Sure, okay. Yeah. So, uh, it, so the, the newer five, six, uh, 10 megawatt turbines have larger teeth, so yeah, there you need a, a larger machine.

Allen Hall 2025: Okay.

Søren Kellenberger: But let’s say for, uh, Vestas three megawatt, the, the [00:04:00] complete machine weighs about 250 kilos. That’s it? So yeah.

So it, it comes up in smaller components. We just use, uh, the, the internal crane in, in the nacelle, and, uh, then we can lift the components to the yaw ring, assemble the machine, and then we are basically good to go. So it take, takes less than a day to get everything up and, uh, get set and be ready to, to machine.

Allen Hall 2025: So if you wanna fix a yaw gear problem, how long does it take from start to finish to get that done?

Søren Kellenberger: It typically, it takes one day to get everything up and get ready, and then per six teeth, which is a typical segment, it takes about a day to machine that. Okay. So, uh, let’s say you have, uh, somewhere between 10 and 15 teeth, it’s, uh, two to three segments.

So we do that in a week. Um-

Allen Hall 2025: Wow … and- ‘Cause the alternative is call a crane, have them lifting the cell off.

Søren Kellenberger: Yeah.

Allen Hall 2025: Take the yaw gear off, put a yaw gear on, if you can find a yaw gear. Yes. Put the nacelle back on. [00:05:00] Well, and I guess obviously the rotors are coming down too, so- Yeah. You’re talking about- Yes

hundreds of thousands of dollars in downtime. Yeah. It’s a big ordeal. The CNC Onsite method is so much easier.

Søren Kellenberger: We will just put our equipment in the back of our truck- … and then, uh, we’ll, we are ready to mobilize in a few days. So yeah, we can significantly, uh, bring down the downtime and, and as you said, the crane cost is of course extremely high.

And then you can add all the project management. You know, con- do I actually have my access roads, uh, still available? Right. Is the crane pad intact? And all of that stuff you need to organize. You can just forget about that and, uh- And

Allen Hall 2025: get it done …

Søren Kellenberger: get it done. Yeah.

Allen Hall 2025: Yeah. There’s, there’s a lot of owners, we, everybody knows who the machines are that have the, the, the yaw tooth problem.

Søren Kellenberger: Yeah.

Allen Hall 2025: So if you’re one of those owner operators, you better get ahold of CNC Onsite. Now, flanges on tower sections. It’s become a, a really critical issue. You hear a lot of, of [00:06:00] operators, OEMs talking about, “I’m putting together these tower sections and those flanges don’t really meet up quite right.”

Søren Kellenberger: Yep.

Allen Hall 2025: “I’m creating uneven torque pa...