EchoBolt Advances Wind Turbine Bolt Maintenance
Pete Andrews from EchoBolt discusses their advanced ultrasonic technology for inspecting and maintaining wind turbine bolts, which can reduce maintenance costs by up to 90%. He emphasizes the importance of proper bolt tensioning during installation and highlights recent improvements in their automated inspection processes.
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Allen Hall: With wind turbines growing larger and critical bolted connections under strain, the wind industry needs smarter inspection methods to prevent costly failures. This week we speak with Pete Andrews, managing director at EchoBolt. EchoBolt has developed ultrasonic technology that makes bolt inspections faster, more reliable, and saves wind farm operators up to 90% on maintenance costs while preventing catastrophic failures. Stay tuned.
Welcome to Uptime Spotlight, shining Light on Wind. Energy’s brightest innovators. This is the Progress Powering tomorrow.
Pete, welcome back to the show.
Pete Andrews: Hi, Allen. Hi Joel. Good to be back. I was trying to work out when I was last on here, but it was it two years ago. It’s been a while. Anyway, we’ve had a lot change at alt yeah, it’s good to catch up with you guys again.
Allen Hall: It’s been too long and so we’re glad to have you back because I know there’s been a lot of improvements and EchoBolt has been really busy checking bolts all over the place and we’ve, Joel and I have been traveling around quite a bit and we’ve noticed problems with.
Bolts in the United States and we think where’s Pete? Where’s Ebol? We could really use you in the United States to help us on some of these bolted connections because it does seem like there’s a lot of issues from tower bolts to blade bolts to bolts in general, there are a number of problems that exist.
And I wanna start off there, Pete, because I think you’re the knowledge base for bolts. Are bolts being tightened correctly based upon all the measurements that you have done?
Pete Andrews: Say, it’s a very mixed picture. I think you’re right to point out, it’s every wind operator will have issues in their fleets with the bolt of connections, but it’s almost always.
Blade studs that caused the most headache. You do see things on towers. You do see a kind of occasional issues elsewhere, maybe with foundations. I’d say it’s probably, I. In our experience, once, once sites are in operation, there’s not too much that happens that influences the integrity. An awful lot happens at the point of installation, and it’s what we always try and say to customers if it.
If you confirm that the bolts are tightened to the load, you expect at the point of installation, you’ve set yourself up for a fantastic operational li life. But if it’s wrong at the start, you’ve got embedded integrity issues that are really hard to manage going forward. So yeah it’s a mixed picture, but what I’d always say is focus on the QA at the point of installation and things should go easy from there on in.
Allen Hall: It does seem like blade bolts are becoming more of an issue. As you mentioned, the blade insert question of are we over tightening fasteners that go into the blades and pulling out these inserts and causing some of the problems downstream root cracking, instruments becoming loose, blades becoming loose and wobbling on the pitch bearings.
It does seem like we don’t have a really good way of consistently tightening or tensioning. Those fasteners are bolts that are in composite structure just a lot more sensitive to or the composites more sensitive to the tensioning tightening that happens? I
Pete Andrews: think without doubt it’s a harder joint to design and I think probably all of the major turbine OEMs.
It’s the area, I guess probably with the most dynamic loading or the most variable dynamic loading and probably the hardest to anticipate the performance of the joint. I guess we see a couple of things. We see a. Occasionally you do get overt tightening, particularly on torqued joints. Most blade studs tend to be tensioned, where you stretch the bolt rather than turn the nut or the bolthead.
But where it’s torked, you have a very wide degree of variability and there can be, there can be issues with going back and retalking and trying to measure an angle of turn and over overstretching the bolt and failing them. So we’ve seen that. I think on the tensioned joints, typically you get very good variability and the bolts tend to be within a narrow band, but probably not enough is being done to ensure that you’ve got as much preload safely within the bolt as you can.
And I think. The one meaningful action operators can take without having to redesign the joint or try and redesign the fastener, is just to measure the preload and see how much operational headroom you’ve got and maybe look at increasing it slightly. That’s probably the one area. If you’re suffering a lot of TED failures, you can address quickly and cheaply without getting into.
Design fundamentals.
Joel Saxum: Pete this week we were at the Blades USA conference here in Texas and we had many side, everybody’s talking blades, right? So what blade issue do you have? What blade issue do you have? And one of them that Allen and I had a couple conversations on with operators, there was, oh, we have the root bushing pullout issue.
And some people were very familiar with the issue and, but some people just weren’t. They were like, what do you mean by that? I was like, these things are actually loosening in the, breaking bonds and pulling through and all kinds of stuff. So in a blade root, you have upwards of a hundred studs or a, or a hundred of those blade bushings.
How many of them have to start to become loose before it starts to be like a cascading effect? For that blade,
Pete Andrews: the failing of the fixing within the composite structure is not really something we’ve encountered or looked into a lot. I think typically most manufacturers would place a limit on how many alts failed be before you need to stop the turbine.
Some of them have overall limits about the number in the joint and some have adjacent limits. I think it’s pretty normal for people to run with one or two failures and the structured still be still be safe to operate. But I think where you start getting consecutive failures, you have to look quite hard about.
The decision to continue to operate the unit, but particularly since the failures often in segments. So there is typically leading and trailing edge segments where you’ll see higher risk of failure. So as soon as you’ve got a couple of bolts in that area that aren’t doing what they want or what they’re supposed to be, then yeah, I think it’s a much harder decision to carry on.
Carry on operating without replacing those fasteners.
Allen Hall: Are there OEMs that are asking for those blade bolts to be torque still or has everybody moved on to tensioning? I
Pete Andrews: think every modern turbine we work on is tensioned. Some of the, we get quite involved in life extension projects where turbines have got to sort 20, 25 year operating life.
People are trying to make an assessment of, is it safe to continue? Do we need to do wholesale replacement of components, et cetera. And so a lot of the older fleet or some of the older fleet would have talked talk blade studs, but often, we can go in and if we can prove that the bolts are operating in the preload envelope.
The ideal preload envelope, let’s say. We can also look for defects, so we can look if the bots have got cracks in them and help the people make that call to just continue to operate safely with a monitoring regime in place rather than perhaps following a recommendation. From an OEM, which might involve wholesale replacement.
Allen Hall: I think that’s fascinating, but I asked that question because there’s a lot of repowering happening in the United States, and it did seem like turbines that are 10 plus years old. There was a lot of torquing of blade bolts, and now that we’re going to repower, one of the questions is, do I need to go back and look at that blade root area and do I need to address it because I overt, tightened, and or retort over the years and damaged that root section.
Is that something that EchoBolt and its technology can actually check? Because I think that’s one of the variables that we don’t know right now is this bolted connection okay. To live another 10 or 15 years. Is that something that the technology at EchoBolt can derive? We can
Pete Andrews: definitely to derive the bulk loads so we can have a look if.
If the bolt is over or under tightened, what we don’t do is the structural non-destructive testing. So we couldn’t look at the blade root bolt fixing structure and make any comments about the integrity of that. But we can look with you or with operators. What’s the tension or tithing process they’ve followed?
Does it generate the preloads that you would expect? Is there a risk of overti or in the tighten box? So that’s really our specialism.
Joel Saxum: What you guys do is very valuable at different life’s stages of a turbine, right? ’cause what earlier we talked about hey, right at commissioning you should be doing, you should be checking all these bolt connections or tension connections.
Either way. And then we talked a little bit we jumped forward, talked a little bit about lifetime extension during the repower phase. But another critical phase of life, specifically in the States that we deal with all the time is end of warranty. And it’s a worldwide problem. Are you guys getting into a lot of end of warranty campaigns right now where you’re checking everything before it gets handed back to the operator?
Pete Andrews: Yeah, we sort of, you’re absolutely right. There’s a few kind of obvious moments where you want to do more than the standard sort of asset status, asset health check and end of warranty is clearly one of those points. We have done end of warranty projects. Particularly a lot of our offshore customers, the age of the sites are at that point where sites are coming outta long-term service agreements.
The operators may be the owner is maybe taking on the operational responsibility and they want to transition from. What’s gone before to their own maintenance philosophy. So yeah, you’re right that’s one of the moments that we’ve been involved in, particularly when there’s been a serial defect.
And the OEM has proposed an upgrade, so we’ve had that on blade studs where just before end of warranty, an OEM has changed the design of the fastener. To alleviate bladed failures, we were actually able to show that in the population of the modified fastener, there were more defects than in the non-modified fastener.
So right at the end of warranty, we were able to show the customer the proposed solution was actually it actually made the situation worse. So they were able to, carry on the commercial. Debate with the their OEM and hopefully get a better res resolution.
Allen Hall: Okay, Pete, so I want to dig into that a little bit ’cause I know your technology is improving and one of the issues that’s we’ve seen quite a bit more recently is defects in the studs or the bolts themselves in the clin structure of the metal.
Occasionally there are some. Embedded defects that visually they can’t really detect. But it does sound like there’s new technology that can help delineate like that. Stud. That bolt has a defect in it where the next one doesn’t, which is incredibly valuable because depending where that bolt is on the blade ring, it could be critical or not critical.
I Is that technology now available more worldwide because of what EchoBolt has done?
Pete Andrews: Yeah, I think the. The technology we use for looking for very small defects is an ultrasonic technique called phase array, which is a more complex, non-destructive testing methodology than we would use for a preload inspections.
It’s a bit more specialist, but that can be really quite precise here. So down to the one or two millimeter. So scale or resolution for defects? So where we know there’s a problem in a population of bolts and the customer’s really keen to identify all the studs that are in the process of failing, we might use that to, to get themselves like a clean joint, if you like, of defect free fastas.
So they’ve got a good baseline to monitor from going forward, but as I said, that’s a bit more specialist. So it’s not it’s not trivial, let’s say, for customers to carry those inspections out themselves. But our bulk inspection technology that we use for monitoring a thousand bolts a day, to get through all the primary structure of a turbine.
We’ve worked on a lot over the last two years since we last spoke, to really optimize that to be as straightforward and user friendly for customers to adopt directly. And that methodology, whilst it’s primarily designed to identify the load within the bolts where we get big defects in bolts, we often see.
A fatigue rack propagating maybe 70 or 80% of the diameter of the bolt before it ruptures. So once you’ve looking at defects of that sort of size, our standard technology will also identify that, that there’s an issue with that fastener. So it does give you a chance to capture the fastener before it.
Catastrophically fails, which is quite useful, particularly for the blade studs because when they fail they can do an awful lot of damage. There’s all the hitch system, electronics, cabinets, lighting, et cetera. The number of turbines that have been in where the lights don’t work in the hub because there’s been, been half of a blade stud or a nut rattling around in there, smashing it all to pieces. So it is quite valuable to get to get the bottles out before they actually fail.
Allen Hall: I didn’t think about the associated damage when the studs fall out, but yeah, it does seem like it’s a, I guess it’d be actually dangerous and expensive when that happens.
So not only is it a structural issue, it’s just there’s equipment wiring all the. Activity inside of the hub could be damaged too. That’s really interesting. Okay, so the thing about echo belt is it’s all non-destructive. You’re doing things that don’t affect the bolt themselves.
You’re not playing around with ’em. You’re just using ultrasound technology and some really high advanced ultrasound technology to learn about the tensioning of the bolt, make sure it’s been elongated properly. That the structure of the bolt is all intact. So you know that bolted joint can have a long lifetime.
Now, there’s been a lot of advancements that at echo, EchoBolt to one, make that faster because the number of bolts that you’re doing in a day has increased quite a bit. But also the whole system, the way you guys operate, is now really automated from what I could tell. You want to describe what it would be like to have you come on site and go.
All right, Pete, we’re just gonna have you go check out the critical bolts in these turbines go. What does that look like now?
Pete Andrews: Yeah, perhaps if I go back to what it was like before. So when we started the company, we were primarily really a service provider and we were using off the shelf hardware, and we were quite technology agnostic really.
We just we’re trying to find different technologies we could bring into the wind industry to help with this problem. And we were using off the shelf ultrasonic bolt measurement devices, but I. I don’t think any of those devices were really conceived with the wind turbine use case in mind. So they’re very good at, if you have a small number of very high-end fasteners that you’ll really want to be super precise in a laboratory environment or a, a very specialized piece of equipment.
You can be very precise, but you have to be quite a skilled operator and it’s relatively time consuming. Whereas what we were trying to do is inspect a wind turbine a day, the whole primary structure. So the foundation, the tower joints, the your joints up to main shaft plate studs. Pitch bearing to hub, so all the connections that if that connection fails, a part of the turbine would fall off.
So you’re into needing to inspect a thousand bolts plus particularly on more modern machines which are getting larger and larger. You’re into the multiple thousands. So that hardware was just really suboptimal for it. It was a very clunky way of trying to export data. Onto your laptop with CSV files and manipulating Excel, and it just, it, it was taking almost as long to do the post inspection analysis as it was to do the inspection.
So we’ve completely re-looked at the technology purely from the perspective of what’s the optimum device for the wind industry. And we recognize that we are quite a small company, so the ability for ebol to service. The global Wind industries a as a service business with our own technicians is, we can only do so much.
So all of our effort has gone into really streamlining the experience. So now it’s very straightforward for a customer to pick up one of our devices. We have a sort of half day training course. The. The main sort of ultrasonic electronics device is wirelessly linked to iPhone. So you download an i an iPhone app and all the user interface is via phone.
So it’s a really familiar platform for technicians to work with rather than this complex suite of buttons and needing a 10 page work instruction or press this button followed by this. So superficial. Now we have a cloud database where you set up your projects when you’re on the turbine or in the office, you synchronize the projects to your phone.
Once you’re on the phone, on the turbine, you select the project you wanna work on. Take your inspections. It’s probably 10 seconds, a bolt. It’s really very quick. Finish inspections and then resynchronize backup to the cloud. And we’ve got a whole customer platform where you can see all the inspections that have been done, any anomalous readings you can do a level of qa, you can comment on things and say, this reading looks furious.
We’d like to check it again. These bolts look like they’re under load. We’d like to get those RET tightened, et cetera. So we’ve really tried to build this kind of end-to-end technology. Architecture that just solves this very niche problem for the wind industry. So we believe it’s a it’s a much more efficient way of carrying this work out than what it would’ve felt like two or three years ago.
They’re trying to achieve the same thing.
Joel Saxum: So one of the things of course when you introduce a new technology, everybody wants to know, of course, cost efficiency. What’s the business case? All these things. Allen and I talk about this all the time with operators on for our products. But I think one of the things that you’re doing here with EchoBolt, it’s the efficiency of how.
Fast, you can get these things done. So if you’re gonna come in and do, re just retorque or retention a turbine, you’re logging huge equipment, you’re doing all kinds of things. Even if you’re just doing like the the 10 percenting around each connection, that takes a lot of time, a lot of effort, a lot of people, you guys are able to cut that way down.
So is it can you run us through this as a single technician, how fast can you actually get things done? I,
Pete Andrews: I. A large offshore turbine, maybe six megawatts plus, we would always try and do all those primary joints, a hundred percent of the bolts in a single working day. So in a kind of eight hour working window.
Which is a much more efficient than if you tried to re-tighten all of those bolts, as you said, with hydraulic toing or attention and gear. But the really big saving. Comes from the fact that you have a measurement that you can track over time. So you have information about the condition of how the joints are behaving, and because you have that detailed information, you can extrapolate out from a sample.
So you can start to say instead of visiting a hundred percent of the turbines in a wind farm to retighten 10% of the bolts, we’re just gonna visit 20% or 15%. And if the that 20 or 15%, all the joints are where we expect them to be and are not relaxing, then you can quite comfortably start to make some engineering judgment about the behavior of the whole.
Whole wind farm. So we reckon that you could save about 90% of the cost associated with bulk maintenance by moving to an ultrasonic inspection regime. And as a kind of rule of thumb, I, for anyone interested out there, once you combine labor cost, logistics, and turbine downtime. The status quo of we’re gonna reti 10% of bolts every year and a hundred percent every five years is probably costing the industry in the region of $1.2 million per in store gigawatt per year.
If you’re running a wind farm of 500 megawatts, there’s probably five or 600,000. Dollars a year of savings to be made. So it’s, I think once our customers have tried the technology, realize it’s very doable and reliable. We’ve not had anyone make the decision to go back to bolt tightening.
That’s a good use case. Yeah. That’s the, it’s, it is getting yourself comfortable with a change. And different companies will have different levels of, um. Engineering management of change, for their assets. But once people are through that process we’ve found, adoption has really ramped
Allen Hall: up well, if you can save a wind farm a half a million dollars.
In any way. I can’t believe they’re not doing it. And maybe they just don’t realize at this point that Echo Bull exists because you’re mostly based in the UK and you’re busy doing offshore work, which is really important that UK has a lot of offshore wind turbines and those need to be running. And the loss of an offshore turbine obviously is.
Really critical there, but the onshore turbine world also needs your help. And I just think they haven’t realized the amount of money they’re spending on retentioning fasteners automatically because the spec says they need to do it. There are smarter ways to go about and do that now, and Ebot is, I think, the way to, to do it.
And the number of times you have been out in the field and all that learned experience has now culminated into this platform. Which is incredibly valuable. Simplifying the bolt experience for engineering at an operator is immensely valuable because there just aren’t a lot of engineers to go through that data.
So everything that EchoBolt has done in terms of making the platform easier is a huge advantage. So not only are you saving a lot of money on physically going out and Retentioning, but you’re also saving a lot of engineering time. This is, this makes imminent sense. So your phone must be ringing quite a bit right at this point because you’ve, you cracked the nut, so to speak.
Pete Andrews: Yeah, it’s it’s quite an interesting sort of how the business has evolved, has been a really interesting and satisfying things to witness. We’re obviously based in the uk, the majority of our works. The uk but it’s, I’d say we’re probably 60 40 between the UK and other markets.
As you said, we do a lot of offshore work in Europe, but we also do a lot of onshore. We probably do 30% of our turnovers onshore. But yeah, it’s I feel that we have been. Historically when we were running a much more service focused business using technology that was hard to put into customer’s hands, we’ve been somewhat constrained by our own size.
It’s not trivial for us to get teams out to other parts of the world. It’s not always. The most cost effective solution for people. But that said, we’ve been out to the states for a number of projects. We did a offshore project in Taiwan, which was really interesting just over a year ago.
We do a lot around Europe, a lot of the other European wind market, Germany, Denmark Netherlands, et cetera. So yeah, we’ve been growing. I guess within our being, yeah, let’s say the team’s been kept busy, for the people we have, we’ve been growing as fast as we can.
But I think we’re gonna see a bit of a step change now where it’s much more, it’s much more credible to hand the technology over to customers to deliver themselves and get really good results. Um. Yeah, I think the opportunity, it’s it’s a really timely conversation because the opportunity for people to take this on with self-service teams really, really, it’s a bit of a game changer for us.
Allen Hall: So now that EchoBolt has grown in scale and operators are reaching out to you, and they should, because if they really want to cut the cost of the operational side and save themselves literally millions of dollars here, which is what we’re talking about, you need to get a whole the P to EchoBolt.
Pete, how do they find you? How do they find Cobolt?
Pete Andrews: So probably the easiest way is our website. So that’s cobolt.co uk. We’re also on LinkedIn. I’m on LinkedIn. They’re probably the main channels we’ve got. You’ll find us on YouTube. You’ll find us on Instagram, but they’re more just for marketing and like a bit about, outward facing stuff, but yeah, website and LinkedIn are the easiest ways to get in touch.
Allen Hall: Yeah, checked out ALT’s LinkedIn page. You can check out the YouTube page. You can actually see them in action, which is really interesting, so you can understand what the process is and how efficient. Alt is at determining if your bolts are okay.
Pete, thank you so much for being on the podcast again. We love having you. You gotta come on more often because you’re really changing the wind world at the minute. Love having you.
Pete Andrews: Thanks very much guys. It was, yeah, nice being back and we’ll, we will do it again sometime.
https://weatherguardwind.com/echobolt-wind-turbine-bolt-tech/
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CNC Onsite Cuts Repair Costs With Uptower Machining
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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.
Sign up now for Uptime Tech News, our weekly newsletter on all things wind technology. This episode is sponsored by Weather Guard Lightning Tech. Learn more about Weather Guard’s StrikeTape Wind Turbine LPS retrofit. Follow the show on YouTube, Linkedin and visit Weather Guard on the web. And subscribe to Rosemary’s “Engineering with Rosie” YouTube channel here. Have a question we can answer on the show? Email us!
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 patterns, bolt pat- my bolt tightening is not quite right.”
Søren Kellenberger: Yeah.
Allen Hall 2025: And it never really seats right, so you have this mechanical, built-in mechanical problem. CNC Onsite is now fixing that so those flanges are actually really flat. Really flat, yes. ‘Cause that’s what you need.
Søren Kellenberger: Yeah.
Allen Hall 2025: Yeah. They’re highly loaded.
Søren Kellenberger: If, if you want, uh… If you want your joints to be, uh, basically maintenance free, uh, we can, uh, achieve that with machining the flanges. And then, of course, you need to be in control with your bolt tightening process. Sure. But if you do those two things, you can have maintenance free bolted connections, and there’s so much money to be saved in the operations.
Um, and of course, when you have these bolts that end up fatiguing, some of them don’t get caught in time and you end up ha- having a catastrophic failure on the turbine. Uh- We’ve [00:07:00] seen that … because you have that zipper effect. Once a bolt starts breaking, the neighboring ones take that extra load and it accelerates really quickly.
Uh, yeah. Sure does.
Allen Hall 2025: Yeah. It’s a very serious situation, but it starts with this very simple solution which is just make the flange flat.
Søren Kellenberger: Yeah. But I think it’s some… a part of the issue is that those buying the towers aren’t necessarily responsible for the operational cost of maintaining that bolted connection.
So they might save a little bit of money when they buy the tower sections with rougher tolerances, but you will spend the money 10 times in the operations. Uh, and, and that’s, I think that’s where some of the operations, uh, re- the, the, those responsible for operational costs should, uh, get a little bit more CapEx spend, uh- Oh, sure.
Yeah. And, and then, uh, actually save a lot of money and, and reduce risk. Uh, it’s a huge, huge risk
Allen Hall 2025: It’s, it’s one of those lessons learned. You [00:08:00] don’t know that they should be flat. You shouldn’t know… You don’t know your flanges should be flat until you experience the problems, and then you want all your flanges flat from here on out.
Søren Kellenberger: Yeah.
Allen Hall 2025: But there’s only one way to do that really, and that’s to call CNC Onsite to come in and to make them flat.
Søren Kellenberger: Yeah.
Allen Hall 2025: Because it’s a difficult thing to do. You really need to have the machining prowess and the tight tolerances that CNC Onsite’s gonna deliver in a tool that can actually be adapted to that tower ring and make those surfaces flat.
It’s complicated. Exactly.
Søren Kellenberger: It is. Uh, but that is what we do every day, so, uh- Yes, I’ve noticed … yeah, so
Allen Hall 2025: so- You take on those challenges
Søren Kellenberger: So we are optimizing our machines to be not only fit for one-offs, but actually to go into a manufacturing, uh, process. So we have op- optimized our machines a lot with, uh, automatic alignment and, uh, stuff like that to, to really make that process, uh, easier.
Because it has been considered that when you had to machine a flange, you weren’t in [00:09:00] control with your production, uh, processes. But I think that is, um, a bit of a misinterpretation. It’s, it’s a little bit like saying when I have a casted component, I cannot get a bearing fit, uh, in my cast process. That’s not because your cast process is wrong, there’s just some limitations to what you can do.
Sure. And it’s basically the same here. Yes. And, and if you apply that con- uh, planned machining, you can gain some real benefits, uh, later on and the cost will, of course, drop dra- dramatically if you plan it, rather than call for one, uh, every time you have one that is out of tolerances and, and you can even narrow those tolerances down and get the benefits from maintenance-free bowler connections.
Allen Hall 2025: Right.
Søren Kellenberger: Uh-
Allen Hall 2025: Right, ’cause you’re gonna pay for it for the next 20, 30 years. Yeah. Yeah. That’s absolutely right. Now, you’re getting involved in some of the safety aspects of operating a turbine. Uh, some of the pins and the lockouts on the low-speed gearboxes get a little worn over time, so the hole [00:10:00] you put the pin in gets worn.
There’s a lot of loads on that and- Yeah … it starts to oblong out and eventually, if you’re trying to work on that gearbox, you’re trying to keep that and your technicians safe, which is what you’re doing- Yeah … that lockout pin doesn’t quite fit in the hole and it creates a little bit of a safety risk.
Yeah. So now CNC on-site’s coming in and saying, “Hey, wait a minute. We can realign that, clean that hole up, make that safe again.”
Søren Kellenberger: Yes.
Allen Hall 2025: Explain what that looks like and what that process is to do that.
Søren Kellenberger: Yeah. So again, it’s the same thought like with the, with the O-ring, uh, that instead of bringing a component down and trying to fix it, we have designed some machinery we can bring uptower and then make that repair.
So basically what we do is that, that we mill that hole a little bit larger and then we bring a bushing, uh, that we, uh, freeze into that hole- Okay … and to recreate that tight fit again with a, with a locking pin. Uh, so it’s, it’s not that [00:11:00] complicated, but you still need to know, of course, what you are doing.
So finding the center of the original hole is one of the critical things because you want the center of the new ring to be in that same position- Sure … to make sure it fits with the pin
Allen Hall 2025: right. So- Right. You can’t just take a drill up there and try to clean out that hole. No, no. That is not the way to do that
That,
Søren Kellenberger: that
Allen Hall 2025: won’t work. No, no . I’m sure it’s been tried, but- Yeah … no, you wanna have accurate mach- actual, uh, tight tolerance machinery up there to, to align that hole, drill it properly, put that insert back into that spot- Yeah … which is gonna be a hardened insert so it’ll last longer, right?
Søren Kellenberger: Yeah, yeah.
Allen Hall 2025: So once you do that, y- it’s a permanent fix to a otherwise nagging problem.
That’s wonderful.
Søren Kellenberger: Yeah.
Allen Hall 2025: So, th- again, that kit just goes right uptower, right up the, the lift, right up the cl- crane- Exactly … and bang, you’re done. Yeah. Okay.
Søren Kellenberger: So all our machines are designed to be able to be lifted with the internal crane-
Allen Hall 2025: Yeah …
Søren Kellenberger: of that specific nacelle.
Allen Hall 2025: Okay.
Søren Kellenberger: So obviously as the cells go bigger, they have more load cap- uh- Me too
load capacity. Yeah. So for the smaller [00:12:00] turbines, the machines come in, in a bit smaller parts- Okay … so that we are sure we stay within that 250 or 500 kilogram or even whatever the limit is of, of that- Yeah, yeah, yeah … crane. And then we can, uh, reassemble everything uptower and still do tolerances within a few hundredths of a millimeter.
And, and I think that is, that is really the core of, of what we do that, that we can achieve those workshop tolerances on site, um-
Allen Hall 2025: It’s crazy when I tell people that. I say, “Well, you know, CNC on-site, they can’t… I mean, those, those tolerances can’t be that tight.” And I say, “No, no, no, no. They’re talking about, you know, fractions of a millimeter,” which in, in American terms means fractions of a mil.
Yeah. That’s 1/1000th of an inch. That’s the tolerance you’re doing.
Søren Kellenberger: Yeah.
Allen Hall 2025: Uh, and that means quality at the end of the day. If you can machine things that tight, that means what you’re getting is gonna be right for that job. Yeah. It’s gonna fix that, fix that problem permanently, which is the goal. Yes. Don’t recreate the problem.
Just fix it once and be done. Now, blade root [00:13:00] inserts, huge issue. CNC on-site has been developing tooling to drill out those existing inserts and, and put in new inserts, and you’re having success with that.
Søren Kellenberger: Yeah.
Allen Hall 2025: That’s a… it seems like a complicated process, but you have owned that quite well. Talk about what that machinery looks like today, how you’re doing that process, and what have you learned from doing some, uh, field work.
Søren Kellenberger: It’s, uh… we actually, we’ve, we’ve developed two different machines now. Okay. So we, we have, we have one that is, uh, fully CNC controlled, uh, when you need to do a lot of bushings. Yeah. Um, that one takes a bit more, uh, time to set up, but, but, uh, each drilling process is, is really fast. Uh, and then we have developed a semi-automatic machine as well, uh, which is a little bit easier to mount, mounts directly on the blade.
And it’s, uh, really perfect when you only have smaller areas of the, the blade root where you don’t need to replace all bushings- But maybe typically it’s, it’s in the high load [00:14:00] area, which is 15 to 20 bushings maybe. Right. Something like that, right? Yes.
Allen Hall 2025: Yeah.
Søren Kellenberger: So, so there we can just mount it directly on the blade and, and then drill from, uh, from there.
Um, and it works really well. We completed, uh, the first large scale, uh, commercial, uh, project, uh, together with our good friends from, uh, We4C. Uh- Right.
Allen Hall 2025: Yes.
Søren Kellenberger: And, uh, and now we are producing, uh, two more drilling machines- Oh … uh, for, for new upcoming, uh, projects also together with, uh, the guys from, from We4C.
Allen Hall 2025: Wow.
Søren Kellenberger: So now it’s, it’s starting to, uh, to pick up. Um, it’s been a relatively long process, and I guess no one really wants to be the first mover on, uh, on new technology, right? Right. So we’ve had a lot of questions. Oh, that… And that looks interesting, but how many, uh, turbines, uh, or how many blades have you repaired?
And it’s been up until now, well, it’s only tested in the lab. Uh, but now we have the first, uh, large scale commercial, uh, project with, uh, 26, uh, turbines, [00:15:00] uh, repaired and, uh, and 1,000 bushings, uh, that were replaced, uh, across those, uh, 26 turbines. So-
Allen Hall 2025: Wow …
Søren Kellenberger: so I guess that is now large scale. Uh-
Allen Hall 2025: That’s large scale.
Yeah. Yeah. I would consider 1,000 a large scale test. Yeah. Yeah. Yes. And that brings all those turbines back to life.
Søren Kellenberger: Absolutely. They are up running, uh, full power again, so, uh, that is, uh-
Allen Hall 2025: That’s huge …
Søren Kellenberger: really nice.
Allen Hall 2025: For the operator, I’m sure they love that.
Søren Kellenberger: Yeah. And, and of course, uh, there’s, there’s been a lot of discussions about blades and, uh, bla- the, the waste, uh, issue you have on, on worn- Oh
out blades. Sure. So by being able to fix them instead of replacing them, not only is the, the cost for fixing a blade a lot lower than buying new ones, uh, but, but also from a, an environmental perspective. The not having to scrap them and create that waste is, uh, is also a nice, uh,
Allen Hall 2025: thing. Yeah, it’s one of the things that pops up more recently about replacing blades, and I think the [00:16:00] industry and the operators are pushing back on that.
Uh, because a lot of times the OEM wants to replace a blade, it’s just easier for them to do.
Søren Kellenberger: Yeah.
Allen Hall 2025: But the reality is, is that yeah, you’re creating this additional problem. What are you gonna do with the disposal of this blade? Do we really need to do that? Is it so far gone that I can’t recover it? I think a lot of times, especially with fiberglass blades- Yeah
you can bring them back to life.
Søren Kellenberger: Yeah.
Allen Hall 2025: Just with a little bit of engineering, uh, prowess and some good machinery- Yeah. You can, you can make magic happen, and that’s what CNC OnSite is doing. So that, that’s really amazing that, uh, you’re starting to get more adoption of that on, on the blade root inserts. I know across the United States there’s all kinds of issues, and you’re proving it out.
I think the adoption rate in America and all over is gonna really step up. Now, uh, you always have some cool new project, sort of top secret. What are you working on that the world needs to know about?
Søren Kellenberger: Yeah. W- I mean, we are constantly, uh, [00:17:00]expanding our, our line of services. Uh, so- Sure … so we are just out there trying to listen to what kind of issues do we see in, in the industry-
Allen Hall 2025: Yeah
Søren Kellenberger: and how can that be fixed, uh, uptower. So, so some of the, the latest, uh, innovations we’ve been doing is a, a new machine on, um… to, to do shaft milling. Uh, so that c- that can be on generator shafts, uh, for instance. There are some machines out there, but we’ve decided to go, uh, against CNC control- Okay
because it gives us a lot of, uh, opportunities both on, on speed, uh, of the process. It’s a more safe, uh, way to, uh, to do it.
Allen Hall 2025: Sure.
Søren Kellenberger: And we can actually also do different, uh, shapes on the shaft, so, so we can do more advanced, uh, repairs. Okay. We, we don’t need to stick to a certain diameter all the way. Now we can, we can mo- make grooves, and we can do, uh- Really?
all sort of sorts of stuff, uh- Oh … along that process because it’s CNC controlled.
Allen Hall 2025: Oh, sure. Okay. Um, and- Boy, okay. That makes a lot of sense. So you can actually take a, a, a basic, [00:18:00] basic, basic design of a shaft and make modifications to it- Yeah … to extend the lifetime and make it work better.
Søren Kellenberger: Yes. So typically we would mill down, uh, the shaft and- Sure
install a sleeve- Sure … to recreate a, a bearing fit, for instance.
Allen Hall 2025: Right. Yeah.
Søren Kellenberger: But we have possibilities to, uh, to create, um, grooves or anything that would do a stress relief or whatever you need, lubrication, or if you, if you want to do something, uh, afterwards, we, we can do that with, uh, with our machines.
Uh- Yeah. So yeah, we, we have some new machines for, for hollow shaft, uh, machining, so we can do stuff, uh, inside the main shaft, for instance. We can do stuff on the, the outside, as I mentioned on, on the generator shaft, but that could be on the gearbox as well. So- Sure … sometimes we see issues on the main shaft to, to gearbox, uh, connection.
Allen Hall 2025: Yeah.
Søren Kellenberger: We are able to, to fix, uh, those, uh, things uptower. Wow. And, uh, so yeah, lot of new, uh, stuff being, uh, developed.
Allen Hall 2025: That’s, that’s awesome.
Søren Kellenberger: [00:19:00] Yeah.
Allen Hall 2025: And I, I know you guys are busy, but- If somebody wants to get ahold of CNC Onsite and get work done this year, they better be making phone calls to you- … quickly. So I, I know your order book is filling up and you’re, you’re having to devote crews and machinery and time.
Yeah. How do people get ahold of you and get on that contact list and can start working the process?
Søren Kellenberger: I would say go into, uh, cnconsite.dk and, uh, there we have all our, our contacts. Uh, so just reach out. There’s a, yeah, formula you can, uh, fill in, uh, or you can find our direct contacts in our webpage, and, uh, then we can start looking at it.
So we are quite busy, but we are always- Yeah … open for, uh, discussions and, uh, yeah. That,
Allen Hall 2025: that’s a problem with being successful, is you’re just always busy running around trying to take care of problems, and that’s the thing, is that everybody I talk to that’s used CNC Onsite loves it-
Søren Kellenberger: Yeah …
Allen Hall 2025: and loves the process and loves the work you do.
So there’s gonna be a lot more phone calls and a lot more orders coming your way, and that’s- Yeah … that’s awesome. [00:20:00] Soren- Yeah … it’s so good to see you again and it’s so good to see you in person. Yeah. And congratulations on the promotion and everything that’s happening at CNC Onsite.
Søren Kellenberger: Thank you, Allen. It’s a pleasure.
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