How CICNDT Qualifies Inspectors for Complex Blade Scans

Allen Hall: A lot is happening in your world. And in our world, too, as lightning protection people, because we are all dealing with damage to composite structures and wind turbine blades. Over the last couple of months, there have been some really complex problems in the field. And what I am seeing, and maybe you’re seeing the same thing, is that some of the technicians out there trying to scan blades are just not qualified to do some of these complicated inspections. Blades are getting very complex now, with carbon in them and all the bonding issues. Are you seeing something similar from where you sit?
Jeremy Heinks: It’s not just service. It’s at the supplier level, and it’s at the OEM level, where they’re trying to do something, but it’s hard to come by the right people and make sure you’re following a standard of sorts. But yeah, we’re seeing that there’s a genuine lack of properly qualified and certified people doing the work.
Allen Hall: Is that a training issue, or just because there’s so much demand for that expertise?
Jeremy Heinks: A little bit of everything. Wind, even though it’s been around for a while, is still relatively new to a proper inspection system. So having the right training in place, not getting taken advantage of by training centers, and having training that’s actually focused on what we use for day-to-day inspection of blades is one thing.
The other side of it is there’s a global shortage of NDT technicians. It’s just like any of the other trades that are really in demand. If anybody wants to get into something and have, not an easy life at work, but a decent chance at success and making a decent amount of money, then NDT is definitely the way to go, because there are huge shortages. Aviation and space programs are booming right now, and they’re all looking for technicians.
Allen Hall: Yeah, I’ve seen a lot of requests out there, particularly from defense companies that are building complex composite structures, and the job postings for NDT personnel. And they’re paying really good money right now to find those people.
Jeremy Heinks: Oh, absolutely. We just got a request from one of the big names here in the US for 86 technicians. And I’m like, there’s no such thing as 86 technicians out there.
Allen Hall: Yeah.
Jeremy Heinks: You’ll get one or two here and there, but there’s just not that many available at the moment.
Allen Hall: Well, back in the blade world, we’re kind of wrapping up the blade season this time of year, and it gets a little bit heavy as everybody realizes, oh, I have some damage I didn’t see before. A lot of drone inspections are happening, which then draw you in on NDT. As an operator, what are people to do here? I hear a lot of complaints that it’s really hard to find somebody who knows what they’re doing. I always point them to CIC and tell them to call you and get started there. But what should they be doing, and what should they be looking for when they have complex composite problems?
Jeremy Heinks: Like you say, a lot more people are bringing inspection companies in, which is great, and we need to see that. But once you’ve made the decision that you need NDT, you’ve got to make sure you’re getting what you pay for and the quality of service you expect to receive.
So typically there are some questions you want to ask. Do you have a Level III in the method of inspection who is going to oversee everything from education to certification and qualification? And if they have Level IIIs, how do they take care of their technicians in the field? Are they qualified and certified? Do they log their hours? They have to have this whole structure around keeping up these standards. And this is why NDT technicians and NDT inspection are so expensive compared to a regular field tech. The repair guys are expensive too. They pull a lot of money because they’re highly skilled. Same thing on the NDT side. You’re working with a very small group of people who have the skill set and keep up with the training and certification. So you want to make sure they have the proper Level III, and you want to make sure their technicians are properly trained and certified.
You also want to know their equipment and their application, so their techniques for the inspection. Let’s say you have a root inspection or a bond inspection. They need to have something to show you that says, this is our application technique for that specific inspection, if there is one. A lot of times, like with lightning strikes, there isn’t really anything that’s perfected. Even though we’ve done a lot of work on the aviation side, bringing that over to wind is a whole other animal. But that’s part of the process. You do your R&D in-house. We do that here at our lab, where we get samples from the customer if we’re lucky enough, or we have something from different sources, and we perfect the inspection method and the technique, and that gets written into a work instruction. That way you have something to show the customer, and they can feel comfortable with the results you’re going to give them.
Allen Hall: So having a plan before they get on site, which doesn’t always happen.
Jeremy Heinks: And it’s tough, right? Because a lot of times these blades are older, or the OEM [inaudible], so you don’t have samples lying around. Then you’ve got to figure out what this blade type is similar to, and hopefully we have samples. We have a bunch of different samples in-house that we go to for different blade types, different laminate stacks, different bond line setups, different sections. And unfortunately, with the number of blades that are failing or getting repowered, there are a lot of places you can go to get these samples nowadays. But when you’re buying a brand-new blade from the manufacturer, it wouldn’t hurt to see if they can make you some samples and put them in storage, just in case.
Allen Hall: Right. And that world is so wrapped around the actual construction. Even if you had a set of drawings, it doesn’t really help you too much. You need an actual sample to see what’s happening deep inside, particularly on really thick composite parts, like root bushing issues or root inserts. Those are complex areas because you have metal, epoxies, resins, and composites. Having a section of that at least gives you a chance to see where defects lie and to bring the right tools to site, which is my big complaint. When I see technicians arrive with the wrong tools, I think, what are we doing? It almost should be standard practice in the NDT world to at least have some cross-sections.
Jeremy Heinks: Right. Blades are extremely complex, even compared to the things we see in the aviation world, because you’ve got these really different materials coming together. In aviation, you typically have a composite structure where everything is going to be kind of the same. In a root section, you have steel bushings, and some of them have protrusions. There’s a whole bunch of different material types stuck in a small area, and that makes it extremely difficult. Even bond lines and different web types, where you have PET core versus a regular foam or balsa, all those things throw off your inspection completely. We typically use ultrasound, and ultrasound will react differently to all those materials.
So when you scan across the bond line, or if you’re using thermal or something else, the energy is going to transfer and reflect differently with each of those materials. If you don’t have a representative sample, it’s really hard to know what you’re getting yourself into as an inspector. And that’s where the Level III support comes in.
We learn a lot of stuff in the field. Unfortunately, we’re reactionary. We’ll go out there, they’ll say, hey, start scanning, and we have to get that raw data back to our Level IIIs to look at and say, all right, this is what’s going on with the sound as it penetrates the part, and these are the materials that are in there. Then we use our experience, because we’ve got multiple guys who have been doing this for 10, 15, 20-plus years. We know what’s out there and what we’ve seen before, and we can make adjustments so the inspection is successful.
Allen Hall: So what happens when you have three or more manufacturers of the same blade? When you show up on a site, particularly in the US, you will have that. GE is a good example: LM, TPI, and MFG. So we have three different manufacturers. Plus, LM may have different factories producing the same blade. Those blades are not identical in terms of their construction and materials. Does that mean we need a TPI cross-section, an MFG cross-section, and an LM cross-section to really understand what’s happening inside?
Jeremy Heinks: At the end of the day, it would be perfect to have those, because there’s a lot of difference. The manufacturers’ molds have different fitments, or their material suppliers are different, so you’re getting different things. The internal geometry of the part will be different, not just the actual shape. And the material velocities will be different because there’s a different resin supplier, a different adhesive supplier, different everything. All that stuff does make a difference, and it would be better to have those things. But unfortunately, you probably couldn’t get something like that from everybody.
Allen Hall: Well, that’s what a Level III is there for, to sort of determine, this doesn’t look quite right. Maybe it’s a different resin system than we’ve seen before, or maybe there’s a repair there that’s throwing off our measurements.
Since I have you here, one of the topics that’s been coming up more and more on the podcast is trailing edge disbonds and torsion. Especially as you get to longer blades, 100-meter blades, maybe it’s 80 meters, there seems to be more concern about torsion breaking that trailing edge bond, and then everything essentially coming apart from there. How critical are those bond lines? And can they be checked adequately in the factory to know that the blade is actually built the way the engineers wanted it built?
Jeremy Heinks: Yeah, you can definitely get the testing done. The trailing edge has always been a main part. I’ve been on sites where you’d have main webs that are delaminated or disbonded for 10, 15, 20 meters, and the blades ran for years. It’s similar with the leading edge, depending on how the leading edge is set up, until the erosion got to it. But the trailing edge just causes all sorts of issues, because it’s a quick failure.
As far as checking for those twisting failures, I think it comes down to the basic stuff we can check. What we’ve been seeing is improper preparation of surfaces, contamination of surfaces, or improper closure. So they’re not closing on time and the adhesive has started to set up. Or the adhesive doesn’t have the proper mix, or it’s too hot or too slow. All those things we can check with nondestructive testing. We can see if it’s uncured or not cured properly.
The other part of that is if it’s not prepped right, let’s say you have dust everywhere, we’ll be able to see that to a point. But once it’s in operation, or once it’s been transported and flexed, what you have a lot of times is a physical bond but not a chemical bond. They’re pressed together, they’re stuck together, energy transfers through, all that good stuff. But once they get under strain and get put into motion, they’re not chemically bonded, so they’ll pop apart. That’s the good old kissing bond, which people always talked about and which was considered a myth for the longest time years ago. It definitely can be tested for. There are a lot of things we can look at and a few different methods to do it with, and it needs to be done.
Allen Hall: So what are the new tools? I think everybody sees the ultrasonic heads and the couplant you put underneath when you’re scanning around. That’s pretty obvious to most engineers. But I know in the NDT world, there are a lot of cool tools coming down, mostly from aerospace into wind, that are starting to get used a little bit more. What are those, and where can we be using some of that technology today?
Jeremy Heinks: As far as the basic methods go, ultrasound is still the key. The low-frequency stuff we typically use in wind has become standardized, and the aviation sector now uses it just as much as we do. It’s kind of funny that wind, maybe not pioneered, but made low frequency more mainstream before aviation did. Aviation composites were usually thinner, and you could get through them with a higher frequency, so there was no real need for low frequency, especially the larger low-frequency arrays. A lot of that came from wind, and now you see them being used in aerospace, because aerospace composites now have thicker materials, multiple stacked adhesive bonds, different joints. You need low frequency if you’re using ultrasound to get through those.
So that technology overall has caught up. All your standard providers have really good low-frequency equipment out there. What we see now on the ultrasonic side is delivery of that technology. We’ve been working with a bunch of different groups on getting crawlers and different kinds of drones out there, because access is still the biggest issue, and a rope access crew isn’t always the best or the cheapest way to go about it. There’s a big push for those types of things. That’s the technology push right now: delivering the technology to the area where the inspection needs to be done.
And we have to be really careful there too, because it needs to be proven out, just like everything else. We’ve come across a bunch of different groups that have really neat solutions, but maybe it drifts one way or another, or you don’t have really exact positional data. Those are things we’re still working out with different providers. But a lot of the technology now can be linked in with laser trackers, vision, and encoding, so you can see exactly where on the blade the data is coming from.
Right now, if you go out there with a semi-automated scanner or a drone of some sort, it’s going to scan that area, and you know you scanned a one-meter-by-one-meter area. But where exactly was that on the blade? That’s tough. So what we’re trying to do with the groups we’re working with is take the technology we already have for three-dimensional encoding, if you will, and bring that over so the drone, or whatever we’re using, is part of that system. That way we know exactly where the data is being pulled from, and it’s easier to take that data, if available, and compare it to data from the plant, data from inspections on the ground, all sorts of different stuff. That’s the big push technology-wise right now.
We’re also seeing more X-ray and CT. We have our robotic CT in-house, where we’ve been able to look at some small samples. It’s really nice not having to take a defect apart. We can look at it without destroying the actual indication and see what’s going on. That helps you figure out what kind of defect you have, whether it was a material defect, a manufacturing process issue, lightning, or who knows what.
Allen Hall: The one thing I’ve been seeing more recently is thermal imaging, trying to use it to detect disbonds and delaminations. It gets advertised quite a bit, but every time I see it, I think it’s not really a perfect tool. Is it worth even looking at, maybe for gross measurements or just first passes?
Jeremy Heinks: There’s no perfect tool when it comes to inspection. Thermal imaging is the same thing. We’ve worked with some groups in the field, and I’m not going to name any names, but they didn’t have anybody in the company who knew anything about thermal imaging. They had a drone pilot who flew a drone with a thermal imager on it. They didn’t have a guy with thermal imaging experience, certification, or any specific training. So these guys go out there and take these really cool images. Like you said, they’re popping up everywhere, and they’re very cool. But most of those are what we call passive inspections.
They’re just looking at existing heat on a surface. You should be able to find really near-surface stuff with that, so thin skin-to-core issues would probably pop. But typically, when you do an actual thermal inspection, you want to measure the transfer of energy through the part. So you have to have some sort of active source for that thermal energy, ideally on the other side of the part, or single-sided if not. Either way, you still have control over the whole system.
When you just have a thermal camera on a drone, you don’t have that control, so there tend to be a lot of false positives with those types of inspections. Still, when it’s done right, it’s a great tool. The OEMs use it in the factories a lot of times to check adhesive curing. And the funny thing is, when the adhesive cures, you have your heat source right behind the laminate, so you can look for dry laminate or sometimes disbonds. But again, you have a source. When we used to do thermal inspection in the field, we’d have an AC unit on one end of the blade pumping cold or hot air into the interior.
Then we could see the energy transfer through, and of course you get a much more accurate inspection. It’s a full through-thickness inspection, which is typically not what you’re getting from a drone inspection. We also used to inspect at dusk and dawn, because you have the temperature changing, and again you get the transfer through the whole material, which gives you a much better inspection.
Allen Hall: That leads me to a lot of questions, mostly about standardization. We’ve discussed the NDT world a couple of times now on the podcast, and it does seem like it’s still a bit of the Wild West, where people can show up on site and not really be trained adequately or have the wrong tools. Is there an effort right now in the standards world to put some requirements on what kind of qualifications a person should have, what kind of training they should have, or what kind of tools they should have? Is that being worked on yet?
Jeremy Heinks: Yeah, that’s been a project led by the folks at [inaudible].
Allen Hall: Oh, good.
Jeremy Heinks: Yep. They’re doing good work there. There’s a whole bunch of people involved. It’s not just them. It’s people throughout the industry. They pull from all over the place, whether it’s OEMs, other laboratories, or groups like mine. Everybody’s putting information in, and I just got to see the latest revision of the pre-release, and it’s definitely heading in the right direction. It’s going to focus on standardization, making sure you’re asking the right questions when you talk to any provider that says they do inspection.
It goes for the OEMs too. A lot of times they’re not following their own rulebooks. I remember when I used to work at LM Wind Power, before the GE stuff and everything, we would have inspectors from our customers come in, and we’d have to show them certain amounts of what we were doing, depending on what was in the contract. So having the right questions when you get those opportunities is really good. This IEC standard, which is getting updated, is going to have a lot of that in there. It’s going to have a lot of the basics. There will be a lot of ultrasonic stuff in there, some thermal stuff, maybe shearography and some other methods, maybe bond testing. These are things that are typically able to be used on wind. So it’ll give people something to look at to gauge their providers and what they’ve got for inspection.
Allen Hall: What is that IEC number going to be when it’s released?
Jeremy Heinks: That IEC standard is 61400.
Allen Hall: Going forward, it really is the end of the inspection season right about now. It’s going to start throwing some snow up in the sky here shortly, and then the panic hits where everyone wants to go and start doing inspections. They need to be booking time right now with CIC if they want people, because there is a shortage of technicians. How far out in the future are you booked right now?
Jeremy Heinks: Right now we’re probably two months, going into three months, out.
Allen Hall: Wow.
Jeremy Heinks: It depends on where. We’ve got stuff in South America, we’re working on stuff in Europe, and we’re trying to get some stuff rolling in Australia as well. Those, of course, take a little more time. We can still squeeze stuff in here and there if it’s a smaller scope, but typically we’re some time out now.
Allen Hall: One thing about CIC NDT is that you’re global. And I think a lot of times we in the wind industry don’t realize the competency behind a company like CIC. You’re working with aerospace companies on the most complex things. You’ve worked with space and some really complex things in the past. You’re working in racing, with composites on race cars, and then you have this wind turbine business. I’m sure I’m not even covering all the areas you’re in right now. How much experience are you bringing to the table when somebody calls you and says, help me?
Jeremy Heinks: With our team, we’ve got a cumulative 100-plus years of experience.
Allen Hall: There you go.
Jeremy Heinks: For the most part, like I said, I’ve got almost 30 years in this, and my two other senior Level IIIs are at the 16- and 20-year mark themselves.
Allen Hall: That matters. That’s really key. When you’re looking for any NDT person, the experience matters. The war wounds and the battle scars make a big difference to the quality of the product you’re about to get.
Jeremy Heinks: Yeah. And our services manager has 20 years in wind. Most of our wind inspection technicians have 10 to 20 years of wind blade experience. So not just composites, but specifically blades and blade manufacturing.
Allen Hall: Wow. And if someone needed your services and wanted you on site, where do they start? Do they go to LinkedIn, or to your web page?
Jeremy Heinks: You can look us up on LinkedIn. We’re on there as Composite Inspection and Consulting, which will take you to our LinkedIn. Look for me on LinkedIn too. Otherwise, the website is cicndt.com.
Allen Hall: Yeah, and it’s a great website, with a lot of references and resources. So reach out to Jeremy, reach out to CIC, if you have some inspections that need to be done. Jeremy, thank you so much for being on the podcast. I love hearing what’s happening in your world. It’s very interesting.
Jeremy Heinks: Yeah, thanks for having me. We’ll have to get you out here one of these days.
Allen Hall: Yes.