160. Idea – What is Pulsed Electrochemical Machining? Transcript
Welcome to EECO Asks Why. Today, we’re going to be talking about a brand new topic for us. What is pulse electrochemical machining, and have us walk through this topic I have with us Daniel Harrington, who is the CEO at Voxel Innovations. So welcome Daniel.
Thanks. Thanks for having me, Chris.
How you doing today, man?
Great. Another good day in Raleigh, North Carolina.
That’s right. We were actually able to meet, I was able to go to a shop see some of the cool things they’re doing. And it was just a great time for me to get out there and meet him and had to invite him on the podcast. He graciously accepted. So excited for this. Again, it’s a brand new topic, so Daniel get our listeners up to speed, man. When you’re talking about pulse electrochemical machining, what exactly is that?
Yeah. So it’s really a derivation of electric, chemical machining and electrochemical machining as a process has been around for a long time, maybe since the sixties here in the US but at the very basics, what we’re doing is we’re dissolving metal.
And the way we do that is we use a conductive tool as an electrode. It’s roughly the inverse of the part we’re trying to make, we move that close to the wprk piece and in between the two, we have a conductive saltwater solution, and then we apply a voltage potential or a current potential, and that current plus the saltwater, that conductive solution and those two metal electrodes our tool and the workpiece basically sets up a corrosion cell.
So in effect, what we’re doing is corroding the material, but doing it very quickly. So we can our tool realizes that roughly inverse shape into the workpiece so much in the same way that you think of a stamping operation or sinker EDM operation, you know, it’s like stamping without the contact or sinker EDM without the sparks. So similar to those processes and a couple of different ways.
Yeah. I’m thinking through our listeners who may be thinking in that traditional machining world where you’re cutting parts away. There’s no actual contact here.
Yeah. No contact. It is subtractive process like machining is, but we aren’t forming ships. We are literally dissolving a material atom by atom and that’s part of the genesis of our name as well. Voxel is a 3D pixel and it, to some extent embodies the fact that we’re moving a voxel at a time, you know, a very small unit material with every pulse of energy.
That’s very cool. Okay. So we made the tasks to the company brand right there. That’s awesome. You know, I think you mentioned that it originated with the electro chemical machining. So maybe the pulse part, how long has that process been around and what was the origin there?
Yeah, so electrochemical machining the power that I talked about, we apply the electrical potential to the process traditionally an ECM it’s just been a continuous current or continuous voltage. So you’d start the process. You get the electric moving towards the workpiece. You turn the power on and it sits there and runs. And that’s pretty good for bulk material removal and roughing applications. And there are many people that have used that successfully, but if you want to get good resolution out of that process, the distance between your electrode and your work beasts. So that’s your tool and the workpiece needs to be very small and by small, 25 to 50 micrometers and at a gap that small. It’s critical in this process to remove the waste products that you create to flesh between that tool and workpiece and with a one thou gap or 25 micrometer gap, it’s really hard to flush those waste products.
And so the pulse process can do a couple things. One, you can apply a duty cycle to that power supplies instead of a continuous current or continuous voltage. You apply pulses of voltage or current and slows the process down. You’ve now got a duty cycle, but it gives you time for those waste products to be removed from the gap.
So that’s one pulsed technique that we apply. Another is to vibrate the axis. So in many cases we’re doing a single sinking access operation. So our electrode has three axes of complexity built into it. Like, ABM electrode might. And we sink that in the part but we will flesh the electrical electrode by vibrating it up and down, and that we can dynamically change the gap from 25 micrometers up to 500 micrometres or a millimeter or something like that.
And that’s another way to enable us to flush waste product or the waste in and out of that gap. So really the pulse process is just a way to get more resolution of a machining operation. And we can get better surface finish as well. And we can run a higher current density as we get even more polished surfaces in our process.
So it’s got a number of advantages but by and large, we’re really just expanding the tool sets we’ve got with electrochemical machining. So pulsed and vibration and other sort of patent pending techniques we’ve developed are all just ways to make the process better and more efficient and suit a wider market.
You probably have a lot of listeners thinking when you’re saying pulse and electrical, what types of voltages and currents are we talking about here? I’m just curious on the bandwidth of what you’re working with.
Sure. So we’re typically a low voltage high amperage process. And so we might run five to 50 volts in our process, but we’re running hundreds to thousands of amps and it gets the power supplies getting big in a hurry. If you’re working on big parts, you need a lot of power. And the way to think about this is that if you have a surface, you know, say you’ve got a flat plate, you’re trying to machine an area on that flat plate. The bigger, the surface area, the more current we need to machine all of that area continuously.
So you, you could do one area that moved the electrode over her, do another area. And that way utilize less peak current, but a real sort of advantage that our process has above many other techniques is that if we make a part that is twice as large, we do need twice the amperage, but we still go into the same feed rate. So you are effectively doubling your throughput. So it’s a big advantage for us to be able to utilize larger surfaces or in some cases, multiple parts together in parallel, you can get her a big speed boost out of the process doing it that way. And that’s in stark contrast to many conventional machining operations or EDM operations you need multiple spindles on a CNC machining operation to get that same comparative throughput advantage that we get in our process.
Right. And I’m curious too, like for this technology, is there a particular industry that aligns better for the output? You know, what’s your producing?
Yeah. So when we started the company, we knew that this process had value that it had been used in a couple of niche applications in the past. Honestly, we weren’t sure all the different areas of it fit for it. And so we started by just focusing on the applications that had hard to machine materials and tight tolerances. And honestly, those materials, those applications were they’d have an engineering cost trade-off. So applications where they might pay more for a better performing part, rather than just chasing the cheapest part possible.
And so those are typically engineering, heavily heavy applications, and we find those commonly and aerospace medical, some energy applications. So our focus is really on those aerospace, medical, energy applications, but since we started, and especially over the last year or two, we found people and industries and applications that I’ve never heard of. And that’s kind of the point of getting our name out there and explain the technology is that you start learning about all these different things you didn’t even know existed and can benefit from our technology.
Do you find that the solution aligns better when you have batches of product to make where it’s repetitive, or is it a one-off type scenario?
Yeah, good question. It is not a one-off process, at least not yet. Maybe in some future iteration, we’ll figure it out how to get there, but the best use of this process is in volume production. And you know, if you’re making a complex turbine engine component or something maybe you could make tens of them a year and be competitive, but if you’re making a smaller medical devices, with adisposable we’ll have reusable component and you know, you better be in the sort of tens of thousands to hundreds of thousands, even millions of parts. And that’s where the process really shines its advantage really comes through when you get to production.
When you talk about this pulse electrochemical machining world, how big is it? How many people are out there doing this type of work?
It’s small. I think I have interacted with a lot of them in this space. It’s fairly small, especially in the US so when I first started the business, I noticed that there was greater adoption and uptake and practitioners of this process in Europe, but the US market really lagged behind them, even though in some ways we were pioneers in the sixties of electrochemical machining, this pulse to some extent originated out of Europe particularly out of Phillips they make the electric razor caps for their electric shaver in the Netherlands with this technology. And so they did a lot of work and innovation around the technology in late nineties.
And then we started seeing a few other people pick up the practice and the mid two thousands, but predominantly in Europe and the US has been very slow to adopt. And that’s probably for a few reasons, you know, partly just due to education about what the process is and how it works. There’s also some bad stigma around electrochemical machine in the past, the people that used it here, they didn’t manage the waste correctly, or they found challenges with it, abandoned it in favor of CNC machining, particularly as that technology evolved.
So that’s meant that in the US there has been a very few people here that work on the processing and, you know, less than 10 companies, I’d say they’re doing anything with electrochemical machining, full stop. And then maybe half of that are working on the pulse process and almost all of those are focused on buying equipment from a European vendor. So they’re not really focused on this as their core business. So that’s how we are a little bit different here in the US market’s really trying to focus entirely on this electrochemical machine process. Not only running in as contract manufacturers, but developing innovations, filing patents, developing new technology that really pushes the state of the art forward here in the US.
That’s really cool. Now, how long have you been there at Voxel?
So started about five years ago and it was literally me and a garage.
Okay. Well love that story.
It wasn’t, it wasn’t my garage. I rented a garage, but it was still small, 800 square feet. And when I started, you know, there are machines especially in Europe to do electrochemical machining, but they can be pretty expensive. I didn’t have the cash to buy one of those. So I built my own machine from scratch here in that 800 square foot shop.
And at some point hired my first engineer to really help me with that process and probably spent a year and a half, you know, if you count the value of our time, I’m sure we spent more than what it cost to go buy a piece of equipment, but that’s invaluable. You know, we learned a lot about the technology, how it works, what matters, and now we’re in a position where we can either continue to build our own equipment, or we can go spec equipment that we know will work to our needs.
So absolutely it has been the right way to go in our mind, but in that first year or two, it was really the blind leading the blind here.
Yeah, probably a a lot of energy drinks being consumed.
Right. Lots of energy drinks, late nights. Google was our biggest resource for trying to understand what we’re doing. You know, this is a very multi-disciplinary technologies. I’m a mechanical engineer by training. I know a lot more about electrochemistry and chemistry that they ever thought I would six years ago, I’d say.
I know people may be thinking in their mind, like I just a typical CNC machine when they walked through and they see a pulse electrical chemical machine at work. Is it similar in the type setup in the look and the aesthetics, and maybe just try to paint that visual for them for a list of who may be new to it.
It’s similar. It’s probably more similar, to sinker, EDM operation people run across it. You know, the big difference between us and a CNC machine out from the outside, they look pretty similar, but inside don’t have a big spindle. So we don’t have a big motor and deal with that. We don’t have to move as fast as the CNC. So, you know, having high Fitch fall screws and stuff to move quickly is not important for us. But the biggest difference is that we need our work environment to be sealed and we’re running in a saltwater solution.
So if you just put cast iron or steel in there, it will rust in a few days and become unusable in a week. So, all of our enclosures are stainless or plastic or some mix of the two with some composites and we need to make sure to manage that electrolyte system pretty well. And so that’s kind of the other big piece that’s different from a CNC machine is we have a whole waste treatment system and it is literally, it looks like a small municipal wastewater treatment plant, but really tailored specifically to our application.
And so a CNC machine really can get away with just a coolant tank and a pump. And maybe some filtration on that, coolant to pull chips out. We’ve got multiple, a couple of hundred gallon tanks and metering pumps and filtration systems all to take that electrolyte, clean it of the dissolved metal and recycle it back into the process. So that’s, you know, that’s as big as the ECM or PCM machine.
That sounds really cool. When I tell you for our listeners, we’ll have that link in our show notes as well. So you can go check out Voxel. I think you got some pictures. If I remember correctly on your website to give that visual a little bit more. Now I’m curious, you know, five years you’ve been doing this, I’m sure you’ve learned a lot. I’m sure it had been some headwinds as well. When he tried to explain this technology to other people.
Where do you find that friction point at, and maybe you have to get past CNC versus now electrochemical machining? What’s been the way you’ve been able to combat that?
Yeah. It’s constantly a challenge. I think the first one, it was just some education, you know, get them comfortable with the fact how this process works. You know, we take a very engineering, heavy approach with these conversations. So that’s done on purpose. We want people to understand what it is, feel confident that we understand the fundamentals that are happening here in this process. And if you don’t understand that it’s hard to certainly innovate the really practice technology well and second is to try and make some prototype or sample part or see it in action.
That’s honestly where the first sticking point comes because I already described those processes, not great prototyping. And so someone says, Hey here’s our part, can you make a first attempt at it? Make us a sample of it? And can you do it for a thousand dollars? I say no way, you know, we need $10,000 or $50,000. You know, it depends on the application, but to really make a good first attempt. And it may require a little bit more iteration from there and takes us, you know, eight or 10 weeks to do it. So it’s not so straightforward. So that’s the second barrier.
The third one is just figuring out, getting them comfortable with where the ECM operation that’s going to happen. We are mostly focused on providing a contract and fracturing service, so they don’t have to understand how to handle the waste treatment system and how to make sure that process runs consistently and keep up with the maintenance and all that sort of stuff. That’s our responsibility. I think in most cases that’s a good solution, but there are companies that are making 5 million parts a year of some widget and it’s right next to some other line.
And so they really want that in their facility. And that’s another bigger barrier that we are just starting to really address some of these customers. Building a turnkey system and getting them comfortable with what that entails and the waste stream that comes off the machine and how you manage it and what the maintenance cycles look like. That’s really the next evolution of our company is helping enable some of those turnkey operations it’s of our customers when necessary.
That sounds exciting. Now, when you think about. The people who actually operating these machines, where would they need to be going to spend time to learn? What resources should they start, you know, evaluating? Because I’m sure, you know, the skills gap for just operating one of these. It may be extremely high. I don’t know some I mean where would you point people or give advice if they want to get into this industry and start walking that road?
Yeah. I’m not sure. I even know the answer to that question today. You know, the hard part has been. Oh, I’d say all the people we’ve got employed here have been a mix of engineers and tool and die machinist, and, CNC operators could be taught how to make this work, but no one really is out there with ECM experience. Those are few and far between, and the tool and die people are have the right sort of mindset.
They’re thinking about what’s happening in the process and how can I make this better, more efficient, even if they know nothing about ECM and how it works, right? They at least have the concept for tolerances and fixturing components and keep an eye on the process consistency and repeatability.
So they’ve got that kind of mindset. I think people that have experienced sinker EDM at especially sinker EDM in a production environment, they’re probably familiar with lots of the same phenomena that happened in the process and it’s a completely different mechanism, but similar in many ways more similar than they are different.
But the rest of that is really just a training, you know? We also are because we’re doing more focus on production applications rather than job shop or one-off application. It means that we consider it and think a lot about automating this process and trying to make it simple so that, you know, maybe an operator could be running a couple of machines or it’s all robotically loaded and run lights out. That’s kinda the route we want to be heading, but know we also deal with tight tolerance things. So if you’re used to plus or minus 5,000 that’s not our world. We’re routinely talking about sub thou tolerances on lots of our components. And that’s just the nature of the applications and customers we’re dealing with. People don’t come to us with easy problems. They come to us with the hard stuff.
Chris: Well, this has been exciting to learn about this technology and Daniel we call it the show EECO Asks Why, we always save the why towards the end. So why does this pulse electrochemical machining solution, why should that be considered as industry start evaluating these technologies in the future?
Yeah. Good question. So there are really three value propositions to the technology that I want to make sure people are aware of. So, first is the high quality surface finish we get. So, we run a process that has very similar material, ruble mechanism as electropolishing. So we are often getting mirror-like surfaces or at least very good quality services out of our process.
Second the process is a very low stress. So even EDM, which is a non-contact process and laser cutting processes, you know, they’re non-contact, but they still use thermal mechanisms to remove the material. Ablation or something along those lines. Certainly CNC, machining cuts the material so it can induce a lot of stress in the process. Our removal mechanism is very clean. It produces very low heat in the environment. You know, you’re going to be well below boiling temperature of water. And we have to be because our solution is aquious and we don’t induce any stress in the material or not touching it. We’re not putting a heat into the process.
So that means not only do we get surfaces that are high quality, they don’t have retests layer, heat affected zone. We don’t get any burrs on these parts either. So you don’t have to go and do any secondary finishing operation. And we can produce very thin wall features. You know, we produce features that are a couple of thou wide and 10 or 20 or 30 to one aspect ratios without too much issue. We’ve also done some work recently on creating slots that are 400 micrometers wide and they’re blind and they go five millimeters deep. So these are, we’ve got some interesting capability here because of that low stress environment.
Third, and lastly is the speed of the process. And this always comes with the asterisk. It kind of depends on what we’re discussing here, but the areas where our process is faster than others are first, if you’ve got a really challenging material. So we just care about the chemistry of the material, not its hardness or toughness. So we can machine a single crystal, a nickel super alloys. That’s in a jet engine about as fast as we can machine aluminum or copper, you know, that the difference in those materials really doesn’t affect us. There are some other chemistry reasons we might care about the material, but generally it’s pretty flexible and fast across a lot of different materials.
So we find that those hard to machine materials are a good fit for us. And then second, the other sort of speed advantage we have we discussed briefly earlier is the fact that we can do multiple features simultaneously or multiple parts in parallel to get this through, but in the process up. So, particularly when you’re talking about doing, and there are hundreds of thousands or millions of parts a year, you know, that’s critical to making the parts affordable enough for volume production.
So it’s really those three benefits that I think people should be aware of the high quality surfaces the low stress so you can produce thin-walled features and delicate features and the speed of the process, particularly for hard to machine materials or higher volumes of parts are all what set us apart.
But the process is hard. You know, I want to make sure people are aware that this is not just an easy process. If it was you would find a lot more people doing it. So it required more money and time upfront, figure those parameters out and get those benefits to deliver. But that’s something we’re working on. We’re trying to reduce those barriers so we can offer the service for cheaper and for more industries.
Man, this has been a fabulous episode of being able to learn about this technology, Daniel, thank you for sharing your wisdom and insight with our listeners. For those that want to check out and connect with you directly to learn more about Voxel what’s the best way to do so?
Yeah. So, you can go to our website, which is voxelinnovations.com. Voxel is V O X E L. And there’s a lot of good content on that website. Actually to help you learn, in particular, our blog posts. We put a lot of effort into trying to educate website visitors about what the process does well and what doesn’t, how you can apply it.
And then if you want to reach out to me, there’s an firstname.lastname@example.org website or email address you could use, but also a form on our website. And that will come really straight to me. So that’d be a fast and easy way to get in touch with me or learn a little bit more about what we do.
We’ll make sure for our listeners that those links are in our show notes. And Daniel, thank you again for taking the time. What’s the day we really enjoyed this it was exciting. Love breaking new ground here on EECO Asks Why. So you do a great things there in Raleigh and we hope to support you in your future. And just thank you again for sharing what you did today.
Great. Thank you, Chris. I enjoyed it.