Flex PCB Primers

Hello, and welcome to the macro fab engineering podcast. We're your hosts Parker, Dolman

and Steven Gregg.

This is episode 262. So, next week, we have Chris Carter on the podcast again.

Love it. It's gonna be great. No last episode with Chris Carter was actually really informative and fun. And I think Chris had I had a good time to.

Yeah. And so yeah, the last episode was 244. I was chatting with him yesterday about it, about him being on next week's podcast, and I already forgot what we're going to talk about.

I was about to say, what's our topic?

I think we're gonna talk about design for not manufacturability. But I think for designed for testing.

Oh, okay. Yeah, yeah, because Chris Carter, is he does a lot of test rigs and jigs and things like that, right.

Yeah. So I think that's what we've been talking about. It's funny, like that conversation was, like, 24 hours ago and already forgotten.

You're a busy man partner.

So yeah, he's gonna be on the podcast, it's gonna be a lot of fun. So he is active in our Slack channel, the back fab.com/slack Slack channel. So go ask him questions in there, and we'll talk about on the podcast. Looking forward to it. So my first topic today is kind of like a follow up from last week's topic I had, which was, like the number two important thing, most important thing when selecting a component for your new design. So the follow up on that is, Robert Franek, I think is how you pronounce his last name you

for a neck or whatever. I mean, he was also part of my topic last week.

It was it last week,

wasn't that last week when we talked about the crosstalk signal? Crosstalk? It

was either last week or two weeks ago. Yeah, yeah, that's his video. Oh. So yeah, he published the video, like, the day that our podcast came out of like, what to consider when selecting chips for your new board design. So I'm not going to steal his content and lists like what he talks about in this 20 minute video. So go check them out, listeners, we'll have a link in the description of the podcast. And I'm going to ask Robert, if he wants to be on the podcast, because it sounds like we talk about the same stuff all the time. And so he looks like he typically does is like hardware design and PCB layout online courses. So go check out his stuff, especially if you're like, new to the, to the layout and hardware. Stick.

You know, I've found I've watched a handful of his videos, and I found all of them to be really educational and and like, I think he is good for if you're brand new, or if you've been in the game for a while. Yeah, I mean, if you're brand new, a lot of this stuff might be a little overwhelming, because it does go into detail. And it's pretty. It's pretty in depth. But it's all really fantastic information.

I mean, I watched I started watching his videos. Yeah, then when you send me the cross, I didn't know that was his crosstalk video. Yeah, watch that. And I actually enjoyed it a lot and learned a lot from it. And then I watched his video on the considering in selecting chip components. And I liked that too, because it expands more on that subject. It's like the number one and the number three, four or five and six things you have to think about. Yeah, I left them or two because that was ours.

You'll never guess what number seven is?

Is that a rhetorical question? Nevermind.

That was that was my failed attempt at doing a clickbait title title.

I was like rhetorical question or clickbait. I can't figure out either they're the same, or am I supposed to respond? I don't know.

That was that was a fail. Actually, I wanted to talk this week about flex PCBs. That's something that I'm sure at one point in time in the past, we've talked about them, or at least mentioned them, but I don't think we've ever gone into any kind of detail with them. And it's something that I've been looking into, and I say that kind of loosely. I just I have some ideas for some stuff, both in my personal work and at work that could benefit from flex PCBs. And and I thought it would be interesting to chat about a little bit. Before we get into it. I'm curious. Have you ever worked with flat flex PCBs? Parker? I mean, like in terms of work, have you ever designed one

I've never designed one by I shouldn't say it because there's so we have a side tangent now. We have A rule that Steve and I came up with with talking about projects on the podcast is, we can only mention a project that we are we want to work on like Steven and I want to work on if it's halfway done. Okay? Now, we can come up with an idea and say about it on the podcast. But that idea is like anyone can kind of just take it and run with it. It's like, if we're saying we are doing something, it has to be halfway done already. Because there's, like, millions of dead projects on our podcast. Oh, yeah. Anyways, back to flex PCBs. I have not built one or design one. But I have a project I want to use a flex PCB for, because it'll be perfect for it.

Yeah, well, so do I. But I'm talking about it less about, like what I have done and talk more about the concept of it and how to do it in a way. And really, I'm not coming from a position of any kind of authority on this. So like in any, for the most part, I'm just distilling information that I've gathered about it. And just going through that, because it might be in, in talking about this, it might be worthwhile for someone out there who's doing a project that's considering options on how their system goes together. And maybe maybe this will be helpful. So a flat or a flex PCB is basically polyamide. Foil with deposited copper on top of it. So it's literally a flexible PCB, if you've never seen one. Actually, I'm sure most people have seen one. And maybe they just don't know the name of it. It's that kind of tan, orange looking, flexible thing that looks like a connector. But technically, it's considered a PCB, because it's built in a method that is similar to how PCBs are actually constructed.

Is it etched? I must say, assume, yes, yes, obvious,

extra closeted there, I think there are multiple ways of doing it. So I found I found an interesting link, or basically a PDF, that's by worth electronics, that gives a rundown, it's like an eight page, little, just intro to flat flex PCBs, that I think is really useful to just get like a overhead view of flex PCBs. We'll post it up in the show notes here. But I'm going to pull a handful of information out of it and talk about those. So they, they define three different methods of system design that they call heterogeneous, homogeneous, and partial homogeneous, which are just fancy words for saying, if your system has two PCBs that you connect with solderable connectors and a cable assembly, they call that heterogeneous. There's a different version called homogeneous, which is two rigid PCBs that are connected via a flex PCB that is actually bonded to the PCBs themself. So that's like a Rigid Flex assembly, that's called a Rigid Flex assembly. Then there's a third type, which is called a partial homogeneous, where one PCB has the, the flex cable bonded to it, and then the other one uses a connector, that the piece that the flex connects into. So it's like a half rigid, you know, yeah,

so that's kind of like if you had a, for example, like an FCC style cable that was actually part of one of the boards. Right, right.

So the some of the benefits of flat Flex is, is pretty obvious, you can get complex shapes, and you can bend a single circuit into a three dimensional shape. So if you have an enclosure that has the need for PCBs on different axes, you can develop one PCB that conforms to the shape of the enclosure, one of the one of the examples that always comes to mind when I think of flat flex PCBs, and one place I've seen them 1000 times is if you open up, like a camera, like the insides of cameras are absolute nightmares of system design, like all the PCBs everywhere, and I've seen some before where they like the whole system is literally on multiple rigid boards that are all connected via flat connections. And then it all just like wraps into this crazy monstrosity that fits inside, like, like zero airspace inside of a camera. It's kind of ridiculous. In fact, there was a back when I was working at the FAB, you probably remember the sparker there was a scope for a gun that came in to the engineering department. And this was like a side project thing where it was just like, hey, you know, buddy's got a scope and it was like this crazy digital scope that was military grade, something rather like there was no information about this scope. Let's just put it this way. And I remember cracking it open To look what's on the inside of it, and it was just an absolute nightmare of flex cables everywhere. But, but yeah, if you if you need to get PCBs, all compacted into a small, uniquely shaped enclosure, flex PCBs allow you to do that, but they have a ton of added benefits on the manufacturing side of things. So in general, from what I've researched, and what I just know about them, they they have the possibility of being more expensive than just a connector solution. Like what comes to mind is the hobbyist level, jst style connector versus a flat flex, you potentially will spend a lot less money on on a jst style connection. But you have to remember that in manufacturing, perhaps it's a lot easier to have one PCB that all comes in one array as one singular thing versus having to stock different PCBs with cable assemblies, and have your purchasing team work all of that out and go through the nightmare of, you know, figuring out logistics and things like that. Flat flex PCBs allow you to put your entire circuit in one PCB as an array. So one of the big benefits that comes to mind with that is that you can potentially power up and test your board earlier on. And it's all in the basic format of what the final product would be. So you can test on a panel, as opposed to breaking everything apart, assembling it into what it needs to be, and then testing, and then potentially finding out that it failed, right?

Yeah, that was actually the first thing I thought of when you were talking about this. I'm like, Man, you could basically do a full system test. If your product allows it on a flex rigid board.

Yeah, right, right. And so, flex comes in a handful of different formats, there's full flex, and then there's also something else, I'm not entirely sure if this is industry specific to this worth document or whatnot, but they call it semi flex, you know, someone out there might be yelling at me right now. But in semi flex, instead of it being polyimide, it's still actually a flexible fr four style board, where they basically do a deep mil through the board and leave just a small amount left over. And then you can actually flex that into whatever shape you want. And actually, so semi Flex is okay, so flexible boards allow for a little bit of play in in the flex because it's basically just, it's like a, it's like an FCC cable, right, that just kind of flips around. But with semi flex, it's, it's flexible, but it's like one time flexible, and only flexible like one axis, right? Right. And they suggest that you use tools. So you can still put things in an array on a PCB, test it all and then put it in a jig, bend it into its final spot, and then it's there, and then it's done. So that's, you know, if someone's out there looking for high volume manufacturing, for something that you know, you're only going to flex one time, maybe that's a good solution. But But that's, that's a little bit different from the full flex that that you kind of think of when you're looking at flex PCBs. So a full flex PCB actually has the capability of being multi layer. So if you need to have multi layer for whatever reason, in this document, they say they can go up to 12 layer flex, and I'm sure that makes the cost absolutely skyrocket. But if you do need that you can, the cheapest option is to do single layer, all your all your traces on one side of the flex. The kind of one of the benefits, though, is that it doesn't necessarily have to be on the external layers of a PCB, you can have a rigid PCB, where the flex portion actually exits from the center of your PCB or internal layers. So that's potentially helpful based on your design. So it kind of all adds up to making a 3d system designed a lot easier. One part becomes your whole 3d part after you've ended up and it has the added benefit of making assembly a lot easier to so. I don't know. That's, there's a lot behind it there. The one thing I can't speak to right now, and I hope to get some information on this in the next few weeks is how much more expensive would it be then a connector solution? And in lower quantities, I can pretty much guarantee that it's going to be more but in your high volume situations. That's where you might start seeing the added benefit, especially when it comes to the labor of assembly.

Yeah, the one thing to think about with Flux Is you pretty much have to run PCB tooling, like a panel tooling for those like to run through like your, your pace machine and your your pick and place and reflow, just because, I mean, you can take the panel and then you wiggle it, and all the flex boards kind of wiggle in the boards, it's like, okay, you got to keep those rigid, so you got to have the right kind of carrier setup. So that's what that's kind of the downside, from the Assembly standpoint is, in reality, like to its fixturing is not that expensive, especially when you start, if you're building 1000 units, now, it's like, you know, maybe $1 unit.

Well, and it depends also on how long the flex cable is, if your flex cable is, you know, a quarter of an inch or something in between boards, you may be able to get away without it. But if it's like a six inch long flex cable, yeah, you might get droop in your panel. And then then you have problems. And as we've said multiple times, about, you know, dealing with CRMs. If there's stuff like that, contact the CM and just have a chat with them. There's no real standard around that. And in fact, a CRM that is capable of doing flat flex probably has a bazillion rules that you should take into account beforehand, before doing your design. So if flat flex seems like something that could make your design better, I would say get in contact with your CRM as early on you design processes possible, such that you can start working out the cost, but all the design constraints that go around that. And you might think, Oh, great, I can get 12 layers and they can all be on the internal side of this board and it can be 12 feet long. And this is awesome. And then it's a bazillion dollars, you know? Actually one of the one of the most interesting so

it's not a bazillion dollars it just says contact sales. Yeah, right cannot quote online.

One of the coolest flat flex cables I've seen actually was at the fab and it's inside the pace jetter Yeah, the my 500 The my 500 page letter yet so in so for a lot of machinery that have like gantry controlled or gantry movement, they use E chain to be able to flex the all the cabling that goes from one side of the gantry to the head that actually moves. But in the My 500 Instead of using E chain, they have a enormous flat flex cable. I mean, this thing is like the size of your arm. And it does. You know, I'm sure they've done all their testing to know how,

how many cycles you get,

how many millions of cycles, but like when you see flat flex cables, a lot of times there's like communication cable, it's like you have your main board and the flat flex goes off to a front panel or something like that. But on on this, it's actually passing power. So some of the traces on this flat flex are like like,

why? No, somewhere like four? Yeah, they're

huge. They're absolutely massive. So that's, that's cool. I wish we had a picture of it

available. Alright, go to Fabian, take us take

Yeah, if you get a chance to take a picture because it looks really cool. So yeah, especially in a homogeneous system, having the ability to do do the test as a whole panel, it makes life considerably more simple. Especially in volume. I've run into situations in the past where if you're able to test your system way early in the process, then you catch failures and you fork them off of the assembly path and you move them into whatever like failure analysis and and repair path and then fork them back in your engineers

inbox.

Effectively, right? It makes things so much easier and it makes the suits have a top a lot happier because the work in progress. Cost is a lot less if you're catching it way earlier on. I've gotten into trouble with that before where like you have a truckload of failed product that is like Final at the end it's at his last test and just like we could have caught this earlier.

They're putting this sticker the seal sticker on like the on the boxes. Yeah. And you're like oh no. Backup.

Yeah, sound the klaxons and and yeah, hit the Shift button. Yeah, so So this a lot of this just is really applies to kind of higher volume, but but it's still worth considering in in your mid to low volume because it might actually you might break even by spending more on your PCB but considerably less on your assembly if it makes something a lot easier to assemble and maybe even easier to repair.

Just not having the bill of wiring harness This. Yeah, is that's a big cost savings.

Absolutely, absolutely. So some of the cool things about this, you can, you can tree, flat flex in a lot of ways similar to a Rigid Flex board. So you can expose copper, you can put test points on the Rigid Flex, if needed be. So, some of the things to consider when doing layout for this. So most EDA tools I've run with and looked at don't handle flat flex boards separately from the rest of your board. It's not like there's a flat Flex mode or anything like that, because it's not necessarily super standard. So one of the first suggestions is to create a brand new layer in your EDA tool and label it like your flat flex layer, and put your information on that layer. So like you know, the like the overall dimensions and size of the flat flex you could put on that layer. And an extra information on that because one of the things that's that is going to help because these are more custom than your regular PCB. One of the things that's going to help is having a fab drawing to go along with that. I've did a bit of research before this podcast, and I didn't find anyone that has like a macro fab style, anything near that is for flat flex, where it's like, oh, here, we can help you define things, we can help you upload things. Every place I went to, even if they mentioned it and had like quoting tools, it's still like, oh, yeah, upload your files, and we will review them. And that, at that point, the best option is to create flat flex, I'm sorry, a fab drawing, that shows your entire board is very clearly defined as in this is the flex section, and then put notes on one side that is you know, here's the thickness, here's the layer count is color, if applicable, and all of those things and send that along with your files and include that Gerber file that you created. That is your new EDA. I don't know, flex layer or whatever you want to name it. So don't put vias in the flex portion. vias don't like to flex. Try to think of the flat flex as just a connector. You're not doing anything unique in the flex portion. You're just two dimensional connector. Yeah, yeah, two or three dimensional, right. And try not to fold the it over in two axes. So in other words, like, don't do any mountain Origami Folds or anything like that. Do this there are some that can accept that. But once again, that's a situation where like, if you need that, you probably already know what you're going for. Most of the time, flex cables just allow you to make 90 degrees or 180 degree you know flip overs with with the cables. Oops, yeah, basically Yes. Oops, make sure that you design in strain relief and like extra length or appropriate length of the cable so you're not applying stress to the cable itself or the the bond points on the PCB that like

have a little extra slack. So there's because there's no strain

relief, not Well, I mean, the adhesive is the strain and really Yeah,

so I'm saying this you have to have a little extra there. And that is your that is your strain relief is basically don't strain it. Right?

Right. Use teardrops if you're EDA tool allows for it cuz that adds a little bit of extra copper bonding and adds rigidity, use as wide of tracks as you can. So if you define you know your your flex area by some amount, like try to space everything so you using as much copper as possible. And if applicable, try to use the same width of copper for each signal. So you can just basically increase your tear strength and increase the whole strength of the flex itself. And try not to change width of the whole flex in the Bend area and the part that you know is doing the swoop you can change it, uh, you know, in other areas where it's where it makes straight runs onto your PCB or into the middle of your PCB, but the actual Bend area, try not to make any changes on that. And then and then with documentation. You got your PCB Gerber's, you have your extra layer, include any drawings and any extra information on a fab drawing. And I think that'll kind of get the overall gist across and then once again, call your CM and just say, hey, let's have a chat about this because this is super weird.

So if you call your CM, this is what they're going to say because I actually did research on the other end of like, if so in the macro app platform right now is basically just a little button that you click, and it means it's Rigid Flex Okay, so

and that just goes to the inbox of

engineering goes into box engineers, right? No, that's totally what it is. Yeah, right, right. Because we don't the platform, the, you have to have a lot, okay? This is this is why, okay? This is why it's not simple like A, so A rid of normal rigid PCB has one stackup. Okay, it has one specification for the PCB, a Rigid Flex board has that for every single section of the board. So if you have an your example, you have two rigid boards, and then a flat, A flat flex section in the middle that's connecting to, you actually technically have three stack ups, you have one for the rigid A, which is like one of the boards, one for the flex section, and then one for the other rigid section. And then you're so when you're designing this thing, you can you can have all your rigids can have different layers, you can have one, it's a six layer one that's a two layer, then you're inside your flex, your flex can be all different setups as well, they can connect from, let's say, internal plane one, and then go to like airplane six on the next board, like, step down into your stack up basically. So that's what you're gonna have to provide to your CM is like this complex stackup. And then on your assembly drawing, you're going to have basically an overlay of like, this is what it all looks like. And this section here is this stackup this section here is this stackup this section here is that stackup. And so you know, telling you, okay, all these sections are Rigid Flex, or rigid areas. And then these are the flex sections. And these are all the associative stack ups for them. And I haven't found an EDA tool that actually handles that.

That's why it comes down I think to fab drawing for the most part. Yeah.

Maybe like Altium, and cadence probably handles it. But I don't know, like, I've never even seen an ODB plus plus file that has like Rigid Flex in it.

Well, and you'd like it was saying that from this worth document that I have here that kind of details it down at the bottom, they talk about the necessary documents. And they basically just say, well, I should flip that around. I basically said what they say in their way. It's just like create a new layer and make sure you're clear about it.

And then interesting enough is it's kind of interesting and unfortunate because I forgot to mention this last week is sera circuits EMA design automation? Ema? I don't know if it's EMA da. Anyways, I got it in my inbox, that they're having a webinar for flex PCB design guidelines for manufacturing. Oh, nice. And so I put the link in the show notes. Unfortunately, this podcast probably will come out after that. But I'm going to tweet it and put it in our Slack channel so that people can go watch it because I'm totally gonna.

I'm signing up literally, right now.

It's 1pm. Eastern Time on February 3. Yeah. Which is tomorrow. Yeah, it's like, an hour after this podcast comes out. Yeah, no, I really wanted to. I just forgot to put on notes for last week. So

cool. So yeah, I want to I want to check back because I'm doing a bit of research onto this. I want to I want to check back in in a few weeks and talk about what I've kind of learned mainly from the cost side of things. A flat, where's that breakeven point? Where's that breakeven point? One of the so so for most of my boards, there's no need for these kinds of things. The one thing that we've been thinking about is potential replaceability of components. So instead of like soldering in, you know, potentiometers, or panel components to panel things. What if they could come on their own carrier board such that if one goes bad, you can just unscrew it, put a new one in and plug it into a connector? And if if you know if you have a panel of 50 pots that all get soldered automatically by a selective solder machine, are you saving money by doing it that way? And does that make our amaze easier, you know, so there's a lot of like back end analysis that I have to look at like how many times do we get a board in that has a bad pot? How much does that cost? Would it make sense to go with this for you know particular company? So there's a lot of that kind of analysis that's just digging deep into those things. But regardless, I kind of want to get some quotes and get an idea for the cost of these things on a medium scale, maybe.

I'm looking forward to that, because I want to know the answer as well. Yeah. My project is kind of like, just low volume is mostly like exploring, what does it take to design a flex circuit? So okay, so my big topic for today is comprehensive power supply system designs for harsh automotive environments can consume minimal space, preserve battery charge, and feature low EMI. I didn't write that analog

did oh, my can it be true? Yes.

I don't remember how I stumbled upon this. But I was working on a project that I can't talk about because it's not 50% done yet. But I can talk about this research I did, which was a this is a article that analog wrote, It was a very interesting because a couple of years back analog bought LT linear technologies that was like, it feels like just yesterday, it was actually like 2016 or 2017, analog engineer, Ben Wu, and previous linear tech engineer, Zhang Yi, wrote an application note using linear tech devices on analog.com. So I just thought that was kind of interesting that that, like the engineers, backgrounds, they didn't just like wipe, linear tech to like, be analog, and they're still keeping linear Tech's name around on the website. But anyways, I was going I haven't fully read this document yet. It's pretty beefy topic and article, but just some interesting notes. At least I got through like, halfway through, like, why you need to worry about this. So why is like, you have to care about like your power supply on a car. It's like 12 volts, right? It's 12 volts.

I'm sure the chassis is dirty, like electrically. Right?

Yeah, that's the big problem is your your power is coming from an alternator, which is a three phase, basically a three phase generator, that's just running through diodes to rectify it. There's nothing fancy about it. And so you get this really choppy, in quote, DC waveform that comes off of it, and then your battery is the capacitor that's trying to smooth it out. It doesn't Okay, job edits. But, um, so they talked about cut, there's actually a ton of different standard. I didn't know about this. And looking back, it's like, Oh, that makes sense. There's like, I think they list like 10 or 15 Different like standards of like, basically trying to qualify, the standards qualify what is automotive power, and all the different weird events that your power supply has to handle to actually be functional, like, and pass all the regulations. So the first one is a load dump. So a load dump means is like, your battery just gets disconnected. Right? So you have this the only thing that's trying to keep the the power smooth in your old system, and you completely disconnect it. You basically your your alternator will spike up to depending on the system. 35 To 100 volts positive.

Oh, wow. Okay, because of what? parasitic inductance ism,

yeah, parasitic inductance. So you have that huge spike, and then it will basically go haywire and everything blows up. The other one is cold cranking. So when you turn the key over, basically, you're dumping about 300 amps into your starter motor. And that starter motor is going to put a big drain on your battery. Like crazy. Yeah, so you'll, on average, it dips like four or five volts. And so all your electronics have to be able to handle basically 12 Minus five or six volts. So six, so they have to operate on six, seven volts actually. And, and that's actually 12 volt as automotive power is actually alive as well. It's more like when it's running, it's more like 14 volts. So that's another thing to think about is like, Oh, you have an extra two volts, like when everything's operating normally. And then you have pulses. So like ISO seven 632 dash two is a pulse event. I don't know what actually causes this pulse event but it's a negative voltage. We have 220 volts from, I don't know what kind of event that happens at, but that's one of the ISO standard set your car, anything that hooks into your car has to be able to handle. reverse polarity, which makes sense, like just putting the battery in backwards. And then AC ripple, which is like, if you have a motor that's PWM controlled, or you're, you're dropping the bass really hard at 60 beats per minute, or whatever. So you have that AC ripple that's on your DC line.

So in other words, what this all kind of boils down to is car electronics in terms of the power supply that the you know, if you're designing something that is supposed to run on the on car power, like you have to realize that you're just getting like kind of the worst power.

It's pretty, pretty bad. And I did like this one thing. This one comment is basically like you look at the schematics, it's like the first line of defense is an ideal diode. Like, like if you had an idea, ideal diode, all this is solved. Right. But you don't have an ideal diode. So what's the next best thing, the LT 8672, which is a active rectifier controller, which sounds really cool. It's basically a active controller that's looking at the power line that's coming in. And it has a a and channel N channel MOSFET that it's using as a diode and shutting it off and turning it on at certain events. So like it's protecting reverse polarity, it's protecting from spikes, and like good stuff. I haven't read too much into how it does that it's an active component. So it's got some linear tech voodoo in it. That's my next step is to actually like fully read that whole article, and then go into the datasheet for the LTE six, seven to read about how it works. And then on the other end, you have like a wide input voltage regulator, which they also recommend and linear deck part that basically spits out your nice smooth 33 Or not 33.3 volt or five volt or whatever voltage you want, at the end. So hopefully I have something built up the next couple of weeks. But it won't be next week. Maybe the week after that. I'll share more of what I learned from that article. Nice, pretty excited. Like I found it and I'm like this, they get like we've always talked about like linear tech having really good application notes. Oh, yeah, this this right here is like cream of the crop. Oh yeah. That's perfect. That's cool. So basically, this

is reverse protection in like awful situations.

Yes. All situations like, how does it like? lt 86? Dude, like, I don't know how but rejects AC ripple. Like by modulating that n channel MOS MOSFET Hmm, that's interesting. Yeah. I want to read more about it. That's really cool.

You know, one thing that came to mind, I was I was I was sweeping up our shop the other day. Trust me this applies. I was vacuuming the shop because I basically gone for a few months on our CNC mill without cleaning up. And the chip tray was basically at max capacity. So I had to get rid of all the aluminum chips, but just spillage and stuff from the past few months, there was tons of aluminum everywhere. So I got out our shop vac and I was I was vacuuming things up. And being that it's winter in Denver, Colorado. It's like negative 5% Humidity here. And like I was getting shocked like crazy from the from the plastic hose of the shop vac. Like I had to pull that out at like an incredible distance just to knock it blasted in the leg. And it was like painful shocks through genes if it touched your leg kind of thing just because of like the air flowing through it. Yeah. And that's a big problem in vacuum systems, right? Like you have to be able to ground them and mitigate charge buildup. Because of rubber tires on cars and cars driving through dry environments. Do they suffer from the same problem? Do you get static charge buildup on cars due to driving through dry environments, and I'm wondering if there's well I'm sure there's some times never been shocked by their car at least once. Oh, for sure. Yeah. So I'm wondering what kind of sparked that is that whole 220 volt spike. I'm wondering if that's a static buildup spike that could be caused by that, you know,

I guess I guess if we look up with this ISO number ISO 7632 dash two road vehicles electrical? Do notice a whole list of transit events and that's just one of them. Yeah,

they don't tell you what causes these. They're just like make sure handles these. Make sure handles. Yeah. I'm sure somebody knows up there. every little aspect of everything a car can go through. Cool. I love these these like application specific chips. They're They're super

cool. On before I get to, can I actually buy this part?

Save me Bowser. Oh, stock doesn't look too good.

I bet you I. In

fact, someone else's mouse has got about 1000 of them. That's okay.

How much do they go for? In 1000s and

1000? piece? Yeah. $2.70. Not too bad. It's okay. For a chip that basically solves all your problems,

or Yeah, yeah, I could see that being reasonable. That's not bad. I bet you that somebody out there develops an automotive power supply that replicates all of these errors? Oh, yeah.

Yeah, you can actually I think in that document, they, they have a couple pictures of like the test, test stuff that they were thinking of a different thing now.

Like, what's the lightning event? generators at, like test labs and things? You know, that's a very specific power supply or power generator of sorts. I'm sure somebody has like a lab based car power supply simulator?

No, my bad. I was thinking of actually, I was looking at OBD simulators, different that kind of thing. OBD is onboard diagnostics, which every car after 1996 has to have in America. And you can buy simulators so that you can test equipment that hooks up to cars? Oh, like you can throw faults and things like that? Yeah, you can. You can throw faults and that kind of stuff. And sim you basically simulate a running car on OBD and it's a lot better than you know firing up your a test car in the lab.

Right Great.

Well, if we can get a car in there. Oh, cool.

That does it for me. And then that's it for me.

So that was the macro fab engineering podcast. We're your host Parker Dolman. And Steven Greg. Later everyone take it easy thank you yes, you our listener for downloading our podcast if you have a cool idea project. Let Stephen I know Tweet us at Mac fab at Longhorn engineer or at N log N G or emails at podcasts at Mac fed.com Also check out our Slack channel. You can find it at macro fab.com/slack