- The owner of Mercury Inc.
- Mercury Inc. is a design consulting firm with expertise in electrical mechanical software and firmware development
DFM for PCB Assemblies
- Industrial Design
- What is this?
- Special Assembly
- Unique processes
- Sequences and events
- Design for Serviceability
- Change logs
Special thanks to whixr over at Tymkrs for the intro and outro!
About The Hosts
Parker Dillmann is MacroFab's Co-Founder, and Lead ECE with backgrounds in Embedded System Design, and Digital Signal Processing. He got his start in 2005 by hacking Nintendo consoles into portable gaming units. He also runs the blog, longhornengineer.com, where he posts his personal projects, technical guides, and appnotes about board layout design and components. Parker graduated with a BS in Electrical and Computer Engineering from the University of Texas.
Stephen Kraig began his electronics career by building musical oriented circuits in 2003. Stephen is an avid guitar player and, in his down time, manufactures audio electronics including guitar amplifiers, pedals, and pro audio gear. Stephen graduated with a BS in Electrical Engineering from Texas A&M University.
Host 1 00:11
Welcome to the macro fab engineering podcast. I am your guest, Chris Carter.
Host 2 00:16
And we're your hosts Parker, Dolman.
Host 1 00:17
And Steven Craig.
Host 2 00:19
This is episode 244.
Host 1 00:21
Chris Carter is the owner of mercury Inc, a design consulting firm with expertise in electrical mechanical software and firmware development.
Host 2 00:30
Thank you so much, Chris, for coming on to our podcast. Yeah.
Host 1 00:35
So why don't you give us a quick little rundown of Merrick mercury, and then we'll get into the topic that we're going for? Yeah, no
Host 2 00:42
Problem, or an about you?
Host 1 00:44
Okay, I can do both. So the company Mercury Incorporated, primarily, we do, you know, electrical, mechanical and software engineering. Yeah. So, we, what we really do is we slide into a company where they need us. So we offer staff augmentation, we offer basic consulting, the problem comes out, they call us and say they want to make this product or they call us and say we've made this product and we just need to make this mod, you know, whatever it is they need, we slide the right people into their team and and either design it for them or, you know, fix their problems, manufacture it make a little part. So we've had, we've had customers where we just do a quick wire mod and turn their board. And we've had some that literally come to us with a napkin with an idea they wrote down during lunch on, and we take it from concept to completion box, build all the way out the door to shipping and distribution. So that is essentially what the company does. Me personally, a little bit of background in history, I guess. When I was really young, my aunt called me and asked if I could fix her VCR. I told her no, but then she's like, Well, I heard you were good with electronics. So I asked her I just clarified or is it broken? Right. Like I can't make it worse, right? And she told me no. So I totally think apart. You said this at the time. Oh, yeah. Yeah, no, no, actually what it was it she had eaten one of her capes, right. So I had to reset the time and pull the tape out of it. But I when I dove in there, I saw this green shiny thing with crap plugged into it everywhere and silver shiny stuff. And it seemed like there would be a reason why each of those components were there and what was going on behind it. And those little like roadways between it had to mean something. And so I just kind of got interested in that stuff. And from that day on, I took anything that came across me apart. If I got something in my hands, I just tore it apart and looked into it. And I just kind of reverse kind of understood whatever was going inside of it. And that carried on until I got out of high school. And people just started asking me questions like, I actually wouldn't go to database job doing software development and database administration at a company called Melaleuca. In the town that I live in, and they just kept asking me if I could do stuff like, Hey, Chris, we want you to do this. Okay, I would jump in and do that thing. And it just worked out well for me. And then I would start getting external calls. I was on Rinna coder for a really long time. And people would call and, you know, I would just tell him, if I felt like I could do it, I would do it. Even if I lost money, I would I would accomplish that thing. And, you know, it built up a lot of experience. I mean, a lot of mistakes. And all of those mistakes are essentially how I guess, give good answers now, right? I've screwed up a whole bunch of stuff. So now I don't screw up people stuff anymore.
Host 1 03:22
Just out of curiosity, do you think do you think that makes an engineer or a designer or somebody who works in a field like yours? Do you think that makes that's almost required? Should I say?
Host 1 03:33
Yeah, I mean, I think I think there's two parts of it, that's required. The first part is to make the mistakes, right? And go through that and learn what I mean. I don't know that I always call it a mistake. Sometimes I purposely break stuff, right? Drive it to failure to see what causes it to fail and make a better solution. But the second part of it is realizing that your mistakes aren't mistakes, right? Like they are learning opportunities, schooling opportunities, and and if you approach it from that perspective, it's not like, dang it, I just screwed up. It's like, you know, great, I can prevent that from happening to the next customer down the line, or to my next, you know, side project I'm working on.
Host 1 04:10
For sure. So, so did you. Did you go to college for any of this?
Host 1 04:15
Ah, well, yeah, no. So I did register and go to the university for one semester, and I have a few credits from when I was in high school, like AP classes. But, you know, in retrospect, I did not go to college and become an engineer. I actually couldn't figure it out, couldn't work out how college kind of operated. It just like blew me away. And I couldn't I couldn't connect all the dots and get what I needed done. And so I kind of just left and started doing what I said, right, like answering people's questions. If I thought I could do it, I would take care of it. And it just got more and more involved in deeper and deeper the questions that would people would answer me until finally you know, somebody asked me Can I can I do firmware? And I was like, Yeah, I can do forever. Where and I went and did his firmware. And then, you know, the firmware was hooked to IO pins. So I needed to toggle some IO pins that were no longer available or not on the schematic. So I had to modify his schematic. So, you know, I download eagle and start modifying the schematic and just kind of kind of grew my own chops that way. So I'm sure you're gonna cover, you're definitely going to come across some technical jargon, that is not real. I make up words, because I don't know what the technical word is.
Host 2 05:26
I mean, that's how the technical word came about.
Host 1 05:29
Right? Yeah, just make it up. Because it sounds fancy. Right? Exactly. So that's my schooling background. I mean, I do spend a lot of time, you know, reading and going to, you know, I love CES, you know, any of those sort of things, especially embedded versions, any sort of, you know, basically comic cons for engineers, I try to get to, and so it's not like I don't know how to learn, it's just that organization of college and that sort of thing. And then when kind of looking back in retrospect, I'm super glad I don't have like a ridiculous amount of student loans to overcome. But in the same same vein, it took me a long time to get to a point where I would be valuable, I guess, to accompany, right, it took me a lot longer to get to a point where I can actually engineer something.
Host 1 06:17
Yeah, sure. I mean, the piece of paper does mean things to certain people. But in a lot of ways, it's arbitrary.
Host 1 06:24
Yeah, I mean, the document, right, it always gets your it gets your foot in the door, and it will probably set your base pay. But if you want to keep your job, you need experience, and that sort of thing. And you just, I mean, you don't get experience in school, you get some basic education, you know, and some technical detail. But really, what it boils down to, to me is the engineers that come out of school, tend to not have any applied Apple application of their knowledge, right, they don't know how to apply it. And so I spend a lot of time with the engineers that come in, especially right out of college, in our company, just helping them build that experience of failure, so that they can operate in the real world with our customers, because it's not turning in an assignment, right, they're not turning in an assignment and maybe getting a C or a D or be like, this is the customers livelihood, this is how they make money. And so it takes a little while to build that, you know, kind of up from from some people. But you know, aged people who have who have worked in the industry for longer tend to be late tend to slide in a little bit quicker. And so that's why, you know, at first I was really hesitant and was worried about telling people that I had been to school or whatever, but after I've done a job with them and worked with them, that they can start to see that experience is way more valuable than whether or not you know, I have a master's degree or a bachelor's degree or PhD and something you can never use or whatever.
Host 2 07:46
I wonder how popular a class that would be if it was like engineering failures, but like you build something and have to get an app
Host 1 07:56
As long as it followed up with a second course right? It was indestructible in the second round or something like that, right?
Host 2 08:03
Yeah. He called like experience of failures or something like that. Yeah, you know, it actually
Host 1 08:07
It's a hard thing for people to admit you know, if you screwed something up bad every like a lot of companies and businesses will really jump down your throat and and you know, hold you to it. But I try to take a different approach with our employees and make them feel comfortable with their mistakes. I mean, to a degree right like I don't want them run around making the same mistakes over and over. But I know every time they make a mistake it's gonna it's gonna pay back dividends later on. Yeah, cuz it sucks. Yeah, they'll they'll remember it right? They'll remember that mistake and avoid it in the future. Oh, yeah. Yeah, but but if I tell him like hey, don't do this. I get like 50 questions why right like oh, well, what about this? Well, I wanted to do it anyway. Well, I think that's the right way to do it. school taught me and really you know, nothing nothing Nothing says test your your battery charger before you plug it into a battery like through a building on fire. Right? I forgot to put an overcharge shut off on your on your battery charger. And you come back in and you know the whole building is smoking. That I'll never forget right now when people send me a battery charger. I test that thing before I just plug it in and leave it for the night.
Host 1 09:10
Wait, don't tell me you came to smoke. Smoking building? Oh,
Host 1 09:15
Yeah. Yeah, I still have the chair. So it didn't it didn't actually burn the building down. But I had a guy submit a volt battery charger for me. He told me he told me everything was done and good just soldered up and give it a test. And I did. So I ended up and gave it a test and it was actually a multi cell charger. So it had four lithium polymer battery cells stacked on top of each other. And what ended up happening was there's no overcharge protection so the top battery got hot. Then it got a little too hot and the second battery melted and when it melted it melted through to the second and first battery and when it hit the first battery, it blew up. It blew molten copper and lithium all over the room. And occasionally it was in our build lab. So occasionally I've got all these little like component drawers right that you can open up. I'll go back in and open a component drawer and Smoke will come out even and still is, like 15 years ago when I set that thing off. My wife hates me I've got I've got the chair that the brunt of the damage sitting in the server room and she was pissed that I won't throw it away. It's like, it's like a room. It's like, remember to test the stuff people. Don't just walk off and assume it'll work.
Host 1 10:19
I That would be amazing. If you were sitting on that chair right now.
Host 1 10:22
I it's not comfortable. It's not comfortable. That's why it was in the build lab in the first place. That's great.
Host 1 10:27
I guess that's a hell of an intro. Yeah, I
Host 1 10:30
Guess I got a little out of control there. So anyway, no, no, it's great. That's
Host 1 10:33
Fantastic. So I guess we can move on to the main topic that we were gonna get into today, which was a DFM for PCB assemblies.
Host 2 10:42
I think it's a little bit more than DFM. But we'll just call it that. We'll call it Yeah. Okay. So I think this is going to be a multiple part podcast, too, because we have like, like 10 things on this list. And we're probably going to scratch two of them this episode. So we'll definitely have to have Chris back on later. But the first one is industrial design. So what does that mean to you, Chris?
Host 1 11:07
So to me, and to the you know, the handful of customers who brought me industrial design, think I can make product, industrial design is kind of it's not exactly what it sounds like, at first. First, I would have thought industrial design meant hardware or mechanical engineering. But it turns out industrial design is really just like, art, right. So like, somebody draws up your part, your product, the 3d printer you're gonna make or whatever. And the funny thing about it is when they draw those up, it's usually an artist that doesn't, not a CAD designer. And so what we end up with is a wire mesh of maybe five or six lines that has an image wrapped around that, that mesh, and they'll come to us and say we'd like to build this product, look how great it looks. And there's no dimension, there's no size, there's no material, there's just like some great looking art, right? Don't get me wrong, industrial design is my least favorite thing, because I can't do it. But it's the most important part from a customer perspective, right? What you're selling to your end customer. They have to love how it feels, touch, tech, tactile, all that sort of stuff. But industrial design is not sufficient to fabricate a product or a part. If you bring industrial design to, to a manufacturing party, what you're going to end up with is a list of contacts that can fab each component, the plastics and the electrical, and mechanical and all that sort of stuff. You really need to take that one step further and go into actual mechanical design and mechanical engineering and electrical engineering if your protocols for you
Host 1 12:41
Know, I think it's funny, because it's very parallel to the classic idea of you got architects and civil engineers, draws up something give us to civil engineer, and they're just like, dear God.
Host 1 12:54
Yeah, that's exactly how I look at industrial design, right? Is it looks right on the computer screen. But it's not fabricate trouble, for sure.
Host 2 13:02
So how do you fix that? Ah, so again, I think it comes back
Host 1 13:05
To customer engagement. So I have had a couple of customers bring me their industrial files and asked me to manufacture them. And it turns out that that's a human issue, they didn't realize that they had needed the build files. And so at that point, it's just a matter of navigating back to the engineers and finding what we need to fabricate. And then working with that group to, you know, get what actually needs to happen to produce their art. I have had a few people come to me with those wire meshes and asked to build it. And to be honest, those engagements are more expensive in terms of like the overall cost of engagement. But in terms of that customers, you know, experience and cost from India, from industrial design to completion, right shipping to the customer, it's always been my opinion that you get a better result, if you use one engineering group that is capable of doing mechanical, electrical, industrial is less important, but industrial, if they can do it, and then your final assembly, right DFM and manufacture. And what you get if you if you can find a single consolidated group is you don't spend a lot of time with different engineering groups and meetings, transferring ideas and knowledge, you get the opportunity to have fewer engineers have a deeper understanding of your product. And the more they understand the deeper and they can get. You know, I was I was chatting about an alternative product we were building a while ago. And we actually deployed into firmware in a little IoT tag code that made our database more performance, right. Like, we wouldn't have been able to do that if we'd outsourced electrical engineering and said, make the IoT device and then we'd outsource database administration and design and then outsource software development. Like our guys are in house in house we sit down, have that conversation, explain the whole product to everybody. And then you know, the DB guy says well That's gonna slow us down. So yeah, I mean, I can, I can build and calculate my timestamp. So it comes across in time that sequel needs don't have to waste time processing some arbitrary time format to get it into the database, my electronics provided it in that way. So I got major scalability and didn't have to bother with ETL and crunching just by taking one step backwards. And I think that those are the two most common ways I solve industrial design problem. Obviously, there's the ones that come to us with industrial design, and then hear that they have to actually design their product and move on, right, because it's too high, or the duration takes too long. But those are the two, the two real solutions are to help them design their files or to find the dude who created the originals.
Host 1 15:44
That being said, Do you Do you prefer if you kind of get control? Or if you get more control over things? Is that what you usually try to steer for? Yeah,
Host 1 15:54
It actually it depends on why I picked up the project. Are you familiar with the KonMari? method? So she's a girl who like teaches you how to clean your house?
Host 2 16:03
Oh, is that the only keep things that make you happy? Yeah,
Host 1 16:09
You have to ask every article of clothing. If you're happy about it.
Host 1 16:12
Yeah. So you hold like you. Yeah, so we pick up this roll of tape, right? Hold it to our hearts and ask because this tape made me happy. If it doesn't you toss it. I pick customers that way. So when a customer calls and asked if I like their product, or their concept, or something just like strikes me as like, oh, I should do this, I do that project, I don't usually calculate or make a plan or be like, Oh, I'll only work on this. If we can make this amount of money this quarter. I'm really more interested in having fun at work. And so I pick jobs that I think will be interesting. So that is one way that I can filter out the industrial, you know, things that I'm that I'm not really interested in working on. But in terms
Host 2 16:54
Of it's got to be some really good art.
Host 1 16:57
Yeah, exactly. Right. But in terms of like, you know, the original question and which ones do I prefer, if I just need something to like, take my brain off of, of, you know, the current project I'm working on, I really like I like projects that I don't have a lot of say in, right, because they're fixed in scope, they basically told you what to do. And now it's just my, it's just a matter of math to get the thing to do it that way. If I'm really looking to like Phil's to feel fulfilled in the day or the week or whatever, I prefer the ones that drop an industrial design on you. And you're like, Well, I don't understand why you can't just make that from that file. Because then like, I really have to go into it and and decide like, should I use machine screws? Or should I use you know, wood screws? Are should I use this electrical component? Or this schematic layout? Or Solid State Relays? Or should I use a mechanical and like, right, I get to make those decisions. But if I'm if I'm kind of overwhelmed, or or feeling like I'm behind, I rather have an industry or like something that I don't have control over? Because it's not my responsibility, right to make sure that thing works. On timescales not on you either. Yeah, I mean, that takes the pressure off, right? If I can take the pressure off, immediate boils down to that, but I don't think so I actually, like, sometimes I just need to unwind my mind and do a dumb task, you know, start to finish. And sometimes I actually just want to sit down. And I guess for lack of a better term, make the world better, right? Simplify design, minimize cost, help a customer out whatever the case may be. So I don't have a single answer for you.
Host 2 18:32
I think the answer to Yeah,
Host 1 18:33
That's the trouble is like, it's definitely scope related and project related. But generally speaking, there's usually three paths No. expensive and cheap, right. Those are the three paths you can go down. So yeah, I mean, so how do you guys feel about my, my definition of industrial design? Is that pretty spot on? I kind of I heard it once, and then I made that definition up.
Host 2 18:58
I think that's pretty close.
Host 3 18:59
I'm curious, because I've certainly, I've tossed it around a bunch, and I've heard it a bunch, but I don't think that I've ever seen like an official definition of industrial design. I think it's just this nebulous term that people throw around. And it's just like, oh, it's kind of big picture in a way.
Host 1 19:17
Yeah. You know, the first time I heard it was actually from a mechanical engineer. So the mechanical engineer that had built this product, was going into version two of the product and he called me aside and was like, hey, look, this is going into industrial design. When it comes back, we'll send you the mockups, and I said something stupid thinking he meant it was like their CAD files he's like No, no, they won't come back with CAD files. This is just like the art the original design and that's where I kind of formulated my whole opinion from was this one dude like corrected me so that's that's probably that's probably a little bit like I've read into it a bit but you're right. I've never seen a written down like a formal degree in industrial design or anything like that.
Host 2 19:56
Yeah, I view industrial design is is how The device interacts with the rest of the world. So either in humans interacting with it or interacting with other devices, or like how it plugs in, but like what goes on on the inside? Doesn't matter. It's black box.
Host 1 20:15
Yeah, I can see it that way, like basically a visual theory of operation. Right? Yeah.
Host 1 20:20
Well, let me let me rock your definitions real quick. And you give you the official definition from Wikipedia.
Host 1 20:28
Yeah, but I wrote that. Just kidding. Just go ahead. Go ahead.
Host 1 20:33
Industrial Design is a process of design applied to products that are to be manufactured through techniques of mass production. So in many ways, it doesn't necessarily have to, according to this definition, doesn't have to do with the actual design of the products, inner workings. This definition is more about how it gets mass produced.
Host 1 20:56
Interesting. So really, then it would be more like what we just talked about would be more like a mock up, right, like an art mock up. And industrial design is kind of bleeds over into DFM. I mean, by that definition. I mean,
Host 2 21:09
So says hesket, in 1980. That's what that source is from way
Host 1 21:15
Up to date, right? Sure. Sure. Yeah. Wikipedia, it's the source of all information.
Host 1 21:21
I was close, I was close enough, right? For the for the purposes here.
Host 1 21:25
I think in general, like, whenever I hear industrial design, I think my mind leans a little bit more towards system design, where instead of the part that I'm good at, I'm thinking about all the parts. So it might be Oh, I have to contact my me or my firmware guy, or even the artist who you know, put text on a on a cylinder and said make it you know,
Host 1 21:48
Ya know, that could be I guess it really to it depends. I think if you asked what is industrial design to a different group of dudes, you probably get a more like concise or at least a different answer. I think it's contextually based, right? Where I spend a lot of time answering DFM questions and things like that. I tend to think of industrial design as a step one, you know, not not a real engineer, but just somebody who's going to start the process rolling. It's probably a little unfair. Sorry, all you industrial designers out there, you guys do good work. You start the ball rolling, get the juices flowing.
Host 1 22:24
Well, and so for DFM, I think DFM in so many ways, is reliant upon somebody who's done the job before. It's DFM is basically just understanding that somebody has requirements for the task that they're doing and trying to compile all those in one place and apply them to whatever you're designing. Yeah,
Host 1 22:47
Yeah, for sure. So did we define DFM? Maybe we should have defined that before we designed to find industrial.
Host 2 22:53
What are you doing right now? Yeah, sure. 24 minutes into the podcast, what
Host 1 22:56
Do you want? Maybe you should just check with Wikipedia first. Design for manufacture, right? So for to me design for manufacture takes an existing product, usually an existing product, and modifies the steps that it goes through so that it can be manufactured in an auto or semi automatic fashion. That's how I that's how I look at DFM is, if you can take that back into the industrial design and into the mechanical design, you should at all at all costs. And try and plan your design around not needing to build those efficiencies in later. But that's essentially what I consider it to be. No disagreements.
Host 2 23:35
Host 1 23:36
Yeah. I think it's concise. It's good.
Host 2 23:40
And speaking of basically that, that definition of DFM the next topic, special assembly, yeah, is what you should be avoiding. Yeah, breaking the DNA breaks DFM.
Host 1 23:52
So if you're a mechanical or your electrical, right, like, avoid, avoid specialist ability, like Parker said, right, like, good. A good electrical example, would be border wire, right? Use a connector, don't use soldered wires directly to the board, that'll almost always be a manual process. Or at least an extra machine that needs to be brought into the to the mix. And then you know, mechanical, you could talk about things like screw bosses versus snap that, you know, if you need screws, that's one thing. But if you don't need them, don't put screws in the system because somebody or something has to turn them and that takes time. And it doesn't sound like a lot until you turn you know 200 million screws and get charged one penny for each of them. It adds up definitely an industrial or in DFM. And so yeah, I guess that's that's definitely some of the special assemblies that I've come across. Board edge connectors like roll your own board edge thinking like Nintendo cartridge style sockets, right? That people just want to cheapen up one half of it and they make their own PC. Use the leads, especially if they're not designed for that many insertions or removed spine for one time, especially if we're going to solder it or tin coated or something, but multiple insertions by something by by a connector that cost you more than it will cost you to repair it or cost you less sorry, cost you less than it costs to repair it. Or troubleshooter DFM, special assembly, you know, the other things that can go under special assembly would be things like, plan for the ability to make contact to your root firmware or root device from outside. So whether that's over the air firmware updates on a Bluetooth unit, or a special connector or bootloader, on a USB device, or serial device or something like that, like you can avoid special assembly by designing your jack or connector or programming port directly into the enclosure and PCB. You know, take take a few steps backwards before you take that step forward and design the circuit board and think about where that circuit board is going to go. And what you're going to need to do to it to make it function. And then seriously think about what's so think about the day when you get 600 of them back, and you have to evaluate all the 600 for some unknown bug. That's that's really how you should be like planning and designing ahead of time,
Host 2 26:28
Or, or your you get them and you have to take them all apart to repair.
Host 1 26:33
Yeah, so that's another reason to not put screws in is if you're the one that has to take them apart to update the firmware or to program them because you've it's because they didn't come out of the factory program. Yeah, I mean, that bleeds into DFM in general, but special assembly. You know, you can so so this is counterintuitive to the to the topic, right? I just said avoid special assembly. But in some cases, a special assembly process may be less costly than like RMA process.
Host 1 27:00
You know, I think another thing that can be added to that is if you look at your device, as you're designing it, ask yourself the question, does this require a tool that just doesn't that you know, doesn't exist at the manufacturing facility? Or does this require a tool that you have to design and provide to the facility? Like leaking rid of that? Like do you get the like don't do those? Or if you have to do them have a very good reason. MB
Host 2 27:28
Leetle? Custom lead for me is right up there. Yeah. Yeah, the parts
Host 3 27:33
Or something something like exactly like you were saying, Chris with, you know, connections of some sort. If if a connector if just sourcing a connector and putting that on your board fixes the need to have a special jig for you to put boards down and wire them together in a special way. That is superior. Almost all that. Yeah.
Host 2 27:54
Actually, Steven, you built that like last week? Oh, my thing your your potentiometer board?
Host 1 28:02
Yeah, yeah, absolutely. Yeah, I got rid of seven cable assemblies and dropped it down to two by just going with special connectors and an extra PCB, which is significantly cheaper.
Host 1 28:14
Yeah, well, and that's something to like when you're talking about special assembly. So maybe you have like a wire to wire board interface. Right? If that's required, and you can't use a jumper, at least use breakaway cable. So so we got into this complicated build with pneumatics and electronics and routing, the wires around everything without EMI and all that sort of stuff. And then the machine moves right pneumatics. And, you know, it turned out that having a connector that could break away, it'd be disconnected from the board or disassembled in the center of the of the cable allowed us to service the machine and prototype on it. So what we were doing before I showed up was desoldering the thing to get it out of the chassis to work on it and enhance it and soldering it back into the chassis. So so there's there, I don't want to say don't do special assemblies, right, there's a balancing act between when to use it. And in dev and beta and prototype, I tend to use them more. Because I'm personally can deal with it right and I can rapid prototype. But when you get into production, what you're really trying to think about is how can I get this, this this device from start to finish on the assembly line off that line as fast as possible with as few steps and few costs as possible. And so it's it's more about a balance than it is about not doing it. And I think that leads back into the experience and the things, but there are some hard and fast rules if it takes a special tool, like avoid it unless you can't, you know, that's that's a pretty good one. I hadn't thought about that. I hadn't thought about the tooling side of things because usually what I end up doing is pointing out that a tool is being used and not actually turning it right and then we then we design it out. So I hadn't actually thought about the tool itself being something you should avoid, but that's actually a fantastic catch.
Host 1 29:55
Well, and tools are not necessarily an issue like If you're getting something done at, say, an electronics manufacturer, you can expect that you could call out a number two screwdriver, and there's a really high likelihood they'll have that right. But some weird, like, I don't know, star shaped, you know, driver. Yeah, you're gonna provide that. And you're gonna provide that plus extras for when they lose them or their break or whatever, and be prepared for that. Yeah,
Host 1 30:23
That's absolutely right, they the tools will disappear. For sure. And, you know, the to be fair tooling can extend beyond, you know, a pair of channel locks or, or flush cuts or something like that. A programming jig is a tool. So if you can, if you can avoid the need for a programming jig, do it. So one really good way of doing that is reading your spec sheet, like read the spec sheet, at least on the arm controller or the processor you're using, because that dude almost certainly has a UART bootloader, or an i squared, C bootloader, or USB one, or both, or all three. And if you can, if you can, batch in on a pre existing thing, you don't need JTAG hardware, you don't even need anything like that. And I'm sure people would argue with the JTAG side of things. It's faster. Yeah, but not if you do it, right. I mean, you can do a UART programming just as fast as you can do a JTAG without all the overhead.
Host 1 31:15
Well, and every time I've messed with JTAG in production environments, those 10 pin little tiny connectors get destroyed so quickly.
Host 1 31:25
Yeah, well, they always want 50 panels on the or 50 units on the panel, right. And you're supposed to like jam 10, those 10 pin connectors and 50 spots on a little tight deal. And then you've got like cable routing, the jigs begin to get really complicated, but you can multiplex a you are lying all day long.
Host 2 31:40
Right, right. Going back to what you were saying earlier, we're thinking about the lifecycle of your product in terms of like assembling it, and an Out the door is combining that with what you said earlier, for that, which is thinking of the entire lifecycle of the customer using it an RMA s, and how you handling that, in your special assembly. If you're if you're, if you can afford basically, if someone if one of these things breaks, and you can just throw it in the trash can and give the customer a new one, then yeah, you don't have to worry about ever taking it apart. But that's there's only a few companies out there that do that.
Host 1 32:21
You know what, though, there's something that people don't usually think about. So you find let's put a battery in there. Let's put a primary battery in, and we'll just toss it when it's done and make this a reusable product or re purchasable product, right. That's our business model. Okay, that's awesome and great, until some city calls you up and is like, Dude, we have 200,000 of these in our landfill full of batteries come get them, then you right, you need to think a little bit ahead of like, so it's not just your product lifecycle. It's its death as well. Can it be recycled? Should it be recycled? Should it should it even like? Should we have put a rechargeable lithium polymer battery into a throwaway device? Or should we pick some other way of powering it? Or should we not made it throw away in the first place? So there are some worldly things that can come back and really bite you in the ass from a corporate perspective. You don't want to be you know, a fortune $105 billion, you know, a year company, that that the EPA finds, you know, all your shit and a landmine somewhere. It's like, that's not that's not it. That's not the slot for disposing that, but you'll pay the fines and the recovery and then you wish you hadn't put you know, you had welded the thing shirt or whatever the case may be.
Host 1 33:32
You know, that's, that's something that that is not thought about very often is, let me see DF R or d f s, which is divided designed for repair or designed for serviceability.
Host 1 33:45
Yeah, yeah, really, the design for serviceability actually, is probably a more important thing to talk about when you're talking about RMAs. Because if you design your product in a way that requires an RMA, that is way more expensive than well, like, so blend that in special assembly, if you're gonna get more RMA is and then your cost for having a breakaway cable so they can send you back the front panel instead of your whole washing machine. Right like something like that. You definitely there's there's still some hard and fast rules that you can kind of focus on but there may be a good reason to break away from from some of those. If you look at the baby stage, your products, the prototyping, the completion, and the consumer usage, and then the returns and the final destruction of the product. And if you're responsible for it, certainly countries if you if you're going to be international, this this scope gets a little larger, right because Europe has different destruction processes than we do here. Based on the chemicals that are in the plastics, some semiconductors, tons of batteries. Everybody has different rules about disposal of batteries. They're all generally the same but, you know, destruction in Europe is different than the destruction primary cells here in the States. Thinking about all that stuff saves you these headaches later on down the road?
Host 1 35:04
Well, even that if you have to recover or dispose of the battery, it helps. It helps to design something where you can open it up and get to it.
Host 1 35:12
Oh, yeah, yeah, you know that that is true. You know, like if you want to make a hermetic seal, overmold hot plate weld gaskets and screws, you know, screw bosses and things like that can work too. But if you make the decision to overmold Do you only have one decision to get it out? There's only cut that out, right? If you hot plate weld, it's still kind of the same. You can use a laser and cut it out. But if you put screw bosses in and your primary concern is serviceability and recyclability. If your company prioritizes you know, recycling, then put screw bosses in because screw bosses will always make things easier to recycle.
Host 2 35:48
I'm imagining, like, you turn the device over and says hit here with hammer to recycle. explodes and all the primary components. Yeah,
Host 1 35:57
That's some serious DFS.
Host 1 35:59
Mash mash me. Yeah, that's a good idea. In
Host 1 36:02
Case of recycle,
Host 2 36:05
Battery just pops out. Yeah, batteries are? No, it's actually the funny thing is I do a lot of automotive work, and do a lot of retro modding of vehicles. And that's actually the one thing is I think about when I'm putting stuff together and modifying things is how in like four years, am I going to service this thing. And also remember how I put
Host 1 36:26
It Yeah, you know what you did on the head there. So documentation is not really listed out here quite well. But document what you did and why you did it and how the assembly process works. Don't just get through the first batch and think you you're out of the weeds, right? Keep track of it. Basically, it works like this. Like if you run into a problem, don't solve it, like document it first, and then start your solution and then document the solution. If you start with the documentation approach, you can always come back and solve the problem later. But if you don't, you'll you'll have that problem every time you order.
Host 1 37:01
Oh, come on. That's no fun. Really. It's almost
Host 1 37:03
Like I've done that a couple of times. Maybe? Even Maybe you just haven't done it enough. Yeah, that's
Host 1 37:10
The problem. I want to get to the solution you give me
Host 1 37:14
I'll be honest, when I'm engineering, I am not the documentation. Dude, I am I am about a Fender when I'm doing when I'm doing DFM, like the whole point of it is to find these little like nuances and loopholes and making it faster or serviceable. And documentation on DFM is a little bit easier, especially if the the engaging company brings a project manager which is not always the case but
Host 1 37:37
You have someone to debug you if they have a pm or
Host 1 37:41
Someone to translate for me right i rattle off a whole bunch of nonsense words and make up some stuff and and then they just come back and get clarity off the off the video recorder or voice recorder or whatever. So right under documentation, you know, I mean like change logs, absolutely keep track of where you were at what you were doing and make a revision program right? So that if you need to make a version 1.086 Again, like you can you can fab it with the notes and if it's five years ago, you can still bring it back to life and manufacture that thing. You know, the auto industry does a pretty good job of of documenting and leaving that sort of stuff. So that is serviceable. And so if I mean if you need examples, use use the automotive industry go by a Chilton or download a Chilton manual and look at those and they'll show you how to assemble it what the theory of operation is why you put this in that place? Why you decided on screw bosses instead of you know overmoulding So keep track all that stuff because even if you remember it, you're gonna forget it. I forget all the great ideas I had all the time.
Host 1 38:43
So you mean it's not just buried in an app note somewhere that they that they put somewhere deep on the website?
Host 1 38:48
Well for minor for sure. They're buried somewhere. I haven't deleted anything ever. But
Host 2 38:53
Oh man, that that design for serviceability is bringing me back to that project earlier this year. Or is it last year? It was last year? Oh man. It was the is the shark. The pool vacuum Steven. Oh, yeah, yeah, so So Chris, this is my parents pool vacuum broke. And is this like little rover that's like, you know, goes underwater and sucks up everything. And the motor unit stop working well in the manual. It has you know, the exploded diagram and shows what the motor and what the part numbers and it says not serviceable. And I said hell no, it's not. And I unscrewed it and popped it open. And what they meant by that is that there was a seal on there that just won't go back. So that seal got replaced by about half a tube of silicone caulk. It's still working
Host 1 39:43
Today. Yeah, that's funny. I do the same thing. I tend to anything that I can get a hold of it. It doesn't. I've run into that a couple of times when what they mean by not serviceable is not that you can't find the parts and do it yourself and see the scorched board and replace the component but physically if you disassemble this It's destructive.
Host 2 40:01
Yeah. And that's the thing is like, because it has screws, like so they put it together with screws. But what happens is that seal just absorbs chlorine from the water and just swells. And so you can never get that seal back into the channel that was ever supposed to go for. Yeah. Now the thing is, they could sold a brand new seal, but they
Host 1 40:21
Did. Yeah, I mean, so that's a planned obsolescence thing I was just gonna bring up right like, if you're, if your goal is to plan obsolescence, your product or parts of your product, then you can actually just listen to this podcast in reverse, right? Yeah, that's great. So I don't know, I but it does play a role in that, like, if you have a goal of that, for whatever reason, if that's your business model is to have some sort of planned obsolescence or version two is how you make your next set of money, right, then you do need to kind of think about some of these things. Because in reality, it's not, it's not like screwing the customer over right, what you're really doing is making a decision to not have an RMA process, you're just gonna build version two and discount it for the customer, roll it forward, or, you know, send them a new one without even worrying about it. So there, there is another path to serviceability, and that is to just shoot them a new device. I don't particularly like that path. But if you've got a good build process, and you can keep your failure rate low, then that may be like if you're building hammers, the failure rate is going to be reasonably low. Right. So it's not a big deal. If you get a few returns, just send them a new hammer. Don't troubleshoot. Yeah.
Host 2 41:30
And so are you come up with hammer? 2.0? Yeah, right, with a
Host 1 41:34
Claw in the back or whatever, then send him that. And so, but there are some, there are definitely some clear caveats to this discussion that I'm pigeonholing out of this discussion, right, I'm talking about the serious offenders who think that they're going to be able to manufacture something and then really need help, because their product has so many manual steps that automating it would be cost prohibitive.
Host 3 41:56
You know, real quick back on to change logs, something I was I was dealing with just a few weeks ago. So in my opinion with change logs, I, whenever I make them, or I deal with people that make them like, I feel like in so many ways 5% of the change log is for me. And then 95% is just as a cya for me to tell everyone else what happened? Like the 5% is like, oh, yeah, I need to remember what I did. But you guys have probably run into this, like the golden age of service manuals, like you get an old stereo or something like that. And it was, it was hand written by somebody. And then you turn to the last 20 pages, and it was every revision they've done. And it's all hand drawn, like a through hole resistor with a wire that's like, go to this trace and cut this one to do that. And you're trying to fix your stereo and look at him like, Oh, my God, I have to interpret every one of these pages to see if this happened to it. Like, I feel like there's an art to writing a good changelog such that it makes sense. And and that people can read it and interpret it.
Host 1 43:01
Yeah, I think you know, in a manual style situation, that's important. So so when I added change log here to the list of topics, right? What I was originally thinking was my personal change logs for that 5%. So what I what I do in all of my schematics, when I first start one up, even if I'm just gonna throw the schematic away, is my first page is always a page that I label notes. So an eagle, I do it in Altium, I do it like, just create a notes page. And then I just create a change log. And anytime I open that file, I go into the note page first because it's first step, and I type what I plan on doing in there, why am I in this file? Right? I just changed. Oh, 40220805 or whatever. And then it just like if you get into that habit of of keeping track of what you're doing and why then you won't have to remember that's really what I was talking about. But yeah, I hadn't thought about someone else trying to consume those notes. You know, back to the whole fire burning the building down with a battery charger. If he had kept good notes, and I'd read through him and he'd been like, I didn't bother to do overcharge protection. So make sure you shut this off after one hour a charge time. I would have gone and turned it off. But no notes right? No detail, no nothing. And at least somebody's half assed attempt, keeping track of what they were trying to accomplish is better than just having nothing for
Host 1 44:20
Sure. For sure. Yeah. Well, and even though you may think that you're writing something for you to read, it may be read by someone else, you know, especially if it's a critical situation where all the units are coming back from the field, well, then you're really hoping that you have those notes written correctly.
Host 1 44:38
Yeah, and not only that, but so our engagement style can be a little bit weird, right where we offer staff augmentation. A customer can have their product fully developed and built and turned and they've made you know 10s of 1000s or hundreds of 1000s of units. And then they want to make a minor change. So they'll engage with a third party engineering From like ourselves because they didn't bother to keep staff they were making their product. And having a little bit of context about why you removed your bypass capacitor or ignored the DC decoupling recommendation from the spec sheet, like a handful of notes for the dude who's going to take over your project? Like do him a favor, right? Put a few little don't leave all those Easter eggs just staying around for
Host 1 45:22
Him to find Easter.
Host 1 45:25
Yeah, PCB easter eggs, man, if you found when you know, for sure. So yeah, anyway, that's, that's definitely it's interesting to talk to you guys. Because everybody's view on what a change log is or what DFM is, or what industrial design is ends up being different. And I hadn't thought about the change logs being a part of the actual end user detail. But I know there's firmware that I've written, the end users are out like in, you know, GitHub or whatever the end users go out and read. And I definitely didn't document it well enough.
Host 1 45:56
Yeah, it's hard. It's it's almost as much work as the development. Well, it is the development if you think,
Host 1 46:03
Yeah, if it's if it's a paid important gig, I almost always pseudocode first, so my pseudocode becomes my notes and my documentation, and especially if it's a large complicated, like state machine and firmware or something like that. Pseudocode is your best friend, but it's still the same statement, right? Make your notes first. Do your work.
Host 2 46:23
Yeah, that's actually I've been doing some code at work. And I'll usually draw out or write out what I'm going to do first, before I start even writing characters into that Python script, right? Is doing that first. So that at least when I can look at it be like, okay, it needs to do this. These are the inputs, and these are the outputs, that's like bare minimal for software development notes.
Host 1 46:49
Yeah, the one exception, I would say to that is fit testing. So occasionally, somebody will call me up and be like, hey, I need you know, to dissipate 250 amps, you know, 50 volts into, you know, this motor. And, you know, you go back and look and the details of the component in the device are not, are not completely adequate and capable for it. I just lost my train of thought, why was it going down that path? All right, next question. I lost, I lost my train of thought on that one.
Host 1 47:22
Well, I'm interested now, have you had a customer that has given you multi 1000 watt motor control?
Host 1 47:29
Yeah, I mean, like, like, we don't have that. So yes, I have one customer. And this was a mechanical thing. There is a design for like, it's planned obsolescence, but it's in a really stupid location. So power substations that will be distributed around your city, right, they have these mechanical arms that can be pulled down and then disconnect the high voltage lines, right. But there's a stepper motor that is attached to it, that actually does the articulation of that arm, through a neoprene washer that's designed to fracture after three or four cycles, like iterations of opening and closing. I don't know why they did that. I don't know if it's on purpose that they have to touch that or if it was just like somebody just shoehorned the neoprene washer into that thing or what the heck was, but we we printed out using a bunch of different we've got a Formlabs 3d printer here. So we went through a lot of their different high temp and industrial resins, and printed it in like five or six different ways and rebuilt the gearing mechanism inside these industrial arms. And they're using them in production now to basically save their servicing. So when they get a failed part, the substation still sends them in the gearbox. And what they do is drop in the new fixture and replacement and send it back out and then they never get them back again. They're starting to get RMA calls, where they're wondering why their parts haven't broken yet. Rather than actually ask him to send it back in and what we're gonna do about it, they'll call up and be like, Hey, shouldn't Shouldn't we have sent you like 10 by now?
Host 1 49:07
And I suppose that's a good problem. Yeah,
Host 1 49:09
So that was more on the mechanical and but yeah, there occasionally you get, you get some crazy, some crazy requests like that. The mechanical ones tend to be more weird than the electrical ones. Like we've got, we've got some some really weird requests for like bone cutters, crazy shapes that like go into your shoulder and, like spread the skin as they're drilling in and then can like clean out the cavity, what to do a shoulder replacement, and the designs are like, elegant. It's really cool to see how they make those bits fold into this little tiny incision that would go into your knee and then spread out like an umbrella and cut you to bits and then fold back in and come out. Really, really cool stuff on the mechanical side. Crazy, gross, gross and crazy.
Host 2 49:51
I want to talk more about neoprene washers, fracturing
Host 1 49:54
Neoprene washers fracturing his list disgusting. Yes. Yeah,
Host 2 49:59
It is interest doing that that would have been bizarre that must have been a design oversight or something. Well, you
Host 1 50:04
Do that but I mean, they're using them everywhere and on like a two to three cycle thing like across the country. They're breaking all the time. So I don't know if it was like, forces them to plan maintenance and gets them in and what maybe that's for carbon clean off or something. Or we
Host 2 50:19
Could be or we are doing, you know, government contract conspiracies.
Host 1 50:25
I was just about to say potential nefarious acts. Yeah, well, okay, now,
Host 1 50:29
So I'm going to have to process that I don't usually on the electrical I go pretty crazy on the conspiracy theory side, but I'd never thought about it in our field. So now now, I'm gonna have to actually put some thought behind that.
Host 1 50:43
I mean, to design something to break the electrical grid or to break regulate on the electrical grid, it will guaranteed sale. Like, you're guaranteed, like, that's not something they're gonna let you know, sit around,
Host 1 50:55
Start watching my back, make sure I don't get like sniped on the way home for fixing the problem.
Host 2 51:01
You got it. You got to find what Senator is in the district. Yeah, yeah, that's let me what Senator Did you just make?
Host 1 51:12
Yeah, no kidding. Yeah, I didn't thought about that. Now. Now. I'm sitting here wondering if there was an actual design reason, see if they, if they put the notes down, that we would have known why they why they purposely made that break. Exactly.
Host 2 51:23
Well, because neoprene is very good at you know, water resistance and and slippery, right? And yeah, keeping moisture out. Yeah. Sounds and vibration stuff. So it's like, why?
Host 1 51:33
Yeah, I don't know. I mean, it's, it should have it should have been fine. I mean, they just needed to make the plastic like a tiny bit harder. But basically, when like that solenoid kicks over, when the actuator moves, it reaches over and slams against it. And that's why they're shattering their fracturing is it's actually like a very fast motion to kick that arm and pick it up and move it. And I just can't imagine why they wouldn't have I mean, they knew that that impact would happen. It has to been planned. That's all I can figure out is that some guy was just like, I'm gonna screw these guys over, I'm gonna get a second. I'm gonna get a second turn on this PC on this board.
Host 2 52:09
No, that's actually no, that's or it's, or it's the same company who sells them also services. Yeah, that could be I actually don't know that. And they will also the design or the service or so they're saying you have, you know, these are big industrial things. So if you know you have to service them after three or four uses that's normal in quotes.
Host 1 52:28
Intolerance. specified to do that. Yeah. Yeah. Yeah, that's crazy.
Host 2 52:36
I'm gonna wrap up this episode. Yeah, thanks. So yeah,
Host 1 52:40
Sure. So that was the Mac Feb engineering podcast and I was your guest, Chris Carter.
Host 2 52:45
And we're your hosts Parker, Dolman
Host 1 52:47
And Steven Craig. Let everyone take it easy fixes and we'll have
Host 2 52:51
Chris Carter back on and next couple weeks.
Transcribed by https://otter.ai