Outer Layer Imaging w/ CAM Engineer Dave Wilcox

CircuitHub CAM engineer, Dave Wilcox is back on the show to teach us more about the PCB fabrication process. In our last episode with Dave, we went into the fine details of drilling a PCB. Today we move on to the next step Outer Layer Imaging. 

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Transcript

Chris: 0:09

Welcome to the Pick Place podcast, a show where we talk about electronics, manufacturing and everything related to getting a circuit board into the world. This is Chris Denny with Worthington

Melissa: 0:17

And this is Melissa Hough with CircuitHub.

Chris: 0:19

Welcome back Melissa,

Melissa: 0:21

Welcome back Chris.

Chris: 0:23

good to be back. I know, I think we're recording kind of late, right? So we're probably gonna miss a week. Is that right?

Melissa: 0:30

Depends on how quick my editing skills are.

Chris: 0:32

Okay., I, time is a blur for me. It's an absolute blur for me, as we discussed in the previous episode,

Melissa: 0:40

hopefully, hopefully pending my productivity, we will be back on schedule.

Chris: 0:44

oh, beautiful. Wonderful. Yeah, so good to be back. When we talk about recording something, it makes me so anxious and nervous cuz I know how much stuff I have to get done. And I'm like, I, I don't have time to record, but at the same time, this is like one of my favorite things to do. So gotta gotta make time for it, right?

Melissa: 1:03

And it's the listener's favorite thing to do is listen to you talk.

Chris: 1:06

Well this week they're not gonna listen to me talk very much. They're gonna listen to our friend Dave talk. We got Dave Wilcox back. Welcome back Dave.

Dave: 1:13

Thanks for having me.

Chris: 1:13

Yeah, yeah, yeah, absolutely. We'd love to have you. Again for listeners, perhaps you're new to the show. Go back and listen to some of the previous episodes where we're marching our way through the PCB fab process with the world's foremost expert in PCB Fab. Is that correct, Dave? Is that, is that, I think I read that on your Wikipedia page.

Dave: 1:32

Someone put that in there. That's not, not my, that's not my writing.

Melissa: 1:37

Well, at least at CircuitHub, he is

Chris: 1:39

That's right, that's right. For sure. Dave is our, he is our chief guru in charge of PCB Fab. And yeah, I will say like, for listeners who, who may not be aware, most of the time folks like myself who are working on the assembly side don't really get a chance to work very closely with people like Dave on the fab side. Usually somebody like Dave will be working for our supplier and not directly with us. And so you have kind of a disconnect of their needs versus our needs and it makes it complicated to understand how my requests. His life difficult and how his requests make my life difficult. But then when the, you, the two of you get to work really tightly together I, I don't know. I think magic happens. I, I've really, I've really, really enjoyed, like, I love having Dave and bouncing ideas off of him and, and trying to work through complicated processes. It's, especially with some of the stuff we got coming up, right. Dave , we got some fun stuff coming up. we got, we have some customers asking for some big, big, big, big orders, like huge volumes that we have no Right. Getting involved. I say no. Right. Getting involved in, we just have to plan for it and prepare for it, and I think we'll execute it just fine. But it's, it's interesting where. Like minor annoyances on a 50 piece build, become major issues on a 10,000 piece build major, major issues. so pcb fab and assembly have to work really closely and design, to be honest, right? It design has a huge part of it. If, if there's something in the design that makes life difficult, we gotta talk about it and revise the design, or we gotta spend lots of money on a custom solution to make the design work.

Dave: 3:29

Yeah. It's gotta make things repeatable. If you make it repeatable. PCB fab doesn't have a problem. The new one have any problems.

Chris: 3:35

That's it. Yep. And I'll tell you what, had we not gotten this new equipment, there's no, we, we would've run kicking and screaming to the hills when customers came to us with these kinds of volumes because there's no way we could have pulled it off. Like just the first past yields we're getting out of these machines. I, I've never experienced anything like it. It's just absolutely incredible. Very, very exciting. And our poor rework girls, you know, they're just, I mean, they're having to, you know, having to find stuff for 'em to do. No, I'm just kidding.. There's plenty for them to do. But yeah, it's been it's been great. Very exciting. Very exciting. Well, let's get us up to speed. Last time we had Dave. We talked about drilling and boy howdy. Did we talk about drilling? We went into depth on drilling cuz Dave might be the world's foremost expert on drilling

Dave: 4:27

I can talk about drilling PCBs all day,

Chris: 4:32

That's awesome. So you're still exactly right. Oh, I mean, isn't that the truth though? Like, I could talk about the SMT process. Like we could literally have a show just about the SMT process and I could endlessly. I mean that Melissa, here's a new podcast idea. Sleep Stories. Sleep stories with Chris Denny about the SMT process. And all I do is like, with less enthusiasm, just speak about the SMT process. And I think, I think we should do it. I think we should do it. yeah, I think people will appreciate, you know, better sleep with Chris and Melissa

Melissa: 5:07

Especially her grandma.

Chris: 5:09

especially my grandmotheer. Alright, so, after drill we wanna get into kind of like what is gonna happen next to our PCB and Mr. Dave, what happens next to our PCB once it's been drilled out? And, and what do they tidy up the boards from drilling? Do they have to like, blow out any oh, what was the word you used? What was the uh, swath? Yes.

Dave: 5:33

Swarf, let's just call it, let's just call it Deb

Chris: 5:37

Debris. Yeah. Yeah. Like does this debris build up? Is there like a cleaning process? The boards go through after they get drilled or anything.

Dave: 5:44

it should, it should be taken out by the vacuum monitor drilling machine. But the, the, but you still get some left in there. You get little strands of fiber. That will hang in the hole maybe. Especially if, if your drills get blunt, they don't cut cuts cleanly that has to be cleaned out. But the boards will go through a cleaning process after drilling. So, so make sure that there's no burrs they get brushed and they might have to go through a de-smear line. So if there's an smearing of the resin in the.

Chris: 6:14

A de- smear line.

Dave: 6:15

Yeah. So if, if, if you melt plastic and you push it across your table, it will smear all over your table.

Melissa: 6:23

Mm-hmm.

Dave: 6:25

Well, that happens in a hole if it gets too hot and the resin melts, it will smear across the copper interconnections on the inside.

Chris: 6:34

Oh, so, but this is a much later process. This isn't immediately after drilling.

Dave: 6:38

It will go from, from from the drill shop straight to this process. Yeah.

Chris: 6:41

Oh, it will? Okay. Yeah, yeah, yeah.

Dave: 6:44

Yeah, so, you'll have etch back as well, and etch back takes away some of, some of the substrate. So the, the copper interconnections on inner layers will slightly protrude the edge of the hole, so you get a better connection when it's plated through

Chris: 6:59

etch back.

Dave: 6:59

etch back it's called etch back

Chris: 7:02

hold on. You've lost me, right? So hang on a second. The, the, let's, let's talk about the smearing first. So you're, you're talking about Okay. You, you can smear plastic on a table. I get that. I, I understood that. But you don't have any plastic on your board when you're, when you're doing the.

Dave: 7:18

but it's, it's epoxy resin in glass, so the, the epoxy melts

Chris: 7:23

right from the, from the heat of the drill.

Dave: 7:25

if it gets too hot. Yeah.

Chris: 7:27

Oh, no kidding.

Dave: 7:29

So to, to make sure you're getting a good connection for, for your placing through your hole to the inner layers. You have to, you have to clear that, that that epoxy resin off the hole, off the

Chris: 7:43

Okay, so, so if I understand correctly, Eventually we're gonna get to plating. And what happens in plating is that, that whatever magical soup that you put it into, it wants to adhere to the walls of that hole. But if you have any epoxy resin smearing those holes, then it won't wanna adhere to it.

Dave: 8:05

if it smeared over the copper,

Chris: 8:07

Yeah.

Dave: 8:08

the, the copper plating will adhere to the The smear, the which is insulation effectively.

Chris: 8:16

Yep.

Dave: 8:17

you won't connect to the, to the copper plane or copper connection on the inside.

Chris: 8:22

gotcha, gotcha. Okay. Fascinating. Wow, that's fascinating. Okay, so you, so, what is that process called again, when it's cleaning the, it's, it's just a smear cleaning or something. What, what'd

Dave: 8:32

just, it's these de-smear it goes through a series of tanks and it's got potassium.

Chris: 8:39

Ooh, now we're talking.

Dave: 8:40

And that's a whole dirty, smelly process as

Chris: 8:44

Is that the thing that the Joker fell in, in the first Batman from the

Dave: 8:47

I don't know,

Chris: 8:52

Isn't that what they did? I swear, I, my, my memory is pretty foggy on that, but I'm pretty sure in the Batman from the nineties, the Burton was, was his something. Burton

Dave: 9:00

Did he, did he all bubble up and dissolve?

Chris: 9:03

Yeah, I'm, I swear. Didn't they like, toss him into a vat of like chemicals or.

Dave: 9:07

Yeah. That's probably sulfuric acid or the salt, but yeah, it's, it's nothing like that . It's,

Chris: 9:14

So . Okay, so that's fascinating. I didn't realize it. So, so it goes through this, it goes through this process of cleaning, cleaning the resin off the, off the inside of the holes if there is any resin on the inside of the holes.

Dave: 9:25

Yeah. It go through either a brushing process or a chemical clean,

Chris: 9:31

Okay.

Dave: 9:31

which will take the stains off the copper. If there's any stains caused by heat.

Chris: 9:36

And you're talking about copper on the inside of the holes, or you're saying anywhere?

Dave: 9:39

On the outside, on the outside. of that point. So, yeah, so it basically, it's cleaned in the holes, outside the holes,

Chris: 9:48

Yeah.

Dave: 9:48

Before it goes into there's, there's two ways. You can put electroless copper in the hole or you can put you have that black hole and. Dms E Direct metalization

Chris: 10:00

So electroless copper, I, I feel like I'm more familiar with that term, but I thought that was a finishing a finishing term? No. Oh, okay. What's electroless copper?

Dave: 10:09

electric. Copper is a two or three micron film of copper in the hole. Which gives the. Electro plated, copper, something to adhere to but you can, that's been superseded by a DMSC

Chris: 10:27

Okay.

Dave: 10:28

line.

Chris: 10:29

the it, am I hearing you right? D M S C.

Dave: 10:33

Let me check. Is it dmc? I'm sure it is.

Chris: 10:36

Direct

Dave: 10:37

Or it,

Chris: 10:38

something. Something.

Dave: 10:39

yes, it's. It's, it's dms e direct metalization.

Chris: 10:45

Direct metalization

Dave: 10:47

Or black hol street. But it, it's a, it's a

Chris: 10:49

black hole. They call it black hole.

Dave: 10:52

Because,

Chris: 10:53

I like it. Now this is all I want. Now I just want the black hole boards.

Dave: 10:56

when you hold it up to the light, all you see is black. The holes are black inside.

Chris: 11:02

Really interesting. And is that because it's just what's some carbon in it or

Dave: 11:07

It is a, it's a polymer polymer.

Chris: 11:10

Yep.

Dave: 11:10

coating that again, the copper, electro copper can adhere to that.

Chris: 11:18

Yeah. Yeah. Interesting. So it's, it's just a It's just a different for lack of a better term, substrate in on the inside of the holes that the later, the later process, the plating process can stick to,

Dave: 11:30

Yes.

Chris: 11:31

saying? Yeah. So you can either do electroless plating or you can do direct metalization. And, and if I understand correctly direct metalization is kind of the, that's the new it process.

Dave: 11:41

Yeah, yeah. It, it's conveyorized and it, it can take, it can take literally two minutes to, to run through this conveyorized piece of equipment.

Chris: 11:51

Fascinating.

Dave: 11:52

and the electric plate in line is 30 foot long with load of tanks, rinses, sulfuric acid.

Chris: 12:01

Oh man. So you're

Dave: 12:02

Palladium catalyst. Yeah. Yeah,

Chris: 12:05

everything. Fresh water probably. How do, you don't have to answer this if you don't know Dave, but I'm gonna put you on the spot and we can edit this out, but how, how do things like this get invented? Is there, like, is it universities, are there businesses, like, is it foxcon? Just like, we need a better way to do this. Like how, how, how does it go from this electroless plating process is so necessary? There's no other way to do it till somebody else is like, yeah, here's a better way,

Dave: 12:32

A lot of these things happen by chance, someone's probably like, well, I've got this, this material coated in this polymer, and I've, I've managed to plate copper to it. Well, maybe, maybe we could use that. It just, just starts with a seed, doesn't it? Sorry.

Chris: 12:49

Yeah. Find a way to do it in a pcb.

Dave: 12:52

The black hole. Technology's been around 20 years.

Chris: 12:54

Oh, it has? Okay. So like since the nineties or early two thousands.

Dave: 12:58

Nineties. Yeah.

Chris: 13:00

I hate to break it to you. It's 2022, so it's been over 20 years. It's been around for Dave

Dave: 13:04

Yeah. So, so only just over 20 years. If you go to 1999

Chris: 13:10

I know, but like I, I think of probably like you, Dave, I think of the nineties as like not really being that long ago. Like if somebody said they had like a 1999 car, I'd be like, oh, okay, that's not too old. Then I'm like, wait a second. No, that's a 23 year old.

Dave: 13:23

Yeah.

Chris: 13:25

That's just, I don't know, that's how my brain works. But yeah, so I I, so I get it. You, I think about, you know, when you mention sometimes these things can happen by accident. I don't, I don't know if this is apocryphal or if this is true, but apparently that's how penicillin was discovered. It was kind of an accident, like he just left a window open and then all of his bacteria was dead, and he was like, Hey, what happened here?

Dave: 13:47

Well, it, it the, the, the myth is he had some bread on the side and it, it, it grew spores and all this sort of stuff, so I, I don't know it. Yeah.

Chris: 13:59

Like I say, I think it's apocryphal, but it is, it is fascinating either way, how sometimes these things just happen. Well, it's like, you know, in our industry we have okay, so you have double sided circuit boards. I hate to break this back, bring this back into assembly, but inventions happen in very interesting ways. So in our industry we have double sided circuit boards, and. To support the bottom side of a double sided circuit board, you need to have pins set up where they're not gonna make contact with any components. Otherwise, you crush the component under the force of the, of the process. So like when you're stencil printing, you need to support the bottom of the PCB so that it stays nice and flat. And when you come over with the stencil, you have a nice crisp, clean print over it. If you, if it was sagging, you'd have a giant mess on your hands. They've come, they've, you know, people have invented these, these conforming like sort of, ah, it's not, it's not, it's not exactly like this, but it's something like a bed of nails basically. Right? Like you have a conforming, you have a nest of pins that conform to the shape of the bottom of the pcb and it supports the bottom of it. Well, that's, that came out of somebody like myself who was struggl. With putting all these pins inside his machine and he said, there's gotta be a better way to do this. And, and

Dave: 15:13

Spring. Spring load pins.

Chris: 15:15

Yeah, exactly. Spring loaded pins a better way to do it. And it's just, it's cool how these, and now there's, there's a whole, you know, there's like three, four competitors doing this now. Right. And I met, I met the guy who was. If he wasn't the one to invent it, he was one of the earliest ones to invent it. And and he was telling us his story about, it's, it's, it's really fascinating how these tools develop and evolve from people trying to solve their own problem and, and having an enormous impact on the world because the amount of time it saves us not having to set up all these pins, the amount of chemicals it saves Dave not having to run through an electroless plating line. It's, it is super cool how these things advance. It's one of the things I love about manufacturing is. The, the improvements to efficiency is just so fun to see

Dave: 15:59

Yeah, but you still need electroless copper sometimes.

Chris: 16:03

sometimes. Yeah., so what, what would the application be where you, you it, it becomes, you can't really do the direct metalization.

Dave: 16:10

If you're doing small hole microvias you might, you might want to use it. Um, it's just more robust

Chris: 16:17

Can you, can you do both? Can you do some electros in some direct metalization?

Dave: 16:22

when you get down to microvias less 0.1. It might be a bit more difficult, so the electroless copper might be the way to go.

Chris: 16:30

would you just do the whole, that whole PCB in electros or, or would you do some of it? Direct

Dave: 16:35

No. No. If it goes down one or the other,

Chris: 16:37

Okay. Okay. Okay. Yeah. And, and is that gonna have, like if you're a designer Are you gonna have, when you think about this process are, you know, is this an area where, what am I trying to get at? Okay. I'll give you an example because this is just the, the, the industry that I know of, right? We have, we have a customer, great customer, long, long time customer. I. Don't have permission to talk about him or his product, so I won't, but I'll just, he has this motor controller chip on his board that gets very warm. Okay. And, and he talked to us recently and said that, Hey, you know, I'm getting about a 7% failure rate on my boards from you guys. We were shocked, we were shot close. We never would like a 1%, maybe, usually less than 1% is what we're expecting. 7% is astronomically high for us. And we said, whoa, man. We investigated it. And it turns out due to some of the other components in his design, we had to use a particularly thin stencil. To, to process it properly. But by making that sensor so thin, we were starving this one chip of getting sufficient solder and, and conducting enough heat away to make it operate properly. But once we discovered it, we, you know, we have all these tools, we have to, to improve that. So now whenever he submits an order, he makes sure to call out, like, Hey,

Dave: 17:56

Yeah.

Chris: 17:56

requires a certain process. You know, I know you guys normally follow your own process and your own best practices, but this chip is unique and we need you to do something special for it. Is there anything about direct metalizatiion or the electroless plating process where somebody might be like, Hey, I know you could use

Dave: 18:14

Um,

Chris: 18:14

or direct mentalization, but because of this I need you guys to, you know, use this different process.

Dave: 18:20

the PCB fab will know, they will know.. If they've used the wrong one, then the, the boards will fail at test. They won't, they won't have a connection. Cause they've got no copper in the holes and so they will fail anyway, so they'll know if they've used the wrong one.

Chris: 18:37

So there's gonna be an enormous cost savings to the PCB fab and, and potentially to the end user. If, if they, if a PCB fab is reputable by going direct normalization, but then if they have to go electroless, it's gonna be more expensive. So, and, and, and the reason they'd have to go electroless is cuz they have very tiny drills. Is that correct?

Dave: 18:53

Yeah, my, I, yeah, yeah. We mechanically drill as we said before, down to 0.25. Anything less than that is normally done by laser and

Chris: 19:04

laser. And so those are gonna be electroless. So like if it's going through a laser, it's going through electroless.

Dave: 19:09

Yeah.

Chris: 19:10

Yeah. Cool.

Dave: 19:11

Yeah. It's a more proven and reliable process. Been using it for like Decades. and we know what he does.

Chris: 19:22

Yeah, yeah, yeah. You just gotta , you just gotta control the, the speed of everything because you don't have a climate controlled building. It still cracks me up.

Dave: 19:30

Yeah. Well, you do.

Chris: 19:36

blows my mind, man. Blows my mind. Only in England only.

Dave: 19:40

A copper etch etchese differently than the older, the older the etch gets because it gets more copper into the etch it doesn't etch efficiently. And it's the same with temperature. If the temperature arises, if it's a particularly hot day, then you have to change the speed, the convey speed of the edge.

Chris: 20:02

That, that just blows my mind. It just blows my mind. But you guys know all that. You know how to deal with it and you know how to use it, and you, the end product comes out the same way. That's

Dave: 20:10

Oh.

Chris: 20:10

right?

Dave: 20:11

My favorite saying is we build PCBs in spite of our equipment. Sometimes

Melissa: 20:16

Ha.

Chris: 20:19

Yes. For listeners who aren't familiar with Dave is talking about his old company, not, not the current fabs that we use. Yeah. The current fabs we use, I believe, are They're climate controlled. Yes. And, and computer controlled everything and monitoring and yada yada yada. We, we, we work with some really nice fabs. I, I gotta say, I've been very impressed with the boards we get from our suppliers. They've been top notch. Okay. So you, so that's kind of so that this, this plating process or direct mentalization process, I shouldn't call it plating electros, what was it called?

Dave: 20:47

It is, it is illustrating electric copper.

Chris: 20:50

But it's not the, it's not the major plating that gets done in the later process, the electroless copper or the direct metalization. So after a cleaning, it goes into that process. And that's kind of the one two punch after drilling, would you say? Is that correct?

Dave: 21:03

Yeah, it gets, it gets cleaned. Go through electroless copper. electroless Copper can take 40 minutes to run through a line. If you go, if you do have DMSE then it will, it will take five minutes.

Chris: 21:17

Holy cow. That different. Wow.

Dave: 21:19

difference. So from there it can go into outer layer print.

Chris: 21:25

Okay. Outer layer print. that?

Dave: 21:31

so it is exactly the same process as the inner layer printing process. you're doing it on the outer layers..

Chris: 21:40

Oh, okay. So that was a few episodes ago. see if I can find, that was a while ago, man. Inter interlay production to the drill shop. So that was episode 29. That's going way back. We talked about inter layer production. So outer layer, outer layer production, our outer, outer layer print. It's the same thing we talked about in episode 29. Except now, now your sandwich is done. You don't have to worry about your sandwich anymore. You, you, you're just worry, worried about the outside or it's like, or it's like a two-sided board, right? If it's a two-sided board, there's no sandwich. You're just,

Dave: 22:16

exactly that. Yeah. So it is gonna go through the same processes whether it's laser imaging or using film. You're exposing it with an artwork. So you put a photo photoimagable film on the surface. You're using either laser imaging, use a laser to expose your pattern, or you are using an artwork

Chris: 22:41

Okay, so I've seen these before when I've been touring. PCB fabs, they have these drawers full of these transparencies with, with.

Dave: 22:51

That's it.

Chris: 22:52

basically a negative of the board of some

Dave: 22:55

Yeah.

Chris: 22:55

And they lay that over the copper and they, they register it somehow. I, I'm sure there's a fancy process for registering it to the, to the board to make

Dave: 23:04

I'm sure, I'm sure every PCB shop's got something slightly different to each other, but Yes. Yeah.

Chris: 23:11

And then they, then they expose the copper to. Some very particular type of light because aren't these rooms usually like yellow? Isn't there like, like they have a different light bulb than most rooms so that the humans can see. Yeah, and it's yellow.

Dave: 23:30

it, it's yellow light. So, if it looks different, obviously, cuz you're, you haven't got any UV light, any blue light at all.

Chris: 23:36

Ah.

Dave: 23:38

So it takes all the UV out cuz you're using UV in your exposure units or in your laser imaging

Chris: 23:47

Yep.

Dave: 23:48

to, to expose the photoimagable film, which is gonna create your pattern cuz your, cuz If you expose it to uv, it hardens.

Chris: 23:59

Okay.

Dave: 24:00

If you just took it out into a normal room, the whole thing would harden and you would just send that with a, with a blank sheet of copper again.

Chris: 24:08

right. We talked about that. On the inner layer production, there's a special film that goes on the copper that changes when you expose it to UV light. Gotcha. Yeah. I, I don't wanna repeat too much because, well, then again, it was like 20 episodes

Dave: 24:22

It was, it was, it was 28 ago. The only difference between inlays and outlays is you, this time you are exposing on an inlay, you're exposing a negative of your image,

Chris: 24:36

Mm-hmm.

Dave: 24:37

your tracking pattern, and on an outer layer you are actually gonna expose. A positive image, so when it comes out, so once it's been exposed, it, it goes through the same, the same developer, developer line to wash off everything that hasn't been exposed by UV light.

Chris: 24:58

Cause, cuz the UV light hardened it so that stuff's staying. Yep.

Dave: 25:02

So anything that's still, that's unexposed will get washed off. But this time you will see if you take it out, out of that room. You'll see a panel which will have a purpleish film over it, and you'll see the copper track, copper tracking underneath.

Chris: 25:22

Mm-hmm.. Mm-hmm.. Mm-hmm.. Mm-hmm.

Dave: 25:24

So, and that's, that is what is gonna get played.

Chris: 25:29

Okay. And the laser doesn't use a transparency, it just directly lasers the, the film.

Dave: 25:38

Yeah, but it's hardening the film where the laser goes.

Chris: 25:41

Whe yeah. Wherever the laser goes, it's getting hard and, and it's it must be slower than, than imaging has to be. Because imaging you do all at once.

Dave: 25:51

Some of the laser imaging equipment's quite fast, but not as fast as. Put it in a drawer for 30 seconds. I'll take it back out of a drawer and then next one,

Chris: 26:01

Yeah. So that, that but, but there's no setup. You don't have to print these films. You don't have to store these films. You, you can switch from job to job to job to job, to job. But you don't have to.

Dave: 26:12

And it's, it's gonna be more accurate.

Chris: 26:15

Oh, more accurate? Yeah.

Dave: 26:17

Oh yeah. You could, you could you could print down to two thou lines.

Chris: 26:21

Oh, geez. Wow.

Dave: 26:22

With a laser,

Chris: 26:24

And why, why, why is that, Dave, do you know? Is is it because the shadowing or something? Because

Dave: 26:29

Yeah, yeah. With a, a film and artwork, a photo tool, you gotta get total contact

Chris: 26:36

Yes. I was almost wondering if you vacuum sealed it or

Dave: 26:39

It, yeah, it, it, yeah. It's normally vacumed between two, two pieces of glass.

Chris: 26:44

Mm-hmm.

Dave: 26:45

But that imaging process, you get a little bit of what do you call it? Refraction.

Chris: 26:52

Sure.

Dave: 26:53

and you get an undercutting of the light

Chris: 26:57

Yeah. Cuz your light, your light is being projected by some kind of a bulb. Right. And that's gonna, that's gonna broadcast not in a perfect line necessarily. You probably have a diffuser or

Dave: 27:07

yeah. Of, of. Of sorts, but that's not gonna be perfect. Like a, like a

Chris: 27:12

gonna be perfect. Yeah. Whereas a laser's gonna, because lasers can get. Really, really small , like, I can't believe how small the apertures are that they're cutting on some of our stencils now. Cause we're starting to get orders for Imperial oh 1 0 5, which is, which is metric 4 0 2. So 0.4 by 0.2 millimeter capacitors and resistors. And the apertures on those stencils are just insanely small and they're cut by a laser. So if they can do it on a.

Dave: 27:43

Think

Chris: 27:43

Stainless steel, they can do it on a pcb probably even more accurately. Cuz I have to imagine that a laser's not as intense cuz it's just exposing some film. It's not cutting through stainless

Dave: 27:52

yeah. Obviously the problems come. You can image a two thou line in a two thou space, but the problem is etching it

Chris: 28:01

etching it. Yeah, yeah, yeah, yeah, yeah. There was, there was one shop I was talking to. Maybe I mentioned them on the show before. I don't know if we interviewed them on the show. We should maybe think about it, but there are shop out in Michigan who they came up with an additive process to do one mill lines

Dave: 28:21

Yeah.

Chris: 28:22

really wild.

Dave: 28:23

yeah, where you are adding a copper on instead of taking a copper away with etching.

Chris: 28:28

Yep.

Dave: 28:28

Yeah. Yeah. I dunno how expensive that process is.

Chris: 28:33

Oh, I don't think it's cheap.

Dave: 28:34

I've never, I've never actually seen it myself.

Chris: 28:37

I think my understanding is they have one customer for it, and I believe it's a defense contractor.

Dave: 28:43

Yeah. yeah. It doesn't

Chris: 28:44

they're the only people with enough money to probably afford it, you know,

Dave: 28:48

Yeah.

Chris: 28:48

Okay. So that's, so, that's fascinating. The, the, I, I guess I didn't, you know, We've talked about my memory on the show before. I, it's, it's, it's all up there, but my forklift is broken. And if this is , if this is repetitive for listeners, I apologize, but I forget these things., I don't, I, my, I don't recall talking about laser imaging. Do you laser image inner layers to, or is that just an outer layer

Dave: 29:14

no, you can you can laser image soldermask as well. Sorry. so

Chris: 29:20

Oh, oh boy. Okay. Yeah, now that's So

Dave: 29:25

Yeah.

Chris: 29:26

Now, now that you've imaged it, then it's going through that process of removing the film where it's, where it's soft, leaving the film, where it's hard what happens next to it.

Dave: 29:37

That will go to the electro placing line.

Chris: 29:41

Okay, so we'll get into plating. I think that's probably a good place to stop right there if you ask me , because I suspect that's, that's a whole other can of worms that we could open right away, huh?

Dave: 29:51

It can do, yeah, again, small house cause problems.

Chris: 29:56

Yeah. Cool. Yeah. So, alright. So Dave, if you've got what we like to do every time we talk about an in-depth topic is we like to give designers a, a takeaway something for them to think about as it relates to this specific design. That, that like, Hey, if you're doing X, Y, Z, it's gonna make this process more difficult. So we talked about the, the cleaning away of the resin. We talked about the the plating of the, of the holes. Well, the. Like the pre plating, I dunno, there's gotta be a different term for that. And then and then the outer layer imaging. Is there anything about their designs that, that, you know, if they're, if, if they do this, it'll make life easier. If they do that, it'll make life more difficult, more expensive, yada yada, yada.

Dave: 30:37

Not as far as those processes go. But, but generally, generally speaking, the smaller the whole, the smaller tracks, the smaller gaps, the harder it is to make. But as far as that process go, that's just preparing the panel to be able to place it properly. Obviously electroless plate is only two or three microns.

Chris: 30:56

Yeah.

Dave: 30:57

IPC standards is a minimum 18 microns.

Chris: 31:01

Of of the finished plating

Dave: 31:03

Yeah. so so there's a lot more placing gonna go on through, through the electro plating, and that's when the small holes can cause problems. And you have to primarily because the tin lead that we use is E. After plating

Chris: 31:23

Yep.

Dave: 31:24

can't get in the hole.

Chris: 31:26

right, right.

Dave: 31:27

mo the molecules, molecules just can't get to the bottom of the hole. It's like putting marbles in a small tube. They'll stick together.

Chris: 31:35

Yep. They'll all get stuck.

Dave: 31:36

You, you gotta shake'em to get 'em to the bottom of the bottom of the tube.

Chris: 31:41

can you literally vibrate the boards? Do you guys do that

Dave: 31:43

Oh, oh, oh yeah. The most primitive method is to hit with a hammer.

Chris: 31:48

come on,

Dave: 31:49

No, I'm not kidding you. The most primitive method is to go along every couple of minutes and whack with a mallet. You have some of these are automatic, automatic like vibrate

Chris: 32:08

yeah,

Dave: 32:08

And you, you have air bubbles in the solution, like to agitate the solutions and all sorts of things. So,

Chris: 32:15

Oh man. Well, let, let's, let's, let's hold onto that for next week. But I will tell you, it, it reminds me of we've got we've got guy works for us who's, who's been in this industry. For, for a long time. And, and he said that, well, so during the reflow cycle of, of surface mount assembly when you're melting all your solder paste, which we talked about in episode oh boy, 11, it's going way back. Episode 11, we talked about reflow the the components if they weren't placed perfectly. In the tin lead days before lead free they would straighten themselves out. They, they would kind of like, once, once the solder melted, they would, they

Dave: 32:54

Yeah, they just, they just settle in through gravity.

Chris: 32:58

Yep. And so, he was telling me how what they used to do is they used to set up they used to set up a stereo at the end of the reflow oven. Playing some like really bassy music.

Dave: 33:08

Yeah.

Chris: 33:09

and they it through to get to get the components to settle even better. I don't know if it actually worked or not, but it sounds pretty cool. I like the idea

Dave: 33:19

yeah. That's, that's a, that's a rather gentle way of bagging a plating rack.

Chris: 33:25

hitting it with a mallet. That's so funny. Yeah, it's just, that's wild. Well, we deal with the same thing. Your, your, your analogy of marbles going through a tube. That's basically what we struggle with on really small apertures on stencil. So when we're doing these like.4, .3 millimeter pitch BGAs trying to pack the so pace through the stencil, the smaller we can make those marble. The easier they'll get through the apertures, but those small marbles get more and more expensive. We have to go to a type four, type five, type six solder paste, and it can be done. It just, it just gets more challenging and we have to go with a very thin stencil. Ugh. I'll tell you what, for anybody who doesn't know, like about circuit board manufacturing and is listening to the show to learn more, the 90%. Every process engineer's time is spent on the stencil. It's like . It is the, it's the, and it's, and it takes about 1% of the overall manufacturing time. Is the stencil print itself? It's such a difficult process. And jet printing. Jet printing is getting pretty good, but it's still nowhere near as good as stencil. It's very flexible, very easy. You know, you can go from, like you were talking about, like with laser. You can go from job to job, to job to job, but it is not more accurate. It is not more repeatable than stencil. Stencil. Still way more accurate, way more repeatable. But the jet printer is getting there. We, we were able to successfully jet print 01005 boards. It was a little heavy, it was a little, little more solder pace than we would've wanted to have seen. But it did it, it did, it got the job done. So, And then you got special reflow requirements with nitrogen. Anyway, it's a, it's a whole complicated thing. This isn't a show about sense of printing. This is a show about outer layer production and the swath off of drilling

Dave: 35:16

Yeah. So yeah, I mean, you haven't, as it comes out outside print, you haven't actually, technically, technically got an outer layer yet.

Chris: 35:27

right. you still have you, you still, well you've, you've gotta wash away the soft stuff and you've, you've got the hard stuff left over and you still gotta do stuff

Dave: 35:35

Yeah, you still gotta plate it. You gotta plate the copper.

Chris: 35:40

Yeah.

Dave: 35:41

So that will go down a series of, of baths and plate for however long, however much copper got a plate, usually about, there's about 45 minutes as a standard, like one ounce. Finished

Chris: 35:58

Do you wanna get into this now, Dave? Or do you wanna hold this for a future

Dave: 36:01

but yeah, it depends if you wanna, we've done outer layer printing

Chris: 36:05

Okay. And this is part of it.

Dave: 36:07

And, but you haven't actually got an outer layere yet.

Chris: 36:09

Okay. All right. That's fine. Let's do it then.

Dave: 36:13

you got an image of an outer layer so to, to actually finish it off. It's gotta the electro plate so you plate in copper. You're plate copper into the holes and you've gotta have 18 marks down the holes. So you are putting, I think it's two thirds on the top or one third in the hole. Some of that, that you end up what you end up with.

Chris: 36:38

Oh, okay. So if. Let's say, let's say you have let's just say 20, just to make the math easy. Let's say, let's say your walls are 20 micron thick. Then you potentially have 40 microns thick on the, on the surface.

Dave: 36:51

surface. And that's basically a one ounce. If someone asked for a one ounce, outer layer, that's, that's what the, that's what they would get.

Chris: 37:00

Fascinating. And again, I know we talked about this before. Where, why don't they just call it the thickness? Why do they call it one ounce ? I don't.

Dave: 37:10

it's, it's,

Chris: 37:11

It's gotta be a legacy thing.

Dave: 37:12

but it's the amount of copper plated. On on a foot of material in an hour, I think it is. So like that? Yeah,

Chris: 37:21

yes, It's some super bizarre calculation that rather than just calling it a particular thickness, they call it one ounce. Yeah. It always drives me crazy.

Dave: 37:31

I think if you take that copper off, it actually weighs an ounce. I don't, yeah. Yeah.

Chris: 37:36

Yeah, that's my understanding too. Yeah, that's my understanding too. And, and when you're doing this plating, so is the material that the film that is left on the pcb, is the copper attracted to that? Is that why it no. Opposite.

Dave: 37:53

All right. So, so the, the film will be again, if you, if it's just a a one ounce board

Chris: 37:59

Mm-hmm.

. Dave: 38:00

It's gonna be like, like 20 micron film cuz you're not plating more than more than 20 microns onto the board

Chris: 38:07

Mm.

Dave: 38:08

because you got, you got 17 half an ounce of copper to start.

Chris: 38:13

Mm-hmm.. Mm-hmm.

Dave: 38:14

So you probably use a 25 micron film to be honest. But if it,

Chris: 38:19

So, for listeners who don't know, normally in PCB fabrication, you, if you want a one ounce board, you start with half ounce and you build up to one ounce. Just repeating that.

Dave: 38:27

Occasionally you'll build it with a like half an ounce a quarter of an ounce or, or nine micron film if you got really small tracks. But, but you are then, you're then gonna plate copper into that cavity where you've exposed all your tracking, you've. Like a little trench if you like, and you are gonna put copper in there.

Chris: 38:55

Okay.

Dave: 38:56

so if, if you are building a two ounce board, you're gonna be plating one ounce of copper onto the top. So you need 40 micron film?

Chris: 39:06

So you're kind of, you're kind of filling the valleys with this process.

Dave: 39:11

Yeah.

Chris: 39:12

Okay.

Dave: 39:13

right. so so you don't want to over plate it but too much copper on cuz then it will mushroom over the top and trap, trap the filming

Chris: 39:21

Yeah. Yeah, that makes sense. Yep.

Dave: 39:23

that film then then does not get washed away

Chris: 39:27

Right

Dave: 39:28

through the film strip process. Will cause that's how you call shorts on your board.

Chris: 39:33

when you, when you put it through the film strip process, isn't there still copper underneath that? Yeah. Okay, so then there's another process to remove that.

Dave: 39:43

Yeah, be before. Before the film strip process, you put it through a tin plating

Chris: 39:50

Right. That's okay. So, okay, so hang on.

Dave: 39:53

and then that becomes your etch system.

Chris: 39:56

your, your, your your film is the mountains. Your plating process is filling the valleys so that now the valleys are the same height as the mountains. Then you're putting tin on.

Dave: 40:08

Top of the

Chris: 40:09

The on, on that copper where the, the, basically the valleys on the top of the valleys, you're putting tin and then that's protecting the valleys, and then you're gonna wash away the

Dave: 40:18

so, so, so then you wash away the mountings

Chris: 40:21

Yeah.

Dave: 40:21

and then you'll see your outer layer image in tin, but the rest of it all copper. And that's the, that's the copper that you then etch.

Chris: 40:35

Oh,

Dave: 40:37

And then, and then you have to strip the tin lead off the board, and then you, and then you have copper.

Chris: 40:43

my goodness. This,

Melissa: 40:45

But.

Chris: 40:46

it is such a, a it, it, it is such a, How do I, I, I can't think of a good analogy for it, but you're, you're going back and forth and back and forth and back and forth so many times. That's where my brain always mixes it up and, and why I struggle to, to wrap my head around the process to create these things. So, but that makes me wonder though, we've been talking about a one ounce board. If, if you have a really small track, like you were saying, if you had a two mill line for some reason, Is it easier to do a half ounce board than it is a one ounce board when you have really thin lines, or is it no different?

Dave: 41:20

I've never built anything below 3000 personally. When you build, when you build three or three mill tracking gap,

Chris: 41:31

Yep.

Dave: 41:34

you have to have a maximum, like one ounce, a maximum, one ounce. If you build it, if you build 3000 tracking gap on, on an ounce layer with one ounce copper, then you do extreme well. But, but you have to start with nine micro.

Chris: 41:52

okay?

Dave: 41:53

So you only etching nine microns

Chris: 41:55

Mm-hmm.

Dave: 41:56

because, for example on two ounce copper, the reason why you can't, you can't build a four thou track on two ounce copper. Copper is because the, the track is then becoming you. You, you're getting tower blocks.

Chris: 42:12

Yeah. Yeah.

Dave: 42:14

So that the tracks become unstable and you can just brush them off the board

Chris: 42:19

Wow. Holy moly.

Dave: 42:21

cause they just collapse on each other.

Chris: 42:23

Yeah, yeah, yeah. It's like building a Lego tower too tall.

Dave: 42:27

Yeah. It sat Jenga.

Chris: 42:30

Jenga. Yeah. Jenga. Did I tell you I built a like a adult height Jenga set, like a lot of two by fours, this massive, massive Jenga set. I will never do that again. That took. I think I spent like 40 hours making this stupid thing and I made all different colors and everything. So when we go camping, all the kids get to play with it. Everybody loves it. But I will spend the money. Don't try to build one of those things yourself. It's crazy.

Dave: 42:58

Yeah, cause you gotta make, you gotta make them all different thicknesses and slightly different so you can slide them out.

Chris: 43:03

Well, I, I sanded them all so that they, they were all irregular, which, which added to the game, you know, and, and the sanding, the amount of sanding pads I went through and I broke my rotary sander and I was like, oh my gosh. It was never, ever, ever, I'm just gonna, if, if, if, I ever lose it and I want one again. I'm just buying it. I'm never building one of those things again. But I had, I had taken apart this workbench I had built outta two by fours. I'm like, oh, I got all these two by four s. I'll build the giant Jen set. No, no bad idea. This is what the listeners tune in for, right? Chris Then's special special camping projects. So that, that's fascinating to me though, because we actually had. Total coincidence. But the customer I was telling you about earlier where he had this motor control chip that was overheating he needed the extra copper because he's pushing a lot of power through the board. So he needed a two ounce board, but he designed it for a one ounce board. So all the track gaps and widths and everything were really only robust and had high yield on if it had been a one ounce design. But because it was a two ounce and he requested two ounce, we could get it. Our PCB supplier would send us all these X outs. We would, you know, we'd have, we'd, we'd, you know, if we, if we got a 500 of 'em, we, we would get you know, a two up panel. So normally you'd expect 250 panels, but we'd end up with like 400 panels cuz so many of them were X outs cuz they just couldn't do it. And it, and I, I'm not sure why that was the case, but anyway, and his new design, he still needs a two ounce copper and he designed this, this time, he designed it. Two ounce copper process and much better results, which I think, if, correct me if I'm wrong, Dave, but that's an eight mil

Dave: 44:36

Yes, yes..Yep. Yep.

Chris: 44:40

So if you need that extra copper for power requirements or whatever, go eight mil. Yeah. Yeah. So, if you're doing a if you're doing a three mil track or four mil tracking gap, you, you wanna consider the fact that you might only be able to do a half ounce copper board or a three quarter ounce copper board.

Dave: 44:59

Yeah.

Chris: 45:00

It might be difficult to do a one ounce copper board with, with that tiny.

Dave: 45:05

a, a good PCB fab will be able to do around three, three and a half mill tracks and gaps on one ounce

Chris: 45:16

they will. Okay.

Dave: 45:18

Yeah. You go any longer than that, they probably won't make it. Like they just won't be able to do it.

Chris: 45:22

yeah, yeah.

Dave: 45:24

Um,

Chris: 45:24

know.

Dave: 45:25

Our PCB fab we use in China, they've posted on their website just recently, they've actually made two mill tracking gap board recently. So they, they're, they're pushing to get down that far.

Chris: 45:38

Yeah. Very nice. They've been a good supplier. You talk about our new supplier or our, our, the one we've been using for

Dave: 45:42

I don't wanna be been using for a while. Yeah.

Chris: 45:44

Yeah. They've been great to us. They, we, they've really grown along with us. It's been fun to watch them and. Good team there. Good, good Folks like working with them. It's like anything, you know, it doesn't matter where you are in the world, you can be a good shop or a bad shop and we happen to have found a good one. So works out nice. Alright, so I think, I think I get it. Is there anything we're missing on the outer layer production?

Dave: 46:05

No, you should have, once you strip the tin off, you should have a, a nice and etched copper strip. The film, you'll have a nice, nice, shiny outer layer plated board.

Chris: 46:19

What gets stripped first? The film or the, or the tin.

Dave: 46:21

The film gets straight first. then he gets etched and then he strip the tin

Chris: 46:27

Oh, boy. See, I told you, I warned you this was gonna be too much, Dave, because now , I warned you. I warned you this is gonna be too much because now I have questions about, I have questions about, The etch because I feel like etch is like, we should have like this PCBs are called etch. Like this is like a whole show. We could just talk about etch.

Dave: 46:48

Yeah.

Chris: 46:49

All right, so we'll save that. We'll save that. Can we save that?

Dave: 46:53

etch actually is probably the hardest thing.

Chris: 46:55

Yes, exactly. We need to have a whole episode just on Etch.

Dave: 46:58

Yeah. I don't know much about it.

Chris: 47:00

Ah,

Dave: 47:01

It won't be long. I'm not a chemist.

Chris: 47:04

It's okay.

Dave: 47:05

I know the fundamentals.

Chris: 47:07

Well, we'll talk about the fundamentals cuz your, your fundamentals are gonna be like my details, you know what I mean? That's how little I know about it. So, well, that's great. That's great. I, I, I, I, I love having you on Dave, because it just, every time we talk about these things, it blows my mind and I continue to learn more and more, and I, and it's, it's, it really is so valuable. Once I understood a little bit about the pcb design process and learned a little bit more about the PCB fab process, it made me a much better PCB assembler because I finally understood why things happen in certain ways, and I was able to identify problems in the process that weren't in my control, but I could go back to the designer and say, Hey, I know this is what you did here, and you can change it this way and make my life easier. And I could go back to the fab and be like, I know what you did here, but I need you to change it to make my life easier. It's all about me, Dave. It's all about me and my, my

Dave: 48:10

I'm exactly the same, but before I joined CircuitHub, I, I was engineering PCBs with no idea about what components were going on the board. I didn't, I didn't care.

Chris: 48:22

Right? Didn't matter

Dave: 48:23

I got care in the world. I just built the boards. We talk about having solder dams boards, and we have discussions about solsolderms weekly, I guess

Chris: 48:33

Dave. Dave, you and I probably have more discussions on solder dams than my wife and I have about discussions about what were having for dinner. I mean, it is just, we talk about this endlessly.

Dave: 48:43

But, but, but now I, I now understand some of the components that going the boards, and I'm looking, I'm looking at data sheets for boards and what the minimum recommended pads are. And if a customer's put a four pad on and the minimum recommended pads like 0.25, I'm, I'm going, well, I can show you a bit off that then I, I can show you that a little bit and, and that will give us a down.

Chris: 49:07

Exactly. Thank you very much for those. We, we do appreciate the solder

Dave: 49:12

Yeah, so like,

Chris: 49:12

the assembly very easy.

Dave: 49:15

it must be a better, a better cam engineer as well. Knowing a bit more about, about the components.

Chris: 49:20

Awesome. That's great. Super cool. Super cool. I love it. I, this is, this is this is a cool collaboration that Worthington has had with CircuitHub and, and bringing you in and, and and doing some of our own in-house design has helped as well, albeit very limited in house design, but does help a little bit. Great. All right. Are we ready for my favorite part of the show?

Dave: 49:43

go on then.

Chris: 49:44

All right, let's do it, Melissa.

Melissa: 49:46

Let's do it.

Chris: 49:47

I know you, you got one queued up for

Melissa: 49:49

I do, cuz I've been encountering this several times this past, past week. I got another packaging one for us, cuz I know that's one of the.

Chris: 49:57

packaging. Pet peeve,

Melissa: 49:58

of our favorites is when you go to open, I don't know, like any kind of like mayonnaise or ketchup or like any, any sort of a tube squeezy like container that has the, that has the small opening and they have that little white protector, and then it has the little clear plastic tab that always says like, you pull it up and then like you pull that to open and it never works. It never works either it is just like not strong enough, or maybe your hands are slippery and then you end up having to just, I don't know. I usually take, I usually get a knife and I just stab the whole

Chris: 50:38

That's what you end up doing. Right? Just cut the thing out. I know, I, I, well, it's because I think they started out with just the, just, just the white film and everybody couldn't get it off. And they're like, this thing sucks. And they're like, okay, we'll give you a little tab. And we all know tabs don't work. We've already talked about this. Yeah. I don't mind. You know what, I think it's heinz they give you, they give, they give you a little extra paper on the. That hangs over the edge and that you can get your fingernail on those work pretty

Melissa: 51:08

Those work better.

Chris: 51:09

Yeah, those are better. You know what, I wonder if you know how like, glue gets easier to take apart when it gets warm. I wonder if you like run that under some hot water or something and then, and then maybe the tab will work because then the glue isn't quite as strong. I'm gonna try. Follow up future episode. I'll try that out next time. My poor wife is gonna be like opening a brand new thing at ketchup and I'll be like, no, I need to try the hot water test Yeah. Amen to that. You know, and it's like, let, let's say, let's say the hot water test is successful, then how come they don't say, warm this up first? You know, why don't they just say, run this under hot water first. Right? You could print on it. They print on it cuz it says pull here. They should say Run under hot. Then pull here.

Melissa: 52:01

That's just a lot of work though.

Chris: 52:05

This is true. Or maybe, maybe,

Melissa: 52:08

wasting water.

Chris: 52:09

is this, refrigerated before you, before you open it, or are you pulling it out of a cupboard?

Melissa: 52:15

I would say it's usually out of cupboard

Chris: 52:18

Mm-hmm.. Mm-hmm.. Mm-hmm.

Melissa: 52:20

depending on who has put away the groceries.

Chris: 52:25

Honey, why did you put the steak in the silverware drawer? It was who was telling me? Oh, is a coworker of ours. He was telling me that he visited a friend of his in France and he had a roast beef in his cabinet. He cut off the mold that had grown on the roast

Melissa: 52:47

Oh no. Oh.

Chris: 52:49

it up. And he considered this to be perfectly normal because the French just buy their, like their food each day rather than like store it in giant refrigerators like Americans do. And I'm thinking to myself, I think that might just be your friend

Melissa: 53:06

It has mold on it, then it has been out for more than just a day in the first place.

Chris: 53:12

something I right there. I don't know. Dave, is this a European thing? You guys keep your roast beef in the cupboard?

Dave: 53:17

It's, it's all dry. That's, that's dry cured, isn't it? Dry cured for 30 days. Just, just, just hung up and dried. I dunno about the mold part, eh, , I'm not sure about that.

Chris: 53:29

Well, like, yeah. I guess if you're buying a prosciutto, like, you know, the prosciutto, they hang up in the butcher, you know,

Dave: 53:35

Yeah, it, it, it's all dry, dry cured. But yeah, I'm not sure if fat a mold, I mean like what the cheese is mold. So they cheese.

Chris: 53:48

is moldy cheese. I love a good moldy

Dave: 53:50

And the funniest thing about buying cheese is they wait right until the last four weeks of its life before they sell it, because it's got used by daily on it. But it's, it's moldy. It's been maturing for two years.

Chris: 54:03

That's right. That's right. Oh man. I love a good gonzo. Oh, man.

See, it's, it's, it's 11: 54:07

59 AM which means it must be Turkey sandwich time. And that's why I'm hungry and I'm ready to eat.

Melissa: 54:14

Okay.

Chris: 54:15

gotta wrap this up. Gotta wrap this up. Well, thank you very much, Dave. It's a pleasure as always. We look forward to having you back. What, what are we gonna talk about in the next episode then? Just to, just to prime the listeners.

Dave: 54:25

We now gotta put a, a nice colorful coat in on the

Chris: 54:28

Oh, solder mask.

Dave: 54:29

US

Chris: 54:30

So that's before the etch.

Dave: 54:32

it's been etched.

Chris: 54:34

No, no, no, no. We gotta have a, we gotta have an episode where we get into Etch.

Dave: 54:38

It's, it's gone through, it's gone through a, like a strip, an X line already. So it's, it's, it's gone through, it's gone through a conveyor, taking the film off, etched it, taking the tin lead off, and at the end of the line you got a nice finished outer line

Melissa: 54:55

Chris is saying he wants to talk more

Chris: 54:57

how long have we worked together? Do you, do you think that that is satisfactory? You have any idea? No way. I, I have so many questions. I have so many questions. We'll, we'll get into that. Everything you just said in 30 seconds, we'll, we'll get into in 30 minutes on the next episode.

Dave: 55:13

right. Okay.

Chris: 55:14

All right.

Dave: 55:15

And then, and then we put some pretty colors on the outside.

Chris: 55:20

Yeah, then we put pretty colors. I'm actually super excited to talk about that. We'll, we'll get into that cuz that, that affects my world. And then it also affects our customers world quite a bit. And I think a lot of, a lot of listeners would be surprised to hear what an impact that has on assembly. So, pleasures always Melissa, pleasures always Dave. As usual, we really, really appreciate the listeners listen. recommending and reviewing and all that kind of good stuff. And please, please, please, as always, let your friends know about the show. If you've enjoyed it and you think somebody else you work with or in a similar field might be interested to hear about it, we would love to have them as a listener. And please do continue to write in with questions and episode ideas. And if you were unsatisfied with Dave's response about the processes, let us know because I don't wanna be the only. So , you can email us. Contact pick place podcast.com. I am at W Assembly on Twitter, and Melissa and her crew are at CircuitHub on Twitter.

Melissa: 56:18

Thanks for listening to the Pick Place podcast. If you like what you heard, consider following us in your favorite podcast app, and please leave us a review on Apple Podcast or wherever you get your podcast from.

Chris: 56:30

Thanks very much everybody. Thanks Dave.

Melissa: 56:35

Thanks, Dave.

Dave: 56:36

Great stuff. Cheers.