G'day friends, this one's an exciting one for me. I have in my hands a panel of PCBs that I've designed and I'm going to attempt to place components on one of these PCBs with our pick and place machine. If you don't know what I'm talking about, check out our intro to the factory video for more information.

But if you didn't know, this is how PCBs are manufactured. You have one design that's replicated across what's called a panel of PCBs and that panel goes through a placing machine that places parts in all the positions all at once so that you have some batch efficiency there. Then once that's gone through say some reflow soldering, an operator can break these apart and you have your individual PCBs.

Now I have the machine already prepared for placement, I just thought it would be good to press the pause button and capture this process. So let's head out to the factory and check it out.

So I have some adhesive tape on this section of the board and we're just going to pick up these LEDs and place them where they ought to go but without solder paste and the tape's just going to hold them down so we can inspect the placement. Here we go. Because I've got the tape over, the fiducial hasn't been recognized. It's found the right spot but I just need to manually align it so I'll just center that, save and back. I'll do the same for the other fiducial. So you can see I'm using two nozzles here, there's two nozzles assigned to the 5050 LED. Bring that out. Oh yeah, look at that.

Well that went just about as well as I could have hoped. The machine placed the parts onto double-sided tape. I didn't paste this board because I would just have to clean it off again. I'm not soldering the whole board, the point here is to make sure that everything goes where it ought to and in the right alignment. Now to show you this I'm going to have to bust out the microscope.

All righty, I'm just going to take a walk around the PCB and see how we went. There's our first component. Look at that. What I'm looking at here are the centering of the pads on the component leads. So it's very centered in this axis and it looks pretty balanced in this axis as well. We also have the notch of the LED and that's aligning with a little silkscreen mark that maybe you can see in this corner of the LED just on the little white notch to align with this one on the LED. Let's have a look at the others.

It's really quite fascinating seeing the inside of the LED as well. It's worth remembering, like these LEDs, they have a microprocessor inside the LED and I always thought that the light came off these large land patterns here but actually the light that's emitted comes off these tiny little yellowish silicon dies. So you'll see three silicon dies here, one for red, green and blue each. Enough of that though. Let's continue our inspection.

This is very pleasing. The rotation looks good. This one you can see a slight gap. The LED is maybe pushed all the way up on the pad. That's not a problem at all. Once you have solder on the pad and it turns liquid, the surface tension will tend to pull that LED back into the center. Beautiful. Here you can see this is a feature of panelizing. These are what's called mouse bites. So this creates a local weak spot so you can snap the board apart. So you can snap the board apart. All that seems to be in order. Everything seems to be in order here.

Oh yeah, very last one. I don't know if I've bumped that or if that was placed like that. Let's see how. Let's see how. Oh, I am just grazing that. I wonder if that's been moved since it hit the tape. I don't know. I don't think that's a problem either. I think surface tension would have no trouble correcting a part like that.And these are the fiducial marks that I had to manually align. That also could have something to do with it. Since the pick and place machine needs to know where this PCB is in space, it hunts for these fiducials. And because I have tape over this, it had trouble recognizing the fiducial using its computer vision.

Overall, I think that's a very successful dry run. Now, the key to that among you might have noticed a fair few components in the trashed area of the pick and place machine. That is the area that a component gets thrown to if it gets rejected by either by me or the machine. In fact, I did have a crack at placing all the LEDs on the panel just to make sure I understand the panelizing function. But of course, because there was no tape, those LEDs didn't stay put. So this is the first time we've had a crack at putting on some tape and actually inspecting the quality of the placement. Overall, really happy with that.

So we can make a PCB and we can place parts on the PCB, but next we will have to solder those parts. So I'm going to have to get familiar with the solder paste stencilling machine. That's a machine that will hold a stencil over this panel and we can squeegee solder paste onto each one of these little pads. So in one pass, you can apply solder paste very precisely to where it needs to be on the panel. Then we just we do the same operation again, except this time the board is charged with solder paste, goes through the pick and place machine, gets components, comes out and we can put it through the oven for reflow. And at the other end, we should have nine beautiful functional PCBs. I can't wait.

I hope you learned something. I know I did. I'll see you next time.