A little toasty

I've got so much to learn about this whole process, so I dove right in! 

Duke Nukem from the GHI forums wanted a Gadgeteer Module to connect multiple MaxBotix ultrasonic distance sensors to a mainboard. After some research and designing I came up with my DistoMatic line. I'll discuss these boards a little later on when I have more to show off.

I found connectors which I liked and that were surface mount, and bought some. Putting the cables together was an adventure for another post. In all my research, I neglected to check if they were compatible with non-leaded solder temperature profiles. 

They were not. 

You can see the discoloration when compared to the raw sockets on the left. Also the right most connector is slightly melted - the walls should be perpendicular.

So more research and testing is needed. Lesson learned is that I have much still to learn! But this all part of the learning process I expected. 

Here's a quick overview of my current process.

1 - Prep

I've only used OSHPark.com for my boards thus far so I can't compare, but I've been rather pleased with the results. They provide 3 boards at $5 sq inch, so quite reasonable for prototyping. The ordering process is very easy, all you do is upload your .brd file, they show a preview of the different layers, and then can order it.

Fresh board from OSHPark.com

2 - Apply solder paste.

I submitted my design to OSHStensils.com and in a few days the post man brought me a 3mm stencil to apply the paste. In each order, they also include a plastic business sized card to spread it. The board is being held in place by their Acrylic Stencil Jig ($6) - figured it was the same thickness of the PCB, so it would be useful.

With paste applied

3 - Place the components

The capacitors were placed with a angled tweezers and the sockets were placed by hand. If some of the paste gets smudged by moving the parts, it's ok, within reason. The board has a layer that prevents the solder from sticking to the purple areas, so it adheres only to the exposed pads.

Notice the paste is still gray and all the pads are fully covered 

Because the 0603 components are beyond tiny, I got a visor magnifier from ebay for about $8.

4 - Bake 'em

My first attempt for these boards was on #6 (as that worked well on my previous attempts). But the sockets came out brown and slightly misshaped.

Attempt 2 was on profile #3, hoping that the short time at max temp would be ok. Not so much...