The story of paste mask vs. pad size is a lot more complicated than this (using PCB's that don't have solder mask withstanding). While pads are are around the 1206 component size they can be pad defined (the same size as the pad) but when you go smaller there's a risk of tombstoning unless you can guarantee that the solder cools on all pads at the same rate so 5-10% undersizing is beneficial. When you have a part such as a TO252 you need to reduce the area by about 30-40% (for the big pad) and place it as 4 1/4 of that area to prevent the part from floating too much. When you have a layout for DFN/QFN you need to have a 5-10% reduction in area for the small pads and a 30-40% reduction for the the centre pad. This ensures the device pulls down closer to the copper surface which largely guarantees the smaller pads solder properly. The list goes on :-) My recommendation is to always carefully observe the footprint design requirements as laid out by the IC manufacturer, Texas Instruments, NXP, On Semiconductor and Maxim are particularly good for this sort of information. They won't always explain why you should do this or that, but they will give valid examples of what you end up with.

Awesome video thanks. I was wondering how you could make your own solder ask and silkscreen for a diy pcb.

👏👏👏

Looks great! I'll definitely try this. Mine is 40W so I'll see if it's possible B]

any reason for engraving instead of cutting?

Are any toxic gases produced by co2 laser cutting polymide?

What is the material you used for the stencil and what was the spec on the laser cutter? Can this be cut on a 20W diode laser like the Ortur LM 2 Pro? If not, do you know what material would work?

@Core-Electronics

2 жыл бұрын

Hi! Definitely you could cut a stencil with a lower powered laser. You'll just have to experiment with the power/speed settings of the engraving - like I did. The material here is Kapton and from memory it is 0.05mm - but something thicker might be better. These days we just order a small stencil to fit in the same box as our prototypes. Most PCB houses allow you to order a custom-sized stencil. Choose it to fit in the box and you're good to go!

Why polyamide if it's notoriously heat resistant?