日本語
I designed 2 very small PCB and just got a few copies in the mail from the fab.
One is a light emitter board and one is a light detector board. In Altium, I positioned the light emitter (in a PLCC-2 package) to align bang-on with the detector (8-pin SOIC).
Starting to solder it by hand wasn't too much trouble, but it could use some improvement. They're both slightly askew, due to my human hands and eyes. (Note in the picture below that I need to reverse the direction of the LED tomorrow---my goof)
I was wondering how much improvement I could expect if I mass assembled these at a pick-and-place fab? How accurate will the placements be? I've never had anything mass assembled. Would appreciate any comments!
- Comments(1)
A****min
Nov 28.2019, 09:13:46
Ever done reflow soldering using solder paste and a hot-air gun? If you have, then you'd know that surface tension of the molten solder pulls the components into place, meaning that even parts that are placed severely wonkily by human hands get pulled into perfect alignment -- especially if the solder paste is dispensed well (which it would be if a stencil was used to print it).
In short, the placement accuracy of the pick+place machines are, I'd suggest, completely irrelevant to the accuracy of post-soldering positions of the components (you know, assuming that the initial accuracy wasn't sopoor that the wrong pins are on the wrong pads, etc).
In summary, the quality of your PCB design (oft-overlooked with the freaking enormous solder mask expansions I see often from hobbyists), PCB manufacturing accuracy (solder mask/copper alignment, etc), and stencil design (solder paste quantity is important) will be of vastly more relevance than the pick+place machine in use.
