Svart
Well-known member
PPS caps? I have some but never tried them out. I don't think they come in smd though.
SMD?
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PPS caps? I have some but never tried them out. I don't think they come in smd though.
Andy Peters
Well-known member
jdbakker said:
Advanced Circuits (4pcb.com) offers "Benchtop" stencils for not-a-lot of money (http://4pcb.com/smtstencils/). We keep threatening to try 'em here at day-job for some of the more-complicated protos we build.
We have a kit of 1 mm and 1.27 mm BGA stencils that our ace assembly techs use to attach BGAs to boards. They use a hot-air nozzle above the work and a heater block below the work. They use a stereoscope to look at the balls on edge of the package while heating it, and it's "done" when they see the ball melt and the package sinks a bit.
After doing this kinda stuff for about five years, they've got a pretty-close to 100% success rate. This is important because every board we do has at least one BGA-package FPGA on it.
-a
mwkeene
Well-known member
AVX makes PPS in SMD http://www.avx.com/docs/Catalogs/cb-pps.pdf. I think WIMA and Panasonic do as well
I've had these problems very recently so I'd say nothing has changed... The film SMD caps are very temperature sensitive. We've experienced problems with the outer coating "shrinking" when too much heat is applied via SMT oven or iron. This can render the capacitor basically useless.
-Mike
Gents,
saw this video today, and wanted to share it with you.
http://www.youtube.com/watch?v=_5lksMvmqQc
"amazing" accuracy isn't needed when soldering on the skillet
saw this video today, and wanted to share it with you.
http://www.youtube.com/watch?v=_5lksMvmqQc
"amazing" accuracy isn't needed when soldering on the skillet
Yup.. even in the video you can see a few solder bridges still left, but they can be cleaned up with some solder wick, flux, and heat... It wasn't as scary as I had feared.
JR
JR
radiance
Well-known member
Rochey said:"amazing" accuracy isn't needed when soldering on the skillet
... just whack some solder paste on it and go for a quick beer. Maybe put a pizza in the oven as well.... watch the olives when they align them self to the mozzarella.
Did y'all do SMD like these *without* solder mask on the boards? I can't tell from the pics.
I did one by hand applying the solder paste using a syringe. I was sloppy and while it worked fine for the low pin count larger devices, because of their lead spacing, I had lots of bridging on the smaller (resistor arrays) and high pin count devices.
While a bit of a struggle to get my technique down, some flux and copper braid, can wick away all the excess solder.
I did mine in my kitchen oven, temperature/timing was not very precise, but it worked well enough. I wouldn't rule out tack soldering a corner lead, or leads of a larger device, and would be careful about shaking or handling the PCB while solder is liquid.
JR
While a bit of a struggle to get my technique down, some flux and copper braid, can wick away all the excess solder.
I did mine in my kitchen oven, temperature/timing was not very precise, but it worked well enough. I wouldn't rule out tack soldering a corner lead, or leads of a larger device, and would be careful about shaking or handling the PCB while solder is liquid.
JR
