Hot Plate Recommendations for SMT Soldering

Community PCB Design
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I want to get a hot plate to be able to more easily solder some SMT components. I know this might not be ideal, but it’s just SOOO expensive to get a board stuffed at an assembly house for small runs. Does anyone have any recommendations on which one to get (maybe an amazon link)? Any advice/caution in general on using them?

I’ve also heard of people using old toaster ovens and am wondering how people’s experiences have been with that too.

Thanks,

2

Hot plates work well - sometimes better than IR ovens (e.g. when you have large connectors which could result in solder not melting in an oven). Sparkfun’s tutorial covers this. Another advantage to the hotplate is that you can see once the solder starts to reflow, and adjust the hotplate control accordingly. I had an IR thermometer that I used to monitor the temperature, but this isn’t essential.

I don’t think the hotplate type is critical - I just used a $20 electric skillet / frypan from a local store. Some people added blocks of aluminium to spread the heat more evenly, but I worry that the additional thermal mass could mean the board takes too long to heat up / cool down during the critical phase when the solder actually melts.

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Do they also work well for BGA packages? I’m wondering if I can hot plate reflow an Atmel SAM9N12, which is in a 217 pin BGA package.

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mrdudeman:
Do they also work well for BGA packages? I’m wondering if I can hot plate reflow an Atmel SAM9N12, which is in a 217 pin BGA package.

You're always going to have a hard time with BGA package, although the 0.8mm pitch isn't so bad. Your biggest problem is going to be placing the solderpaste precisely, and the fact that you (presumably) don't have access to an X-ray machine to inspect the solder joints. At the very least, you'll need a nice lasercut solderpaste stencil (eg a $25 stencil from Ryan O'Hara), but I recommend you look at something like this:

http://www.intertronics.co.uk/products/flextac.htm

Edit: the stencils I was thinking of actually remain part of the PCB after soldering, such as this:

http://www.pcbunlimited.com/stencilquik … p-162.html

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I was under the impression that BGAs didn’t need paste, but maybe that was stupid. Do the solder balls not provide enough solder?

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mrdudeman:
I was under the impression that BGAs didn’t need paste, but maybe that was stupid. Do the solder balls not provide enough solder?

You may be able to get away with just flux, but all of the kits I've seen seem to use additional solderpaste. Obviously you don't want much, as you could get shorts between pads. I wouldn't attempt this myself without something like the stencils I linked to.
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this one looks promising:http://www.amazon.com/gp/product/B000MD … %20skillet