SMT soldering?

Technical discussions around xCORE processors (e.g. xcore-200 & xcore.ai).
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yzoer
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SMT soldering?

Post by yzoer »

Anyone have any suggestions for SMT soldering? Contemplating getting one of the cheap 'T-962' ovens from Ebay but I've read people had some mixed feelings about the quality ( catching fire, smoke, that sorta thing ).

Alternatively, I could have the whole thing manufactured / assembled but I'm guessing that's about the same price as a single reflow oven.

Suggestions welcome!


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leon_heller
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Post by leon_heller »

It depends on the package. QFP devices are quite easy even with manual soldering equipment and the other parts won't cause a problem, but BGAs really need to be mounted professionally. It needn't be expensive, a company I use here in the UK does them quite cheaply.
yzoer
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Post by yzoer »

I guess that all depends on one's interpretation of 'quite cheaply'. The company I work for considers anything under $2m for a game to be cheap... What are we talking about here for prototyping? $500? $1000?

-Yvo
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leon_heller
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Post by leon_heller »

I paid about £30 a board for the assembly of two prototypes (components on both sides) with a Telit BGA module, PIC and lots of other stuff. The stencil was quite expensive, but I'd get one free from my PCB supplier, now.
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tautic
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Post by tautic »

For prototyping, I do all my own SMT reflow. To date it has been all 0805, 0603 SOIC and SSOP components, but i'm pretty confident that I could pull off LQFP or TQFP packages just as easily. I'm tempted to dabble with QFN, but i'm sure that would be quite more challenging.

My setup is a simple toaster style oven. I purchased one with infrared heating elements, two on the top and two on the bottom. I manage temperature through a temperature control, and use a solid state relay to control power to the heating elements.

I produce two products with this method, and for me it works great. My boards are small, around 1"x2", but I can reflow up to about 30 at a time. Your mileage of course may vary.

As far as applying solder paste is concerned, I had done everything by hand in the past. Lately, I've been using kapton based stencils, and a stainless steel stencil for another of my boards. If you're making more than a few prototypes, i'd definitely recommend a good stainless steel stencil. But for prototyping, you might be surprised what you can pull off by hand.
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