Monday, 3 February 2014

SMT soldering

As a result of an interesting discussion over coffee at our local Tesco store on Sunday, I have been loaned a toaster oven and solder paste application system.

This is the first time I have really considered mass producing assembled PCB boards such as my VLNA or the Nacton transverter.
My initial attempts with the compressed air powered paste application system were quite successful, but I can't say the same of the oven part.

Without an automatic profile temperature controller it is very difficult to adhere to anything like the correct temperature profile, resulting in some poor joints.
I am assured it can be done, so I will persevere.

One other thing I want to try is soldering with a hot plate. I have a rather nice Jenner hot plate, obtained from a previous employer when they downsized in about 2004. It has remained virtually unused since then.
Such a hot plate is not suitable for simultaneously soldering multiple boards ( unless they are small), but does have the advantage of being able to see when the solder actually flows. The temperature profilers I have seen look suitable for use with the hot plates, as an added incentive to try this approach.

There will be a demo and discussion session featuring Reflow soldering at the forthcoming Martlesham Microwave Round Table (MMRT). There can be little doubt that with components getting smaller and more complex and the need to cope with heat transfer pads underneath some of the more interesting devices, this is something we all may want to get to know more about in the near future.

Needless to say, I won't be doing the MMRT demo!

Sam



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3 comments:

  1. Sam, looking through one of the lists, I saw that in the US they have a type of paint which will change colour when its heated to the right temp. Perhaps you could use a smear of that on the pcb to indicate when a certain temp is achieved. A infrared temp sensor will do the same. Is that pain available here ?

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  2. John,
    I will beaning a K type thermocouple and meter in order to accurately measure the oven temperature.

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  3. Or maybe ordering.......
    The air compressor has arrived.

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