Through Hole Re-flow Question. Can I DIY?

Discussion in 'Electronics Resources' started by Oaklandishh, Nov 13, 2014.

  1. Oaklandishh

    Thread Starter New Member

    Nov 13, 2014
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    Hey guys,

    I recently picked up 41 of Riacon ASP02 because the site has a minimum order of $30.
    [​IMG] [​IMG]
    [​IMG]
    I thought they would come with headers because there were headers in the picture. They did not, so now I have 41 of these without headers.

    The headers are nonstandard, and as far as I can tell they recommend 31017108. I would just bite the bullet and get 30$ worth of these, but in the spec sheet they are THR (through hole reflow).

    I found a little information online about THR, but none about doing this process manually without an expensive re-flow oven.

    Anyone know if I can do this with either a normal soldering iron or a heat gun?

    Could I do it with a re-flow toaster oven? Any tips?

    I tried putting normal headers on by putting solder on the top of the pins and heating from the other side of the pin, but this did not work in the least.

    Thanks,

    -Eric
     
  2. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
    1,215
    Eric
    I am not exactly clear about your question. I have some similar terminals. The header is soldered on to the PCB. The wires are clamped into the terminal strip. The terminal strip plugs into the header on the PCB. This forms a removeable connector of sorts. The headers are 5mm spacing with .051" dia. pins. You can use a normal soldering iron to solder the header to the PCB. The header is not soldered/reflowed to the terminal strip.

    Did this help?
     
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  3. Oaklandishh

    Thread Starter New Member

    Nov 13, 2014
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    These terminals are quite difficult to pull up the clamp on, so I was under the impression that they had to be soldered to the headers rather than just clipping in.

    You can kind of see this in the color of the headers as the top and the bottom are both covered in solder compared to other THR which only one side is.

    [​IMG] [​IMG]

    I am pretty sure I can solder the side that sticks through the pcb, but I am unable to melt the side that is inside the terminal and I was wondering if I could do it without a reflow oven.
     
  4. NorthGuy

    Active Member

    Jun 28, 2014
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    You probably would be better off ordering TH terminals on eBay.

    If you insist, kitchen owen should work Ok if you figure out temperature regulation.
     
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  5. Oaklandishh

    Thread Starter New Member

    Nov 13, 2014
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    Can't use normal terminals as this brand and kind allow for a very high repeatability with connections to them. The application requires the ability to measure very small changes in resistance.

    Thanks for the tip though.

    Do you think I could do it with a SMD rework station or hot air gun or something?
     
  6. NorthGuy

    Active Member

    Jun 28, 2014
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    I think it'll be difficult to do it with hot air without melting anything. Do make a good solder connection you not only need to heat up the pin and the solder, but also the other surface which you're soldering it too.

    How small are differences in resistance that you're worrying about?
     
  7. Oaklandishh

    Thread Starter New Member

    Nov 13, 2014
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    my initial calculations come to somewhere around changes of 0.00012 ohms, but I am guessing its actually smaller than that?

    It involves strain gauges.

    I put some small headers into one of the terminals and rigged up something, but as you said I melted the bottom somewhat and its not the best connection :/

    Thanks for the help so far.
     
  8. NorthGuy

    Active Member

    Jun 28, 2014
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    So, they say that the contact resistance from insertion to insertion vary substantially less than 120 uOhm? Have you tried to verify that? Shouldn't be too hard. If you put through 8A (max they're rated for), 120uOhm will drop about whole mV, which you can easily measure with decent DMM.
     
  9. Oaklandishh

    Thread Starter New Member

    Nov 13, 2014
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    I have verified that they have no readable change in micro-strain on the device I am currently using to measure strain.

    I used this number to calculate the .00012 ohm value, so measuring the resistance is just a rework of the verification assuming I did the first calculation correctly?

    There might be a lot more going on in the inside of the measurement device, but I am not exactly sure what if anything.
     
  10. NorthGuy

    Active Member

    Jun 28, 2014
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    Just out of curiosity, have you found any substantial variance with other brands of connectors?
     
  11. Oaklandishh

    Thread Starter New Member

    Nov 13, 2014
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    I personally have only checked this one, but I have been told there have been tests in the past where we did different connectors and different connection types such as soldering and desoldering wires over and over and terminals similar to these had the best repeatability.

    Sorry if that was not a definitive answer.

    I will do a test sometime in the future with some cheapo screw terminals I have lying around as now I am interested too, but my guess is that worrying about how many turns I have to do to clamp in will change the connection quality.
     
  12. NorthGuy

    Active Member

    Jun 28, 2014
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    Please let us know the results.

    I often use crimp-on spade terminals on wires for my home-made project. Easy to crimp. Easy to connect to a screw terminal. Easy to cut it off if you no longer need it.
     
  13. Oaklandishh

    Thread Starter New Member

    Nov 13, 2014
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    Just did the test and I got similar results as the fancy terminals (+.5 ue), and some variance with soldering a connection (+-2ue)
    [​IMG]
    Look like these with Phillips head.


    I plan on using these terminals often (~20k uses?) and quickly so screw terminals or ones that aren't beefy probably wont work, but I will probably look into different solutions now.

    Still wondering if anyone has used similar through hole re-flow stuff though. There just isn't any good info I can find out there.
     
  14. NorthGuy

    Active Member

    Jun 28, 2014
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    How about round audio connectors (RCA or speakers)? They're really easy to connect or disconnect. Even children can do it. They used similar ones in phone stations where they connected and disconnected them countless times.
     
  15. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,802
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    I think (pretty sure) that the device tested terminates in bare wires, so requiring an RCA connector is a showstopper.
     
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  16. Oaklandishh

    Thread Starter New Member

    Nov 13, 2014
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    yeah I have bare wires.

    I don't want to have to connect anything to them if I can avoid it.
     
  17. Oaklandishh

    Thread Starter New Member

    Nov 13, 2014
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    Following up with this,
    I contacted the company, and according to them, the thick side of the headers just press fits into the other side of the terminal.

    This should make soldering these particular headers pretty easy.

    Normally THR uses wave soldering, but it can be done with a good soldering iron.

    Thanks for all the replies.
     
  18. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
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    What about soldering 90 degree header pins to the sockets ????
     
  19. Oaklandishh

    Thread Starter New Member

    Nov 13, 2014
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    Not exactly sure what you mean by this, getting the soldering iron to heat up normal pins while they are in the holes is hard to do, but if I was to use 90 degree ones and have extra access to the headers the mechanical connection between the terminal and the board would be much weaker.

    This is similar to how pre-loading a bolt can make it last significantly longer than a loose bolt.

    These will be used quite a bit and I don't want them ripping off :(
     
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