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Author Topic: Another Proposed Minimig Production run.  (Read 7443 times)

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Offline nBit7

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Re: Another Proposed Minimig Production run.
« on: September 21, 2007, 04:10:00 AM »
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Surface mount soldering is *ALOT* more difficult than Through Hole Soldering (Which I can do).


SM soldering not nearly as difficult as you think.  In fact it usually takes less time to get reasonable at it. One common misconception is that you need special tools.  BGA aside, all you need is a reasonable temperature controlled soldering iron. Good quality solder with a reasonably aggressive flux or a standalone flux.  You don't need a fine point tip.  In fact chisel tips are the most versatile.


Small components like Rs and Cs you just put a little solder on one pad.  Then place the part on the pad using tweezers while heating the pad.  Then solder the other side, and then come back and add a little more solder to the original pad.
The process is much quicker and easier than the though hole equivalent.  And the results I have seen from beginners is better than that of Trough Hole.

When doing a fine pitch IC a big tip works the best.  Instead of individually soldering each pin you drag a large amount of solder across the pins with the board held at an angle.  Solder likes to stick together and likes to follow the heat.  This approach is a bit messy but gives excellent joints roughly equivalent to a wave soldered board.  I haven't seen this method written up too often.  I can give more precise details if anyone is interested.  I have taught a few people this method and most of them got a reasonable result on the first attempt (with the aid of solder wick for the last couple of pins).



 

Offline nBit7

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Re: Another Proposed Minimig Production run.
« Reply #1 on: September 21, 2007, 04:32:43 AM »
I don't like your chances of getting some one too hand solder up any real quantity of boards for a cheap price.  I personally won't do it for less than AU$100 per board.
If the quantity was high enough I would consider doing it with production tools: pick and place machine, reflow oven, wave solder.

A company I used to work for has these machines sitting idle most of the time and I am fairly sure they would let me use them for a fee.  Tooling (ie. solderpaste mask) would be around AU$600.
 

Offline nBit7

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Re: Another Proposed Minimig Production run.
« Reply #2 on: September 21, 2007, 08:44:51 AM »
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If you are serious then lets get this confirmed or get a price. Lets get this thing off the ground. We need firm prices first.


I should have pointed out that I am unavailable to invest time till late November.  It may take this long to get all the parts together.  
 

Offline nBit7

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Re: Another Proposed Minimig Production run.
« Reply #3 on: September 22, 2007, 11:46:11 AM »
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a PCB, fully populated with *JUST* the surface mounted components, thats FPGA, Ram, CPU, Pic controller, Serial driver, 74HC4060,Capacitors and Resistors. component cost included (SUPPLIED) is US$105. Included is the AU$25 for someone here *PER BOARD* to professionally solder the components.


If the qty is high enough I am willing to wave solder the TH stuff for a good price.
 

Offline nBit7

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Re: Another Proposed Minimig Production run.
« Reply #4 on: September 25, 2007, 12:47:11 PM »
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Wave soldering is not exactly Ideal for Surface mount (From memory), Okay for Through Hole. The solder wave would wash the components off, especially when you have a multiple (Dual) layer board, and the miniature size of the components in question. (SM Resistors, Transistors, IC's and Capacitors).


To wave solder SM it is usual to glue the bottom side SM parts.  However I would have suggested getting the boards first and fitting just the TH parts and wave solder.  Then hand them on to the SM guy.  Or get the SM guy to only fit the top side SM components and I would manually fit the few that are on the back side.  Or modify the design to only have top parts.