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Selective Soldering - Lead Free

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John S.


Selective Soldering - Lead Free | 3 October, 2005

We are implementing a high volume dedicated product line that will be doing lead free selective soldering. There seems to be 3 basic technologies. Wire fed (Panasonic Softbeam or Laser), solder pumps and chimneys (Pillarhouse, SEHO, ERSA, etc) and solder cups (Streckfuss, Inertec). We've only experienced the solder pump and chimney approach. Has anyone had experience with Streckfuss's machines? What about the Soft Beam? It seems that the Streckfuss machine would require very good natural solderability and wetting, the softbeam would overcome poor solderability, and the solder chimneys would be somewhere in the middle. Any advice would be greatly appreciated. Thanks John S.

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Selective Soldering - Lead Free | 3 October, 2005

There's also microflame which uses a mini gas flame to melt the solder.

We tried a number of ways then modified some conveyorised robot cells we bought at auction, using wire feed & an iron head, incorporating veriable tinning & preheat, with point to point soldering. Worked very well.

The best looking method (& I repeat - best looking) was a laser system that melted printed on paste, however it also looked the most expensive.


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Selective Soldering - Lead Free | 3 October, 2005

Depending on your application, you may need to pre-heat before Soft Beam (unless they make one for it now). Plus, very small connections seem to push it's limits. The beam can only get so narrow. Lasers are good but reflectivity can come into play during the reflow of the solder. Like the Soft Beam, you mask needs to be opened up little more than normal. Strength and consistent wave length are also something that needs to be addressed. Cups are OK but need constant attention to dedrossing and inerting. Depending on the size of your tooling, this can get expensive. Not to mention fixed tooling can get expensive too.

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Metcal soldering rework

Reflow Oven