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Wave Soldering SMT IC


Wave Soldering SMT IC | 16 October, 2000

Excessive bridging on SOICW-20, -16, SOIC-8, -14,-16. I've got a board, 4" x 6" w/ SOICs on bottom-side for wave solder. I've checked topside board temp for flux activation, wave height, wave surface with the glass check-plate going from 1" to 2" spans, conveyor speeds from 3' to 6' per min, pot temp from 470F to 480F with no positive results. I have an ERSA ETS-330F w/ 7 deg. incline conveyor. Board has thief-pads and I�m running them thru last.

Any suggestions?

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Re: Wave Soldering SMT IC | 16 October, 2000

Pete: It sound like somewhere through all that you should have gotten good product. Here�s a couple of questions on your board: * How are the SOIC positioned relative to the wave? * How are you controlling the flatness of the second wave? * What is the accuracy of your second side place / cure process? * Is there flux left on the pads when the component is soldered? * What type of flux are you using?

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Re: Wave Soldering SMT IC | 17 October, 2000

Dave, That's the funny thing, thru all that the output was pretty consistant with at least one bridge per board. * The ICs are going thru the wave in-line, according to IPC-782 figure 3-9, "Preferred IC Orientation". * Flatness of second wave is controlled with the Lev-Check glass plate and adjusted as required with the pot levellers. * Placement accuracy is good. * I do not see any flux remaining. * Multicore X33 12i synthetic no-clean

Many thanks.

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Re: Wave Soldering SMT IC | 18 October, 2000

What's your topside Bd. Temp before hitting the Wave ? Have you done profiling on your machine? What solder alloys you are using (might be due to incompatibility with flux)? Is the IR lamp between pre-heat and Chip wave ON during the operation? What about with your other products, are they the same results or only happening with this board? We are using the same wave solder machine but we do not have this much problems on our bottomside.

regards, regards,

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Re: Wave Soldering SMT IC | 18 October, 2000

Dunno, I'd guess the flux is gone.

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Re: Wave Soldering SMT IC | 19 October, 2000

Top side temp. is 97C before the wave. No, we don't have the IR lamp on; we did try it though with no positive change. Solder alloy Multicore 63/37 Other boards run better. This one is the worse. We have not had good success eliminating bridges on SMT ICs altogether. I mean I don't expect that they can be totally eliminated. That's what sells those hot air de-bridging knives, aye? What should the wave surface area be when running the glass chek plate? ERSA told us 2.5cm to 5cm. What's the best? Thanks Thanks

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Re: Wave Soldering SMT IC | 19 October, 2000

Also, what about the gap spacing on your machine between the top of the second wave baffle to the bottom of the finger? Ours is at 5.7mm.


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