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PLCC LEADS not solder in SAC305 paste

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aci

#66675

PLCC LEADS not solder in SAC305 paste | 27 June, 2012

We are seeing PLCC socket leads not soldered in our SMT process. We are using a KIC thermal profiling device and we are on 50% greem light process window. All other solder joints on the board looks great. The solder flowed what looks like perfect on the socket leads. When you take a pic and move the lead it is like it didn't flow to the board. Anyone else seen this problem We are using SAC305 noclean paste.

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#66682

PLCC LEADS not solder in SAC305 paste | 27 June, 2012

Questions are: * When you rework these pads, can you get solder to flow on the pads with a soldering iron? * When you profile the board during reflow, what is the temperature on these pads as compared with other similar pads in the vicinity?

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aci

#66691

PLCC LEADS not solder in SAC305 paste | 28 June, 2012

Dave, They rework fine. All solder joints on the whole board look great especially for lead free sac305. Here are the reflow specs: SAC305 no clean solder paste – Kester EM907 Kic thermal profiling device – 50%process window green light profile. • Max rising slope – 1.75 • Soak time(150-215C) – 77.11sec • Reflow time(above 217C) -63.96sec • Peak Temp 244.73C

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#66695

PLCC LEADS not solder in SAC305 paste | 28 June, 2012

Matthew: That you can get solder flow when hand soldering, but not when reflow soldering, seems to be telling you that you're not getting the connection warm enough during reflow. You need to have those connections liquidous + 20*C for at least 5 seconds.

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aci

#66703

PLCC LEADS not solder in SAC305 paste | 29 June, 2012

Dave Thanks for the input. The thermocouple read 244 on the pad of the socket. We actually found after extensive investigation that it is the coplanarity of the leads. We were shipped a bad batch of sockets form the manufacture. Go figure!!1

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