Electrolytic caps for high temp reflow application

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I am having problems with SMT electrolytic capacitors expan... - Sep 22, 2000 by jonyoder

Hello Jon (?) Sounds like it's just plain too hot. The Pan... - Sep 22, 2000 by John Thorup

jonyoder

#2958

Electrolytic caps for high temp reflow application | 22 September, 2000

I am having problems with SMT electrolytic capacitors expanding and changing values after going through our reflow. The reflow profile we use includes temperatures of 200 deg C for 60 seconds and 230 deg C for 30 seconds. We need to use this profile in order to get the other parts on the PCB to solder properly. Can anyone offer any suggestions?

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John Thorup

#2959

Re: Electrolytic caps for high temp reflow application | 22 September, 2000

Hello Jon (?) Sounds like it's just plain too hot. The Panasonic VA series specifies a maximum preheat temp of 160C for <120 sec, a maximum time over 200C of 20 sec and a maximum reflow time at 230C of 5 seconds. Tough to do with most recommended profiles. Their VV series is only a little more capable. All manufacturers will publish a typical and/or maximum reflow profile. I'm wondering about your profile. Seems a little hot and short. Or is this only part of it? Are you using 63/37 solder? Is it measured at the components or is it oven zone temperature? Convection or IR and how many zones? In what way do the other components not solder properly? Have you tried lower and slower? John Thorup

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