Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


EL Cap _ Missing & Shifted out of the Copper Pad

Views: 1169

CKH

#42848

EL Cap _ Missing & Shifted out of the Copper Pad | 20 July, 2006

Hi Folk,

i am wondering why they are Missing ELCap and ELCap being totally shifted out of the PCB Copper Pad during the SMT Reflow. Recently we have encountered some boards with the above mentioned symptoms. Appreciate if anyone could advise me.

Thks & Rdgs CKH

reply »


Rob

#42854

EL Cap _ Missing & Shifted out of the Copper Pad | 21 July, 2006

Hi CKH,

Here's some things to consider:

1) Moved by obstruction in/entering oven, such as nitrogen skirts 2) Incorrect air pressure/air leak in oven (large surface area on component) 3) Reflow temperature too hot & electrolyte/air in cap is expanding and poping - profile oven & check against manufacturers Peak Bidy Temperature & duration; check capacitor at the base to see if the can has lifted off of the plug. 4) Vibration on chain/belt either in oven or transferring into oven 5) Displacement during component placement - move this part to the last part placed & see if that makes a difference. 6) Check paste deposit after printing to check adequate paste to anchor component prior ro reflow.

Good luck,

Rob.

reply »

CKH

#42856

EL Cap _ Missing & Shifted out of the Copper Pad | 21 July, 2006

Thanks You for your Valuable Advice. i really appreciate that.

reply »


Rob

#42860

EL Cap _ Missing & Shifted out of the Copper Pad | 21 July, 2006

You are welcome.

Let us know what the problem was if you find it.

Best regards,

Rob.

reply »


RDR

#42863

EL Cap _ Missing & Shifted out of the Copper Pad | 21 July, 2006

these components generally have flattened through hole leads that have been formed for SMT, I have found that they do not sit well on PCBs. They rock, the leads are sometimes angled, etc.... In addition to Robs good advice you may want to just be sure that they are on pads correctly right before the reflow, we find that most or at least some of them usually require some nudging to get back onto pad.

Russ

reply »

Heller Industries Mark 5获得了 2015年中国SMT远见奖 - 回焊炉领域

ii-feed SMD Intelligent Feeder