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Selective stamp soldering – Solder joint analysis Confidential | Fehérvári Péter | 22/04/2011 | © Robert Bosch GmbH 2010. All rights reserved, also regarding.

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Presentation on theme: "Selective stamp soldering – Solder joint analysis Confidential | Fehérvári Péter | 22/04/2011 | © Robert Bosch GmbH 2010. All rights reserved, also regarding."— Presentation transcript:

1 Selective stamp soldering – Solder joint analysis Confidential | Fehérvári Péter | 22/04/2011 | © Robert Bosch GmbH All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights. Automotive Electronics Analysis of solder joints in the selective stamp soldering Written by Fehérvári Péter Mentor: Csurka Péter 1

2 Solder-ball forming during stamp soldering Solder ball forming is a phenomenon caused by many factors and manifested in small solder alloy balls around the solder joint The possible causes are improper fluxing or preheat profile, wetting problems because of surface contaminations, solder mask defects, escaping gases from the PCB laminate

3 Solder-ball forming during stamp soldering The concerned PCB-s showed uneven PTH plating surface which can be a root cause of blow holes Problems occured with immersion tin and also with HASL plated PTH barrels. Although the surface of the HASL was satisfactory, the underlying copper plating was uneven and critical thin.

4 Solder-ball forming during stamp soldering The mechanism of solder ball forming is in correlation with the escaping gases from the PCB laminate resin, caused by the higher temperatures and contact times used in lead free technology The higher copper dissolution rate of the lead free solder alloy aggravates the problem, the critical thin copper plating can completely dissolve which results free out gassing from the PCB laminate.

5 Solder-ball forming during stamp soldering The proposed actions are primarily to eliminate te root cause, which means strict quality control over the PCB suppliers products. Lead free soldering is more sensitive of PCB quality. The yield can be improved by heat treating of the PC boards, thus removing volatile materials from the laminate.

6 Manufacturing and process regulations for EL13 The task was to collect the related documents; regulations, datasheets, heat profiles etc. for each production phases and organize them to a html coded table To collect the required documents, the concerned engineers has been contacted and the database of Salzgitter has been examined


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