Investigating the industrial intorduction of Pin-in-Paste technology

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Dr. Krammer Olivér
Department of Electronics Technology

For my thesis, first I surveyed literature on electronic assembly and soldering technologies. During this, I studied the different component designs, the soldering technologies prevalent in the industry, the soldering pastes used for soldering, the basics for stencil design, the solder joint formation and the processes which result in the solder. Then I did literature survey on the Pin in Paste technology and this technology’s advantages and nature. Following this, I designed stencil for the selected product, which later had been manufactured. I determined the amount of solder paste for each component, than I analyzed the stencil printed boards using x-ray inspection and making a crosssection of them. With the x-ray analysis I measured the amount of paste printed to the PWB’s through-hole, while using the crosssections I examined the solder joints and qualify them in the aspect of hole fill. After the examinations I compared the measured data to the previously calculated paste amounts and stencil aperture’s dimensions. Using this data the required amount of paste for each hole based on the calculated data.

The result of the examinations show, that on the places where the exact required amount of paste for soldering was hard to use, the portion was still within the standard’s limit. With these components the average solder deficiency never rose above 25%. In the case of bigger components, usually equipped with supporting legs, this deficiency was much higher. The cause of this is the oversized hole on the PWB, which in return caused that the calculated amount of solder paste couldn’t be achieved on the boards. In spite of the fact that the deficiency was high on these places, the crosssections showed that the hole fill was 100% on the majority of the holes, so we can’t talk about soldering errors here either. Summing up, despite of the soldering paste deficiencies, the joints formed in accordance with the IPC-610D standard. If it’s needed to use the exact amount of paste, then it may worth examining the introduction of the step stencil, because with this technology the deposition paste could be as much as 20% higher, while in the case of the bigger components with supporting legs, the redesigning of the hole should result in less required soldering paste, which should make the deficiency between the calculated and the used amount of paste less.


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