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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Pin in Paste with dispenser

Hannu

#32218

Pin in Paste with dispenser | 24 January, 2005

Morning all,

Has anybody done any pin in paste job with a dispenser? I read somewhere that the needle i.d. should be slightly larger than the hole diameter, but with holes of 1.4 mm I would have to work with a very large needle indeed. How does paste work with such a large needle? Has anybody tried using smaller gauge needles? What kind of dot pattern have you tried? I tried dispensing four large dots on the hole edges with a 0.58 mm needle (obviously you can't just squirt some paste into the hole with a small i.d. needle because it just falls through) and got surprisingly good results but solder beading seemed to be a problem (also due to the component not being designed to pin in paste work, with no proper standoffs). Any ideas?

Regards Hannu

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#32236

Pin in Paste with dispenser | 25 January, 2005

On "Solder beading seemed to be a problem", consider revisiting the thermal recipe used for reflow. The PTH barrel may not be getting warm enough.

On "Component not being designed to pin in paste work, with no proper standoffs", consider: * Using a tool to form the component leads to provide a proper standoff. * Placing a piece of nonflammable material between the board and the component during component insertion that is removed after solder flow.

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