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

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Solder height after reflow

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#63254

Solder height after reflow | 8 December, 2010

Can anyone tell me if there is a formula for finding the after reflow height of solder with no part attached? I have to print some pads that do not have any parts but there can not be more than 1.5mil of solder on the pad after reflow. I am going to use a 4mil stencil for the other parts that are being placed. thanks

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#63255

Solder height after reflow | 8 December, 2010

What is the solids content of your solder? 50%??? Then, theoretically, if the aperture is 1:1, you'll have 2 thou of solder on your pads.

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#63259

Solder height after reflow | 9 December, 2010

You won't have 2 mil height because the solder doesn't remain brick shaped. It's a dome. In the past I tried doing some calculations using the formula for the volume of a spherical section and also tried using a simulation program that accounts for the surface tension and density of the solder. Neither were particularly accurate. I ended up just printing and reflowing some scrap boards and measuring the height.

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