Manually Adjusting Misplaced SMT Components

> Hi All, > > On occasion we see components that > have gone through pick and place and are slightly > misaligned. Currently, operators manually adjust > these misaligned components to prevent reflow > failures. However, I am wondering if this > readjustment may be unnecessary since the > components should self-align during reflow. Also, > what tools do people typically use to readjust > misaligned components?

First check a few things on the machine, such as board backup supports and clamp as it may be lose.

Can also be the way the machine is placing the part, like the nozzle setup, or incorrect component dimensions etc...

..But any who! yes yes if something mis-aligned "BADLY" you can correct it using tweezers, just be sure that the person is grounded.

You can allow mis-aligned parts to go through re-flow, not all parts will "self-align"

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there can be so many different causes. can be component library height issues. step program z axis offsets - i have seen accidental positive values entered so the components are literally dropped onto the pcb haha. but it does depend on the size of the component. you can sometimes get away with small 0402, 0603, 0805 size caps and resistors, they can sometimes self align (to a certain degree) when they are soldered but i would adjust any larger components with tweezers. weight and size will effect how it solders a lot. micros etc with many legs or any component with a larger surface area likely will not solder nicely.

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We all agree that you need to have your machine fixed. It probably needs calibration. Using Lead paste will help the parts to self align in the oven - however your misplacement should cover at least 50% of your pad. Pb free paste will not self align your parts - they will remain on the same place they were before the oven.

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