Tips & Tricks – Why Do Components Tombstone

Ever wondered what is Tombstoning and why does it happen?

What is Tombstoning?

Tombstoning also known as the Manhattan or crocodile effect is where one end of the component lifts from a pad of the PCB during reflow soldering process and affects mainly surface mount components such as resistors, capacitor and inductors.

Why does it happen?

There are a few reasons for Tombstoning such as the soldering process, contamination of the PCB or the actual PCB Layout.

When soldering a component to a PCB it is important that solder reaches the ideal fluid state, this is known as the Wetting of the solder.

It then forms an inter-metallic bond between the terminal of the component and the pad on the PCB before it cools and becomes solid.

Tombstoning occurs when one end of a component (like a resistor) completes the Wetting process before the other. This end then pulls and tilts the component to create the Tombstone effect.

The PCB Layout can influence the Wetting process. An imbalance of the thermal mass between component pads will result in one end completing the wetting process before the other.

At Eurocircuits we continue to develop our Tools, Information, and Guidelines to help PCB Designer Engineers to create ‘Right First Time for Manufacture’ PCB Layouts.

Why not take a few minutes to review our latest Guideline on Tombstoning.

Should you have any questions about any of our services, please feel free to get in touch via email, telephone or instantly with our online chat during office hours. We will be more than happy to help.