Preventing Solder Balls After Reflow

To prevent solder balls and product failure, rely on Capital Equipment Exchange to utilize dependable reflow soldering during printed circuit board (PCB) assembly. We offer services to ensure that your industry has reliable printed circuit boards for all your electric components.

Why Worry About Solder Balls?

Printed circuit boards are a defining portion of an electric component. Because PCBs are naked circuit boards, the semiconductors, capacitors, and resistors must be soldered onto the board. During assembly, solder balls, a glob or clump of the metal alloy used to attach electrical components, form during the reflow process. They create an unpleasant appearance for your electric components, and sometimes fall off, potentially causing the circuitry to fail.

Assembling PCBs With Reflow Soldering

When assembling the printed circuit board, the resistors and other electrical components are installed using solder paste to hold the components in place. Once all the components are placed in the paste, the entire board is put in a controlled, heated environment. The paste then “reflows” or melts solidly, permanently attaching each piece. Sometimes solder balls are formed when air or water vapor gets caught below the layer of paste.

Causes of Solder Balls During Reflow

Water is on the printed circuit board.
There is too much flux applied to the surface of the PCB.
The flux did not evaporate completely.
The board stencil has not been designed properly or is not clean.

How To Prevent Solder Balls

Once you have figured out why the solder balls are occurring during the PCB assembly, you can take steps to prevent them before they happen.

Do not store the PCB in a humid environment.
Preheat the board to allow for trace water to evaporate before printing.
Ensure the printing stencil is properly cleaned before applying the paste. Our Exchange PCB Wash and Stencil Cleaner provide this service to ensure proper cleaning for your equipment.
Make sure you use the proper amount of flux to avoid excess air and water being trapped.
Check preheating temperatures to ensure the flux evaporates properly before applying the paste.
Check the pad size and space requirements of the PCB assembly to prevent abnormal reactions in the printing process.
The thickness of your printing holes’ copper plating must be greater than 25μm.

Contact the Experts

Capital Equipment Exchange has been a supplier of used PCBs for the last 20 years. We make sure our machines are fully functional and production-ready, help with shipping worldwide, and offer free valuation services for lessors. Our team provides services and equipment for PCBs, including PCB wash and stencil cleaner, wave soldering technology, and reflow ovens.