Cleaning printed circuit boards (PCBs), used to operate electrical equipment, is a common issue; it costs time, effort, and money and can do more harm than good if done incorrectly. Cleaning PCBs is important for various reasons, and this tutorial will help you understand how to clean them correctly.
What Is the Purpose of Cleaning a Printed Circuit Board (Pcb)?
The partner’s techniques employed on electro-mechanical assemblies typically include a variety of chemical processing steps. During each stage of the process, there is the possibility that hazardous compounds are left on the PCA that could put the reliability of the assembly in danger. It is typically necessary to clean to remove any potentially harmful residues, and to increase reliability. Cleaning also eliminates the residues that are useful during an inspection.
Improve the PCBs Aesthetic Appeal
For PCB contractors, their boards’ visual appearance may reflect their performance. The inbound QC inspectors could issue red flags if they observe oily, visible substances around solder joints. Solder joint “blow hole” may appear as the flux residue gets charred and produces spots on the solder joints. This is a fault tag in the rework area, alerting others to the problem even if it isn’t a problem initially.
PCB Reliability Improvements
The nature of the final product is what determines its durability. If a keyboard on a computer malfunctions, nobody will be killed because it’s a disposable item. An EMS supplier might use no-clean flux to avoid cleaning thoroughly. On the other hand, pacemaker electronics need to meet strict standards as malfunctioning boards can result in death. Assemblage and any subsequent rework will require cleaning. The procedure here must be rigorously evaluated to ensure its efficacy and repeatability. Even though cleaning is necessary for long-lasting and durable equipment, it is possible that the results can fall in between the two, lacking strict testing and requirements.
Protect Pcbs and Components from Corrosion
There are acids within the residues of flux left on electrical circuit boards. Residues can attract air moisture and cause corrosion of component leads and PCB connections if a cleaning process doesn’t eliminate them. A manufacturing partner is available to help you in case you need a specific component for your build.
The Conformal Coating Prevents Adhesion Issues
Many people know that painting requires a clean surface. Paint peels if not. Conformal coating is contaminated even through no-clean flux. “No-clean” refers to ionic substances left after soldering, not whether coating may stick.
The coating may lift off or delaminate when the flux remains are left on a PCB after coating. This is obvious when pockets are isolated within solder junctions (except at the base of a PCB that has been soldered with a wave). The layers are typically semi-permeable. They “breathe” some. In the case of flux residue, moisture can cause corrosion.
Avoid Ionic Contamination and Dendritic Growth
Dendrites are formed when polar or ionic particles from flux residues and other substances are subjected to moisture in the air, and a current is applied. Since they conduct electricity, they can cause an unintentional track that may let out current or even shorten the circuit over time.