Tenting is an essential stage in PCB (Printed Circuit Board) manufacturing, it significantly improves the longevity and performance of the end product. This means that via holes (small openings on a PCB that allow the connection of different layers) can be covered with a coating mask. So to that end, we have jotted down everything you need to know about how tenting works and why doing it can help with protecting your PCBs.
Understanding Tenting
Tenting is essentially a process for closing off via holes, which are covered using solder mask — the same material that is used to cover most of the PCB surface. This method also protects against the introduction of solder, humidity, and foreign substances at any point during or after product manufacturing. Tenting is essentially a method used to protect the fragile internal VTs connections of a PCB from the elements and outside mechanical stress.
Benefits of Tenting Vias
Better Protection from Contaminants: Tenting also helps in sealing the vias, so no dust, or chemicals can enter the tunnels and if they creep inside, they will start short-circuiting or corrode the metal joints. This is especially important in gadgets used in hazardous environmental surroundings.
Enhanced Soldering Strength In the soldering process, the exposed vias can draw solder away to form poor joints or even worse open circuits. Tenting helps protect tin joints from contamination, and keep the solder where it was supposed to be, too.
Strengthens PCB: Tenting protects the PCB structure, specifically at via locations, which is recognized as the vulnerable section of a PCB. Doing this creates a PCB that will be more tolerant of certain types of mechanical stress e.g. bending or twisting which might otherwise cause the connections to crack or break.
Cheap Reliability: There are other ways to protect vias, such as via plugging or via filling, however tenting is by far the most cost-effective solution as it does not require any additional materials like epoxy or conductive pastes. This, in turn, makes it particularly suited for high-volume production, with a priority for cost efficiency.
Tenting in PCB Design
In PCB design, engineers three normal options for tenting vias on one side of the PCB, both sides, or to leave them not tented. This decision is usually driven by the particular PCB application. For instance, if you are designing extremely valuable electronics, double-side tenting could be implemented in the PCB even though it may raise production costs somewhat.
There are the benefits of Advanced Tenting Techniques
Copper via tenting solutions often partially or fully fill the vias with solder mask material, you are basically creating tenting solution on just the top side in which will be done prior to copper plating the holes. These methods effectively bolster the protective attributes of tenting by ensuring a stronger seal at via locations and also by adding some measure of mechanical strength to the via sites.
The tenting method used can make a big difference on how the PCB will perform and last. Efficient tenting is therefore a good way of ensuring that the circuit board works as it was intended to for its entire operational life - and does not fail along the way, because of the environment or because of some kind of mechanical stress.
To learn more about how tenting can shield your PCB designs, check out some of the comprehensive guides concerning the different types and uses of different PCB protection methods.