Thru-Hole Silver Circuit: What is It and What does It do?

Last Updated: Mar 06, 2017 | by Trey Hooper | Membrane Switch Technology | 0 comments

A Definition of Thru-Hole Silver Circuit

When printed circuit boards (PCBs) are double-sides, they require a component that connects the top and bottom surfaces electrically, especially when manufacturing complex board designs. Traditional plated thru-hole technology (PTH) allow for holes to be drilled into the PCB and plated with a conductive material to make the electrical connection between the top and bottom surfaces.

Now, thru-hole silver circuits more commonly provide the necessary electrical connection between the two surfaces, because they allow for small laser thru-holes that feature conductive silver ink printed on and through the holes to make the connection. Manufacturers screen print the silver, much in the same way they manufacture membrane switches.

Characteristics of Thru-Hole Silver Circuit

Thru-hole silver circuit PCBs are quite popular because of their low cost, reliability, and environmentally-friendly process. Thru-hole silver circuit PCBs are similar to double-sided copper flex circuit (FPC). Both thru-hole silver circuits and copper flex circuits are double sided and require thru-holes for electrical connectivity.

Thru-hole silver circuit PCBs also feature a carbon overcoat and printed resistors. One thing to keep in mind with thru-hole silver circuit is that it is necessary to avoid silver crossing silver.

Challenges of Thru-Hole Silver Circuit

One drawback of using thru-hole silver circuit is that it requires some design considerations. Because thru-hole silver circuits are plugged with silver paste, they cannot be used as component lead holes. To resolve this issue, designers and manufacturers add extra thru-hole silver circuits.

Another potential challenge of using thru-hole silver circuit PCBs is that their connections are a little less conductive than plated through-hole connections. One solution is to add more thru-hole silver circuits to the board and use multiple holes in parallel. Typically, there is not necessarily a limit on the number of thru-hole silver circuits on a PCB. Some thru-hole silver circuit boards with dimensions of 5″ x 7″ contain more than 800 holes. Under normal circumstances, hole count is not a major consideration.

Thru-hole silver circuit boards also may be difficult to manufacture reliably. This is due to the fact that if a single hole is defective, it ruins the entire PCB. It is best to find manufacturers who have a trusted history of creating reliable, efficient thru-hole silver circuit PCBs to ensure high-quality thru-hole silver circuit boards at reasonable prices.

Benefits of Thru-Hole Silver Circuit

One of the main benefits of thru-hole silver circuit, as compared to plated thru-hole technology, is that thru-hole silver circuit PCBs are less costly than similar PTH boards. The plating process is harsh and involves a complex process with strong chemicals that produces immense waste. On the other hand, the silkscreen printing utilized in thru-hole silver circuit manufacturing is not harsh nor hazardous, which allows for the use of more economical board materials.

Other benefits of choosing thru-hole silver circuit boards is their higher dielectric strength. Intertek succinctly describes dielectric strength: “a measure of the electrical strength of a material as an insulator. Dielectric strength is defined as the maximum voltage required to produce a dielectric breakdown through the material and is expressed as Volts per unit thickness. A higher dielectric strength represents a better quality of insulator.”

Overall, thru-hole silver circuits offer a cost savings of up to 25% over traditional plated thru-hole double-sided PCBs. Specifically, thru-hole silver circuits bring cost reductions to customers, as the technology replaces the costlier process of double-sided plated through hole board designs. Printed thru-hole silver circuit technology is a much simpler and environmentally-friendly process than the expensive plating process that yields hazardous waste. Thru-hole silver circuit board manufacturing also allows for less expensive board materials, while maintaining the integrity of the PCB design. And, some PCB manufacturers use thru-hole silver circuit technology in a completely lead-free way, so the completed thru-hole silver circuit boards are compatible with lead-free processes.