One of my favorite things about engineering is the problem solving. My latest challenge was to solve the production loss issues on a front panel display for a medical device company.
The company was losing a lot of their production to quality control issues due to circuit shorting at the connector end. Our competitor was providing a printed circuit solution, but as we learned it is nearly impossible to print a flex tail with conductors on .5mm centers and designed to mate with a ZIF connector. The reason is not with printing the silver traces but with registering a second printed carbon pass over the silver conductors completely covering them to prevent silver migration and oxidation as well as provide a sufficiently robust interconnect. It is easy to have enough mis-registration or spurious strands of carbon ink spanning across conductors creating a dead short or a high resistance short.
Given present limitations with screen printing, I opted to use a flex circuit that completely eliminated circuit shorting.
While the printing approach does work to an extent, the production losses made it more financially sound to use the more expensive flex circuit.
Problem solved and money saved!