Historically print thickness has been defined on printed segements greater than 20 mils wide. With a given screen and materials selection, print thickness may not be as expected; when fine lines are considered. There is usually a "hump" in the data curve as shown in the figure above. Causes for this as primarily materials.
- Rheological characterics of the conductor paste
- Wetting and release characteristics from the screen & emulsion
- Wetting and leveling characteristics to substrate (dielectric).
Typically, this "hump occurs on line widths that are between 0.01" and 0.018". As you can see print thickness drops off quickly as lines become narrower.
Know your conductors effect because:
- If inner layer circuit in multilayer circuit; it may print thicker than desire. Hence increase chances of between layer shorts.
- Narrow lines may have variable thickness which can impact bonding
- Choosing screens with focus on fine line may make solder pads too thin.
We have design curves for some of our newer conductor products, please call.