What Is Tension?
The tension of your mesh is how tightly it is stretched across your frame. Having tension on your mesh is important during the printing process for registration, ink transfer, ink deposit, speed and consistency. Tension is measured in a measurement unit called a Newton. Most manual screens have a tension somewhere between 15-20 Newtons, typically in the 20 Newton range when they are new. As your screen is used, exposed and printed with it begins to lose tension. Though an average stretched frame can withstand thousands of print impressions, every print affects the tension’s integrity. After 5000 prints, your screen my have dropped from 20 Newtons down to 13 or 14 Newtons. For optimum manual printing you should not print with screens under 14 or 15 Newtons.
How Do You Measure Tension?
A Newton meter measures the bi-directional tension of your screen mesh. They are an important, but expensive tool to have in your shop. You don’t have to have a Newton meter starting out. However, as you progress and accumulate more screens and start printing higher detailed work a tension meter is something you DEFINITELY want to invest in.
High Tension vs. Low Tension
Most manual frames and standard mesh print around 18 Newtons, which exerts about 350-400 lbs. of total mesh force to work with to try and transfer the ink. A Newman Roller Frame with Roller Mesh at 50 Newtons is giving you approximately 1,500 pounds of total mesh force to work with to make the ink transfer properly. It is the force of the mesh that is doing the work for the printer or working against the printer if the mesh force is too low.
• High tension enables you to expose HIGHER DETAIL and transfer maximum ink coverage to the substrate.
• High tension equals BETTER REGISTRATION because the mesh movement is minimized and the off contact needed is minimal.
• High tension increases PRINT SPEED because the mesh force helps the squeegee transfer ink and the minimal off contact means the squeegee doesn’t have to press as hard while printing. This enables the squeegee to move faster, which increases production speed tremendously.