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Mesh Movement and Its Impact on Screen Tension, Part Two

(April 2003) posted on Thu Oct 29, 2015

Dr. Anderson's sage advice still rings true today with this flashback to 2003.

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By John Anderson

On retensionable frames, loose mesh is fixed to the frames sides, which are then rotated or expanded to tension the mesh. The effect is identical to a stretching system for rigid frames that uses only one clamp per side. This approach maintains the mesh count at a fixed value because all the threads are locked into the frame sides. But it also results in the maximum mesh distortion and the greatest potential for tension loss due to fiber realignment. The primary advantage of retensionable frames is that they can reapply tension to the mesh if the tension level drops. This capability also makes them heavier and more expensive than rigid frames.

Mesh tensioning on retensionable frames is normally conducted as a multistage process, and mesh stabilization through fiber realignment is assisted with successive stretching and rest cycles. Once the mesh is stretched to the target tension level, it is ready for us. However, action from printing, cleaning, and reclaiming triggers further fiber realignment, which causes additional tension loss. So the mesh is retensioned on the frame prior to its next use.

As the cycle of mesh use, reclaiming, and retensioning continues, the tension loss experienced after each reclaiming stage is reduced, and the mesh requires less retensioning to reach the desired tension level. Eventually, the mesh attains a stable state when no more tension loss occurs due to fiber realignment. At this point, the mesh is completely broken in and ideal for use on jobs that require a high degree of accuracy and repeatability.

This scenario sounds perfect, but the use of retensionable frames creates other difficulties. One problem is that until mesh deflection has been completely eliminated through multiple usage cycles, the screen’s tension is unstable and can vary unpredictably. Furthermore, relying on multiple printing, cleaning, and retensioning cycles to provide complete fiber realignment increases the risk of mesh damage and is slow and takes expertise. Nevertheless, retensionable frames allow you to get more use out of screens than rigid systems, which can lead to cost savings in mesh.


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