Stretching Smartmesh

Stretching Screen Mesh

The most important part of the screen printing process involves how your mesh is tensioned. The common school of thought is tighter is better. Quite often a ‘ballpark’ figure is used, ‘I stretch all my screens to 30 newtons.’ Lets look at this to determine if it is a ‘best practice.’ Best practices for one shop could spell disaster for another, it all depends on a shop‘s presses, personnel, and other factors as we will see.

Let’s start with a mesh guide. <- click here

Not all mesh should be stretched to a blanket statement like the one above. A mesh guide points this out. Look at the recommended tensions below for a 150/T and 150/S mesh.

Mesh tension capacity is a factor of the thread size used, the number of threads per inch and finishing techniques. Thinner threads require less tension than thicker threads, otherwise any rough handling of the screen will cause mesh to pop. Lower tensions applied to thinner thread doesn’t affect registration when using Smartmesh unlike other import mesh. Smartmesh has mesh memory. The term in the past was low elongation which refers to how well the thread resisted stretching when under tension. Smartmesh’s mesh memory takes this a step further to also resist the forces of the squeegee during printing even when lower tensions are used. So tension is one part of great prints, but the meshes’ ability to return to the same location during printing results in non-stop printing with excellent registration for the entire run at a workable tension. That is key to long term screens. Selecting a ‘workable tension’ that produces great prints and a screen that won’t explode under normal handling.

What is a Workable Tension for my Shop?

Ask yourself these questions first. These conditions are common to most shops, modifying them will help you improve screen life, or allow for more critical types of printing like simulated process where dot on dot register is required that use S thread meshes for today’s soft hand plastisol feel. 

1. How much off contact is normal for your press? If you are at almost a quarter of an inch off contact to compensate for old under tensioned screens you need to use lower tensions on new S mesh screens to avoid having the squeegee corners wear a hole in your screen that can cause a high tensioned ‘S mesh’ screen to explode. You can use a thicker thread to avoid this, but thinner S thread meshes produce softer, brighter prints with less ink due to the greater open area they provide over T and HD threads. Lowering off contact to 3/16-1/8” can allow you to use higher tensions and not cause the mesh to wear as well as rounding off the corners of your squeegee. 

2. How do your employees handle screens? If they stack them against a wall and kick the bottom to straighten them up, or handle them two by two and drop them to the floor, or toss them in a sink letting the corner of the frames bounce against the mesh, you need low tensions from the guide. If you want to stretch to a higher tension you need to handle high tension screens carefully, especially S mesh screens. Use screen racks where possible to transport screens. Screen rooms, especially reclaiming, need procedures to protect mesh, not abuse it through rough handling. 

3. How do your employees set up screens on press? To often during set up squeegees, ood bars, and clips are dropped onto the screen and then attached to the print head. Burrs, screws, and bolts sticking out may not pop a T thread, but they can pop an S mesh that is stretched to the highest tension possible.