Tension And Why related people count It Important to use in Screen Printing Polyester Mesh: The tension of your mesh is how tightly it is stretched across your frame. Having had tension on your mesh is important during the printing processes for registration, ink transfers, ink deposits, speed and consistencies. Tension is measured in a measurement unit called a Newton. Most manual screens have a tension somewhere between 15 to 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 4500 to 5000 prints, your screen might 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 have taken a Measure of 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 progresses and accumulate more screens and start printing higher detailed work a tension meter is something you definitely investing in.
High Tension versus 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 transfers 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 transfers properly thru screen. 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 Details and transfers 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.
Choosing the Right Tension: The tension or tightness of your screen mesh is very important to the quality of image you can produce while printing. As your screens become old they can lose tension. By dropping below the proper tension (15-20 Newtons) your screen will not release properly, causing a less than desirable image.
As the mesh loses tension the fabric begins to distort, making the resolution of the mesh to become unsuitable for use. You can tear out the mesh when it becomes un-usable and re-stretched with new mesh with the proper tools. As your business grows you might wants to investing in a tension meter so you can closely monitor your screen tension.
Do you know much about on your Screen Print “Hand” : In a few words, Mesh Equals to Hand. Hand is the feel of the printed surface on the garment. The less you feel the print is called soft the more is hard. Soft hand being better. Specially, Women are like that.
The hand is determined by mesh count, mesh tension and ink viscosity.
The higher the mesh counts the less ink lay down. You can also modify the viscosity of the ink, by reducing it to create a softer hand. One thing to keep in mind however is that by changing the ink and or going with a higher mesh count in order to screen printing, you will also sacrifice color saturation.
Keep note on Under-Exposure Variables, Under-exposure indicators:
A) Squeegee side of screen feels slimy; This is a sure sign the screen is underexposed. The slime is actually unexposed emulsion. If it is not completely rinsed off, it can dry in the image areas and block the ink. This is called “scum”.
B) Stencil peeling away from mesh; particularly with capillary film. Stencil exposure occurs progressively from the substrate side into the squeegee side. Underexposing the stencil leaves the emulsion on the squeegee side of the mesh soft where it’s literally washed away during development. If enough of this emulsion is washed away, the direct emulsion can actually peel away from the mesh. With capillary film, the fragile interface of stencil to thread can be quickly compromised when the stencil is not fully hardened.
C) Stencil pinholes; If you see scrutiny a lot of them during washout, underexposure is the leading cause.
D) Halftone dots easily rinse off the mesh; Most dots should remain attached to the mesh during washout, when the correct mesh count is matched to line count on printing.
E) Sawtoothing- irregular edge definition; This is caused by too much emulsion washing away due to the softened emulsion Pls cross check that your film is dark enough and that your exposure time is long enough. An exposure calculator will help to determine the appropriate time necessary.
Have You been an Idea What Line Screen And Mesh Count Should be Used: It’s very important not only to choose a proper line screen for your art file to capture details, but it’s equally important to choose a proper mesh count that works with your line screen to best fit to your printing works.
Resolve / Remedy : Here is an accepted formula for determining the correct mesh count. Multiply your line screen by a factor of 5. Take the equal or next ( higher ) closest mesh count ( i.e., Line screens of 45 x 5 = 225 so choose a 230 mesh or higher which are available in current market ).
Mesh to line screen formula is in reverse 230 mesh divided by 5 = 46 ( line screen ). 46 representing the “highest ( means finest )” line screen count that should be applied to a 230 mesh.