An important step in the screen printing process is creating a properly exposed screen print frame.
The Mesh Screen Frame Developing Cycle
A well developed frame will not break down while you’re on-press and printing your job. Additionally, a well developed screen printing frame can be saved for multiple uses. While screen printing is both a science and an art, there are a few basic steps that should be done to ensure a well developed screen.
The major pre-press steps for how to make a screen print frame are: degreasing, applying emulsion, and exposure. These simple steps are important for preparing your screen printing mesh for the emulsion and exposure to U.V. light. Following the proper pre-press steps helps ensure a strong stencil and reduce pinholes while printing.
After finishing the print job, it is similarly important to know how to do the proper post-press clean up procedure. Knowing how to clean up after printing a job helps keep your shop clean and allows for a quicker overall clean up. You want to reduce your clean up time so you can focus on printing more jobs.
The following steps outline the proper procedures in the screen print frame-making cycle. They go from pre-press, through production, to proper post-press screen reclaiming.
Screen Printing Mesh Frame Making Process
1. Degreasing - New mesh must be cleaned of lubricants and grease that was picked up during the manufacturing cycle. It is also a good idea to de-grease screens after every use. To degrease, use a Mesh Degradent
2. Abrading - You want to abrade the mesh of your screen printing frames. This helps ensure proper bondage of the emulsion or capillary film.The best way for how to properly abrase your screen printing mesh is with a flat scrub brush.
3. Drying - There are 4 drying steps when making screens. This first drying cycle occurs prior to applying liquid emulsion. If you are using capillary film, you do not need to dry your frames. This is the stage when you will apply the capillary film.
4. Coating with Liquid Emulsion - A scoop coater is used for applying liquid emulsion. There are many different coating techniques, depending on the thickness of stencil you wish to produce.
5. Drying - This is the second drying cycle. Not allowing your screen to thoroughly dry at this stage will leave moisture in your emulsion and will cause exposure issues. Always dry your mesh screen frames with the print side down.
6. Exposure - Attach your film positive and expose your screen. Exposure times vary depending on your exposure system. LED lights are slower than fluorescent tubes. Emulsion types such as photopolymer, dual-cure, diazo fastest all affect exposure time.
7. Develop - Remove the film positive and develop your screen by using water. The areas covered by the dark, dense image of your film positive will wash away. The rest of your emulsion should have hardened during exposure and will remain on the screen print frame.
8. Drying - Dry your frame for the 3rd time to help maintain the stencil/screen’s longevity while on-press.
9. Taping/Blocking-out/Pinholes - Basically all screens will require taping or blocking out the areas around the edges that were not coated with emulsion. During printing, your screen may develop pinholes. This is caused for several different reasons and is often fixed with a piece of tape or a block-out pen.
10. Removing Ink from Screens - After you are done printing, you can remove and save all of the unused plastisol ink from your screen. Simply scrape off the excess ink and put it back in your bucket.
11. Reclaiming - You want to scrub off the remaining ink and emulsion so you can use your screen frame again. Using an ink degradent, emulsion remover, and a haze remover if need be, apply the chemicals and wash your screen. It is best to use a high pressure washer for reclaiming. Alternatively, you can use a dip-tank and all you will need to do is wash away the ink and emulsion.
Once you have reclaimed your screen, it can immediately be de-greased to start the screen making cycle again.
