Screen Making Area
Written October 17, 2019
Screen making activities involve several processing steps, each with their own unique requirements. Stretching equipment should have adequate space on all sides to accommodate workers and the tasks associated with stretching mesh. Shelving, or other storage options, should be within easy reach and store tools necessary for stretching (tension meter, adhesive, scissors, etc.)
Setting up an area dedicated to coating screens with light sensitive stencil material requires sufficient space not only for coating but also for drying the coated screens. Manually coating screens does not require specific building design work except a sturdy wall to attach a manual screen holding device for uniform coating.
If automatic screen coating equipment is considered, a variety of configurations are available that are either a wide configuration or a tall one. For the large format screen printer, automatic screen coaters reach to the ceiling or require a “pit” for the base of the coater if the overall height exceeds building limitation for going through the roof. The smaller format screen maker is able to install a screen coating configuration that holds multiple screens for coating and is wider and often free standing.
Screen Room Lighting
Safe lighting for today’s light sensitive emulsions do not require total darkness or walls painted black. The spectral sensitivity of the sensitizer in the emulsion does however require subdued and or color correct filtering. A variety of options are available for this dedicated area for screen coating and storage after coating.
Light sensitive sleeves are an inexpensive way of covering the fluorescent type tubes and effectively filter any unwanted UV energy that might fog or prematurely start a cross-linking of the coating. Covering the acrylic portion of the casing in front of the fluorescent tubes with the correct amber type masking film works well and effectively blocks the unwanted light. The best but probably most expensive method is to purchase the lamps with the light sensitive color correction manufactured into the bulb.
Many screen making areas have a “pin hole” examination area for touching up screens. These are typically large acrylic sheets with fluorescent tube type bulbs in a large case. Yellow acrylic sheeting works effectively in the light safe area. Freestanding configurations are the most popular as both sides of the unit can be used to examine screens.
Screen Drying Equipment
Drying light sensitive emulsions or films by removing the water in the stencil can be performed by the use of a heated cabinet or enclosed chamber and re-circulating air. Blowing air across newly coated screens sitting on a drying rack using a fan is not as effective and can introduce dust and dirt onto the stencil.
Regardless of the method used, the moist air must be replaced by drier air either by elevating the temperature in the drying cabinet or removing the moisture in the air by the use of a de-humidifier. Excessive heat is not necessary, as most emulsions will not tolerate temperatures above 105 degrees Fahrenheit, or 40.5 Celsius. Removing the water out of the emulsion is absolutely necessary to ensure proper and consistent exposure. Today’s screen dryers have adjustable heat with re-circulated air to ensure proper exposure.