Here at MicroScreen we offer a wide range of specifications to meet your individual screen needs.
The theoretical wet print thickness can be calculated from the mesh specifications and emulsion build up by using the following formula:
Tw = (Tm x P) + Te
Tw = wet print thickness
Tm = mesh thickness
P = decimal equivalent of % open area
Te = emulsion build-up thickness
Results are also affected by printer variable such as squeegee pressure and durometer, angle of attack, speed, and snap-off distance. Dried or fired print thickness is a function of the volume of volatile materials in the printing material and other factors. Consult your materials supplier for further information.
Photosensitive emulsions of several different types can be applied to the mesh covered screens. Mesh equalization is the process of filling the mesh opening with emulsion and building up a thick enough emulsion to equalize or smooth out the surface structure of the mesh. Additional emulsion is applied to match a customer specified emulsion build up or overall screen thickness.
One of the functions of the emulsion is to control edge definition by gasketing the ink at the print edge. To properly achieve this gasketing, the emulsion must have good mesh bridging. For example, if the image travels diagonally across the mesh opening, the emulsion must be capable of adhering to the wires in such a way that it will precisely and sharply image across the mesh opening. This gasketing also allows the screen to retain the ink in the exposed area without bleeding under the emulsion. Bleeding will cause poor print definition, creating a sawtooth effect at the print edge. With good gasketing, the screens do not have to be cleaned as often and have a longer emulsion life.
We use automatic, PLC controlled coating machines to assure emulsion thickness repeatability from screen to screen that cannot be accomplished by any other method. Parameters, including number of coats, speed, dwell time, and length of coating, have been set for the processing of all direct emulsions.
These machines, with their uniform coating pressure and precise coater movements, provide excellent control of emulsion and is repeatable from screen to screen and within a screen to within one micron.
Quality Control and Process Management
MicroScreen has made the management commitment to produce screens of the highest quality every time. We manage our screen quality control based on in-depth experience and knowledge of all the variables of the screen production process. We use only the finest materials available and measure, test, and document every stage of the process.
Each bolt of mesh is selected to meet our published specifications, and a reading taken during manufacture at the mill accompanies each bolt. When the mesh is received, it is inspected for wire diameter, mesh opening, weave thickness, mesh count, uniformity, and other variables. These parameters are important because they are the primary contributors to wet print thickness.