He uses a very labor-intensive setting that you do not have with dye sublimation pressures.
Im going through the screen printing process as I know it quite intimately because this was where I started my career in the graphics industry.
Central to the screen printing process is the screen duh right? The screen is still often called silkscreen although the page has not been used for many decades since the Nylon Song came.
There are many types of screen networks starting at about 100 threads per square inch and up to several hundred threads per square inch. The more coarse mesh becomes less common because it is used with oil-based enamel paints replaced with UV ink as we run through a 220 mesh figure because the ink particles are much smaller than in the older solvent colors.
The screen network typically stretches and glues to a wood or aluminum frame or is attached to expandable frames or rolling frames. When you extend the grid over a frame we usually take pounds per square inch shown on a Newton Meter up to 25 or 26 and allow the fabric to extend overnight.
By the time 16-24 hours have elapsed the meter shows that the voltage has fallen to about 15 pounds per square inch and we repeat the process and the screens should have the correct voltage of around 20-22 lbs. per square inch voltage giving a tense screen that will deliver a good clean print.
When the screen is tied and attached to a frame we usually use a fabric strip to strip around the edges of the frame both inside and out. This is a semi-permanent solution for bleeding around the edges of the emulsion.
Now the screen is ready for photo-sensitive emulsion which is applied with a scoop coater a variable length tray into which the emulsion is poured. After applying the emulsion to the screen we move the screen to a flat cured drying / storage cabinet where it dries. Different systems with coated screen storage dry the coated screens at different rates but we are usually ready to expose within a few hours unless we put a blow on them.
When the emulsion-coated screens are dry we can now place the film on the print side of the screen opposite drop it into place and move it to a vacuum frame. The vacuum frame has a large piece of glass where the screen is located the print side facing the glass. A blanket is placed over the screen frame and a vacuum motor is plugged in and the screen is pressed tight against the glass.
The vacuum frame is now rotated to meet an exposure light which is normally on a timer. The light turns on and the photosensitive emulsion is exposed but the areas behind the films positives remain susceptible to water. After the set time typically 6 to 10 minutes the light extinguishes and the vacuum frame is rotated back to lay flat the pressure is released and the screen is removed and moved to a wash tank.
There are semi-automatic washbasins that when you insert the screen it will expose the image with water in a short period of time. At this time we allow the screen to dry and be ready to place it on the screen press.
When you are sure there are no pinholes if there are we use a blockout emulsion to fill them we drop the edges to make sure ink does not leak around the edges of the printout more of a problem at a clamshell press than one that lifts up and down leaves the screen flat all the time. We set up the substrate put in blockers micro-adjust the screen to the substrate and be ready to print.
The biggest weakness of screen printing is that we need to make a new screen for each color print which means that the time for screen printing is quite time consuming. But because the printing process is very fast if there are a large amount of characters or decals or banners etc.
Then we pour ink on the screen and print anything for printing season bumper stickers or bumper stickers or stickers or window sticker for a company or characters or what our customers order.
After printing the excess ink is returned into the ink bin and the screen is removed to a wash tank degreased and prepped to repeat the process.
Color sublimation Printing of monitors and banners is virtually always made on polyester fabric because the polyesters chemistry is suitable for dye suppression. The chemistry involved in color sublimation printing is fascinating for me not only because its a complicated process but because the final result is the absolutely perfect print of fabric ribbons posters and displays available.
There are four dyes involved similar to an inkjet printer. The color coding for color-dimensional sublimed printing is a little different from the CMYK printing that the inkjet printer performs. The color code is CMYO cyan magenta yellow overprint clear.