The screen-printing process, used today worldwide for printing on garments, was basically developed in China over 1000 years ago and essentially, has changed very little. Developments in materials, inks, and chemicals have refined the process but the basic way of passing inks or dyes via a mesh screen onto the printable surface remains the same.
It’s possible to have similar quality prints if you are using homemade manual equipment in your garage or operating large automated machines in a manufacturer – something which will vary greatly though is production times. The next explains the basic’spot color’process from somewhere in between, ie dealing with a small-scale professional set-up using a guide printing carousel:
The first faltering step is to separate your lives the colors in the design using standard software such as for instance Adobe Illustrator or Corel Draw – or even to employ the services of any certainly one of a number of graphic designers advertising on the internet. Us Space Force T-Shirts For every color, a screen must be produced which will be found in turn with the others to print the image (if printing onto dark garments an extra screen to generate a’flash’undercoat of white ink is likely to be needed to make the colors in the design more vivid). After the colors have been separated they are printed to scale in black onto acetate sheets, together with registration marks, utilizing a standard ink-jet printer. The blacked our artwork then must be utilized in the prepared screens.
The conventional screens used have a metal or wooden frame with a tightly woven mesh, usually made of nylon or polyester, stretched across them. Screens with different mesh counts are employed with regards to the intricacy of detail in the design (generally speaking higher mesh counts are used to reproduce greater detail as less ink can pass through the screen). Screens are prepared by coating them with a photo-reactive (light-sensitive) emulsion and then left to dry flat in a place free from UV light. When this solution is dry the screens are ready to really have the artwork’burned’or exposed onto them.
A lightbox is now used that is basically a box containing UV light-emitting tubes, a definite glass surface above and a product lid. Each acetate is put upon the glass area and a prepared screen laid on the top – mesh side down. The material lid is closed and drawn tight over the screen utilizing a vacuum pump – a timer is then set as the image is developed onto the screen. The emulsion on the screen now reacts and hardens where the UV light hits it and stays soft where the regions of opaque black areas on the acetate block it. Once the timer has stopped (anywhere between 1 and 20 minutes with regards to the intensity of UV light) the screen is ready to be washed off with water utilizing a hose or low powered pressure washer. The water washes away the regions of emulsion that have not developed, creating areas on the mesh for the inks to pass through.
After the developed screens have dried masking tape is applied across the edges to avoid ink seeping through areas so it should not. Each screen is then clamped onto an arm of a carousel, mesh side down, and special’plastisol’or water-based ink in each corresponding colour applied on top. To join up, or make, the screens a scrap little bit of material is put over the platens (boards which hold the garments to be printed) and a test print is produced. This is done by forcing the ink through the clear spaces in the mesh utilizing a hand-held rubber’squeegee ‘, printing the lighter colours first. If printing onto dark coloured garments the flash coat of white is printed and then passed under a temperature lamp to touch dry before the colours are applied. The registration marks which can be printed onto the scrap material are arranged consequently until the finished, registered image is produced. To cure the ink the printed garment is put on the conveyor belt of a tunnel dryer and heated to 320 degrees F (160 C). This may avoid the ink from washing away ensure the image will remain for as long as the garment lasts.
If a number of garments can be printed time is saved by dealing with a colleague, one T-shirt printing and one loading/unloading. To be sure of having the best reproduction of one’s designs and logos always use the very best quality T-shirts and inks that your budget can accommodate.