How It Works: Screen Printing
Have you ever stumbled upon one of those shows on TV that brings up an ordinary, everyday item and then proceeds to delve in to the fascinating and often complex processes that goes in to manufacturing those items on a large scale? Before you know it you've watched 6 episodes back to back and the day is gone but hey... at least now you know how marbles are made. Well guess what--the processes involved with bringing your promotional projects to life are just as fascinating and it's very common for the average person to come in to contact with this manufacturing process during their lifetimes.
There are a few different ways to decorate promotional products; screen printing, pad printing, embroidery, heat transfer, and sublimation to name a few. To start this series off let's talk about one of the oldest industries in the United States, screen printing. Whether you're an artist looking to research the craft, an enthusiast who just loves the process, someone looking to place their first screen printing order, or a seasoned veteran who just wants to get a better understanding of how it all works, more knowledge never hurt anybody and a deeper understanding of this process could help if you ever need to procure some new products.
Screen printing is an incredibly versatile art and the process can be applied in so many different ways that it can be staggering but regardless of your application of the art, the process remains largely the same give or take some technological advancements that you may or may not have access to. To sum up the process via Wikipedia, screen printing is a printing technique whereby a mesh is used to transfer ink onto a substrate, except in areas made impermeable to the ink by a blocking stencil. A blade or squeegee is moved across the screen to fill the open mesh apertures with ink, and a reverse stroke then causes the screen to touch the substrate momentarily along a line of contact. This causes the ink to wet the substrate and be pulled out of the mesh apertures as the screen springs back after the blade has passed.
Here at South Shore Customs, the screen printing process begins in the office with a client and an idea. We coach our clients through the process, making decisions about their project with regard to substrate (what we're printing on), ink types, ink colors, print locations, order quantity, and more. With artwork in our hands and our plan created, we can start our work.
To make a comparison, let's think of a silk screen as a print head like those found in a home printer. Each color requires it's own ink cartridge or print head--logically speaking, you wouldn't be able to print two different ink colors through the same print head/reservoir or else the colors would mix undesirably. For this reason, artists will break apart your artwork in to the various colors that make up the whole which are later translated in to screens. Let's say as an example that we were printing an American flag. We would separate the design up in to the red information, white information, and blue information. Each piece will then be printed on a sheet of transparent film and taken to the dark room.
The dark room and the wash-out room attached are where our screens live when they're not being used for printing. Screens in the dark room are prepped with a light-sensitive emulsion which hardens and bonds to the screens when exposed to light for a certain period of time. This is where our films come in. Films are temporarily adhered to the screens where the color information printed on the transparent film will block the light from a controlled exposure unit. Everything that the exposure light touches will harden and bond to the screen while everything blocked from the light, your design, will remain soft and pliable.
Exposed screens will then be brought to the wash-out room where screens are usually being cleaned of ink after being used or being reclaimed and recycled. With a hose or pressure washer, exposed screens are bathed or agitated with water until your design completely washes out. The remaining emulsion on the screen will harden up further upon drying which will be impermeable throughout the printing process. The areas in the screen where your design is will be open, uncoated mesh which will allow ink to pass through.
After the screens have dried from the washout process, we're ready to start printing. Screens can be printed in such a wide variety of ways. There are hinge/clamp systems, manual presses, automatic presses, or you can print entirely by hand. Due to the ease of setup and consistency of printing, South Shore Customs uses automatic and manual presses for all garment printing projects.
The press manager has final say, making all of the necessary decisions about setting up screens on press. It is their job to make sure the project runs smoothly and as efficiently as possible. Once they place the screens on press in their desired print order, the screens are registered and each screen is loaded up with the appropriate ink colors.
Garments are loaded on to the press on boards called pallets which hold the garments in place throughout the printing process. The pallet is moved to the screen being printed or vice versa. The ink is run over the screen, filling up the porous mesh. The screen is lowered to meet the pallet and a long rubber blade or squeegee is run along the screen with pressure, transferring the design on to the surface of the substrate. In some cases, additional colors can be printed while the ink is still wet. In others, the prints must be dried first with an on press heat unit in order to print subsequent colors of a design.
Finishing off the process, the garments are unloaded from the presses and cured with heat. Running garments through the conveyor dryer, basically an oven running over a conveyor belt, the ink is more-or-less baked to a cure. The curing process is incredibly important to the life and longevity of a print. Different ink types require different methods of curing with regard to cure time and cure temperature. If you aren't careful and the ink isn't cured adequately, prints can crack or fade prematurely. Once the ink is cured, garments are stacked up and boxed, ready to wear! The screens used are cleaned of ink in the washout room and saved for future printing or reclaimed and recycled for another project and this print run has come to a close.
When it comes to bringing your project to life, the importance of who you choose to work with can not be overstated. The team at South Shore Customs is not only committed to providing a fast and affordable service, we also stand by our craft as artists who are invested heavily in creating the highest quality products for our clients. Have questions about process or pricing? Want to get started on a project? Speak with one of our knowledgeable team members today.