When your squeegee is sharp and in good shape, it will completely fill in the details of the stencil, giving you more control over the flow of ink and peeling the screen cleanly from the substrate for your print. In short, a well-maintained squeegee will help you produce crisp, crisp prints.
How Screen Printing Squeegee Degrades
Conversely, a worn squeegee will mean a degraded print. If your squeegee becomes dull, it can leave behind heavy ink deposits that can blur the edges of your prints and obscure printed details. A chipped squeegee can leave a long, heavy streak of ink on your image. A damaged squeegee may start to "skip" parts of the ink and screen, leaving defects in the image. A dull scraper will cause you to use more ink, which will cost you extra money.
Squeegees inevitably break down over time. Exposure to inks and solvents can cause blades to swell and warp. The pressure of pulling the scraper across the screen weakens the scraper, and the constant drag of the scraper on the rough surface of the screen dulls the edge of the scraper.
Proper squeegee care can help lessen the effects of a bad squeegee. It can also save your shop money: taking good care of your blades can avoid overuse of ink and frequent purchases of replacement blades. There are some simple guidelines to keep your scraper in good shape.
1. Effective and quick cleaning of the scraper after each use
Rubber blade materials can swell and warp when exposed to moisture from inks and solvents. Cleaning the scraper immediately after each use will help reduce warping. Never soak the scraper blade in solvents, as this can cause excessive swelling and warping, as well as premature failure of the scraper blade. Letting the ink dry on the squeegee can also be detrimental: the squeegee blade is easily scratched and damaged in the process of scraping off dried ink.
2. Give the squeegee time to rest
It is important to limit the use of each individual squeegee as moisture in the ink can cause the squeegee to swell and soften during use. It is recommended that you change the squeegee blade after 4 to 6 hours of printing, or after one day of printing if the production day is low. There is a rotating supply of blades so that each blade can rest for 24 to 48 hours between uses. This gives the spatula time to dry and return to its original shape.
3. Store the scraper properly
Proper storage of scrapers can help them retain their shape and prolong their life. For spatulas that have been installed into the handle, store the spatula blades in a spatula stand or rack; make sure there is no pressure on the spatula during storage. For a scraper blade that has not been installed in the handle, store it flat - never curl it, even if it was shipped to you that way. You can cut the new stock squeegee blades to your preferred length for printing before storing to make storage easier.
4. Sharpen the blade as needed
You can throw away and replace the scraper as it wears out, or you can extend the life of the scraper by sharpening it. There are a variety of squeegee sharpeners available for the job, and each squeegee blade can be sharpened 25 to 50 times before needing to be thrown away. Each scraper has a recommended blade height, and it is usually possible to grind ½ inch of the scraper blade before replacing the blade - the scraper manufacturer should provide advice on scraper height and grinding allowance.
Scraper care may be simple, but it is necessary! By maintaining your squeegee, you will maintain the clarity and quality of your screen prints, and you will ultimately save yourself the cost of replacing squeegee blades and ink.
