Pad Printing ... One of the Promotional Product and Decorating Industry's Best Kept Secrets.

Have you often wondered how golf balls and pens were printed? Pad printing is one of the lesser known but most widely used decorating methods. 

Pad printing was developed about 100 years ago as an extremely flexible printing process to print on watch faces. Through solvent evaporation, pad printing transfers an image out of an etched plate, onto a transfer pad and then onto the part. Because the pad conforms to the shape of the product, you can easily print almost any curved, irregular or flat surface. With the development of the silicon transfer pad, pad printing has become one of the most widely used (but little known) printing processes. Pad printing offers such tremendous versatility it is used to print in industrial applications, the automotive industry, medical products, as well as ad specialty and promotional items.

To begin pad printing, you will need the basics: the pad printer itself, an exposure unit, transfer pads, inks, hardeners, thinners, printing plates (clichés) and accessories. Consumables consist mostly of inks and printing plates.  

How is it pad printing done? The first step is to make a printing plate, starting off with good opaque artwork. Artwork needs to be on either laser film or transparency and should read right. Once you have your artwork, you are ready to make a plate. Place your artwork on an unexposed plate, close the glass and insert into the exposure unit. Repeat the process with screen tint to regulate the depth of the image and then you are ready to rinse the plate in warm water, dry it and post expose.

Once the plate is done, it is secured to the ink tray for printing. It is important to have a good fixture for your product. Fixtures can ranging from hard fixtures to flexible fixture putty enabling you to fixture the small irregular products such as golf balls, pens, sunglass clips, pocketknives, etc.

Now it’s time to mix your ink and prepare for production. Pad printing inks are specific to pad printing and vary according to what substrate you are printing on. The most durable types of inks are two component epoxy based, but there are many single component inks as well for leather, vinyl and specific substrates. A good all purpose two component ink can be used for most substrates by merely using a different hardener for glass, metal and ceramics than for plastics, acrylics and wood. Mixed your inks according to the instructions using a gram scale to measure the proper viscosity.Once mixed, pour the ink into the ink well.

To set up your registration, center the transfer pad over the image in the plate and tighten the pad mount. Next, bring the product under the pad and micro adjust the part so it is in the correct position under the pad.Tighten the turntable thumbscrew so that you are in perfect registration every print.You are now ready to print.

The basic steps of printing are, Load: Place the product in the fixture. The 990 Series Systems Printa offers have a roller that automatically floods the printing plate with ink and doctor blades the plate squeegeeing off the excess ink. Pick up: pull the print handle down and pick up the image. Print: bring the product under the pad, pull the print handle down to print on the product. You have now completed one print cycle. Remove the printed product, replace with an unprinted one and repeat the cycle. To maximize production, place clean, unprinted product to within reach to be able to load quickly. Have an area ready to place printed product. The ink image is very thin in pad printing and dries to the touch in just 30-45 seconds. With a manual system such as the 990 Series, you can expect to print 200-300 parts per hour.  

Once product is printed, you often need to cure with some heat. There are air-dry inks available for some products, but items such as glass, metal and ceramics surface temperatures need to reach between 300-350 degrees in order for the ink and catalyst to molecularly bond to the product. A curing oven that is designed for three-dimensional products and employs convection heat as well as a conveyor belt works best.

Pad printing is an excellent process that allows you the versatility to print a vast array of product sizes, shapes and substrates. Pad printing solves many printing challenges and is an affordable and profitable addition to any personalization business. To learn more, you can view a demonstration video www.youtube.com/watch or visit us at www.printa.com.