Many of our readers are quite well-versed in printing technology, so, “What is a pad printer?” may seem too basic a question to address. We hope, however, that even a printing expert may gain a nugget of helpful insight from this “back to basics” topic.
Having said that, a pad printer is a highly practical and versatile piece of printing technology, capable of printing a flat image onto a vast array of products. Simply put, pad printers use rubber-molded pads to transfer two-dimensional images onto three-dimensional objects. Whether a surface (or substrate) is concave, cylindrical, textured, or even highly sensitive, a pad printer can be tailor made to fit nearly any application.
Pad printing first became popular after WWII, when watchmakers began printing on curved watch faces. The introduction of the pad printer opened up all sorts of possibilities, as designers and engineers discovered that previously un-printable objects were now printable. Pad printing became a well established printing method, quickly making its way into the medical and automotive industries, as well as appliances, electronics, and countless others.
All pad printers include three main parts: the image plate (called a cliché), ink, and rubber-molded pads. But, while the basics are fairly straightforward, not all pad printers are alike. Each of the three main parts present opportunities to optimize a pad printer for your specific application.
Pad Printer Plates:
Image plates used in pad printing contain the etched image of what will be transferred onto the substrate in ink. The two main types of cliché or plate material are steel and polymer. Polymer plates are easy to use and best suited for short to medium production runs. Steel plates are the preferred material for longer runs: long life thin steel is best for medium to long runs, and thicker steel is recommended for very long production runs.
Another category of image plates is the laser plate. Laser plates are made of silver aluminum or other laserable material. Plates that are laser etched offer long performance life and exceptional precision. Laser plates can also be etched on both sides and either end.
Pad Printer Inks:
The type of ink used in pad printing will depend greatly on its compatibility with your substrate’s material. For example, pad printing on candy will require food-grade ink, and medical applications may require medical grade ink. Aside from those types of customizations, ink is formulated for the best adhesion to the substrate material, be it glass, aluminum, or various types of plastic. Overall, most inks will fall into one of two categories: solvent based (cured with time and/or heat) or UV based (cured quickly with UV light).
Pad Printer Pads:
Printing pads are molded of silicone rubber, and depending on the application, will vary in size, shape, and hardness (durometer). The silicone rubber pad can adapt to the substrate’s shape, and the variations in durometer allow for endless optimizations, from printing fine detail on delicate electronics to large images on uneven material.
So, what is a pad printer? Yes, it’s a printer that transfers a 2-D image to a 3-D object. But, it is also a piece of technology that holds a critical place in the history of printing. Weaving its way through countless industries and applications, the pad printer continues to leave its mark. Effectively choosing the right pad printer (and plate, ink, and pad types) can take a great amount of experience. That’s where Diversified Printing Techniques comes in. Contact us today to draw from our knowledge and expertise. We’d love to help you find or customize the right pad printer for your needs.