Pad printing cycle

1. From the home position, the sealed ink cup (an inverted cup containing ink) sits over the etched artwork area of the printing plate, covering the image and filling it with ink.
2. The sealed ink cup moves away from the etched artwork area, taking all excess ink and exposing the etched image, which is filled with ink. The top layer of ink becomes tacky as soon as it is exposed to the air, that is how the ink adheres to the transfer pad and later to the substrate.
3. The transfer pad presses down onto the printing plate momentarily. As the pad is compressed, it pushes air outward and causes the ink to lift (transfer) from the etched artwork area onto the pad.
4. As the transfer pad lifts away, the tacky ink film inside the etched artwork area is picked up on the pad. A small amount of ink remains in the printing plate.
5. As the transfer pad moves forward, the ink cup also moves to cover the etched artwork area on the printing plate. The ink cup again fills the etched artwork image on the plate with ink in preparation for the next cycle.
6. The transfer pad compresses down onto the substrate, transferring the ink layer picked up from the printing plate to the substrate surface. Then, it lifts off the substrate, returning to the home position, which completes one print cycle.

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Pad printing

Pad printing is a printing process that can transfer a 2-D image onto a 3-D object. This is accomplished using an indirect offset (gravure) printing process that involves an image being transferred from the printing plate (cliché) via a silicone pad onto a substrate (surface to be printed). Pad printing is used for printing on otherwise impossible products in many industries including medical, automotive, promotional, apparel, electronics, appliances, sports equipment and toys. It can also be used to deposit functional materials such as conductive inks, adhesives, dyes and lubricants.

Physical changes within the ink film both on the cliché and on the pad allow it leave the etched image area in favor of adhering to the pad, and to subsequently release from the pad in favor of adhering to the substrate (material being printed).
The unique properties of the silicone pad enable it to pick the image up from a flat plane and transfer it to a variety of surface

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Printing pad

Printing pad
Pads are three dimensional objects typically molded of silicone rubber. They function as a transfer vehicle, picking up ink from the printing plate, and transferring it to the part (substrate). They vary in shape and durometer depending on the application.
There are three main shape groups: "round pads", long narrow pads called "bar pads", and miscellaneous shapes (square, rectangular, etc.) called "loaf pads". Within each group there are three size categories: small, medium, and large size pads. It is also possible to engineer custom-shaped pads to meet special application requirements.
Image plate
Image plates are used to contain the desired artwork "image" etched in its surface. Their function is to hold ink in this etched cavity, allowing the pad to pick up this ink as a film in the shape of the artwork, which is then transferred to the substrate.
There are two main types of printing plate materials: photopolymer and steel. Photopolymer plates are the most popular, providing a good do-it-yourself option. These are typically used in short to medium production runs. Steel plates come in two choices: thin steel for medium to long runs, and thick steel for very long runs. Both steel plate types are generally processed by the plate supplier as it involves the use of specialized equipment.
Printing ink
Ink is used to mark or decorate parts. It come in different chemical families to match the type of material to be printed (please consult the substrate compatibility chart for selection).
Pad printing inks are "solvent-based" and require mixing with additives at the time of use. They typically dry to the touch in seconds although complete drying (cure) might take a substantially longer period of time.
Climatic conditions will significantly affect the performance of any pad printing ink, please bear this in mind when planning the location of your pad printer. Always consult Federal, State and local regulations regarding proper handling, storage and disposal of inks.

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