Silicone pad is necessary printing consumables for pad printing.There are different size,shape and hardness silicone pad for different printing requirements.
Size, shape and hardness are the three most important considerations in
choosing a pad for a given application. Size is determined by the size of the image
to be printed, and by the size of the machine. Measuring the image diagonally,
the pad should be 20% larger to prevent image distortion. The machine needs to
be able to compress the pad far enough to pick up and transfer the entire image
in an even motion. In addition, the pad must not interfere with the ink cup or
other parts, and it must not roll off the edges of the cliché during image pick up.
The shape of the part determines the shape of the pad. There are three basic
shapes from which all standard pads are derived (with the exception of rotary
pads.) The three basic shapes of conical, rectangular, and roof-shaped are
illustrated to the right.
There are many variations of each of these three basic shapes. To determining
which pad works best for a specific application have your supplier test print your
parts for you.
Once you have the correct pad you need to concern yourself with setting the
proper compression and correctly locating the pad.
Compression should always be set for the minimum amount necessary to pick
up and transfer the image. Over compression causes excessive pad wear as well
as poor transfer efficiency.
In set-up, the pad should be located so that its point is not in the image area
when the image is picked up. The point is the first place a zero degree angle will
be created during compression. Having the point in the image can result in a void
in the printed image in that location. It is helpful to keep a record of set-down
point and machine compression settings if you're going to run a job frequently,
so as to expedite machine set-up.
Hardness is the last of the three main considerations in choosing a pad.
Hardness comes into play for three main reasons. First, the same pad of two
different hardness requires different amounts of energy to compress the same
distance. A given machine may not be able to compress the harder of the two.
Second, a hard pad may damage the part you wish to print, thus limiting you
to pads of a lower durometer.
Third, textured surfaces are more successfully printed using harder pads.
(Some textures are very difficult or impossible to print regardless of what pad you use.)