An important choice: the pad
Choosing the right pad is required to keep in mind some basic notions on pad printing
The pad is the medium that physically transfers the ink from the cliché to the piece to be printed. It is therefore very important, for the success of our prints, to choose the right pad for the job we have to do.
But what does the choice of the pad depend on?
The parameters to be determined are mainly three: size, shape, hardness.
As it regards the dimensions the basic indication is that the size of the pad must be greater than at least 20% compared to the printing area, to allow a correct positioning of the graphic, whereas the material of which it is composed, once compressed during printing, expands. If you do not respect this relationship there is a risk that your printing is distorted near the edges of the image.
The hardness and the shape instead are determined by various factors. First you need to consider the surface to be printed, if it is flat or curved, and what kind of shape and size has; in this phase are of particular importance also the size and position of the print area.
We must remember that: a rooftop shaped pad is suitable for short and wide images, and straight text; a round/cone pad for flat surfaces with a round image area; square and rectangular pads are recommended for square or rectangular images; half moon pads for curved surfaces and long texts.
Of crucial importance is the angle that is created between the pad and the surface to be printed. The ideal is a steep, opposite angle of the print area. Otherwise, it creates an air pocket that can damage the transfer operation of the image by “splashing” ink.
You also need to assess the physical characteristics of the surface to be printed: if it is smooth or rough, what kind of material it is, its possible degree of ink absorbency.
Adding up and studying all this data you can figure out what is the most suitable pad for each print job, without forgetting that hard pads produce sharper images and less distorted, soft pads produce longer-lasting images because of the deposit of a larger amount of ink.
The hardness of the pad is expressed in Shore A, units of measurement that refers to the hardness of the elastic products. As an example, for non-smooth surfaces it recommends the use of soft pads, hardness 2-4 Shore A.
For every degree of hardness it corresponds also a different color of the pad: Shore A 4/6 Green and White, Shore A 8/10 Yellow, Shore A 12/14 Blue, 16/18 Shore A Red.
There are also anti-static pads (RED 1), to reduce the risk of contamination of the printing area.
The Comec Italia catalog includes over 1500 pads; furthermore our technicians are always working to study the most suitable shapes for all your printing needs, creating customized pads.