Ink Adhesion & Process Development

Ink Adhesion Testing

The surfaces of plastics and other materials vary not only in terms of texture, but in terms of surface tension, too – a characteristic also referred to as “surface energy” or “surface wetting”. If the surface tension of a substrate is lower than the surface tension of the ink, the ink won’t stick. It’s a sign of inadequate chemical covalent bonding & “bad ink adhesion,” in layman’s terms. Likewise, if the substrate is wettable, that is, if it has high surface energy, the ink will adhere properly to the surface, allowing it to be marked or decorated.

One simple test of a plastic’s printability is to drip some water on the surface. If the water beads up, the surface energy of the substrate is lower than the surface tension of the water, and vice versa. If the water “sheets” its surface tension is lower than the substrates’. Beading is bad. Sheeting is good. The scientific test is to check the surface of your plastic using a dyne kit. These specialized dyne markers contain a fluid that mimics ink adhesion and allows printers to choose the type of ink that will most likely stick to the product’s surface.

Process Development & Testing

We’re here to support you every step of the way through the development of your machine. Our team will work toward a solution to your particular challenge, including testing samples of your product parts.


Ink adhesion & sample testing are free services provided to our customers. You can submit your information using the form on this page or call the EPS Customer Service department directly at (800)-272-7764 to find out more.
For Ink Adhesion: We ask that you send us sample parts as the initial step in this process. As a part of this free service we will provide the imprinted sample (if return requested), a corresponding report with our recommendations, and a consultation with our internal teams to discuss the next steps.
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