Conventional Surface Energy Measuring
For years, manufactures have implemented a conventional method of testing surface energy using a polyethylene solution called dyne inks. Dyne, when applied to a surface, can reveal the surface’s potential adhesion ability.
Dyne inks operate under the principle of surface energy or wetting, a phenomenon that correlates to the potential adhesive ability of a surface. When a substance comes in contact with a new material, the substance can show information on the surface energy of the material. The dyne will react depending on the surface energy.
When applying dyne, it will either bead up or spread out. If the material contains a higher surface energy than the dyne, it spreads out in attraction to the higher energy. If the material contains a lower energy level than the dyne, the ink retracts back into itself. The examiner must watch for characteristics of beading up or spreading out. If the ink beads up, that indicates a lower surface energy on the material than the ink. If the ink spreads out in a continuous film, the material has a higher surface energy than the ink. There are different dyne concentrations that can help discern the level of surface cleanliness.
Limitations of Dyne Inks
Typical dyne ink uses include research, product and process development, and monitoring. The portability of dyne allows for use on the factory floor or in the lab. However, this method is very limited. The ink determines a pass/fail level and these results are based on the user’s interpretation of how the ink reacts to the surface, making the process very subjective. This method fails to determine an objective, quantifiable surface measurement.
Furthermore, dyne can potentially contaminant the material it’s measuring, so a coupon, or sample of the material or product must be used instead of the actual piece. More importantly, the chemicals can contain teratogenic elements which are harmful to the user–potentially causing birth defects.
It is imperative that manufacturers confidently know the surface energy of their parts to predict the surface’s ability to paint, seal, coat, print, bond, or seal. Without knowing this information, manufacturers are opening up their products and processes to inconsistency, failure, waste, and even recalls.
For the development of the Surface Analyst™, BTG Labs noted these limitations and created a device that would overcome the subjective and contaminating nature of dyne inks. Using highly purified water ballistically deposited on the surface, the Surface Analyst can precisely, accurately, and objectively measure surface energy.