Preparing plastic parts for adhesive assembly, labeling, or printing often requires a treatment to make surfaces more acceptable to adhesives and inks. The chemical baths and solvent washes commonly used to prepare surfaces have drawbacks. For example, a surface after drying may be left with a thin-film residue that can act as a barrier to inks and adhesives. Also, treatment consistency varies over a day as the treatment baths lose their potency, not to mention the environmental concerns of disposing waste chemicals.

“A gas-plasma treatment solves the problems because it's a dry process that leaves no surface residue,” says Dr. Demetrius Chrysostomou, director of technology at PVA TePla America Inc., Corona, Calif. (pvatepla.com). “Process gases are continually refreshed in the reaction chamber and by-products pumped away so that processes are highly reproducible run-to-run,” he says. More importantly though there is no need for storage and disposal of wet chemicals making plasma a more environmentally friendly method.

“Plasma by definition is an ionized state of matter,” says Chrysostomou. “Think of it as a gas carrying a lot of energy, but not heat. Energy from the plasma changes the properties of surfaces by cleaning and chemically activating it so the surface is more receptive to inks and adhesives.”

For it's contribution to eliminating solvents in the workplace, the M4L Plasma machine is the June Medical Design Machine of the Month.