Ink and paint formulations currently used for identification marking at Department of Defense acquisition and sustainment facilities are stenciled or stamped onto mechanical hardware and electronic components for a broad spectrum of applications. These formulations contain volatile organic compound (VOC) solvents such as methyl ethyl ketone, methyl isobutyl ketone, toluene, and xylene that confer desirable properties such as reduced viscosity for easier application. The use of these formulations and their disposal are subject to stringent environmental regulation. The objective of this project was to validate, through extensive laboratory testing, two potential alternatives to the currently-used epoxy-resin-based inks and high-VOC paints: (1) low- or no-VOC alternative, ultraviolet (UV)-curable and waterborne stenciling inks and (2) self-adhesive labels. Validated alternatives were then demonstrated at Tobyhanna Army Depot in Pennsylvania and at Naval Aviation Depot, Jacksonville (NADEP-JAX) in Florida.
A water-reduced ink uses the same equipment as conventional inks; however, UV-curable inks require a hand-held UV lamp. Self-adhesive labels require Ink Jet, laser, or thermal transfer printing.
Ink and label alternatives were applied to bare and coated panels and then compared to the baseline ink in several tests outlined in the Joint Test Protocol. In the analysis of ink alternatives, nine alternative inks were stenciled onto panels of eight different substrate types. One ink alternative (Dell Ink DPI 311, Opaque Black) met the highest Grade A applications (i.e., suitable for external duty) on more than one substrate. However, this water-reducible ink still required the use of solvent for spray gun and stencil cleaning. Although VOC wastes were reduced, the need for environmental reporting remained.
During the analysis of label alternatives, ten alternative labels were tested on six aluminum substrates and six non-aluminum substrates using Ink Jet, laser or thermal transfer printers. All labels were found to be suitable for Grade A applications except in cases of possible exposure to solder flux and solvents, in which they would be limited to the least critical Grade C applications such as inspection stickers, drum labels and temporary parts numbering of components prior to assembly.
Little or no cost savings would be realized by replacing paint with the ink alternative because the raw material costs for ink were higher than for paint and cleaning solvent was still necessary. Although material costs would rise when replacing silk screening with labeling alternatives, labor costs would be significantly reduced. Label-based marking is easier to perform than silk screening or stenciling. Implementing label options would also reduce worker exposure to hazardous chemicals and time spent performing rework due to illegible markings. The estimated capital costs for the computer, monitor, printer and software necessary to implement the thermal transfer label-based system to replace silk screening were $15,500, which would be paid back within six months. The annual operating cost savings were estimated to be $58,000 for a 75 percent transition to labels at NADEP-JAX, where black and red thermal transfer printing onto Critchley clear, white, yellow, and metallized polyester material has been implemented. (Project Completed - 2003)