Non contact marking uses multiple types of spray media. These fall into two main categories, pigmented ink and dye. Each of these type of spray media have benefits, but each also have issues that should be thought through when selecting a marking system. Selecting the proper type of media for your application is critical to the proper operation and results in your application.
Pigmented ink contains solid pigments that create bright opaque colors. Whether you’re spraying a light colored substrate such as aluminum, or dark substrates such as steel, pigmented ink will produce highly visible marks. This is often very desirable in applications where a mark is being sprayed for identification purposes. A bright mark is easier to see at longer distances than a semi transparent or dull mark produced with dyes.
Solid pigments tend to settle over time in reservoirs and material lines if they are not agitated regularly. This can lead to large settlements of solids in the bottom of tanks and inconsistent marks. This is typically overcome by pressure tank agitation and/or recirculation systems. By recirculating material through the system while it is not in use, the pigment doesn’t have the opportunity to fall out of suspension in the media. This results in very consistent marks and minimizes extra maintenance for settled solids.
Non pigmented dye is typically a less viscous material than pigmented inks. They do not have the solid pigments that are present in inks, and therefore leave a more transparent mark than inks. Though on light substrates, they often leave a bright mark that is visible at acceptable distances.
Because dyes do not contain solid pigments, they can be sprayed with excellent repeatability without needing additional agitation or recirculation. They also tend to leave less material buildup on a nozzle over time, reducing the system maintenance required.
It is important to determine the exact requirements of your application to select the appropriate spray media to be used. Whether pigmented ink or dye are to be used will depend on the substrate to be sprayed and the desired brightness. With that decision, other features may be required to successfully spray consistent marks that meet your needs.
– Anthony Kowalski, Systems Engineer