Sublimation Problems Problems encountered in sublimation are usually rooted in the process described in Figure 1. Abnormally Shaped Parts. The uneven surfaces of ceramic parts can cause problems with sublimation. An uneven surface prevents even application of pressure, which is necessary to direct the gas to the part. Regular part measurements, however, can identify problem parts before they are decorated.
Color is a result of dye penetration into the coating.
The amount of penetration can vary with the coating characteristics. A coating with a lower glass transition temperature would be softer at a 400 F sublimation temperature, allowing greater dye penetration and showing darker colors, but some sharpness would also be compromised. Heat and pressure also affect dye penetration, and can be adjusted for the coating. A quality program with color testing is critical to isolating the cause of a color matching problem. Referring back to Figure 1, the coating becomes soft when heated.