Both the textile material and elements of the screen printing process can lead to variations in curing of plastisol inks printed on textiles. Inconsistencies and incorrect parameters can lead to excessive ink use, poor curing, and reworked products, all leading to waste.

Fabric
The best fabric on which to print plastisol inks would be a 50/50 cotton/polyester blend because of its heat absorption and transmission properties. Moisture in any fabric, especially heavy cotton, will add to the ink curing load since the moisture must be driven off before the ink is cured. High stitch density fabrics will allow for a thinner ink film and faster cure. Darker fabrics will absorb heat faster and cure faster.

Printing Parameters
Retensionable frames allow for proper tension settings to allow for proper ink shear to minimize ink film thickness. Especially in textile printing, proper tension keeps the ink from being driven deep into the fabric by excessive squeegee pressure. 

A hard squeegee will work with a high tension screen to deposit a minimal thickness ink layer. The printing edge of the squeegee should usually be as sharp as possible, except when printing on coarse mesh counts and special inks. In this case, a slightly rounded edge will allow the blade to pass over the rougher fabric and print in a single pass.

Parallel planes of the screen and platen will lead to consistent ink thickness. Areas of excessive distance lead to thicker ink layers, and inconsistent cure. Check the distances regularly. 

A forced air gas-fired drier is preferred over infrared dryers, especially in high humidity environments, because they circulate saturated air away from the fabric. These systems can also cure water-based inks.

Author: Rick Davis
Source: SGIA Journal, Q3 1999, p. 20-23.