Why DTF powder sticks to the film around the print/art design area?

Vian
May 2, 2023
2 min read

Updated: Mar 11

For optimal printing, your workspace temperature should be between 18-30°C, with humidity levels between 40%-60%.

How humidity affects DTF film and powder?

When DTF PET film and powder exposed to air, they will absorb moisture. This may not be noticeable until you print. If the film has excess moisture, it will evaporate when passing over the pre-heat plate. However, if the moisture level is high, the film won't have enough time to release it before reaching the powder area. As a result, the powder may stick to areas with excess moisture.

More detailed information:

When the film contains moisture, it will evaporate into the ink, causing the ink to take longer to dry. If the ink hasn’t dried properly and powder is applied to these areas, more powder will adhere, leading to an uneven cured surface. This can make the peeling process difficult, and some parts of the print may come off during peeling.

Additionally, small bubbles may appear beneath the powder’s surface. These bubbles form when excess moisture from the film is absorbed into the powder (see figure 1).

If the print is left for a few days, the moisture will slowly escape from these bubbles as water, causing the print/film to appear as if it is sweating.

Trouble-shooting tips:

Moisture on the film: Typically, moisture affects the first one to two meters of exposed PET film, depending on humidity levels and exposure time. If the film hasn’t been sealed in an airtight package, it's recommended to cut off the first meter or two before starting the printing process.
Excessive powder: If you notice excess powder on the film outside the print area, you can gently tap the back of the film or use a soft brush to remove it.
Moist powder: If the powder inside its packaging is too moist, set it aside and use a fresh bag. Store the moist powder in a sealed container with silica pouches to absorb the moisture, and let it sit for a few days. This should help restore it to usable condition.