Water Transfer Printing Machine

Water Transfer Printing (WTP) is an advanced surface decoration technology that transfers patterns from a water-soluble film onto the surface of three-dimensional objects using water pressure. It is widely used in automotive interiors, electronic products, military equipment and household items such as phone cases, motorcycle helmets, and more. Its core advantage lies in its ability to perfectly adapt to complex surfaces, achieving high-precision, high-fidelity texture coverage, such as wood grain, carbon fiber, marble, etc.

Standard Water Transfer Printing Process

The water transfer printing process follows a standardized seven-step procedure, with each step closely connected and indispensable:

Substrate Pretreatment
Thoroughly clean the objects to be printed (such as plastics, metals, ceramics) to remove oil, dust, and static electricity. For non-polar materials (such as PP, PE), a special primer must be applied to enhance adhesion; materials like ABS and PC can proceed directly to the next steps. The quality of pretreatment directly affects the final adhesion strength.

Priming
Evenly spray a layer of white or light-colored primer on the substrate surface as a background for the pattern. The primer must be fully dried (usually baked at 60–80°C for 10–15 minutes) to ensure vivid ink colors without bleeding.

Application of Water Transfer Film
Lay the polyethylene (PVA) water transfer film with the printed pattern flat on the water surface, with the pattern side facing up. PVA film has excellent water solubility, high elasticity, and tension, allowing it to closely adhere to complex surfaces. The film thickness is typically 20–40 μm and is made from a composite of PVA resin, plasticizers (such as glycerin), and surfactants. It is biodegradable and environmentally friendly.

Water Activation Treatment
Evenly spray activator on the film surface. The activator mainly consists of propanol, isopropanol, polyethylene glycol, and surfactants. It dissolves the PVA film base, separating the ink layer from the carrier and placing it in a suspended active state. Key parameters:
Water temperature: 27–30°C (too high causes premature dissolution, too low reduces activation effectiveness)
Activation time: 1.5–2 minutes (adjust according to film thickness and pattern complexity)
Water quality: must be neutral and free of impurities to prevent affecting pattern transfer.

Pattern Transfer
Slowly immerse the pretreated workpiece into water at a constant speed and angle so that its contours fully adhere to the suspended ink layer. Water pressure ensures the ink evenly covers the surface, and the PVA film dissolves automatically. Smooth operation is required to avoid bubbles or wrinkles. Complex items may need multi-stage transfer.

Washing and Drying
After transfer, immediately remove the workpiece, rinse off residual PVA film fragments and activator with clean water, and then dry with hot air (40–60°C, 10–20 minutes) to ensure a residue-free surface.

Application of Clear Protective Coating
Finally, spray a layer of transparent UV-cured clear coat or polyurethane topcoat to enhance the pattern’s wear resistance, weather resistance, and gloss. Modern environmentally friendly processes (like E-cubic, S-cubic) achieve UV curing without spraying, directly curing the ink layer with high-energy ultraviolet light, eliminating conventional spray steps and reducing VOC emissions.

WTP Material Characteristics

Shenzhen AFNT is professional producer of water transfer printing machine and related technology development. Feel free to contact us for a tailored WTP solution.