| Parameter | Primary Effect | Operational Tip |
|---|---|---|
| Screen Tension | Ensures clean off-contact peel, preventing edge smudging. | Maintain $30 - 35 \text{ N/cm}$ using low-elongation polyester mesh. |
| Emulsion Thickness (EOM) | Controls deposit of adhesion promoter or anti-bleed blocker base. | Target EOM: $10\% - 15\%$ of thread diameter (230–305 tpi mesh). |
| Surface Pre-treatment | Increases fabric surface energy beyond $42 \text{ dyne/cm}$. | Apply flame or plasma treatment on siliconized/water-repellent nylon. |
| Ink Elastic Modulus | Guarantees elongation without cracking under fabric stretch. | Formulate plastisol or HSA inks with crosslinkers for elongation $\ge 200\%$. |
Measure surface tension: Test fabric surface energy with dyne pens prior to ink application.
Apply a dye blocker: Print a carbon-based grey/black bleed barrier on dyed polyester fabrics.
Always perform a Cross-Hatch Test: Execute tape cross-hatch testing (ASTM D3359) after complete curing.
| Check | Frequency | Responsible | Action if non-compliant |
|---|---|---|---|
| Fabric Coating / Dyne Level Check | Every new fabric batch | Head Printer | If < 38 dyne/cm, apply chemical primer or flame/thermal treatment. |
| Adhesion Promoter / Catalyst Mix | Shift start (Pot-life 4-8h) | Ink Technician | Mix 3–5% adhesion promoter for nylon; discard expired ink mixtures. |
| Dryer Film Curing Temp | Continuous / Batch start | Process Technician | Keep ink film temperature between $150^\circ\text{C}$ and $160^\circ\text{C}$ using thermo-strips. |
| Adhesion Tape Test | Sample at end of run | QA Inspector | Reject production batch if cross-hatch rating drops below 4B. |
| Indicator | Target |
|---|---|
| Tape Adhesion Test (ASTM D3359 / ISO 2409) | Grade 4B / 5B (Zero film detachment) |
| Elongation at Break (Flexibility) | $\ge 200\%$ stretch without micro-cracking |
| Dryer Curing Temperature | $150^\circ\text{C} - 160^\circ\text{C}$ (Dwell time 2–3 min) |
| Domestic Wash Resistance | Grade 4/5 after 30 home wash cycles at 40°C (ISO 105-C06) |
| Tip | Benefit |
|---|---|
| Add 3% to 5% isocyanate catalyst to ink for 100% Nylon substrates. | Penetrates water-repellent/silicone barriers by forming covalent bonds with synthetic fibers. |
| Utilize Computer-to-Screen (CtS) technology for stencil imaging. | Delivers crisp edge resolution and uniform ink laydown even on fine mesh counts. |
| Use triple-durometer squeegees (70/90/70 ShA). | Provides firm shear force needed for high-viscosity technical inks without blade deflection. |
| Allow 24-hour post-print cure time before wash testing. | Enables chemical crosslinkers to fully react and bond with the substrate. |
"On technical fabrics, ink cannot adapt automatically; proper surface chemical preparation and tight thermal control dictate final durability."
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