22 Colors Automatic Oval Screen Printing Press

Mesh selection: Large solid block pattern: 80T mesh; normal pattern:100T mesh; fine text, thin lines:120T polyester mesh.

Screen stencil inspection: Check photo emulsion layer integrity. Repair pinholes, cracks or broken emulsion with screen filler. No leakage on non-printing area.

Mount screen onto oval machine print station. Align screen registration marks, adjust horizontal balance of screen frame.

Adjust off-contact gap: The gap between screen and fabric. For thin cotton knit fabric: 1.5 ~ 3 mm. Ensure mesh separates cleanly from fabric after squeegee stroke, avoid trailing paste and smudge.

Pre-wash new screen and dry fully before production to remove residual emulsion residue.

Water-based Pigment Paste Mixing

Add base binder paste into mixing tank first. Slowly add color concentrate while low-speed continuous stirring.

Add small dosage of anti-clog agent and humectant as required. Do NOT over-dilute with pure water. Over dilution leads to pattern bleeding and blurry edges.

• Stirring duration: 8 ~12 minutes at low speed, to achieve homogeneous dispersion of colorant.
• Viscosity test: Target viscosity range: 3000 ~ 6000 cps. Large solid patterns use lower viscosity; fine line patterns use higher viscosity.
• Filtration: Filter mixed paste through 100 mesh filter sieve to remove solid particles.
• Sampling & labeling: Keep paste sample, mark order number, color code, mixing time and operator name.

During production, keep paste tank gentle stirring continuously to prevent pigment settlement.

Reactive Printing Paste Mixing

Reactive printing paste must be prepared on demand, use within valid pot life. Reactive paste will hydrolyze and lose dye reactivity after long storage.

Formula: Reactive dyestuff + printing thickener stock + alkali agent + resist salt + wetting agent.

Low speed stirring until fully dissolved, filter through 100 mesh sieve.

Check paste viscosity immediately after mixing.

Discard leftover reactive paste once pot life expires. Do not reuse expired reactive paste.

Warning: Alkali agent addition timing is critical. Improper alkali dosage will lead to poor fixation or premature dye reaction.

• Squeegee pressure: Set moderate pressure to force paste penetrate into cotton fiber. Too high pressure will cause strike-through and fabric stretching. Too low pressure results in incomplete coverage and missing print.
• Squeegee speed: 250 ~ 400 mm per second. Reduce speed for heavy solid area; increase speed for fine details.
• Squeegee pass: 1~2 passes for large solid areas; single pass for fine patterns. Multiple over-passes will build excess paste and create stiff hand feel.

Tunnel dryer temperature setting:

• Water-based pigment print: 80 ~110°C
• Reactive print pre-drying: 70 ~90°C (low temperature pre-drying, avoid premature dye fixation and color speckle)
• Workshop ambient condition control: Temperature 22\28°C, Humidity 55\65%RH. Low humidity will accelerate paste drying on mesh and cause screen blockage.

Print the first sample piece after machine & paste setup.

QC inspection items on first article: color matching against approved standard swatch, pattern registration accuracy, penetration status, edge sharpness, no bleeding, hand feel & air permeability.

Confirm printing area is soft without plastic film texture, no white spots, no paste trailing.

Fill in First Article Inspection Record. QC and production operator sign off once approved. If sample fails, re-adjust paste formula or machine parameters and re-sample.

Fabric loader lays fabric flat on pallet, align positioning marks precisely, ensure no wrinkles on fabric surface.

Machine operator continuously monitor screen surface during running. Once screen clogging appears, stop machine immediately, clean screen with clean water.

Patrol inspection every 30 minutes: check color consistency, pattern sharpness, paste penetration, fabric flatness.

Stir paste in the bucket intermittently to avoid color sediment.

Keep pallet surface clean. Remove residual paste or lint from pallet to prevent fabric indentation defects.

Record machine parameters, paste batch number and production time in production log sheet.

Water-based Pigment Print Post-treatment
Only tunnel drying required after printing. Dry at 80~110°C until full moisture evaporation. No steaming, washing or soaping needed. Ensure complete drying; insufficient drying will cause rubbing off.

Reactive Printing Post-treatment (Core Process)

• Pre-drying: 70 ~90°C, dry printed fabric thoroughly without scorching.
• Steaming: 102 \105°C saturated steam, holding time 8\15 min. This step enables chemical reaction between reactive dye and cotton cellulose for permanent color fixation. Steaming chamber must maintain saturated humidity.
• Washing & soaping sequence: Cold rinse → Hot soaping bath with soaping agent → Multiple clean water rinsing. Purpose: fully remove unfixed loose dye and printing thickener. Incomplete washing will lead to poor washing fastness.
• Final drying: Dry fabric below 100°C. Avoid high temperature over-baking.

Inspection checklist:

• Visual appearance: Uniform color, no color deviation, missing print, paste trailing, white spots, blurry edges, pinholes.
• Hand feel & breathability: Printed area soft, no hard crust, maintain cotton fabric air permeability.
• Color fastness sampling test: Washing fastness and dry/wet rubbing fastness shall be tested according to order standard. Reactive print achieves better color fastness than regular water-based pigment print.