How a Vietnam PP Woven Bag Converter Upgraded to 6-Color Flexographic Printing

Vietnam's flexible packaging market reached USD 600.8 million in 2025 and is projected to surpass USD 1 billion by 2034 (6.18% CAGR). Flexographic printing accounts for 43.78% of print technology adoption in the sector — and as brand owners in Japan, South Korea, and the EU raise color fidelity requirements for retail export packaging, PP woven bag converters that can only offer 2-color output are increasingly losing tenders to better-equipped competitors.

This illustrative case describes a mid-size PP woven bag converter operating in Vietnam's Binh Duong province. The company supplied laminated bags to agricultural export brands but was losing bids to converters offering 4–6 color quality. Several Japanese retail buyers formally rejected the 2-color bags as below shelf presentation standards.

Requirements

• 6 independent print stations capable of running OPP-laminated PP woven fabric
• Printing speed ≥ 80 m/min at rated quality
• Inter-color registration ≤ ±0.5 mm across all 6 stations
• Repeat length range wide enough to cover both 500 g retail rice bags and 50 kg export bags on one line
• Minimal production interruption during installation

Machine Deployed: Reylong JLRPM-6800BO/6C

The 6-Color Flexographic Roll-to-Roll Printing Machine (Model JLRPM-6800BO/6C) was selected for its substrate compatibility and high-speed multi-station capability. Key specifications relevant to this application:

• 6 printing stations with ceramic anilox rollers — supports 0+6 / 1+5 / 2+4 / 3+3 configurations
• Max printing speed: 100 m/min; max machine speed: 120 m/min
• Printing repeat length: 350–1,300 mm — covers both 500 g consumer bags and 50 kg export bags without tooling change
• Max printing width: 770 mm / max web width: 800 mm
• Automatic hydraulic throw-off protects fabric during stoppages and speeds up ink changeover
• Inter-color electric drying: 18 kW — ensures ink set between stations at full speed

Why woven PP is harder to print than film

A PP woven substrate is not a smooth surface. The tape weave leaves a periodic texture that varies ink film thickness across the sheet, and polypropylene itself has low surface energy, so ink beads instead of wetting out unless the web is corona-treated or carries an OPP laminate. That is why this application runs laminated stock: the OPP layer gives the anilox-transferred ink a smooth, receptive surface, which is what makes six-station process work viable at all on a bag that would otherwise only take coarse two-color line art.

Outcome

• 6-color output cleared brand color approval at the first production run for a Japanese food retail brand — no revision cycle required
• Production speed: 95 m/min achieved in standard 3-color mode during routine runs
• Full repeat length range utilized — single line handles both 500 g and 50 kg formats, eliminating the need for a second dedicated line
• Automatic hydraulic throw-off reduced ink and plate changeover time versus the previous manual-throw-off 2-color line

Where registration drift comes from across six stations

Registration error accumulates station by station rather than appearing all at once. Each print unit applies its own nip pressure and takes its own bite of tension, and the web stretches slightly between them; the inter-color dryers then drive heat and moisture through the material, and it does not return to exactly the width it entered at. With six stations the last color inherits every upstream deviation, which is why tension consistency through the dryer section matters more to final registration than the accuracy of any single print unit. Operators hold it by keeping tension setpoints and dryer temperature stable across a run rather than correcting color by color.