Meet woven bag flexo printing requirements for PP woven sacks and FIBC bags with proper tension, ink adhesion, anilox choice, and robust stack flexo hardware.
Surface Preparation on Woven PP Fabric
Uncoated woven PP has low surface energy and irregular topography that challenges ink transfer. Most industrial sack printers use coated or laminated woven stock with smoother print surfaces. Confirm lamination type, coat weight, and corona treatment level on incoming rolls. Artwork with fine reverse type may need heavier coat weights or switched to simpler bold graphics. YAOSHG recommends trial printing on production rolls before finalizing anilox volume and plate depth for woven jobs.
Mechanical Requirements for Heavy Web Tension
Woven fabric is stiffer and heavier than film or paper, demanding robust unwind stands, wider shafts, and nip rollers rated for higher tension. Stack flexo architecture suits many sack plants because decks remain accessible for maintenance in dusty mill environments. The Nova 8-color stack flexo press supports multi-color cement, feed, and chemical sack artwork. Verify pneumatic shaft sizing and brake capacity for rolls exceeding 800 mm diameter.
Ink Systems for Outdoor and Chemical Packaging
Industrial woven bags often face UV exposure, moisture, and abrasion during transport. Solvent and UV flexo inks provide durability when water-based systems cannot meet resistance specs. Machine dryers and exhaust must match chosen chemistry. Some fertilizer and chemical sacks require specific regulatory compliance on ink components. Document end-use environment with ink suppliers and align chamber doctor blade materials accordingly. YAOSHG drying modules can be configured for solvent flexo where permitted locally.
Repeat Length and Bag Panel Alignment
Woven bag repeats differ from paper bag formats and tie directly to loom width and cut patterns. Misaligned repeats waste expensive laminated fabric during bag conversion. Provide cylinder repeat calculations from your bag making vendor early in press specification. Servo stack platforms such as the Honor 6-color servo stack press help maintain register when fabric thickness varies roll to roll. Allow camera inspection if clients specify barcode or traceability panels.
Dust, Maintenance, and Plant Environment
Cement and mineral sack plants generate fine dust that affects anilox cells and doctor blade life if enclosures are inadequate. Plan compressed air cleaning, filtered HVAC near the print section, and scheduled anilox maintenance. Stack presses simplify deck access for cleaning between color changes on dusty lines. Review high-speed stack flexo press options against your environmental conditions. YAOSHG export packaging and site commissioning include guidance for harsh industrial settings.
Need help selecting a flexo press?
Send your material, web width, color count, target speed and sample packaging format. YAOSHG engineers will recommend a suitable machine series.