Lamination Machine for Woven Bags: Coating vs Inner Liner

A lamination machine turns a plain woven polypropylene sack into a moisture-proof, printable, stackable package, and it is the machine that separates a plant selling commodity sacks from one selling fertilizer, chemical, sugar and feed packaging. There are two quite different processes sold under the same name. This guide explains both, lists the figures for every lamination machine we build, and gives a decision rule for which one a plant needs. All specifications are from our March 2021 catalogue.

Key definitions

• Extrusion coating: a film of molten PP or PE is extruded through a flat die onto the moving fabric and pressed on by a nip roll. The coating itself is the barrier.
• Film or paper lamination: the same molten layer is used as glue between the fabric and a second web, usually a colour-printed OPP or CPP film (BOPP bags) or kraft paper (paper–plastic sacks).
• Reverse (inner-liner) lamination: a tubular fabric woven around a loose film liner is heated so the liner bonds to the inside of the tube; no extruder is involved.
• Coating width: the maximum width of fabric the die can cover, which must exceed the widest fabric roll you run.
• Coating speed: line speed in metres per minute; thicker coatings and wider webs run at the low end of the range.

The two processes side by side

	Multifunctional lamination (extrusion)	Reverse lamination (inner liner)
What is bonded	Molten PP/PE onto fabric; or film/paper onto fabric	Pre-inserted film liner onto the inside of the tube
Input	Flat fabric roll (open tube slit or flat) plus film/paper reels	Tubular fabric roll woven with a liner inside
Output	Coated or laminated fabric roll for cutting and sewing	Bonded tubular roll for cutting and sewing
Machines	SJ-FMF90/1000/4, SJ-FMF90/1000/6, SJ-FMF120/1500, SJ-FMF90×2/1000	YF-NMF/650, YF-NMF/750
Speed	80–200 m/min (50–150 m/min for the 1500 mm model)	up to 50 m/min
Power	71–96 kW gross	10–14 kW gross plus 36–48 kW heating
Typical products	BOPP printed bags, coated cement and flour sacks, paper–plastic sacks	Fertilizer, chemical, sugar and feed bags with a bonded liner

Multifunctional lamination machines

Our multifunctional lamination machine uses the adhesive property of molten PP and PE to bond paper or colour-printed OPP/CPP film to tubular woven fabric under pressure, or to coat the fabric directly. The extruder runs a 20CrMnTi hardened helical gear reducer and a nitrided 38CrMoAlA screw and barrel; melt temperature is held automatically, coating width is adjustable, and coating thickness and line speed are set steplessly. The six-station unwind with pneumatic edge correction keeps the coating in register, the pneumatic nip roll applies even pressure, and counting, edge blowing, perforating, edge folding, cutting or rewinding units are fitted as required.

Model	Screw	Dies	Rollers	Max coating width	Coating speed	Gross power	Footprint (L×W×H)	Weight
SJ-FMF90/1000/4	90 mm, 26:1	2	4	750 mm	80–200 m/min	71 kW	13.8 × 6.0 × 2.5 m	8,000 kg
SJ-FMF90/1000/6	90 mm, 26:1	2	6	750 mm	80–200 m/min	76 kW	15.5 × 6.0 × 2.5 m	9,000 kg
SJ-FMF120/1500	120 mm, 28:1	1	3	1200 mm	50–150 m/min	96 kW	15.5 × 8.0 × 2.5 m	10,000 kg
SJ-FMF90×2/1000	2 × 90 mm, 26:1	2	6	750 mm	80–200 m/min	96 kW	15.8 × 6.0 × 3.2 m	15,000 kg

Three configurations cover most plants:

1. Single extruder, single die (SJ-FMF120/1500) for wide fabric, up to 1200 mm, coated on one side.
2. Single extruder, two dies (SJ-FMF90/1000/4 and /6) for coating both faces of a tube, or coating on one face and laminating film on the other; the six-roller version adds the rollers needed for paper–plastic work.
3. Double extruder, two dies (SJ-FMF90×2/1000) for two different coatings in one pass at full speed.

Dies of other widths are made to order to match the fabric width you run. See the single-extruder four-roller and six-roller product pages for the standard builds.

PLC-controlled reverse lamination machine

The intelligent reverse lamination machine (patent ZL201220197057.1) heats a tubular fabric that already carries a film liner so that liner and fabric bond into one wall. The bag that results is even and attractive, moisture-proof, and stacks well, which is why it has become the standard construction for fertilizer, chemical, sugar and animal-feed bags in our export markets.

Model	Lay-flat width	Max unwind roll diameter	Max lamination speed	Heating power	Gross power	Footprint (L×W×H)	Weight
YF-NMF/650	350–650 mm	1200 mm	50 m/min	36 kW	10 kW	22.0 × 1.7 × 3.1 m	10,000 kg
YF-NMF/750	450–750 mm	1200 mm	50 m/min	48 kW	14 kW	22.0 × 1.7 × 3.1 m	12,000 kg

The machine is PLC controlled from a touch screen: temperature and speed are set once and then tracked automatically, faults raise an alarm, and the pneumatic torque-motor rewinder produces a flat, firm roll. A chiller can be added to run at the top of the speed range. Upstream, the tube with its liner comes from a hollow-shaft liner-inserting circular loom; downstream the roll goes straight to a cutting and sewing machine.

Which one does your plant need?

• You sell coated cement, flour or grain sacks, or BOPP-printed bags → the multifunctional lamination machine. Start with SJ-FMF90/1000/4 for fabric up to 750 mm; choose the 1500 mm model if you weave wide fabric for jumbo or feed bags.
• You sell fertilizer, chemical, sugar or feed bags with a liner → the reverse lamination machine plus liner-inserting looms. It replaces the manual step of inserting a loose liner and gives a bag that fills and stacks better.
• You do both → many customers run one of each; they share the same cutting and sewing line.

Send your bag construction and fabric width through the enquiry form and we will confirm the die width, roller count and whether a chiller is needed.

Why Yanfeng

We have manufactured the full woven-bag chain since 1987, so the lamination machine is matched to the tape line, looms and finishing equipment before it leaves our 60,000 m² factory in Pingyang. The machines are CE certified, come with English manuals, and are covered by a one-year free maintenance period with spare parts; commissioning engineers travel to the customer's plant on request.