PP Woven Bag Machine Guide: Every Machine in a Production Line

A PP woven bag machine is never one machine. A woven sack plant is a chain of five to eight machines, and the throughput of the whole plant is set by how well those machines are matched. This guide walks the chain in production order, gives the figures we publish for each stage, and shows how to size the line for a target output. All numbers are from our March 2021 catalogue and the product pages linked below; we build every machine on this page in our own factory in Pingyang, Wenzhou.

Key definitions

• Flat yarn (tape): the ribbon of stretched polypropylene, typically 60 to 130 tex, that is woven into fabric. It is made on an extrusion line, not on the loom.
• Circular loom: the weaving machine that turns warp tapes on bobbins and weft tape in shuttles into a continuous tubular fabric.
• Lay-flat width (folding width): the flattened width of the tube, which equals the finished bag width. Looms are specified by the range of lay-flat widths they can weave.
• Lamination (coating): a thin molten PP or PE film pressed onto the fabric to make it moisture-proof, or to bond a printed film or paper to it.
• Picks per 100 mm: the weft density. Catalogue outputs are quoted at 40 picks per 100 mm; a denser weave means fewer metres per minute.

The production line in order

Stage	Machine	What it does	Yanfeng range
1	Flat yarn extrusion line	Melts PP, casts a film, slits and stretches it into tape, winds it on bobbins	YF-SPL 280 m/min, YF-GSPL 450 m/min, SJ-FS tape drawing machines
2	Winding machine	Winds tape onto bobbins for the loom creel (integrated in the extrusion line, or stand-alone)	S-STL-II cam winders, 190 to 760 spindles
3	Circular loom	Weaves tubular fabric at a set lay-flat width	Suspension 4/6-shuttle, little-cam 4/6-shuttle, mesh-bag loom
4	Lamination machine (optional)	Coats or laminates the fabric roll	SJ-FMF single/double extruder, YF-NMF reverse (inner-liner) lamination
5	Printing machine (optional)	Prints one to six colours on the fabric or the cut bag	YF-ZNY roll printing, relief, flexographic and gravure presses
6	Cutting and sewing	Cuts the tube to bag length, folds and sews the bottom, inserts a liner if needed	YF-QTF750, YF-850, YF-HKZ-600 valve bag, SQJ/YF-GSZL cutters, YF-FM800 sewing
7	Baling and recycling	Presses finished bags into bales; regranulates edge trim and waste	Hydraulic baling press, recycling granulator

Stage 1: the extrusion line sets the ceiling

Everything downstream consumes tape, so the extrusion line's output in kilograms per hour is the number to start from. Our high-speed flat yarn extrusion lines come in two speed classes.

Model	Screw	Max output	Max line speed	Winding heads	Installed power	Footprint (L×W×H)
YF-SPL-80/33/800	80 mm	220 kg/h	450 m/min	136	240 kW	29.0 × 3.6 × 3.2 m
YF-SPL-110/30/1200	110 mm	350 kg/h	450 m/min	208	320 kW	34.0 × 3.8 × 3.2 m
YF-SPL-135/30/2000	135 mm	550 kg/h	450 m/min	344	450 kW	45.0 × 3.8 × 3.2 m
YF-GSPL-100/33/1000	100 mm	400 kg/h	450 m/min	176	290 kW	32.0 × 3.6 × 3.2 m
YF-GSPL-135/30/2000	135 mm	800 kg/h	450 m/min	344	450 kW	45.0 × 3.8 × 3.2 m

Two choices matter at this stage:

1. Heating method. The lines are offered with a hot-air stretching oven or an electrically heated plate. Hot air is gentler on thin, high-tenacity tape; the heated plate is simpler to maintain.
2. Raw material. For virgin PP the YF-SPL and YF-GSPL lines give the best tape quality. For plants running mostly recycled or heavily filled material, the SJ-FS plastic tape drawing machine is the right base: it accepts 100% recycled material, powder or granules, uses 38CrMoAlA alloy screws and barrels, and its 110 to 230 mm screws produce 60 to 700 kg/h at 80 to 200 m/min.

The number of winding heads can be configured to your creel plan, and bobbin size (standard 38 × 230 mm) can be made to order.

Stage 2 and 3: winding and weaving

Where the extrusion line does not integrate winders, a cam-type winding machine does the job: the S-STL-II series uses a cardioid cam instead of a reciprocating shaft, runs 80 to 150 m/min, and is built with 190 to 760 spindles in four or five layers, so its length matches the tape line beside it.

The circular loom then sets the fabric output. The catalogue figures below are at 40 picks per 100 mm.

Loom	Shuttles	Lay-flat width	Max speed	Fabric output	Total power
YF-XT-750/4X suspension	4	300–750 mm	250 r/min	2.0–2.4 m/min	2.7 kW
YF-XT-1000/4X suspension	4	450–1000 mm	220 r/min	1.8–2.1 m/min	2.7 kW
YF-XT-850/6X1 suspension	6	400–850 mm	180 r/min	2.2–2.6 m/min	3.5 kW
YF-XT-750/4(A) little cam	4	300–750 mm	180 r/min	1.4–1.8 m/min	2.7 kW
YF-XT-1400/4(A) little cam	4	800–1300 mm	125 r/min	0.9–1.25 m/min	4.5 kW

A worked example: a 50 × 90 cm cement sack at 70 g/m² uses about 0.063 kg of fabric per bag plus trim. At 2.2 m/min a four-shuttle suspension loom weaves roughly 130 bags per hour, so a plant targeting 2,000 bags per hour needs about 15 looms, and those looms consume about 130 kg of tape per hour, which a YF-SPL-80/33/800 line supplies with margin. We run this calculation for every enquiry; send the bag size, grammage and shift pattern through the enquiry form.

Stage 4 and 5: lamination and printing

Cement, fertilizer, feed and sugar bags are usually laminated. Our multifunctional lamination machines coat the fabric with molten PP or PE at 80 to 200 m/min, or bond pre-printed OPP/CPP film or paper to it; the single-extruder SJ-FMF90/1000 series covers 750 mm coating width at 71 to 76 kW gross power. Where the customer wants an inner liner instead of a coating, the PLC-controlled reverse lamination machine bonds a film liner inside the tube at up to 50 m/min.

For printing, the intelligent roll printing machine prints both faces of the fabric roll in one pass at 70 to 100 bags per minute and changes bag length from the touch screen without changing plate rollers or gears. Relief, flexographic and gravure presses are available for other substrates.

Stage 6: cutting, sewing and liner inserting

The finishing line decides labour cost per bag.

Machine	Job	Output
YF-QTF750 cutting and sewing with liner inserting	Cold/heat cut, inserts PE liner, sews bottom	22–30 bags/min
YF-850 automatic cold/heat cutting and sewing	Cut and sew in one pass, 600–1200 mm bag length	20–40 bags/min
YF-HKZ-600 valve bag cutting, sewing and mouth folding	Valve (cement) bags 500–900 mm	25–30 bags/min
SQJ II-800 heat cutter / YF-GSZL-800 cold cutter	Cutting only, 200–2500 mm	20–70 / 20–90 bags/min
YF-FM800 automatic sewing machine	Sewing only, up to 800 mm wide	20–30 bags/min

A single operator runs the YF-QTF750, which is why plants in Africa and the Middle East that used to cut and sew by hand choose it first. Details are on the bag cutting and sewing machine pages.

Sizing a plant: three questions to answer first

1. Bag specification. Size, grammage, laminated or not, printed or not, liner or not. This fixes the loom width class and whether stages 4 and 5 are needed.
2. Daily output in bags. Divide by loom output per hour to get the loom count, then multiply loom tape consumption to size the extrusion line.
3. Raw material. Virgin PP, recycled, or filled. This decides between the YF-SPL/GSPL lines and the SJ-FS drawing machine, and lowers the loom speed you should plan with.

With those three answers we return a line list, a layout drawing and power and utility requirements. Plants that start with one extrusion line and eight to twelve looms typically add looms in the second year while the same line keeps up.

Why buy the whole line from one maker

We have built plastic weaving machinery since 1987 on a 60,000 m² site, hold 109 national patents, and are ISO 9001:2015 and CE certified. Because the extruder, winders, looms, laminator and finishing machines come from the same workshops, the tape width, bobbin size and roll diameters are matched before the machines leave Pingyang, and one after-sales team covers the whole line. Our lines run in more than 80 countries, including Nigeria, Egypt, Algeria, Kenya, Sudan and Morocco.