How Are FIBC Bulk Bags Made? A Step-by-Step Manufacturing Process

Dry bulk goods move in huge amounts every day. Grain leaves the farm. Cement heads to building sites. Fertiliser, minerals and chemicals travel from plant to plant. A lot of this cargo rides in FIBCs, short for Flexible Intermediate Bulk Containers. Most people just call them bulk bags or big bags.

A bulk bag looks simple, but plenty goes into one. Someone has to pick the fabric, decide how the bag will be lifted, choose how it fills and empties, and prove it can handle the load.

This post walks through those stages, with Wales Industries, an Australian FIBC manufacturer, as the example.

What Is an FIBC Bulk Bag?

An FIBC is a flexible container built to store and move dry bulk materials. Wales Industries makes its bulk bags from high-strength woven polypropylene, which gives them load stability and durability while they are filled, lifted, and emptied. Typical users work in construction, agriculture, food processing, and chemical handling.

Bulk bags come in many sizes and designs, and they work with automated systems. Compared with traditional woven sacks, 4-loop bags give better load stability, easier forklift handling, and better use of space in storage and transit.

What goes inside varies a lot. Common contents include grain, flour, seeds, feed, fertiliser, cement, gravel, chemicals, milk powder and pet food.

How FIBC Bulk Bags Are Made, Step by Step

The stages below cover the main choices that shape a finished bag.

Step 1: Pick the Fabric

The cloth is the first choice. For 4-loop bags and PP woven sacks, Wales Industries uses UV-stabilised woven polypropylene. For 1- and 2-loop bags, the fabric can be coated or uncoated. Water resistance comes from lamination or a polyethylene liner.

Step 2: Choose the Bag Construction

The build style decides how a bag is lifted and how well it holds its shape. Wales Industries offers five FIBC types:

1 & 2 Loop FIBC: Made from a single tubular fabric. The body fabric extends into the lifting loop, which gives higher breaking strength and easier lifting. Loops can be wrapped in coloured sleeves to tell bags apart.
4 Loop Bulk Bags: Usually U-shaped or circular. The four lifting loops spread the weight evenly and work with forklifts and cranes.
Baffle Bags: Built to keep a square shape and stop bulging during filling and transport. That helps with stacking and freight costs.
UN Certified FIBC: Made for hazardous goods.
Conductive Bags: Type C bags that release static electricity through proper grounding. They suit flammable powders and sensitive chemicals.

Step 3: Set the Top and Bottom

Next comes how the bag fills and empties. Tops can be open, duffle, or a filling spout. Bottoms can be flat or have a discharge spout. The 4-loop bags come in six combinations, such as an open top with a flat bottom, or a filling spout with a discharge spout.

Step 4: Add a Liner if the Product Needs One

Inner liners can be made from PE or aluminium. They add moisture protection, contamination control, and product safety. On 1 & 2 loop bags, the liner can be tubular or shaped.

Step 5: Print the Bag

Bags can be printed in 4 colours. Custom printing is used for product or brand identification.

Step 6: Set the Load Rating

Every bag gets a Safe Working Load, or SWL. That is the most weight the bag is rated to carry in normal use. The safety factor is the ratio between the bag’s tested break strength and its SWL. A 1,000 kg bag at 5:1, for example, has been tested to 5,000 kg.

The 4-loop bags are rated like this:

5:1: 500 to 2000 kg, single trip
6:1: 500 to 1500 kg, multi-trip
6:1: 500 to 1500 kg, UN bags

Step 7: Test It in the Lab

Product tests are carried out in an in-house laboratory. They cover the yarn, the fabric, the coating, and how the whole bag behaves when it is lifted, dropped, toppled, or stacked. The full list:

Yarn tensile and elongation test
Fabric tensile and elongation test
UV test
Coating performance test
Sifting test
Cyclic top lift and load to failure test
Tear test
Topple test
Drop test
Stacking test
Breakdown voltage test
Grounding test

Which Standards Do FIBC Bulk Bags Follow?

Wales Industries takes the steps needed to meet all mandatory legal requirements and industry standards. These include:

ISO 21898: The international FIBC standard for non-hazardous goods.
AS 3668-1989: The Australian standard for flexible intermediate bulk containers carrying non-dangerous goods.
ISO 9001: The international standard for quality management systems.
ADR/RID/IMDG-Code: Rules for moving hazardous goods by road, rail, or sea, which apply to UN bags.
BRC-S&D and ISO 22000: Food safety standards for food-grade bags.
IEC 61340: Testing methods for electrostatic FIBCs.

FAQs (Frequently Asked Questions)

Where are the bags produced?

The Wales group has production and R&D sites in 6 locations across Asia, plus 4 sales and service locations in the Asia-Pacific region. Wales Industries Australia looks after Australia and New Zealand. The wider network spans Australia, China, India and New Zealand, and the group supplies products to 20 countries.

Can a bag be customised?

Yes, a bag size can be customized. Size, fabric type, lifting loop setup, liners, coatings, discharge spouts, baffles, UN certification and printing can all be tailored to the job.

Are bags kept in stock?

Yes, bags are kept in stock. Over 50 types of FIBCs are in stock, with same-day shipping from warehouses across Australia.

How established is the company?

Wales Industries has been making FIBC bulk bags in Australia since 2016. More than 500 customers have been served, and 1.5 million products are supplied each year.

Summary

Making an FIBC bulk bag comes down to seven decisions: the fabric, the construction, the top and bottom, the liner, the printing, the load rating and the testing. Each one changes how the bag performs with your product, your load, and your handling equipment.

Wales Industries builds around those choices and backs them with in-house tests and recognised standards. If you want a bag specified for your material, weight, and filling setup, get in touch with the Wales Industries team through the enquiry page at walesindustries.com.au.