At MPS Packaging Australia, blown film extrusion is at the heart of our manufacturing process, allowing us to create strong, reliable, and custom plastic films for a wide range of packaging applications. This versatile technique is what makes products like courier bags, pallet covers, and custom-printed packaging possible, giving our customers both quality and flexibility.
What Is Blown Film Extrusion?
Blown film extrusion is a process where plastic resin is melted and forced through a circular die, forming a continuous tube of molten material. Air is then introduced into the centre of the tube, inflating it into a bubble. As the bubble rises, it is cooled with air, flattened into a double layer of film, and wound onto rolls. This creates what is known as layflat film, which can later be slit, converted, or printed depending on its end use.
Here’s a step-by-step breakdown of how it works:
1. Feeding the Material
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Plastic resin pellets (usually polyethylene like LDPE, LLDPE, or HDPE) are fed into a hopper.
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Additives (e.g., color masterbatch, UV stabilizers, slip agents) can be blended in at this stage.
2. Melting the Resin
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The pellets drop into a heated extruder barrel.
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Inside the barrel, a rotating screw pushes the material forward.
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As the pellets move, heaters and friction from the screw’s rotation melt the plastic into a uniform molten state.
3. Extrusion Through the Die
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The molten plastic exits the screw and passes through a circular die at the end of the extruder.
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The die forms the melt into a thin-walled tube of molten plastic, called a parison or film bubble.
4. Inflating the Film Bubble
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Compressed air is introduced into the center of the molten tube.
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This inflates the tube into a bubble, stretching the plastic both vertically (machine direction) and horizontally (transverse direction).
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This biaxial stretching improves film strength, clarity, and barrier properties.
5. Cooling the Film
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As the bubble rises, it passes through an air ring that blows cool air around the bubble.
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The cooling solidifies the molten plastic into a thin film.
6. Collapsing the Bubble
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At the top of the tower, the bubble is guided between collapsing frames or rollers.
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This flattens the bubble into layflat film (a double-layer sheet).
7. Winding and Converting
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The layflat film is pulled down by nip rollers and wound onto rolls.
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From here, it can be:
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Slit into narrower rolls
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Converted into bags, shrink film, or other products
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Printed with flexographic or reverse printing
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Why Blown Film Extrusion Matters
The blown film process is highly valued because it stretches the film in two directions—vertically and horizontally. This biaxial orientation increases the film’s strength, puncture resistance, and flexibility, making it ideal for packaging that needs to withstand tough handling. By adjusting the extrusion settings, MPS can also produce films in varying thicknesses, sizes, and finishes, giving customers complete control over their packaging solutions.
Advantages of MPS Blown Film
Choosing blown film extrusion through MPS offers several benefits:
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High Strength & Durability – Ideal for heavy-duty applications like timber wrap or courier satchels.
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Customisation – Multiple layers, colours, and additives can be incorporated into the film for performance and branding.
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Excellent Printability – Blown films work seamlessly with our advanced printing methods, ensuring sharp, high-impact designs.
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Efficiency – Continuous rolls of film allow for fast, reliable packaging operations.
Applications of Blown Film at MPS
Our blown film extrusion process supports a wide variety of industries and packaging needs. Common applications include:
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Courier bags – Strong, opaque, and printable for branding.
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Pallet covers & shrink films – Protecting goods in transit.
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Timber wrap & industrial films – Heavy-duty protection for building and construction materials.
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Custom-printed packaging – Branded solutions that enhance visibility and professionalism.
MPS: Your Blown Film Packaging Partner
At MPS Packaging Australia, we combine decades of expertise with modern extrusion technology to deliver films that perform under pressure. Whether you need a simple protective cover or a complex multi-layer printed solution, our blown film process ensures your packaging meets the highest standards of strength, consistency, and quality.
