3-Layer Blown Film Machine ABA & ABC Co-Extrusion

The difference is in extruder count and whether the two outer layers can carry different materials. The ABA machine uses 2 extruders: the die head splits Extruder A's melt stream into two outer channels, producing a symmetric A/B/A structure where both outer layers are always the same material. The ABC machine uses 3 extruders, each feeding one dedicated die channel independently — all three layers can be different materials, different formulas, and different thicknesses. Both configurations produce 3-layer film, but they serve different applications.

The ABA die head has 3 internal flow channels. Extruder A's melt stream enters the die head and is split by the internal geometry into two separate outer channels — one feeding the top outer layer and one feeding the bottom outer layer simultaneously. Extruder B feeds the single centre channel. The result is a 3-layer A/B/A film produced by 2 extruders. Because both outer layers originate from the same extruder, they are always identical in material composition.

For courier bags, ABA is the standard and recommended configuration. Courier bag film typically uses HDPE outer layers for stiffness, opacity and printability, with an LDPE or LLDPE core for flexibility and seal strength. The ABA structure — where both outer layers are identical HDPE — is exactly suited to this requirement. The ABC configuration adds a third independent extruder, which increases capital cost and operational complexity without providing additional benefit for a symmetric courier bag structure.

No. On an ABA machine, both outer layers come from the same extruder (Extruder A). Because they share the same melt source, they are always the same material and the same formula. If your application requires the two outer surfaces to carry different materials — for example, one surface optimised for printing and the other for heat sealing — you need the ABC configuration with 3 independent extruders.

On the ABC machine, Extruder B (the centre layer) typically has a larger screw diameter than Extruders A and C. This is because the centre layer usually carries the bulk of the film mass — it is the thickest layer in most structures. A larger centre extruder provides higher output capacity for the core layer while the two outer extruders handle thinner, functional surface layers.

Yes. Both ABA and ABC configurations support PCR content in the core layer (Layer B). The WC bi-metallic screw — standard on all LayerQuestar extruders — is specified for the higher abrasion associated with PCR blends and contaminated recycled material. On the ABA machine, PCR is placed in the B layer while both A layers provide clean virgin-resin surfaces. On the ABC machine, PCR can be placed in the B layer while Layers A and C are independently formulated for their respective surface functions.

Yes. Layer thickness ratios are controlled by adjusting the relative speeds of the extruders at the control panel — no mechanical die adjustment is required. On the ABA machine, you adjust the A:B speed ratio. On the ABC machine, all three extruder speeds are independently adjustable. Changes can be made during production without stopping the line.

2 operators per shift. One manages the extruder controls and material feed; one handles the winding station and roll changes. The ABC configuration requires managing 3 independent material hoppers rather than 2, which adds a small amount of operational complexity, but the staffing requirement remains the same.

Five core components carry a 3-year warranty: main motor, variable frequency drive, die head, blower and gearbox. This applies to all extruders on the machine — meaning the ABC configuration's three motors, three drives and three gearboxes are all covered under the same 3-year term. Wear and consumable parts carry a 1-year warranty. Replacement parts are dispatched within 7 days of order confirmation.