How to Choose a Blown Film Machine: Based on the Film You Run and Your Output Needs

Choosing a blown film machine requires considering core factors such as product requirements, raw material characteristics, and production capacity planning, while also taking into account equipment stability, energy consumption, and after-sales service. Below is a detailed step-by-step selection guide:

I. Define Core Requirements: Determine the Basic Equipment Parameters Different film materials require different blown film machine structures; this is the primary basis for selection:

PE (LDPE/HDPE/LLDPE): Most commonly used; a standard single-layer blown film machine is sufficient, suitable for food bags, shopping bags, etc.

PP: PP has a high melting point and is prone to crystallization, requiring a dedicated PP blown film machine equipped with a low-temperature stretching device to prevent film brittleness.

Composite Films (Multi-layer Co-extrusion): For producing high-barrier films (such as food vacuum bags, daily chemical packaging films), a multi-layer co-extrusion blown film machine (2-7 layers) is required, enabling functional composites of different materials (such as PA PE, EVOH PE).

Special Materials: For materials such as biodegradable plastics (PLA/PBAT) and EVA films, customized screws and dies are required to ensure uniform plasticization of the raw materials.

Film Specifications

Width: Select based on the maximum folded diameter of the finished film. For example, for a film requiring a folded diameter of 500mm, choose a machine model with a suitable die diameter (generally, die diameter = folded diameter ÷ 3.14 ÷ shrinkage rate).

Thickness: Standard film thickness is 0.01-0.2mm. Ultra-thin films (<0.01mm) require high-precision models equipped with automatic thickness measurement and die fine-tuning systems; thick films (>0.2mm) require larger screw diameters to increase extrusion volume.

Applications: Packaging films require high transparency and flatness; geomembranes and greenhouse films require high strength and weather resistance, necessitating correspondingly enhanced traction and shaping systems.

Capacity Requirements: Calculate the required extrusion volume (kg/h) of the equipment based on daily output and monthly order volume to avoid using large machines for small applications or overloading small machines:

Small machines: Screw diameter 30-45mm, extrusion volume 10-50kg/h, suitable for small-batch, multi-variety production.

Medium-sized machines: Screw diameter 50-70mm, extrusion capacity 60-150kg/h, meeting the supply needs of medium-sized wholesalers.

Large-sized machines: Screw diameter 80mm and above, extrusion capacity 200kg/h and above, suitable for large-scale orders from brand owners.

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