What Is a Blown Film Machine?
1.Introducing
Blown film machine (also called a blow film extruder or film extrusion machine) is industrial equipment that converts plastic resin pellets (such as LDPE, HDPE, or LLDPE) into continuous, thin-wall plastic film through a blow film extrusion process. This film extruding method uses air to inflate a molten tube into a bubble, creating film with balanced strength and uniform thickness. It is the core production system for flexible packaging materials including shopping bags, garbage bags, bubble cushioning film, and zipper bags
This guide explains the working principle, main types, core components, advantages, and applications of the plastic blown film machine. You will also learn about three common configurations: the T-shirt bag blown film machine, the air bubble film machine, and the zipper (self-locking) film blowing machine.
2. Main Types of Blown Film Machines
Plastic blown film machines are generally categorized by their layer structure and winding method. Leading blown film extruder manufacturers offer various configurations to meet different production needs. The table below compares three typical models within the broader film extrusion equipment family.
| Feature | T‑Shirt Bag Blown Film Machine | Air Bubble Film Machine | Zipper (Self‑Locking) Film Blowing Machine |
| Primary output | Shopping bags, vest bags, garbage bags | Bubble wrap, cushioning film | Self‑sealing zipper bags, resealable packaging |
| Raw materials | HDPE, LDPE, LLDPE | LDPE, LLDPE | PE, PP |
| Film width | 500–2000 mm | 600–2500 mm | 400–1800 mm |
| Film thickness | 0.01–0.15 mm | 0.02–0.2 mm (bubble height adjustable) | 0.03–0.15 mm (with integrated zipper) |
| Extruder type | Single screw | Twin screw (or single screw with vacuum system) | Single or twin screw with dedicated zipper die |
| Typical speed | 60–120 m/min | 80–150 m/min | 50–100 m/min |
| Main application | High‑volume bag production for retail and waste | Protective packaging for e‑commerce, electronics, furniture | Reclosable food bags, cosmetic pouches, hardware packaging |
2.1 T-Shirt Bag Blown Film Machine
This machine produces plain or printed film rolls used for making T-shirt bags, grocery sacks, and garbage bags. It runs at high speed (up to 120 m/min) and can handle 100% virgin HDPE or blends with recycled material. Key features include a single-screw extruder, automatic air ring for thickness control, and a surface winder for tight rolls. It is one of the most common configurations in the plastic blown film machine market and a popular choice in industrial blown film production.
2.2 Air Bubble Film Machine
Designed to produce air-filled bubble cushioning film, this machine uses a twin-screw extruder and a vacuum bubble-forming die. The bubbles (diameter 5–30 mm) provide excellent shock absorption. It can also laminate bubble film with other layers (e.g., aluminum foil, PE film) for insulated packaging. This specialized film extrusion line requires precise temperature control to maintain bubble consistency. Blown film machine automation features such as automatic tension control and servo-driven winders are essential for high-quality bubble film output.
2.3 Zipper (Self-Locking) Film Blowing Machine
This specialized line simultaneously extrudes the base film and the zipper profile (male and female tracks). The zipper is formed inline and bonded to the film edges. The finished roll can be made into stand-up pouches or flat bags with a reusable seal – ideal for food, cosmetics, and small hardware. The blown extrusion film process here is more complex because it coordinates two melt streams. This type of blown film making machine requires precise synchronization between the main extruder and the zipper extruder.
3. Core Components and Working Principle
Regardless of type, all plastic blown film machines share the following key components. These parts work together to enable continuous film extruding and reliable blown film manufacturing.
| Component | Function |
| Extruder (screw and barrel) | Melts and homogenizes plastic pellets under controlled temperature. |
| Die head | Extrudes the molten plastic into a vertical tubular shape. |
| Air ring | Blows cooling air onto the bubble to solidify the film. |
| Collapsing frame | Flattens the bubble into a double-layer film. |
| Nip rollers | Pull the film and adjust thickness by speed control. |
| Winding unit | Rolls the finished film onto cores (single-shaft, dual-shaft, or double winding). |
| PLC control system | Monitors temperature, speed, tension, and line output. |
4.How blow film extrusion process works (6 steps)
1. Feeding – Plastic pellets are poured into the hopper.
2. Melting – The screw rotates, pushing the material through heated zones (150–220°C).
3. Extrusion – The molten polymer exits the circular die as a thick tube (parison). This is the starting point of the blown extrusion phase.
4. Inflation – Compressed air blows the tube into a large bubble; the blow-up ratio (BUR) determines final width. This step is unique to blown extrusion film production.
5. Cooling – The air ring solidifies the film; the frost line indicates where solidification is complete.
6. Flattening and winding – The bubble is collapsed, pulled by nip rollers, and wound into rolls.
For the zipper machine, an additional step integrates the zipper profile via a separate extrusion channel just before the collapsing frame. Modern blown film machine automation systems can manage this entire sequence with minimal operator intervention.
5. Core Advantages of a Plastic Blown Film Machine
- High output – Continuous production from 50 to 150 m/min, ideal for mass orders.
- Material versatility – Processes LDPE, HDPE, LLDPE, recycled pellets, and biodegradable resins. This flexibility is a major benefit of modern film extrusion systems.
- Gauge uniformity – Automatic thickness control (via auto-profile air ring or IBC) ensures ±5% tolerance, a key metric in blown extrusion quality control.
- On-demand production – No need to stock pre-made bags; make film rolls exactly when needed.
- Cost savings – ABA co-extrusion models can reduce virgin resin usage by 20–30% using recycled material in the middle layer.
- Compact footprint – Modern lines integrate tower, winder, and control into a space-saving layout (e.g., 5.8 × 3.1 m for a 1300-type).
- Automation readiness – With advanced blown film machine automation, operators can store recipe presets, monitor production remotely, and reduce material waste. This is a key differentiator among blown film extruder manufacturers.
6. Application Scenarios
Plastic blown film machines serve diverse industries through their versatile film extrusion capabilities. As a core piece of blown film machinery, they support industrial blown film production at scale.
| Industry | Examples |
| Retail & supermarkets | T-shirt bags, vest bags, produce bags |
| E-commerce & logistics | Bubble mailers, protective film pouches |
| Food packaging | Zipper bags for snacks, coffee, frozen food; lamination film for shelf-ready packs |
| Waste management | Garbage bags, bin liners, industrial sacks |
7. Frequently Asked Questions (FAQ)
8. Internal Link Recommendations
- [How to Maintain Your Blown Machine for Longer Service Life] – Daily/weekly checklists
- [How to Choose the Right Blown Film Extrusion Line for Your Business] – 5-step selection guide
- [Single-Layer vs. ABA Co-Extrusion Blown Film Machine: Which Saves More Cost?] – ROI comparison
- [1300 PE Double Winding vs. ABA Blown Film Machine: Which One Do You Need?] – Technical comparison
Call to Action
Need a blown film machine tailored to your specific bag type? Contact our engineering team for a free consultation. We will recommend the optimal blow film extruder configuration – T-shirt bag, bubble film, or zipper film – based on your target output, film width, and raw material access.
