High-Speed Twin-Head PE Film Blowing Machine for HDPE LDPE

Applications

A twin-head blown film line does what two separate machines do — but from one extruder, one tower, one winder assembly, and half the factory floor. One extruder feeds two die heads. Two bubbles form simultaneously. Two films wind onto two shafts. The operator manages one control panel instead of two. For a factory running a single PE grade at high volume — HDPE garbage bag film, LDPE shopping bag film, or LLDPE stretch wrap — this configuration delivers approximately 80% more output than a single-head machine of the same extruder size, in roughly the same footprint.

Who This Machine Is For

• Factories running one PE grade at high volume, year-round. If your production is 80% LDPE shopping bag film or 90% HDPE garbage bag film — same material, same thickness, day after day — a twin-head line gives you two machines' output from one extruder. The single-grade requirement matters: both heads run the same melt, so material changes affect both bubbles simultaneously.

• Producers who are out of floor space but need more output. Adding a second single-head machine requires another extruder, another tower, another winder, and roughly 40-50 square meters of additional factory floor. A twin-head upgrade adds the second die head and winder assembly to the existing tower — approximately 15 square meters of additional space.

• Manufacturers replacing two aging single-head machines with one line. One twin-head machine replaces two separate extruders with one shared extruder, one control system, and one set of utilities (one electrical feed, one compressed air line, one cooling water circuit). Maintenance is consolidated: one screw to inspect, one gearbox to service, one set of heater bands to stock.

Who Should NOT Buy This Machine

• If you run multiple PE grades across different orders. Both die heads receive the same melt from the same extruder. You cannot run HDPE on head one and LDPE on head two. If your weekly schedule alternates between materials, a high-speed single-head PE line with quick-change capability is more practical — or two separate single-head machines dedicated to each material.

• If you need recycled content in your film. Twin-head machines are single-layer extruders. There is no core layer to hide recycled PE. Adding recycled content to the feedstock affects both films identically — and the recycled material will be visible on all film surfaces. For recycled-content packaging, an ABA blown film machine is the correct choice.

• If your order sizes are small and varied. A twin-head machine makes two films simultaneously. If your typical order is 200 kg of one film type, both heads produce it — giving you 400 kg before you can switch. For short-run, multi-product factories, two independent single-head machines offer more scheduling flexibility.

Technical Advantages

Double Output From One Extruder

A single high-capacity extruder feeds two die heads through a melt distributor that splits the flow evenly. The extruder is sized to plastify enough polymer for both heads simultaneously — typically a 75-90mm screw for 120-160 kg/h combined output. The melt distributor is the critical component: it must divide the melt stream into two equal flows at identical pressure and temperature. An unbalanced split — where head one receives 52% of the melt and head two receives 48% — creates a permanent output imbalance that cannot be corrected downstream. The distributor geometry is machined to equal flow-path lengths from the extruder exit to each die inlet.

Half the Floor Space of Two Machines

One tower supports two die heads, two collapsing frames, two haul-off units, and two winders. The tower is structurally reinforced to handle the asymmetric load — the dies, air rings, and collapsing frames are mounted on opposite sides. A twin-head tower weighs approximately 40% more than a single-head tower of equivalent output because the steel structure must resist the torsional load from two off-center die assemblies. Foundation requirements increase accordingly: a reinforced concrete pad with anchor bolts at all four corners, not just two.

One Operator, Two Films

One operator monitors both bubbles from a central position. The control panel displays temperature, pressure, screw speed, and line speed for both heads side by side. If head one's frost line drifts, the operator adjusts head one's air ring — head two is unaffected. If the extruder barrel temperature fluctuates, both heads are affected equally because they share the melt source. Operators learn to distinguish between single-head problems (adjust that head) and extruder problems (both heads affected — check screw speed, barrel temperature, or feedstock).

Real Production Issues It Solves

• Die imbalance between the two heads. Over months of operation, one die head inevitably runs slightly hotter or colder than the other — a thermocouple drifts, a heater band ages differently, or polymer degradation builds up in one die lip more than the other. The symptom: head one produces film at 60 kg/h, head two at 55 kg/h, and the operator compensates by running head two's air ring harder — which changes the film properties. Solution: weekly output comparison between the two heads. If the difference exceeds 5%, clean both dies and recalibrate the melt distributor temperature zones. This is a 4-hour procedure but prevents months of unbalanced production.

• Bubble interference in the tower. Two bubbles running side by side in the same tower affect each other's cooling airflow. The bubble on the windward side — the side facing the factory's ventilation airflow — cools faster than the leeward bubble. The frost line heights differ. In factories without climate control, the difference is more pronounced in the afternoon when ambient temperature peaks. Solution: install airflow baffles between the two bubble paths inside the tower. A simple sheet-metal divider reduces cross-interference by 60-70%.

• One winder failure stopping both films. If head one's winder jams, the operator cannot simply stop head one — the extruder is still feeding melt to both dies. Head two must also stop while the jam is cleared. Solution: specify independently clutched winders. Each winder shaft has its own pneumatic clutch. If head one jams, engage the clutch to freewheel head one's winder while head two continues winding. The jammed roll is scrapped, but head two's production is preserved.

Production Scenarios

How It Works

1. Single Extruder Melting: One high-capacity single-screw extruder — typically 75-90mm diameter, L/D 30:1 — plastifies PE pellets for both die heads. PID temperature controllers maintain barrel zones within ±1°C. Screw speed determines total melt output; the melt distributor splits it 50/50 between the two heads.

2. Melt Distribution: The melt distributor — a heated flow-splitting manifold at the extruder exit — divides the single melt stream into two equal-flow paths. Flow-channel lengths are machined to equal length, ensuring both die heads receive melt at the same temperature and pressure. A 2-3% imbalance is normal and can be trimmed via individual head temperature adjustment; above 5%, the distributor needs cleaning or the die lips need mechanical adjustment.

3. Dual Bubble Formation: Two spiral mandrel die heads — mounted on opposite sides of the tower — each receive melt from the distributor. Compressed air inflates each bubble independently. Separate dual-lip air rings cool each bubble. The operator sets each head's blow-up ratio individually — typically matched, but can differ if the two heads produce different film widths.

4. Independent Bubble Paths: Two collapsing frames and stabilizer baskets — one per side — guide each bubble into its own nip roller assembly. Airflow baffles between the two bubble paths reduce cross-interference. Each haul-off unit runs at its own speed, allowing independent film thickness control per head.

5. Dual Winding: Two independently clutched winders — surface or center type — produce finished rolls simultaneously. If one winder jams, the pneumatic clutch disengages that shaft while the other continues winding. The operator clears the jam without stopping the extruder.

Optional Configurations

Customer Case

Dhaka, Bangladesh — 2024. A shopping bag film producer replaced two 12-year-old single-head LDPE machines with one twin-head line.

The twin-head line freed 47 square meters of factory floor — space the owner used to install two bag making machines, converting film in-house instead of selling rolls to converters. The operator reduction from two to one per shift saved approximately $18,000 annually in labor cost. The single-extruder design simplified maintenance: one screw to inspect annually instead of two, one gearbox oil change, one set of heater band spares.

Why Choose Mingyang Machinery

• 20+ years focused on blown film. Screw design, die optimization, melt distribution engineering. Factory in Jiangyin, Jiangsu Province.

• CE certified. Full documentation for EU and international customs clearance.

• Engineer support: Pre-sales — we calculate your expected output and floor space savings vs two single-head machines. Post-installation — video call, remote diagnostics, optional on-site dispatch.

• Spare parts same-week dispatch: Heater bands, thermocouples, SSRs, seals, winder clutches, melt distributor components stocked.

• 60+ countries: Container loading, sea freight, destination port coordination.

Frequently Asked Questions

Production and Output

What output can I expect from a twin-head machine?

Combined output depends on extruder size: 75mm screw — 100-140 kg/h total (50-70 per head). 90mm screw — 130-170 kg/h total (65-85 per head). Figures based on 25-micron LDPE/LLDPE at 1000mm lay-flat width. HDPE output is approximately 15-20% lower because the melt has lower melt strength, limiting bubble take-up speed before instability.

Can I run different film widths on each head?

Yes. Each die head has its own blow-up ratio and collapsing frame width. You can run 800mm film on head one and 600mm film on head two simultaneously — the melt distributor does not care about downstream dimensions. However, both films must be the same material and thickness: the extruder produces one melt, and both heads receive identical polymer at identical temperature.

What happens to output if one head is down for maintenance?

If one die head needs cleaning or a heater band needs replacement, you have two options. Option one: stop the extruder, fix the head, restart — both heads down for 2-4 hours. Option two (requires melt diverter valve — a custom option): close the diverter valve to the offline head, route all melt to the active head, and run single-head at approximately 70% of the extruder's maximum output — not 100%, because the screw was sized for two heads and the melt residence time increases when flow is halved. The active head produces film while the offline head is serviced.

Operation and Floor Space

How much floor space does a twin-head machine save?

Approximately 45-55% compared to two equivalent-output single-head machines. The twin-head tower occupies roughly the same footprint as one single-head tower plus approximately 30% for the additional die head, collapsing frame, and winder on the opposite side. The real saving is eliminating the second extruder, second tower, and the aisle space between two separate machines.

Can one operator really manage both heads?

Yes. The control panel displays both heads' parameters side by side. Routine monitoring — checking frost line height, bubble diameter, and winding tension — is done from a central position. The operator walks around the tower once per hour to visually inspect each bubble from both sides. During grade changeovers, a second operator helps for 30-45 minutes — one person purges the extruder while the other cleans both die lips and adjusts air rings.

Maintenance and Reliability

What is the most common twin-head specific maintenance issue?

Die lip polymer build-up on one head faster than the other. Over weeks of continuous operation, degraded PE accumulates on the die lip — this is normal. But on a twin-head machine, one head's die lip always builds up faster because the melt distributor creates a very slight temperature difference between the two flow paths. The head receiving melt 1-2°C warmer accumulates build-up faster. Clean both die lips during the monthly maintenance window. Do not clean just the worse one — the imbalance will reverse within weeks. Clean both, and calibrate both die gaps to the same setting.

How often does the melt distributor need servicing?

Every 12-18 months, depending on operating hours and material cleanliness. The distributor is a heated manifold with internal flow channels — polymer degradation slowly builds up on the channel walls. Symptoms of a distributor needing cleaning: one head consistently produces 5-8% less output than the other at identical settings, or one head's melt temperature reads 3-5°C higher than the other. Cleaning requires disassembling the distributor, mechanically removing degraded polymer from the flow channels, and reassembling with new gaskets. Downtime: 4-6 hours. Keep a spare gasket set in stock.

Get a Twin-Head Configuration and Output Estimate

Send us your production parameters. We will calculate your expected output, floor space savings versus separate machines, and provide a detailed configuration proposal:

• Primary PE material and grade (HDPE / LDPE / LLDPE)

• Film width per head (lay-flat, mm) and thickness range (microns)

• Required total daily or monthly output (kg)

• Available factory floor space for the machine (L x W, meters)

• Are you replacing existing machines or adding new capacity?

• Electrical supply (voltage, frequency, phases)

carrie@jymingyang.com | +86-189-6169-1127