Annular Die for Plastic Film Blowing Machines

Product Specifications

Technical details and manufacturing context for Annular Die

Definition

The annular die is the extrusion head in a plastic film blowing machine where molten plastic is forced through a circular opening to form a continuous tube. It controls the initial shape, thickness distribution, and dimensions of the plastic film before it enters the bubble formation and cooling stages. Proper die design and maintenance are essential for producing uniform, high-quality plastic films with consistent properties. The die is typically made from tool steel, stainless steel, or hardened steel alloys to withstand the high temperatures and pressures of the extrusion process. Key parameters include die diameter (50–2000 mm), die gap (0.5–3.0 mm), output capacity (50–1500 kg/h), operating temperature (150–350°C), operating pressure (10–50 MPa), surface roughness (Ra 0.2–0.4 μm, per ISO 4287), hardness (HRC 58–62, per ASTM E18), material grade (S136 or 2316, per DIN 1.2083 or 1.2316), heating power (5–50 kW), and weight (100–5000 kg). These values are reference ranges; actual specifications must be confirmed with the legal manufacturer or supplier for the specific model and application. The die's design and condition directly affect film quality, and regular inspection and maintenance are necessary to prevent defects such as thickness variations, gels, or die lines. Always verify model-specific values and standards with the legal manufacturer or supplier before procurement or use.

Working Principle

Molten plastic from the extruder enters the annular die body and flows through internal channels (often a spiral mandrel design) to distribute material evenly around the circumference. The plastic then passes through the annular gap between the die body and mandrel, forming a seamless tube. The gap width and die geometry determine the film's initial thickness and dimensions, which are further controlled by air pressure and stretching during bubble formation. The die must maintain uniform temperature and melt flow to ensure consistent film properties.

Common Materials

Tool steel, Stainless steel, Hardened steel alloys

Technical Parameters

Parameter	Typical range	Notes & selection driver
Die Diameter	50–2000 mm	Determines film width; larger diameters for wider films.
Die Gap	0.5–3.0 mm	Affects film thickness and clarity.
Output Capacity	50–1500 kg/h	Matches extruder throughput.
Operating Temperature	150–350 °C	Resin-dependent; above 350°C risks degradation.
Operating Pressure	10–50 MPa	Below 10 MPa insufficient melt flow.
Surface Roughness	Ra 0.2–0.4 μm	Lower roughness improves film clarity.ISO 4287
Hardness	HRC 58–62	Wear resistance for abrasive polymers.ASTM E18
Material Grade	S136 / 2316	Corrosion-resistant stainless steel.DIN 1.2083 / 1.2316
Heating Power	5–50 kW	Depends on die size and required temperature.
Weight	100–5000 kg	Affects installation and handling.

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Components / BOM

Die Body Part
Outer housing containing flow channels and forming surface

Material: Hardened tool steel
Mandrel Part
Central core that creates the annular gap with die body

Material: Hardened tool steel
Die Lip Part
Precision edge where film exits the die

Material: Hardened steel

Manufacturers of Annular Die

Manufacturer profiles associated with Annular Die.

Sourcing Annular Die from China?

Tell us your specification and target quantity — we will match it against manufacturer records and come back with the factories that fit.

Request manufacturers We manufacture this

Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review · Page last updated 6 September 2026

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Frequently Asked Questions

What materials are annular dies typically made of?

According to the directory, annular dies are commonly made from tool steel, stainless steel, or hardened steel alloys. The specific material grade may be S136 or 2316, but always confirm with the manufacturer.

What is the typical die gap range?

The die gap typically ranges from 0.5 to 3.0 mm, which affects film thickness and clarity. The exact gap must be set according to the resin and desired film properties.

How does die diameter affect film width?

Die diameter determines the initial film width; larger diameters are used for wider films. The reference range is 50 to 2000 mm, but the actual size depends on the machine and application.

Why is surface roughness important?

Lower surface roughness (Ra 0.2–0.4 μm) improves film clarity by reducing melt flow disturbances. The standard for measurement is ISO 4287, but verify the actual requirement with the manufacturer.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Buyer enquiry

Request manufacturing insight for Annular Die

Ask for use case, specification boundaries, supplier type, and RFQ preparation information for this product.

Where it goes: Straight to the CNFX editorial desk, and to the manufacturer if this product is linked to a claimed profile. Nothing is broadcast to a supplier list.
Your details stay here: We do not sell or rent enquiry data, and we do not add you to a mailing list. Used only to answer this request.
No commission, no middleman: CNFX is a directory. We take no cut of any order and never negotiate on a supplier's behalf.
What we don't claim: A listing is not an endorsement. Qualify every supplier and verify every figure yourself before ordering.

pressure:	10-50 MPa (depends on polymer viscosity and die design)
flow rate:	5-500 kg/h (varies with die diameter and polymer type)
temperature:	150-300°C (typical polymer processing range)
slurry concentration:	Not applicable (designed for molten polymers, not slurries)

Annular Die

Product Specifications

Industrial Ecosystem & Supply Chain Structure

Application Fit & Sizing Matrix

Reliability & Engineering Risk Analysis

Compliance & Manufacturing Standards