Manufacturing Process of Seamless Bulletproof Helmets

Process Overview

The core advantage of the seamless bulletproof helmet manufacturing process lies in eliminating the traditional cutting procedure. By adopting integrated molding technology, it maintains the integrity and continuity of core materials such as high-molecular polyethylene (PE) or aramid fibers. This not only enhances protective performance but also simplifies the production process and reduces labor costs. The product structure adopts a multi-layer composite design, consisting of (from the inside out) a backing layer, a core protective layer, an anti-splash layer, and a surface finish layer. The final product must meet key protective indicators such as a V50 value ≥ 800 m/s and a back deformation ≤ 25 mm.

Raw Material Preparation

Selection of Core Materials

1、Main Protective Materials: Ultra-high molecular weight polyethylene (PE) unidirectional fabric or aramid unidirectional fabric is selected, with an areal density ≥ 200 g/m², to ensure the continuity of the material fibers is not damaged.

2、Auxiliary Materials: Plus material pre-treatment procedures.

Raw Material Quality Inspection

Fiber Integrity: Check that the unidirectional fabric is free from damage and broken fibers, with a fiber arrangement uniformity deviation ≤ 3%.

Physical and Chemical Indicators: Test the material’s Vickers hardness (HV ≥ 500) and interlayer bonding strength (≥ 20 MPa) to ensure compliance with the requirements of the ASTM F1956-19 standard.

Environmental Adaptability: Pass the temperature cycle test ranging from -40℃ to +60℃, with a material performance change ≤ 10%.

Key Production Processes

1. Mold Preparation and Debugging A dedicated seamless integrated mold is used, consisting of a male mold (core + core base) and a female mold (cavity + cavity base). The mold cavity has an open structure, with an open port at the bottom for discharging excess material. Mold Pre-treatment: Clean the inner wall of the mold cavity to ensure no impurities remain; preheat the mold to 80℃-100℃ through the heating and cooling circulation pipeline, with a temperature uniformity deviation of ±2℃. Air Guide Channel Debugging: Ensure the vertical air guide channels at the centers of the core and cavity are aligned to facilitate smooth gas discharge during the molding process.

2. Material Lamination Operation No cutting is required; directly lay the entire roll of PE or aramid unidirectional fabric into the mold cavity layer by layer according to the designed number of layers (18-23 layers), with an interlayer alignment deviation ≤ 1 mm. Backing Layer Laying: Precisely place polyurethane foam on the surface of the mold core to ensure tight bonding with the unidirectional fabric layer, free from residual air bubbles. Composite Layer Arrangement: Lay the resin layer in sequence to ensure the resin evenly covers the surface of the unidirectional fabric, with its weight proportion controlled between 10% and 30%.

3. Integrated Molding Including mold clamping operation, heating and curing, cooling and shaping, and excess material treatment.

4. Multi-layer Composite Processing Including core layer treatment, anti-splash layer compounding, and surface finish layer treatment.