The liquid bag is welded and cut in one step to form

The integrated welding and cutting one-step molding process is a highly efficient and precise liquid bag manufacturing technique. By merging welding and cutting into a single automated procedure, this method significantly enhances production efficiency while ensuring product quality. Below is a detailed analysis of its core principles:

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1. Process Principles

Material Layering and Alignment

• Multi-layer composite films (e.g., PE/PA/PE structure) are used as the base material.
• Films are unwound via a pay-off system and precisely aligned.
• A tension control system ensures flatness, avoiding wrinkles or misalignment during welding.

Synchronized High-Frequency Welding and Cutting

• High-Frequency Welding: Utilizes high-frequency electromagnetic fields to polarize film molecules, generating heat under pressure to form sealed welds. Temperature, pressure, and duration are precisely controlled by PLC, ensuring weld strength ≥ substrate material.
• Ultrasonic Cutting: Upon welding completion, an ultrasonic transducer generates high-frequency vibrations. A cutting die slices the film while melting the edges to seal the切口, preventing fiber shedding or leakage.

Integrated Forming

• Welding and cutting are driven by a single servo motor, synchronized via belts or gears to ensure precise alignment of weld seams and cut lines. This minimizes post-processing errors.

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2. Technical Advantages

Enhanced Efficiency

• Traditional methods require 30–60 seconds per piece for separate welding and cutting steps. The one-step process reduces this to 5–10 seconds, boosting efficiency by 5–10x.

Consistent Quality

• Automation eliminates human error:
  • Weld strength uniformity ≥ 95%.
  • Cutting dimensional tolerance ≤ ±0.5 mm.
  • Sealing performance passes helium leak tests (leakage rate ≤ 1×10⁻⁶ mbar·L/s), meeting food/pharmaceutical-grade requirements.

Cost Optimization

• 40% reduction in floor space for equipment.
• 30% lower energy consumption per unit.
• Scrap rate drops from 3–5% (traditional) to <0.5%, with material utilization reaching 98%.

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3. Applications

Medical Sector

• Production of infusion bags and dialysis solution bags.
• Welds are non-toxic and residue-free, compliant with USP Class VI biocompatibility standards.

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4. Key Equipment Selection Criteria

High-Frequency Welding Machine

• Power range: 5–20 kW (based on film thickness).
• Frequency: 13.56 MHz or 27.12 MHz.

Synchronized Cutting System

• Power: 2000–4000 W; Frequency: 20 kHz or 40 kHz.
• Cutting die: Titanium or carbide alloy, blade angle 30°–45°, ensuring smooth cuts.

Automation Control System

• Equipped with an HMI touchscreen supporting multi-language operation and parameter storage.
• Integrated vision inspection for real-time monitoring of weld quality and cut dimensions.