The application and principle of high-frequency welding technology in drainage bags

I. Operating Principle: Electromagnetic Molecular-Level Fusion

The High-Frequency (HF) welding process utilizes oscillating electromagnetic fields (standard frequencies: 27.12/40.68 MHz) to induce molecular excitation in thermoplastics (PVC/TPU). Fundamental mechanisms:

1. Precision Thermal Management

• Selective surface heating via skin effect (depth ≤0.15mm @27MHz)
• Uniform temperature gradient (ΔT ≤5°C across 150mm weld line)

2. Stress-Free Bonding

• Non-contact electrode configuration (2-5mm air gap)
• Residual stress <0.8MPa (ASTM E837 measurement)

3. Instantaneous Phase Transition

• Cooling rate: 50-80°C/sec (DSC-verified)
• Pore-free microstructure (per ASTM F3039 porosity criteria)

II. Critical Applications in Drainage Bag Manufacturing

1. Mission-Critical Sealing

A. Catheter-Body Fusion

• Leak-proof interface strength: ≥65N/cm (ISO 8536-4 compliant)
• Bacterial filtration efficiency: >99.9% (ASTM F2101)

B. Valve Integration

• One-step molding precision: ±0.03mm dimensional tolerance
• Crack pressure: 30±2cm H₂O (EN 13544-7 tested)

2. Complex Geometries

A. Multi-Layer Lamination

• PVC (0.5mm)/TPU (0.3mm) interface bonding strength: 48N/cm
• Layer-specific dielectric control: 5-15kV/cm field gradients

B. Micro-Feature Welding

• Transparent scale window (Φ3mm) bubble-free sealing
• 85% visible light transmission (EN 170 compliance)

3. Automated Production Systems

A. Integrated Processing Line

• 6-station configuration:
  ▪ Web feeding (SICK CLV630 alignment)
  ▪ High-speed die cutting (±0.1mm)
  ▪ HF welding (15kW generator)
  ▪ Vision inspection (0.02mm defect detection)

B. Flexible Tooling

• Quick-change mold system (3min changeover)
• 150+ bag configurations with single PLC platform