Laser welding has become an established technology for joining diverse materials, from precision plastics to dense metals, with critical applications in medical, aerospace, defense, renewable energy, and other high-tech industries. The fundamental decision lies in selecting between continuous wave (CW) or pulsed laser systems.
Continuous Wave Laser Welding
CW lasers emit a constant, uninterrupted beam, typically utilizing diode-pumped fiber optic gain media. This method excels in:
- Deep penetration welding (≥1.5mm depth)
- Crack-prone materials (e.g., high-carbon stainless steel)
Technical Specifications:
- Power range: 200W to 100kW+
- Minimum effective power: 200W for most metals
- Material compatibility:
▸ Ferrous metals (e.g., stainless steel): Effective at ≥200W
▸ High-reflectivity metals (Al/Cu): Requires 600-800W
Process Control:
- Typical feed rate: ~2.5 m/min (to prevent overheating)
- Thermal balance:
Slower feed rate → Increased penetration + Larger HAZ
Pulsed Laser Welding
Pulsed lasers deliver discrete high-peak-power bursts, with capacitor-stored energy enabling remarkable efficiency. A 25W Nd:YAG pulsed laser can achieve 5kW instantaneous peak power – matching the spot-welding capability of a 5kW CW system.
Process Characteristics:
- Seam welding: Overlapping spot welds
▸ Hermetic seals: 80-90% overlap
▸ Structural joints: ≥70% overlap
Ideal Applications:
- Thermally sensitive components
- Ultra-thin materials (<0.5mm)
- Highly reflective metals
Key Advantages:
- Enhanced pulse effect: μs-level peak power overcomes surface reflectivity
- Superior thermal control: Average power ≈1/200th of CW systems, minimizing heat damage
Technology Selection Guide
| Parameter | CW Laser | Pulsed Laser |
|---|---|---|
| Heat Input | Continuous high heat | Intermittent low heat |
| Best For | Thick sections/steels | Thin/reflective metals |
| Efficiency | High-speed processing | Precision control |