1.Why is it so suitable?
High material compatibility: The optical absorption characteristics of lasers (especially fiber lasers and CO₂ lasers) are well-matched with those of steel materials, resulting in high energy conversion efficiency.
Good surface quality: The surface of cold-rolled coils is flat, smooth, and clean, which is conducive to uniform absorption and stable processing of the laser beam, leading to higher quality holes.
Controllable heat-affected zone: Compared to thick plates, thin cold-rolled coils have faster punching speeds, more concentrated heat input, a smaller heat-affected zone (HAZ), and minimal deformation.
Suitable for continuous production: It can be integrated with uncoiling, straightening, and rewinding equipment to realize a continuous automated punching production line from roll to roll with extremely high efficiency.
2.What are the processing methods and key technological points?
Pulsed perforation: This method uses a high-energy pulsed laser to ablate the material layer by layer until it is broken down. It offers high precision and good hole quality (excellent control over roundness and taper), but is relatively slow.
High-speed rotary cutting perforation: A laser beam rotates at high speed to ablate the hole, or oxygen-assisted gas is used to quickly cut the hole.
3.How to control key process parameters?
Laser power and pulse frequency: Determine drilling speed and energy input. Insufficient power will prevent penetration, while excessive power will result in excessive slag and a large heat-affected zone.
Focus position: Precisely setting the focus on the plate surface yields the smallest possible hole diameter and optimal quality.
Auxiliary gases:
Nitrogen/Argon: Used to obtain oxidation-free, clean hole walls, suitable for applications requiring subsequent electroplating or high corrosion resistance.
Oxygen: Utilizes oxidation to release additional heat, significantly increasing drilling speed, but an oxide layer (blackened or bluish) will form at the hole edges.
Hole diameter to plate thickness ratio: The minimum hole diameter for conventional laser drilling can reach approximately 1/10 of the plate thickness. High-quality drilling generally recommends a hole diameter no smaller than the plate thickness. For example, it is feasible to stably process microholes larger than 0.2mm on a 1mm thick cold-rolled coil.
4.What are its main advantages?
No tool wear: Non-contact machining eliminates drill wear and breakage issues, resulting in low maintenance costs.
High flexibility and adaptability: Hole position, shape (round, square, irregular) and diameter can be changed instantly via programming without changing molds.
Extremely high precision and consistency: Hole diameter tolerance can be controlled within ±0.05mm, with extremely high hole position accuracy.
Capable of machining micropores and high-density pore clusters: Ideal for machining components with numerous dense pores, such as screens and filter cartridges.
5.What are the challenges and precautions?
Hole wall taper: Laser drilling naturally produces a certain taper (wider at the top and narrower at the bottom). This can be significantly improved through focus control, using taper compensation software, or double-sided drilling.
Slag and recast layer: Burrs (slag buildup) formed by molten metal cooling may adhere to the hole exit. This can be reduced or eliminated by optimizing parameters, using assist gas, and employing a high-peak-power pulsed laser.
Heat-affected zone and material properties: Although the heat-affected zone is small, the microstructure of the metal at the hole edge changes (hardening), which may have a subtle impact on certain demanding subsequent forming processes.
Oxidation issues of carbon steel: When using oxygen-assisted drilling, while the oxide layer at the hole edge improves efficiency, it may affect the appearance and subsequent coating adhesion. The gas selection should be based on the application.
Impact of sheet metal surface coating: If the cold-rolled coil surface has a galvanized layer or is oiled, more smoke and sputtering will be generated during drilling. Enhanced dust removal and lens protection are required.