1. Core Working Principle
The laser cutting head uses its internal optical system to focus a high-energy laser beam onto the material's surface, rapidly raising the local temperature to the melting or boiling point. Simultaneously, a high-pressure assist gas (such as oxygen for combustion or nitrogen to prevent oxidation) is ejected coaxially with the beam to blow away the molten metal, forming a kerf. As the cutting head moves along the programmed path, the material is ultimately cut.
2. Internal Structure
From top to bottom, a typical laser cutting head mainly consists of the following key components:
Fiber Connector & Fiber Optic Cable: The channel for laser transmission. The inner core diameter is extremely small (e.g., 50μm, 100μm), with strict requirements for the bending radius.
Collimating Lens: Converts the divergent beam output from the fiber into parallel light, ensuring uniform energy distribution in preparation for subsequent focusing.
Protective Lenses (Top/Bottom): Usually located before and after the focusing lens to block flying slag and dust during cutting, protecting the expensive focusing lens from contamination. These are consumable parts.
Focusing Lens: The core optical element that uses a convex lens principle to converge parallel light into an extremely small focal point, concentrating energy to instantly melt or vaporize the material.
Ceramic Ring: Contains internal metal wires connecting the nozzle to the sensor to transmit sensing data. It is fragile and is designed to break first during severe collisions to protect the cutting head.
Nozzle: Located at the very bottom, it serves as the common channel for both the laser beam and assist gas. Different forms (parallel, convergent, tapered) and sizes directly affect cutting quality and speed.
Sensor & Tracking System: Typically utilizing capacitive (non-contact) or inductive (contact) sensors to detect the distance between the cutting head and the workpiece in real-time, ensuring the focal point remains in the optimal cutting position.
Smart Monitoring Module: High-end intelligent cutting heads are also equipped with LED lights, temperature monitoring, and piercing detection to provide real-time feedback on working status.
3. Key Parameters & Classification
Focal Spot Diameter: Directly determines energy density. A smaller spot yields higher energy density, suitable for fine cutting of thin plates; a larger spot is better for thick plate cutting.
Focal Length: Short focal length lenses are suitable for thin plates but require high tracking system stability. Medium-to-long focal length lenses are ideal for thick plates due to their large depth of focus and higher operational tolerance.
Classification by Laser Type:
Fiber Laser Cutting Heads: Compatible with a 1064nm wavelength, featuring a compact structure widely used for cutting metals like carbon steel, stainless steel, and aluminum alloys.
CO2 Laser Cutting Heads: Compatible with a 10.6μm wavelength, mainly used for non-metallic materials like wood and acrylic, as well as some thin metals. The lenses require infrared-transmitting materials.
UV Laser Cutting Heads: Feature an extremely small focal spot and a small heat-affected zone, primarily used for high-precision micro-cutting of PCB boards and thin films.
4. Major Industry Brands
International Brands: Such as Precitec and LT Ultra from Germany, renowned for high precision, high stability, and smart sensor technology. Laser Mechanisms from the US also excels in compatibility and stability.
Domestic Brands (China): Such as Raycus (Jiaqiang) and BCUT (BLT series). Domestic brands have developed rapidly in the intelligent cutting head sector, launching products with smart features like auto-focusing, melt pool detection, and anti-collision/anti-explosion technologies, leading in market share in segmented areas.
5. Industry Development Trends
High Power & High Precision: To meet the demands of high-end fields like aerospace and shipbuilding, cutting heads are evolving toward higher power capacities (e.g., 30kW and above), faster cutting speeds, and greater precision.
Intelligence & Automation: Integrating AI and sensing technologies to achieve closed-loop focal control, auto-centering, smart piercing, and real-time monitoring of lens temperature and beam divergence, enhancing the adaptive capabilities of the machining process.
Environmental Protection & Energy Saving: Optimizing cooling systems and gas control to reduce the heat-affected zone and energy consumption during cutting, promoting green manufacturing.
