1. Standard positioning and scope of application
GB/T 7247.1 "Safety of Laser Products - Part 1: Equipment Classification, Requirements, and User's Guide" serves as the fundamental standard for
laser product safety. Laser welding machines, classified as industrial high-power laser equipment, typically emit at a wavelength of 1064nm
(fiber/solid-state lasers) or 1070nm (semiconductor lasers), with continuous output powers ranging from hundreds to tens of thousands of watts.
Almost all of them are categorized as Class 4 laser products, subject to the most stringent safety requirements.
II. Laser Class Determination and Accessible Emission Limit (AEL)
The laser level of a laser welding machine must be determined through actual measurement. According to the Accessible Emission Limits specified
in GB/T 7247.1:
Class 4 determination: Any laser product exceeding the limit of Class 3B is automatically classified as Class 4. For 1064nm continuous wave lasers,
the AEL (Average Energy Level) for Class 3B is 0.5W; laser welding machines typically have a power of ≥500W, so they inevitably belong to Class 4.
Test parameters: Measure the laser output power/energy, beam diameter, divergence angle, pulse width (in case of pulse welding), and repetition
rate under specified test conditions, and confirm the specific multiples by which they exceed the Class 3B limits.
III. Design requirements for safety protection
The Class 4 laser welding machine must incorporate multiple safety engineering control measures:
Fully enclosed protective cover: The welding work area must be completely enclosed by a rigid protective cover, which must be capable of withstanding
laser radiation and impact from splashes, and equipped with an interlock device.
Safety interlock: When any removable panel or door of the protective cover is opened, the interlock system must automatically cut off the laser power
supply or reduce the laser output to below Class 1 level.
Key switch: The main control unit of the equipment must be equipped with a key switch to prevent unauthorized personnel from starting the laser.
Remote interlocking connector: Provides external terminals for easy integration into factory safety circuits or emergency shutdown systems.
Laser emission indicator: During laser emission, there must be a clearly visible or audible alarm signal.
Beam stopper/attenuator: Prevents accidental light emission in the non-working state.
IV. Interlocking and emergency shutdown
Emergency stop button (E-Stop): It must be set up in an easily accessible location at both the operation and maintenance positions, and the main
power supply of the laser device must be immediately cut off upon triggering.
Scanning interlock: If equipped with a galvanometer scanning system, the laser must be automatically shut off in case of abnormal scanning or
overspeed.
Cooling system interlock: In the event of a failure in the water-cooled or air-cooled system, automatic shutdown must occur to prevent overheating
damage to the laser or the risk of fire.
V. Labels and Warning Signs
The laser welding machine body must be permanently and clearly marked with the following information:
Laser warning triangle (yellow background, black border, and laser symbol)
Class 4 Laser Products - Declaration of Conformity
Output wavelength (e.g. λ = 1064 nm)
Maximum continuous output power (e.g. P = 3000 W)
Pulse parameters (in case of pulse welding: pulse energy, pulse width, repetition rate)
Manufacturer name, model, and production date
Recommended optical density (OD) values for protective glasses
VI. User Guide Safety Information
According to GB/T 7247.1, the user manual must contain complete safety instructions and be provided in Chinese:
Clear Class 4 laser hazard statement (can cause eye damage, skin burns, and ignite materials)
Requirements for the designation of controlled areas (unauthorized personnel are not allowed to enter)
The specifications (wavelength matching, optical density OD value) of the laser protective glasses that operators must wear
Warning of reflective light hazards (specular reflection on metal workpiece surfaces is equally dangerous)
Ventilation and smoke exhaust requirements (welding fume and ozone protection)
Safety procedures for maintenance and repair (such as power outage, lockout/tagout LOTO)
Precautions for disposal (laser contains sensitive components such as optical crystals and optical fibers)
VII. Technical Documents and Type Inspection
The manufacturer must establish complete technical documentation for future reference:
Overall description of the product's optical and electrical systems, optical path diagram, and circuit diagram
Laser grade classification calculation sheet and third-party testing report
Raw data of Accessible Emission Level (AEL/EL) test
Functional verification record of the protective cover interlock system
Risk Assessment Report (Based on GB/T 15706 / ISO 12100)
Description of the patterns and placement of all warning signs
Declaration of Conformity and List of Executive Standards
Type inspection is typically conducted by qualified third-party testing institutions, such as the National Laser Product Quality Supervision and Inspection
Center, with a focus on verifying laser output parameters, interlock reliability, and labeling compliance.
VIII. Common non-compliance risks
Mislabeling Class 4 laser welding machines as lower levels to circumvent safety design requirements
The protective cover interlock is either malfunctioning or can be easily bypassed (such as by taping the door switch)
The user manual lacks specific warnings for Class 4 or recommendations on optical density
The maintenance access was not equipped with independent interlocking, resulting in maintenance personnel being exposed to direct sunlight
The laser output test conditions do not meet the most unfavorable operating conditions specified in the standards (such as the maximum duty cycle
and the highest gain state)
