In laser cutting equipment, relays are key components used for circuit control and signal switching. Their main function is to control high-power loads through low-power signals, enabling safety control, status linkage, and action logic management within the equipment. Relays are widely used in the electrical control system of laser cutting machines, including light source control, motor drive management, gas control, safety interlocks, and logic switching of peripheral actuators.
I. Working Principle of the Relay
A relay consists of a coil, armature, contact group, and housing. Its working principle is based on electromagnetic attraction.
1.Coil energized to generate a magnetic field
When a control voltage is applied to the relay coil, an electromagnetic field is generated inside the coil.
2.Armature attraction
The electromagnetic force causes the armature to move, which drives the contacts to open or close.
3.Contact switching
The contact group performs switching by closing normally-open contacts or opening normally-closed contacts, thereby controlling different external circuits or loads.
4.Coil de-energized and released
When the coil is de-energized, the magnetic field disappears, and the armature returns to its original position under spring force, restoring the contacts to their initial state.
This principle allows a relay to control high-current loads using small control signals and provides the foundation for multi-channel control in laser cutting equipment.
II. Main Functions of Relays in Laser Cutting Machines
1. Laser source control
Relays are used to control the power supply of the laser source, including the main power, the chiller interlock power, and trigger signal control. Through relays, the following can be achieved:
① Laser start-up protection
② Interlock between the laser source and cooling system
③ Safe delay start-up of the laser power system
2. Motor drive management
The X, Y, and Z axis movements of a laser cutting machine require servo motor drivers. Relays are used to control driver power-on, enable signals, and emergency stop switching, ensuring safe and reliable operation of the motion system.
3. Gas control system
Laser cutting commonly uses oxygen, nitrogen, and air. Gas switching valves and solenoid valves typically require relays for signal isolation and linkage to ensure that gas pressure and gas path status meet process requirements.
4. Safety interlock and emergency stop control
Laser cutting machines include door protection, emergency stop buttons, light curtains, and safety locks. Relays integrate these signals to implement the entire safety chain, including:
① Preventing laser emission when the safety door is open
② Cutting off all critical loads when the emergency stop is pressed
③ Automatically disconnecting the laser power when an abnormal condition occurs
5. Peripheral equipment linkage
Peripheral devices such as fume extractors, air compressors, oil-mist separators, and cutting-head height controllers can be automatically linked through relay control to standardize and automate equipment operation.
III. Importance of Relays in Laser Cutting
1. Electrical isolation and protection
Relays isolate the control circuit from the load circuit, protecting low-voltage systems from high-voltage and high-current impact and reducing component failure risks.
2. Fundamental components of logic control
Action sequences in laser cutting machines depend on relays for sequential linkage, ensuring the machine operates in the correct order.
3. System stability and reliability
Mechanical contact relays have strong anti-interference capability, clear output states, and low failure rates, making them suitable for high-reliability industrial environments such as laser cutting.
4. Essential for safety functions
Laser cutting involves high voltage, high-energy beams, and high-speed motion systems. Relays play a critical role in emergency stop, interlock, and safety chain functions, directly affecting operational safety.
Relays play an essential role in control, safety protection, and logic linkage within laser cutting equipment. Their electromagnetic-actuation mechanism provides signal isolation and reliable switching, making them fundamental components of laser cutting machine electrical systems. Whether in laser source control, motion management, gas switching, or safety interlocks, relays contribute significantly to equipment stability, operational safety, and processing reliability.