1. Use environment
The CNC machine tool tells the cutting process that if an instantaneous power failure may cause tool damage, scrap parts, and even cause machine tool equipment failure, we must ensure that some CNC machine tools with expensive tools or high-value machining parts are foolproof. Even in the event of a major power outage, the cutting process of CNC machine tools is hoped to stop safely and smoothly;
2. Fallback principle
During the cutting process of FANUC CNC machine tools, if the machine is completely powered off due to force majeure, the FANUC CNC system will use its retraction function to retract the feed axis to a safe position and allow the tool to leave the workpiece to avoid causing the tool or The parts are damaged; but when the machine tool is powered off, the drive and CNC will lose power, and it is impossible for the servo axis to generate a retraction distance. Therefore, we need an external power supply, the DC 24V required for the motor drive control signal, and the motor The power supply required for driving is 200V;
3. Hardware configuration
3.1 The control signal power required by the motor drive is DC 24V
Fanuc 24V power supply (PFB-24) can also use a third-party UPS power supply. Commonly used third-party power supplies include Omron, Siemens and Mingwei products from Taiwan;
3.2 Power supply required for motor rotation
Fanuc Capacitor Module (PFB-C). In the event of an unexpected power failure of the machine tool, the Capacitor Module mainly supplies power to the servo axis with the rollback function, so that the servo axis can roll back according to the set amount and speed;
4. Parameter setting
N7702#3=1 ART alarm-based rollback function is valid (when a servo alarm other than the rollback axis occurs, the servo excitation is maintained until the rollback is completed)
N7740=5000 Retraction speed
N7741=10 Return amount
N7745=50 The linear acceleration and deceleration time constant of each axis retreat
5. Summarize
The return function of the FANUC CNC system does play a great role in protecting the workpiece and the tool at the moment of power failure. The setting of the return amount of parameter N7741 may be different from the actual return amount. The main influencing factors are: The first is the use time of the capacitor module. If the capacitor module is used for a long time, it may cause the storage power to decrease, and then the back distance is reduced; the second is whether the back axis is a gravity axis, if it is a gravity axis, the capacitor power will still be It resists the gravitational potential energy of the gravity axis, so the retreat distance will be greatly reduced; and this function requires more complicated hardware connections.
