CNC machining centers represent the pinnacle of automated precision in manufacturing. These CNC machine tools, equipped with tool changers capable of seamlessly transitioning between various machining operations, stand at the forefront of the global manufacturing industry. They are renowned for their exceptional processing capabilities and can perform complex tasks such as milling, drilling, tapping, and turning with unparalleled accuracy.
In addition to their versatility, CNC machining centers are known for their efficiency. Once a workpiece is securely clamped, the integrated CNC system takes control. It orchestrates a synchronized sequence of tool selection and speed adjustments, precisely choreographing the path of each tool. This orchestration extends to automatic drilling, countersinking, reaming, tapping, and intricate milling – making CNC machining centers indispensable in modern manufacturing.
REQUIREMENTS AND OUR SOLUTIONS
- High Low-Frequency Torque: The application required a frequency inverter with robust torque capabilities at low frequencies.
Solution: The GD350A frequency inverter, with its closed-loop vector control, delivers an impressive 200% of rated torque already at 0Hz. This feature is crucial for handling complex machining tasks that require precision and performance at low speeds.
- Output Frequency Above 400Hz:
Solution: The GD350A frequency inverter continuously delivers output frequencies above 400Hz, ensuring a broader operating range for the CNC machining center.
- Rapid Deceleration
Solution: For safety and operational efficiency, the 400V VFD GD350A series offers rapid deceleration. Specifically, models below 37kW are equipped with an integrated braking unit, while units from 45-110kW provide the option for an integrated braking unit. This function ensures fast and controlled braking, a crucial component in precision machining.
- Rapid Torque Dynamics, High Speed Stability: The dynamic machining requirements of the application called for the use of advanced vector control technology.
Solution: The GD350A frequency inverter, equipped with state-of-the-art motor control processors, excels in rapid dynamic response. It quickly adapts to load fluctuations, ensuring stable spindle speed, a fundamental requirement in precision manufacturing.
- Precise Spindle Stop and Indexing: The complex operations of the CNC machining center required precise spindle control.
Solution: The GD350A frequency inverter seamlessly integrates into the system, allowing precise spindle stopping via Z-phase signals or external photoelectric signals. With four zero positions and seven spindle angle indexing options, it meets the high-precision indexing requirements of the application.
- Speed/Position Mode Switching: The flexibility to switch between speed and position modes was crucial.
Solution: The 400V VFD GD350A simplifies this process with terminal-based mode switching, adapting the inverter’s performance to the constantly changing requirements of the CNC machining center.
| Model | Quantity | |
| Frequency Inverter | GD350A-011G-4 | 1 |
| PG Card | EC-PG503-05 | – |
| Brake Resistor | 30 Ohm, 5 kW | -1 |
COMMISSIONING
Commissioning Steps
(1) Auto-Learning Based on the information on the electric spindle label, set the frequency inverter parameters P02.00 to P02.05. Set parameter P00.15 to 2 and give the start command. The frequency inverter initiates the auto-learning of static parameters for the electric spindle. After auto-learning, the learned parameters are stored in the group parameters P2 in parameters P02.06 to P02.10.
(2) Closed-Loop Operation of the Frequency Inverter Set the maximum frequency, acceleration and deceleration times of the frequency inverter, as well as the P20 group parameters. Start the frequency inverter with the keyboard and monitor whether P18.00 and P18.02 are normal. Once they are normal, set P0.00 to 3 and operate it in closed vector control mode.
(3) Setting of Basic Function Parameters Configure the function settings for the connections, spindle positioning, and position mode selection. Test the functions for precise spindle stopping, indexing, and thread cutting using the CNC control.
(4) Adjustment of Power Parameters Adjust the parameters of the speed control loop of group P3 and the parameters of the proportional integral time of the current loop, the position control loop gain, and the number of encoder capture filter steps. This improves the system’s responsiveness and the performance of the inverter torque output.
- Key Parameter Settings
| Parameter | Description | Set Parameter Value |
| P00.00 | Speed Control Method | 3: Closed Vector |
| P00.01 | Operation Command Channel | 1: Terminal Start |
| P00.03 | Maximum Frequency | 401.00 Hz |
| P00.04 | Upper Frequency Limit | 401.00 Hz |
| P00.06 | A Frequency Selection | 12: Set Pulse AB |
| P00.11 | Acceleration Time | 1.0 s |
| P00.12 | Deceleration Time | 3.0 s |
| P03.00 | Proportional Gain of Speed Control Loop 1 | 15 |
| P03.02 | Low Point Frequency Switch | 0.5 |
| P03.03 | Low Point Frequency Switch | 30 |
| P03.05 | High Point Frequency Switch | 1 |
| P05.02 | S2 Connection Function Selection | 45: Precise Stop |
| P05.03 | S3 Connection Function Selection | 51: Speed/Position Mode Switching |
| P05.04 | S3 Connection Function Selection | 9: External Fault |
| P05.08 | Select Polarity of Input Connections | 1000 |
| P06.03 | Relay RO1 Selection Function | 5: Inverter Fault |
| P06.04 | Relay RO2 Selection Function | 30: Positioning Completed |
| P20.02 | Encoder Direction | 1 |
| P21.02 | Position Control Loop Gain 1 | 30 |
| P21.03 | Position Control Loop Gain 2 | 40 |
| P22.00 | Mode Selection for Spindle Positioning | 1 |
INSTALLATION AND FINISHED PRODUCT
