1. Introduction
The primary drive system in CNC engraving machines typically employs a stepless speed control mechanism. Currently, there are two main types of continuously variable transmission systems: frequency conversion spindle systems and servo spindle systems. These systems usually use DC or AC spindle motors to drive the spindle either directly through belt drives or via a combination of belt drives and reduction gears within the spindle housing, allowing for greater torque output. Due to the wide speed range and smooth speed regulation provided by these motor systems, the mechanical structure of the spindle unit has been significantly simplified. Among these, frequency converters have gained widespread popularity in machine tools due to their high performance-to-price ratio. The Inventronic CHE series vector inverters are increasingly being adopted in CNC applications thanks to their unique performance and cost-effectiveness. Figure 1 shows the CNC system:
2. Main Performance Requirements of the System
(1) Minimal speed fluctuations across the entire speed range. (2) Low torque at low speeds to ensure stable cutting performance. (3) Short acceleration and deceleration times for improved efficiency.3. Main Functional Requirements of the System
(1) Control mode: V/F control. (2) Terminal control is used as the command source. Two-wire terminal control: FWD (forward) is activated via S1 input, and REV (reverse) is activated via S2 input. (3) Frequency setting is done via an analog signal from the computer control board (0–10VDC), with the frequency command input through the AI1 port. (4) Normal operating speed ranges from 0–21,000 rpm, corresponding to an inverter frequency of 0–350 Hz for high-speed motors. (5) Acceleration and deceleration times can be adjusted based on customer needs, typically between 3–5 seconds. Given the high-speed operation, a frequency converter with a braking unit is essential. (6) Fault output signal (Y output) and fault reset signal (S3 input) are required for system monitoring and recovery.4. System Description
The electrical wiring diagram of the inverter is shown in Figure 2.
The AI1/GND terminals of the inverter receive the analog signal from the numerical control system to regulate the spindle speed. The AI1 terminal is connected to the positive analog signal from the CNC interface, while GND is connected to the negative signal. This provides a 0–10V analog voltage signal that controls the spindle speed. The S1/S2/COM terminals are used for forward and reverse signals. The CNC system sends the forward or reverse command to a relay, and the normally open contact of the relay is connected to the inverter's S1/S2/COM terminals, enabling control over the inverter’s direction of rotation.
5. Main Inverter Function Parameters
P0.00: V/F control P0.01: 1 terminal command channel P0.03: 1 analog AI1 setting P0.04: 350 Hz (maximum output frequency) P0.05: 350 Hz (upper limit of operating frequency) P0.08: 5 s acceleration time (adjustable according to actual conditions) P0.09: 3 s deceleration time (adjustable according to actual conditions) Group P2: Set according to motor nameplate parameters P4 group: V/F control settings based on actual application P5.00: 1 – Forward operation P5.01: 2 – Reverse operation P5.02: 7 – Fault reset P5.05: 0 – Two-wire control 1 P6.00: 3 – Fault output This configuration ensures precise and reliable control of the spindle motor in CNC engraving machines, meeting both performance and functional requirements effectively.Customized Solutions,Automatic French Fries Production Line,Onion Food Processing,Fruit And Vegetable Processing
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