CNC Router Spindle Quasi - Working Principle

- May 31, 2017 -

CNC Router

CNC Router spindle pinch function is also known as the spindle orientation function, is fine boring and other processing must be the function. Usually the spindle quasi-stop mechanism has two kinds of mechanical and electrical, modern CNC Router using electrical quasi-stop device positioning more, electric magnetic sensor type, encoder type, CNC system control three methods.

First, the CNC Router spindle electrical quasi-stop device

1. Magnetic sensor type spindle quasi-stop device

Magnetic sensor Spindle quasi-stop device is the use of magnetic sensors to detect positioning. Install a magnetizer on the spindle and fix a magnetic sensor at a distance of 1 to 2 mm from the outer track of the magnetizer, and connect it to the spindle control unit via the amplifier. When the spindle control unit receives the quasi-stop signal ORT sent by the CNC system, the spindle speed becomes the set speed when the spindle control unit receives the magnetic sensor signal. The spindle drive immediately enters the magnetic sensor as the feedback element Position closed-loop control, the target position is the quasi-stop position. After quasi-stop, the spindle drive sends a quasi-stop signal ORE to the CNC.

2. Encoder type spindle quasi-stop device

The stop angle can be set arbitrarily by installing the position encoder built into the spindle motor or by mounting a position encoder that rotates synchronously with the spindle 1: 1 on the machine tool spindle box. The spindle drive can be automatically switched inside so that the spindle drive is in speed control or position control.

3. CNC system control spindle quasi-stop device

The angle of the quasi-stop can be set by the CNC system to any value, the quasi-stop by the NC code M19 implementation. When the implementation of M19 or M19S × ×, the CNC system will first send M19 to the PLC, after processing to send out the control signal to control the spindle motor from the rapid rapid acceleration or in the original operation of the higher speed quickly down to the directional stop setting The speed nORT run, find the spindle encoder zero pulse C, and then enter the position closed-loop control state, and press the system parameter to set the directional quasi-stop. If the M19 has no S command, the spindle will stop at a certain default position of the relative C pulse. If the M19S ×× command is executed, the spindle will be stopped at the command position, that is, relative to the zero pulse × ×. Spindle orientation quasi-stop the specific control process, different systems of its control process is slightly different, but much the same.

Second, the spindle quasi-working principle

The speed of the spindle positioning curve shown in Figure 4, the work process is: ① when the actual spindle speed n ≥ 600r / min, the input positioning command, the spindle immediately decelerated to the positioning of the line quasi-speed (about 600r / min) 3r / min after the synchronization, and then enter the position control, so that the spindle positioning to the preset point and keep the position closed loop. ② When 60r / min ≤ n ≤ 600r / min, the input positioning command, the spindle to the current speed to achieve synchronization, and then act into the position control (lower limit 60r / min for adjustable speed). ③ When the actual spindle speed is 0 or <60r / min, the input positioning command, the spindle to 60r / min speed start and achieve synchronization, and then enter the position control.

Third, the spindle quasi-stop device common faults

1. The spindle can not stop

Symptom: A SIEMENS 810M CNC Router, supporting 6SC6502 spindle drive, in the debugging, when the spindle speed> 200r / min, the spindle can not locate the fault.

Analysis and processing: In order to analyze and confirm the cause of the failure, the maintenance of the following tests: ① input and followed by the implementation of "S100M03; M19" command, the machine positioning is normal. ② input and follow the "S100M04; M19" instruction, the machine positioning is normal. ③ input and followed by the implementation of "S200M03; M05; M19" command, the machine positioning is normal. ④ Direct input and follow the "S200M03; M19" instruction, the machine can not be positioned.

According to the above test, confirm the system, the drive is working properly, consider the possible cause of the failure is the encoder high-speed characteristics of the poor or the spindle positioning speed is too high. Therefore, check the actual speed of the spindle motor and find that it is very different from the command value. When the command S200 is executed, the actual spindle speed is 300r / min, and the spindle drive parameters are adjusted so that the actual spindle speed matches the command value.


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