Application of EP5S servo spindle in CNC drilling and tapping machine

Numerical control drilling and tapping machine is a widely used equipment in the field of mechanical processing. It is a metal processing machine that integrates multiple processing functions such as drilling and tapping, also known as drilling and tapping machine. Drilling and tapping machines can perform precise drilling operations on metals or other hard materials, providing positioning or installation holes for subsequent assembly or other machining processes; Threads can be machined into drilled holes to achieve threaded connections between parts; Some drilling and tapping machines also have certain milling functions, which can perform flat milling, contour milling and other machining on workpieces. The drilling machine drives the spindle to rotate through a motor, allowing the tool installed on the spindle to perform high-speed cutting. The equipment precisely controls the servo motor to drive the spindle and feed mechanism through a preset machining program, achieving precise position control and machining actions.

2、 System solution
This article is based on the application of Maixin EP5S series servo spindle drive in CNC drilling and tapping machines. EP5S, as the spindle drive unit, is combined with the Suning EtherCAT bus CNC system to control the motion trajectory and processing parameters of the machine tool through CNC programs. It uses rotation and propulsion to drill the tool into the surface of the workpiece, and can continuously complete precise machining of drilling, expanding, reaming, boring, and tapping in one clamping. The supporting machine tools are widely used in the processing and manufacturing of parts in various industries such as automobile manufacturing, mold manufacturing, 3C electronics, aerospace, etc.

3、 Application site pictures
Machine tool body/mechanical structure/electrical cabinet

4、 Machine tool process requirements
1. The drilling and tapping machine requires the spindle motor to have a maximum speed greater than 10000rpm and support a rotary encoder interface. A higher rotational speed can improve machining efficiency, especially when machining small holes and performing high-speed tapping, which can effectively shorten machining time and improve production efficiency.
2. The drilling and tapping machine requires the spindle driver to support position/speed control mode, feed function (C-axis function), and orientation function (quasi stop function) to meet certain processing requirements of drilling, rigid tapping, and drilling and tapping machines.
3. The radial runout and axial displacement of the spindle of the drilling and tapping machine tool should be controlled within a very small range, usually not exceeding 0.003mm in radial runout and 0.005mm in axial displacement, to ensure the stability of the drill bit and tap during the machining process, improve machining accuracy and surface quality.
4. The drilling and tapping machine requires that the spindle can be automatically controlled for acceleration and deceleration in both forward and reverse directions, and the acceleration and deceleration time should be short. The spindle motor runs smoothly on and off, with minimal speed fluctuations and no shaking during operation, ensuring precise positioning.

5、 Debugging steps
Step 1: Install the EP5S spindle driver and spindle motor, and ensure proper wiring. Power on the system and confirm that the EtherCAT communication network is functioning properly.
Step 2: Adapt the spindle motor. When matching with the Maixin complete set of spindle motors, correctly set the spindle motor code; When paired with third-party motors, use the EP5S self-learning function to automatically identify spindle motor parameters and inertia.
First, enter the single machine mode through Fn-2, and then trigger the offline parameter identification function of the asynchronous motor through Fn6 function to complete the identification of stator resistance, rotor resistance, mutual inductance, and leakage inductance. After running the Fn6 function, the enable light will turn on. When the screen displays DONE and the enable light goes out, the recognition process ends. The recognition process takes about half a minute. After the identification is completed, press the back button to exit the Fn6 function. At this time, you can query the identified parameter results P702~P705 through the P menu and save the results through E-set.
Step 3: Determine the transmission ratio between the motor and the encoder based on the encoder type and installation method, and correctly set the number of encoder lines and electronic gear ratio related parameters.
Step 4: Rotate the spindle motor to determine the direction of motor rotation and encoder rotation. If the direction is reversed, it can be modified through EP5S related parameters.
Step 5: Test the machining effect. The EP5S loop gain parameter can be adjusted to achieve the optimal machining effect in conjunction with the machine tool machinery.

6、 EP5S servo spindle product features
1. Power models: 3.7kW, 5.5kW, 7.5kW, 11kW, 15kW
2. Voltage level: AC380V -15%~+10% 50/60Hz
3. Control mode: EtherCAT bus control, supporting position, speed, and torque control modes
4. Dual encoder interface, fully closed-loop control. Supports encoder signal input in various forms such as square wave, sine cosine, serial communication, and rotation
5. Support synchronous/asynchronous spindle motor control
6. Support self-learning of spindle motor parameters and inertia
7. Narrow body structure design, saving installation space
8. Direct insertion self-locking power terminal block, easy and fast wiring