A Brief Talk on CNC Machine Tool Systems

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A Brief Talk on CNC Machine Tool Systems [Copy link]

A brief discussion on CNC machine tool system

1. What is CNC machine tool system: CNC machine tool is abbreviated as CNC. Its principle is to generate G code through software coding of input CAD drawing information, and then transmit it to the controller, which translates the G code into instructions (logic) and execution signals (displacement). The controller controls the motor speed in the form of PWM wave or PTO pulse train to realize the rotation of the spindle and feed axis, and finally converts it into the linkage of the machine tool and the working arm to achieve the purpose of original processing.

Figure 1 Electrical system of CNC machine tool

2. System composition:

The CNC machine tool system consists of two major parts:

1. Electrical system. As shown in Figure 1, it includes a power system, an operating platform, a communication and G code parsing module (instructions, walking trajectory), an interface circuit, a controller, a motor driver, a motor, and some detection components.

Figure 2 Schematic diagram of the mechanical system

2. Mechanical system. Does anyone feel familiar with it? Yes, except for the spindle (responsible for the rotation of the workpiece and tool), the rest of the feed axes are the same as 3D printers (also G codes). The principle of action is to control the rotation of the feed axis according to the fitted walking trajectory, and when the position is detected, the next action is performed.

Figure 3 Typical CNC electrical system

III. Typical CNC electrical system:

As shown in Figure 3, it has integrated operation control communication platform, control bus, driver (including inverter), servo or stepper motor and other components.

IV. CNC machine tool control system:

Figure 4 Interpolation fitting

1. The controller uses interpolation operation to obtain the fitting curve of the actual trajectory, and then differentiates the trajectory (fitting) according to the corresponding coordinate axis of the lathe with the minimum movement, and obtains the number of pulses required for the movement of each axis, and achieves the purpose of turning through position closed-loop control.

2. The specific control methods can be divided into three categories.

<1>Open-loop control system

Without feedback device.

Figure 5 Open-loop control

<2>Semi-closed-loop control system

Controls the rotation angle of the servo motor through the encoder to indirectly achieve the purpose of controlling displacement.

Figure 6 Semi-closed-loop

<3>Closed-loop control system

With a sensor that directly measures displacement.

Figure 7 Closed loop

In addition, the general machine tool control method now has both servo motor angle loop and machine tool position loop, and has protection and calibration components such as limit switches.

That's all for today. This content was originally created by EEWORLD forum user wugx. If you need to reprint or use it for commercial purposes, you must obtain the author's consent and indicate the source

fsyicheng

Are you in this industry? Let's talk more.

wugx

fsyicheng posted on 2017-12-2 12:52 Are you in this industry? Let's talk more

I just contacted you. There is a machine tool transformation project here. If it goes wrong, the entire electrical control system will have to be redeveloped. If you are interested in this, you can cooperate with me.

lqsgg

Thanks for sharing! Good article! This industry is a high-tech industry! But it has also become an industry where it is not easy to collect payments! Many companies owe a lot of money!

lqsgg

I am engaged in the sales and installation of CNC systems for gantry grinders! If you are interested, please contact me! QQ: 719740308

wugx

lqsgg posted on 2017-12-4 09:10 Thank you for sharing! Good article! This industry is a high-tech industry! But it has also become an industry where it is not easy to collect payments! Many companies owe money...

The industry is in recession now