CNC lathe components and working principle

1 composition of CNC lathe

     Although more types of CNC lathes, but generally the main by the lathe, numerical control unit and servo system has three major components. Figure 12-3 is a block diagram of the basic components of CNC lathes.

(1) the main lathe

   In addition to the basic layout of maintaining the traditional form of lathe CNC lathe parts of the economy, the present, most CNC lathes are designed and finalized by the production.

1) the spindle and headstock

a) Spindle: CNC lathe spindle rotation accuracy, directly affect the machining accuracy; its power size, rotation speed affect the efficiency of processing; its synchronous operation, automatic transmission and directional quasi-stop, etc., affect the degree of automation lathe .

b) Headstock: a gear with automatic speed control function-level CNC lathes (such as Tai-Hite Company production of "sea a few" brand products: CJK6136, CJK6140, CJK6150), due to the use of power brakes, in addition to mechanical clutch, the spindle inside of the transmission mechanism has been greatly simplified; with stepless speed automatic CNC lathes (such as "sea a few" brand products: CK6136A, CK6140A, CK6150A), due to inverter is used, in addition to the mechanical transmission speed and change the role of institutions, the headstock has become a "bearing" and "lubricating boxes" synonymous; for the transformation of type (manual and automatic control with dual processing function) CNC lathe, the spindle which preserves its original box.

2) rail

    CNC lathe feed motion guide is to ensure the accuracy of the important parts. It has greatly affected the stiffness of lathes, precision and smooth low speed when feeding, and is affecting the quality of parts processed one important factor. In addition to part of the CNC lathe is still the traditional sliding rail (metal type), the shape produced by CNC lathe has more use of plastic coated rails ("the sea a few" brand products using plastic coated rails). The new sliding rail friction coefficient is small, its wear resistance, corrosion resistance and good shock absorption, lubrication conditions are more favorable.


3) Mechanical transmission

    In addition to part of the inside of the gear drive shaft and other institutions, the CNC lathe lathe in the original, based on the drive chain, made a substantial simplification. Such as the abolition of hanging round boxes, feed boxes, crates and most of the slide drive mechanism, and retaining only the vertical and horizontal feed screw drive mechanism and drive motor to the screw is no gap between the creation of a flexible joint coupling.

Screw drive mechanism: CNC lathe spiral vice, is to drive the output of the motor rotation into a knife in the longitudinal and transverse direction of linear motion of the deputy campaign. Constitute a screw drive mechanism components, generally ball screw, as shown in Figure 12-4.

Ball screw as shown in Figure 12-4

1-2-nut ball screw 3 a 4 a ball circulation unit

Ball screw friction is small, eliminating axial clearance and preload, so transmission efficiency and high precision, stable movement, movement sensitive. But the structure is more complex, higher manufacturing technology, so the cost is higher. Also, adjust the gap size, the degree of difficulty is also larger.

4) Automatic knife rotation

    In addition to turning centers with random tool (knife library) outside the automatic tool changer, CNC lathe with a fixed cutter bit generally automatic indexing turret, some lathe also comes with various forms of double-knife (such as emission knife).

5) detection feedback device

   Detection CNC lathe feedback device is an important part of the processing accuracy, efficiency and automation of production have a significant impact. Detection devices, including displacement detection device and the workpiece size detection devices into two categories, which are divided into the workpiece size detection device inside and outside the machine size detection device size detection device two. Workpiece size detection device only in a small number of high-end CNC lathe equipped with.

6) device for knife

   Only a few specific nature of the CNC lathe, ordinary CNC lathe using a variety of almost all forms of automatic indexing turret, for multi-tool turning. In this way, each knife knife sites installed on the turret position, relative to the lathe or the location of a fixed origin, are required for the knife, adjustment and measurement, and to confirm, in order to ensure the quality of machining.

(2) CNC devices and servo system

CNC lathes and lathe the main difference lies in whether the servo system with numerical control device and the two parts. If, CNC lathe detection device is equivalent to the human eye, then the numerical control device is equivalent to the human brain, the servo system is equivalent to the human hands. Thus, it is easy to see these two in the CNC lathe in which the majority of the important locations.
a) NC device

    CNC equipment is the core of computers and software, CNC lathe from its "directing" role: CNC machining programs sent by the device to receive all the information, and after treatment and after deployment, issue command to the drive mechanism; in the implementation of process, its drivers, testing and other institutions that relevant information back to the numerical control device, in order to issue a new treated to execute commands.

b) servo system

    Servo system to accurately perform numerical control device orders, through the drive circuit and actuators (such as stepper motors or servo motors, etc.) required to complete a variety of CNC equipment displacement.

2 CNC lathe work process

CNC lathe work process shown in Figure 12-5.

Figure 12-5 CNC lathe work process

(1) First, according to parts processing pattern for process analysis, to determine the processing solution, process parameters and displacement data.

(2) under the rules of writing program code and format a single part program.

(4) a program written by the hand, through the operation panel CNC program.

(5) NC device will accept a series of signal processing, then the results in the form of the pulse signal to the servo system to issue the command to execute.

(6) servo system information received instructions executed immediately after the feed mechanism driven lathe in strict accordance with the requirements of Directive displacement, so that the corresponding parts of the automatic lathe processing.


Tai'an City Machine Manufacturing Co., Ltd. Hite Technology Center feeds

March 20, 2010