1 Classification based on the method of processing and the process used
1. CNC machine tools that are commonly used
CNC machine tools are generally defined as automatic machine tools that implement digital control in a processing technology process, such as cnc milling services, CNC lathes, CNC drilling machines, CNC grinding machines, and CNC gear processing machines. CNC machine tools are also referred to as digital control machine tools.
Ordinary CNC machine tools, despite their high degree of automation, still require manual intervention for tasks such as tool replacement and part clamping.
2. Machining center (also spelled machining center)
It is a numerical control machine tool that includes a tool magazine as well as an automatic tool changing device. It performs the functions of a numerical control milling machine, a numerical control boring machine, and a numerical control drilling machine all at the same time. Once the parts have been clamped together, the majority of the processing surfaces can be processed in a variety of ways, including milling, boring, drilling, expanding, reaming, and tapping.
Because the machining center can effectively avoid the positioning error caused by multiple installation, it is well suited for cnc milling partproducts that require frequent product replacement, have complex part shapes, require high precision, are produced in small batches, and have a short production cycle.
2nd, classification according to sport
1. Control with a single pointCNC machine tool (Computer Numerical Control)
This means that the CNC system only controls the precise positioning of the tool or worktable from one point to another, and then performs fixed-point processing, with the path between points not being controlled by the system. CNC drilling machines, CNC boring machines, and CNC coordinate boring machines are all examples of machines that use this type of control.
2. Linear control of the point positionCNC machine tool (Computer Numerical Control)
Point position linear control refers to the fact that the CNC system not only controls the precise positioning of the starting point and end point of the linear trajectory, but it also controls the linear cutting between the two points at the specified feed rate. Point position linear control is also referred to as point position linear control. cnc milling service, CNC lathes, CNC grinders, and other similar machines are available.
3. Control of the contoursCNC machine tool (Computer Numerical Control)
It is also referred to as continuous trajectory control because it is capable of controlling the joint motion of two or more coordinate directions on a continuous basis.
This function of the numerical control device is necessary in order to ensure that the tool contour processes the curve contour of the workpiece in accordance with the specified trajectory. It performs an interpolation operation, which ensures that the tool contour trajectory approaches the specified contour curve with minimal error, and coordinates the movement speed of each coordinate direction, so that the specified feed speed is maintained throughout the curing process. This type of control is used in CNC milling machines, CNC lathes, CNC grinders, and machining centers, among other applications.
3rd, classification according to control mode
1. Control system with an open loop
Control systems without a feedback device are known as open loop control systems. Stepper motor drive circuits and stepper motors are used in open loop control systems.
Through the control operation, the numerical control device sends out a pulse signal, and each pulse signal causes the stepper motor to rotate a specific angle, as well as driving the worktable to move a specific distance through the ball screw. This type of servo mechanism is relatively simple, stable, and simple to operate, but it has limited potential for improving accuracy and speed over traditional servo mechanisms.
2. Control system with a semi-closed loop
In the servo mechanism of the open-loop control system, an angular displacement detection device is installed in the semi-closed loop control system to detect angular displacement. Because it indirectly detects the displacement of the moving parts by detecting the angle of the ball screw of the servo mechanism, it can then feed that information back to the comparator of the numerical control device to compare with the original command displacement value, and it can then use that difference value to control, so that the moving parts supplement the displacement. The precision, speed, and dynamic characteristics of this type of servo mechanism outperform those of the open-loop servo mechanism, which is used by the vast majority of small and medium-sized CNC machine tools on the market today.
3. Control system with a closed loop
The closed-loop control system is a control system in which a linear position detection device is directly installed on the position of the moving parts of the machine tool, the actual displacement detected is fed back to the comparator of the numerical control device, and the difference between the two values is compared, and the moving parts are controlled by the difference value after the comparison.
The positioning accuracy of a closed-loop control system is higher than that of a semi-closed-loop control system, but its structure is more complex, and it is more difficult to debug and maintain. As a result, it is frequently used in high-precision and large-scale CNC machine tool applications.
4th classification is based on the number of linkage axes there are.
The CNC system directs the movement of several coordinate axes in a coordinated manner in accordance with the required functional relationship, which is referred to as the coordinate linkage.
1. Linkage with two axes
CNC machine tool can control two coordinate axis linkage at the same time, which makes it suitable for CNC lathe machining rotary surfaces or cnc milling milling plane profiles, among other applications.
2-axis and half-linkage configuration
The movement of the Z axis is added on top of the movement of the other two axes. When the X and Y axes of the machine coordinate system are fixed, the Z axis can be programmed to feed at regular intervals. Layered machining can be accomplished using two axis semi linkage machining.
3. A three-axis linkage system
CNC machine tools are capable of controlling the linkage of three coordinate axes at the same time, and they are commonly used to process curved surfaces in general. Three axes are available for processing a general cavity mold.
4. The use of multiple coordinate links
The linkage of more than four coordinate axes can be controlled by a CNC machine tool at the same time.
It is possible to machine complex shape parts such as impeller blade parts using a multi-axis CNC machine tool because of its complex structure, high precision requirements and complex programming. Generally speaking, a three-axis machine tool can perform two-axis, two-and-a-half-axis, and three-axis machining; a five-axis machine tool can only perform three-axis linkage processing, with the other two axes remaining unconnected in most cases.