The difference between NC and CNC(4)

Functions that were only available in high-end CNCs are now used in mid-range products. For those manufacturers who have never used five-axis machining technology, the application of these features makes five-axis machining easier. The use of current CNC technology for five-axis machining enables five-axis machining to have the following advantages:

Reduce the need for special tools;

Allow to set the tool offset after finishing the part program;

Support the design of general programs, so that the post-processed programs can be interchanged between different machine tools;

Improve the quality of finishing;

It can be used for machine tools with different structures, so that it is not necessary to specify in the program whether the spindle or the workpiece is rotating around the center point. Because this will be solved by CNC parameters.

We can use the example of spherical milling cutter compensation to illustrate why five-axis is particularly suitable for mold processing. In order to accurately compensate the offset of the spherical milling cutter when the parts and the tool rotate around the pivot axis, the CNC must be able to dynamically adjust the compensation amount of the tool in the X, Y, and Z directions. To ensure the continuity of the cutting contact of the tool is beneficial to improve the quality of finishing.

In addition, the use of five-axis CNC is also manifested in: characteristics related to rotating the tool around the spindle, characteristics related to rotating parts around the spindle, and characteristics that allow the operator to manually change the tool vector.

When the central axis of the tool is used as the axis of rotation, the original tool length offset in the Z-axis direction will be divided into components in the X, Y, and Z directions. In addition, the original tool diameter offset in the X and Y axis directions is also divided into three components in the X, Y, and Z axis directions. Because in cutting engineering, the tool can do feed movement along the axis of rotation, all these offsets must be dynamically updated to account for the continuously changing orientation of the tool.

Another feature of CNC called "tool center point programming" allows programmers to define the path and center point speed of the tool. The CNC ensures that the tool moves in accordance with the program by commanding the direction of the rotary axis and linear axis. This feature makes the center point of the tool no longer change with the change of the tool, which also means: in the five-axis machining, the tool offset can be directly input just like the three-axis machining, and it can also be explained by the post-program again. Change of tool length. The realization of the movement characteristics of the shaft by rotating the main shaft simplifies the post-processing of the tool programming.

Using the same function to make the workpiece rotate around the central pivot, the machine tool can also obtain rotational movement. The newly developed CNC can dynamically adjust the fixed offset and rotating coordinate axis to match the movement of the part. When the operator uses the manual method to realize the slow feed of the machine tool, the CNC system also plays an important role. The newly developed CNC system also allows the axis to feed slowly along the direction of the tool vector, and allows the direction of the tool tip vector to be changed without changing the position of the tool tip (see the illustration above).

These features make it easy for operators to use the 3+2 programming method that is currently widely used in the mold industry when using a five-axis machining machine. However, with the gradual development of new five-axis machining functions and the acceptance of this function, the real five-axis mold processing machine tools may become more common.

NC

(Numerical Control, numerical control, referred to as numerical control), refers to the use of discrete digital information to control the operation of machinery and other devices, which can only be programmed by the operator

CNC

The development of CNC technology is quite rapid, which greatly improves the productivity of mold processing, and the CPU with faster calculation speed is the core of the development of CNC technology. The improvement of CPU is not only an increase in computing speed, but the speed itself also involves the improvement of other aspects of CNC technology. It is precisely because CNC technology has undergone such major changes in recent years that it is worthwhile to review the current application of CNC technology in the mold manufacturing industry.