What is the difference between five-axis 3 + 2 and five-axis linkage?
1. What is 3 + 2 positioning processing
When a three-axis milling program is executed, the two rotary axes of a five-axis machine tool are used to fix the cutting tool in an inclined position. The name of the 3 + 2 machining technology is also derived from this. This is also called positioning five-axis machine tools because The fourth and fifth axes are used to determine the orientation of the tool at a fixed position, rather than continuously during processing.
The principle of 3 + 2 positioning machining is essentially the realization of the three-axis function at a specific angle (that is, "positioning"). In short, after the machine tool rotates the angle, it is still processed in the ordinary three-axis manner.
2. What is 5-axis simultaneous machining
According to ISO regulations, when describing the movement of CNC machine tools, a left-handed rectangular coordinate system is used; the coordinate axis parallel to the main axis is defined as the Z axis, and the rotation coordinates around the X, Y, and Z axes are A, B, and C, respectively. Usually five-axis linkage refers to the linear interpolation motion of any five coordinates of X, Y, Z, A, and B.
3. Difference between 3 + 2 positioning and 5-axis linkage
3 + 2 positioning processing is different from the industry objects applicable to 5-axis linkage processing. 5-axis linkage processing is suitable for curved surface processing, and 3 + 2 positioning processing is suitable for planar processing.
Advantages of 3 + 2 positioning processing:
1) Shorter, more rigid cutting tools can be used.
2) The tool can form a certain angle with the surface, and the spindle head can be extended lower and closer to the workpiece.
3) The tool movement distance is shorter and the program code is less.
Limitations of 3 + 2 positioning processing:
3 + 2 positioning machining is usually considered as setting a constant angle to the spindle. Complex workpieces may require many oblique views to cover the entire workpiece, but this results in overlapping tool paths, which increases machining time.
Advantages of 5-axis simultaneous machining:
1) No special fixture is required during processing, which reduces the cost of the fixture, avoids multiple clamping, and improves the precision of mold processing.
2) Reduce the number of fixtures used.
3) Eliminate many special tools in processing, thereby reducing tool costs.
4) In processing, it can increase the effective cutting edge length of the tool, reduce the cutting force, increase the service life of the tool and reduce the cost.
Limitations of 5-axis linkage:
1) Compared with 3 + 2 positioning, the rigidity of its spindle is worse.
2) In some cases, a five-axis solution is not suitable. For example, the tool is too short, or the tool holder is too large, so that vibration cannot be avoided under any tilting conditions.
3) Compared with 3-axis machine tools, the machining accuracy error is large.