The five axes of a five-axis machine are usually composed of three linear axes plus two rotary axes, and the structure is very different. Different structural forms will make the machine in the rigid, dynamic performance and accuracy of the stability of some differences. This paper mainly focuses on the five-axis machine tools with different vertical structure, such as vertical spindle swing and vertical spindle swing table (cradle), so that users can understand the structure of the five-axis machine, which is beneficial to the characteristics of the product And economic ability to pick the right machine.

1. Machine tool rigidity comparison

In the process of machining, the rigidity of the spindle is relatively poor due to the movement of the spindle, and the table swinging machine has no effect on the rigidity of the spindle due to the swing of the table.

2. Machine tool efficiency comparison

Due to the difference in the rotation point, the spindle is required to swing a larger angle (similar to the lever principle) when the tool nose achieves the same displacement. Therefore, the same parts are machined and the efficiency of the pendulum machine is lower.

3. Effect of tool length on machine tool machining accuracy

Swing error = swing arm × swing angle, the head of the machine is concerned, the length of the tool is part of the swing arm. In other words, in the case of the head pendulum, the length of the tool affects the length of the swing arm and amplifies the error. The error increases with the length of the tool. For a cradle table, the length of the tool is independent of the length of the swing arm.

4. Position error and shape error

With the swing, the two machines will have a position error, but the pendulum machine will produce a shape error, and the table swing will not produce shape error. The head of the machine tool rotates, resulting in a position error. At the same time, the feeding direction of the machining hole deviates from the center of rotation of the tool, so that the machining hole produces a position error and a shape error occurs, resulting in a wedge-shaped hole.

The position error of the table swinging machine is caused by the swing of the table, the feed direction of the spindle and the rotation center of the tool always coincide, so there will be no additional shape error. This is another obvious advantage over the cradle table swing and the pendulum.

5. Comparison of the five-axis processing size range

As the head of the machine tool spindle swings, the workpiece diameter direction of the processing range will be reduced, that is, the spindle swing angle will eat the trip, resulting in five-axis machining can handle the largest workpiece diameter than its three-axis machining When the table swinging machine table swing, the workpiece horizontal direction of the size will not have any impact, in this sense, five-axis machining and three-axis machining when the workpiece size range is the same. But the maximum range of the five-axis workpiece must also take into account the interference caused by the machine structure. The user should ask the machine tool supplier to provide a five-axis machining interference diagram to analyze the comparison. Under normal circumstances, the same trip, the use of cradle table swing structure of the machine five-axis machining range than the pendulum-type machine tools larger.

So the cradle of the table swing machine tool spindle rigidity, processing efficiency; tool length on the processing accuracy will not have an impact; processing will not produce shape error; the same trip, the machine five-axis machining range than the pendulum machine Big.

The machining rigidity is relatively poor and the machining efficiency is relatively low. The machining accuracy decreases with the length of the tool. The machining will produce a shape error. The spindle swing angle will eat the stroke, resulting in the maximum workpiece size that can be machined Become smaller.

In addition, it is necessary to add that the table swinging machine due to the need to overcome the reasons for the weight of the workpiece, if the workpiece is very heavy, the fixture has a higher demand; also, large-scale heavy parts when the machine can not achieve the table swing, The way the head pendulum.