For the laser cutting machine, whether it is flat or cutting pipe cutting, to equipment for processing in accordance with the established pattern, the key lies in the dynamic response of each axis with the problem between the level of participation and mutual processing. If in the processing process, the overall response of the shaft is too slow, or some of the location of a small deviation of the axis, the other axis deviation of the situation, then there will be the problem of processing contour deformation. There are many reasons for the inconsistency of this kind of deviation. There are many factors, such as mechanical, external force, servo response, control system, and so on. Therefore, the key to solve this problem is that each axis has a better dynamic response and coordination between the coordination, so that it can be more strictly in accordance with the established objectives of the processing action. Servo motor as a mechanical and control system in the middle of the executive body, to a certain extent, make up, optimize and coordinate the actions of each system, in order to achieve a more perfect control purposes.
Factors affecting the normal operation of the servo motor:
1 mechanical factors
Mechanical problems are relatively common, mainly in the design, transmission, installation, material, mechanical wear and so on.
2 mechanical resonance
The greatest impact of mechanical resonance on the servo system is unable to continue to improve the response of the servo motor, so that the overall operation of the device in a relatively low response state. Such problems in the synchronous belt transmission machinery is more common, in addition to a long distance of the ball screw and sometimes there are such cases. The main reason is that the rigidity of the synchronous belt is low, the resonance frequency is low, the long distance of the wire rod itself is of great inertia, and more deformation, especially in the case of small motor capacity selection is relatively easy to start. At the same time, the assembly process and the quality of the material will also have an impact on the mechanical resonance.
3 Mechanical jitter
The real problem is the natural frequency of mechanical dither, usually more appear in the single end fixed beam structure, especially in the deceleration stage performance is particularly evident. Low frequency jitter in the processing of pieces will appear in a large wave shape, the higher frequency jitter will have serrated shape.
4 mechanical stress, external force and other factors
Due to the differences of mechanical materials and installation, the mechanical stress and the static friction force of each transmission shaft may not be consistent. If the equipment involved in a shaft stress axis interpolation control of static friction or greater, will to some extent consume servo torque caused by the shaft speed is slow, resulting in machining deformation. Usually, we can observe the internal stress of the drive shaft by the waveform curve generated by the feedback of servo drive.
The external force acting on the shaft is also similar. General sheet metal cutting machine, the axis and the workpiece is not in contact, may be limited by the external force. But some pipe cutting machine, pipe will be involved in the cutting time of the interpolation, and the other axis is generally non - contact. The pipe due to the impact of the fixture, will produce a reverse force of tube feeding shaft, so in the stress condition of two axis interpolation control is not the same, the effect of the cutting will be affected.
5 numerical control system factors
In some cases, the servo debugging effect is not obvious, at this time may be involved in the adjustment of the control system. Laser cutting machine usually linear speed is relatively constant, in a straight line and the curve is the same speed. This point in the linear motion is not much problem, but in the curve, especially the small size of the arc of the process may be due to the acceleration caused by the deformation of the contour of the situation.