In the process of cutting stainless steel with laser cutting machine, when the auxiliary gas is air or nitrogen, burr will be generated at the sharp corner of the processing shape or the back of the material at the end of processing. What is the reason for this?
The cutting head of the laser cutting machine moves according to the set speed of NC, but at the sharp corner where the moving axis is converted or at the end of processing, the processing speed is slowed down by the characteristics of the laser cutting machine. Generally, the setting of laser power of cutting equipment is fixed, so the balance between laser power and speed will be destroyed (excess output power) at the position where the processing speed is reduced, resulting in the generation of burrs. So how to solve this problem? There are three main methods:
1. General processing conditions
In the setting of processing conditions, reduce the cutting speed of laser cutting machine as much as possible to reduce the difference of cutting speed in the whole processing path. Whether the cutting speed is large or small, the output power should be set to the condition of less burr generation. The disadvantage of using this method is that the average speed will be reduced and the whole processing time will be longer.
2. Modify track
The overtravel trajectory is designed so that the cutting speed will not decrease at the sharp corner or the end. For example, the program is programmed to do annular overtravel processing at sharp corners. When the annular processing is done, the track will change into a gradual change process at the transition of the processing direction, which can avoid the sharp decline of the cutting speed. At the end of the inner hole processing, the annular over-pass image can also be used to cut the inner hole without reducing the cutting speed. However, this method cannot be used when there are products near the sharp corner, or the inside and outside of the sharp corner are products.
3. NC control
In response to the above problems, corresponding control functions have been developed. That is, through the real-time detection of the cutting speed of the metal laser cutting machine, the laser output power can be automatically adjusted to the appropriate value according to the change of the cutting speed. When the cutting speed decelerates at the sharp corner, the laser output power also decreases accordingly. The same is true at the end of machining. The output power will automatically decrease as the cutting speed slows down.