Before cutting and blanking any plate, the interval between the laser focal length and the cutting data must be adjusted first. Different focal length orientations often lead to different fineness of the section of the cut data, different slag hanging at the bottom, and even unable to cut the data; The orientation of the focal length of the laser cutting machine will be different when the workpiece is cut and the data is different, so how to choose it correctly?
How to choose the focus position correctly in the process of laser cutting
Definition of focal length orientation: the interval from the focal length to the upper surface of the cutting workpiece. The focal length orientation above the workpiece is generally called positive focus, and the focal point orientation below the workpiece is generally called negative focus.
The significance of focus orientation: changing the focus orientation is to change the size of the light spot on the surface and inside of the plate. The focal length becomes larger, the light spot becomes thicker, and the cutting seam becomes wider and wider, thus affecting the heating area, the size of the cutting seam and the ability of slag removal.
How to correctly select the focus orientation in the process of laser incision
How to choose the focus position correctly in the process of laser cutting
Positive focal length incision
That is, the cutting focus is on the workpiece, and the focus is positioned above the cutting raw material.
For carbon steel oxygen cutting, it is suitable to select the positive focus. The cutting range of the bottom of the workpiece is larger than that of the upper surface, which is conducive to slag removal and oxygen reaching the bottom of the workpiece to participate in abundant oxidation reaction. Within a certain focus range, the larger the positive focus, the larger the spot size on the surface of the plate, the more abundant the preheating and heat compensation around the slit, and the more lubricated and brighter the carbon steel cutting surface.
About the 10000 watt laser pulse method to cut the thick stainless steel plate, the positive focus is selected, and the cutting is stable, which is conducive to slag removal and is not easy to reflect the blue light;
How to correctly select the focus orientation in the process of laser incision
Negative focal length incision
That is, the cutting focal length is inside the workpiece. In this form, because the focus is far away from the cutting surface, the cutting amplitude is relatively larger than that of the cutting point on the surface of the workpiece, and the cutting air flow and temperature required together are large and sufficient.
When cutting stainless steel, it is suitable to choose negative focus cutting. The texture of the cutting surface is uniform and the section is good.
For the perforation of the plate before cutting, because the perforation has a certain height, the negative focus is selected for the perforation, which can ensure the minimum spot size and the maximum energy density in the perforation direction, and the deeper the perforation direction, the greater the negative focus.
How to correctly select the focus orientation in the process of laser incision
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Zero focus incision
That is, the cutting focus is on the surface of the workpiece. This cutting method generally makes the cutting surface close to the focus relatively lubricated, while the lower surface away from the cutting focus appears rough. This situation is mainly used for cutting thin plates with continuous lasers and cutting metal foil layers with pulse laser peak power vaporization method.
How to correctly select the focus orientation in the process of laser incision
The selection of the positive and negative focus of laser cutting is not determined by the raw materials of the cutting plate (stainless steel, carbon steel), but by the cutting method (oxidation cutting, melting cutting).
Laser cutting machine processing different workpiece needs to use different focus forms, because different types of cutting head focus orientation and conditioning methods are different, users can choose the appropriate focus cutting method according to the different role of positive and negative focus in cutting stainless steel and carbon steel, combined with their own processing needs, so as to give greater play to the performance advantages of laser cutting machine!