With the development of the economy, people’s pursuit of the quality of life is getting higher and higher, and the use of stainless steel thick plates, which are closely related to everyone’s life, has also greatly increased. Nowadays, the laser cutting process of stainless steel thick plates has become more and more mature, and will gradually replace the traditional cutting process. If you want to cut high-quality stainless steel thick plates, you need to fully understand the elements of the cutting process, mainly as follows:
1. Nozzle selection
The diameter of the nozzle determines the shape of the gas flow entering the incision, the gas diffusion area and the gas flow rate, which will affect the stability of melt removal and cutting. The air flow entering the incision is large and fast, and the position of the workpiece in the air flow is appropriate, the stronger the jetting ability to remove the molten material. Under a fixed flow rate, different nozzle sizes, the thicker the stainless steel plate used to monitor the air pressure, the larger the nozzle selection should be, the larger the proportional valve setting, the larger the flow rate, the pressure can be ensured, and the normal slicing effect can be reduce.
2. Selection of auxiliary gas and gas purity
Various auxiliary gases, such as oxygen, nitrogen, air, etc., are often used in laser cutting of stainless steel thick plates. Different gas types are used, and the effect of cutting the section is also different. Oxygen is the black part, air is light yellow, and nitrogen can prevent the original color of stainless steel from being oxidized.
3. Focus position
In order to ensure the cutting effect of the thick stainless steel plate and protect the nozzle from damage, a coaxial test must be carried out before cutting to ensure that the nozzle is coaxial with the laser output beam. Test method: stick scotch tape on the nozzle outlet end surface, adjust the output power of the perforated laser, observe whether there is a center hole and the position of the center hole on the scotch tape, and adjust the adjustment screw on the handle. The lens cavity is synchronized until the laser opens the hole punched on the scotch tape and coincides with the center of the nozzle.
The focus is different, the thickness, material and quality of stainless steel thick plates that can be cut are also different. Different materials and thicknesses need to be adjusted to different focal points. Before cutting, the actual zero focus should be measured, and the cutting process parameters can be tested and analyzed based on the zero focus. Negative defocus is the main process choice for stainless steel cutting.
4. The influence of laser frequency adjustment and duty cycle on cutting quality
The frequency is reduced from 500-200Hz, the cutting effect is better, and the layering is gradually improved. When the frequency is set to 100Hz, it cannot be cut off, and the blue light will be reversed. You can find the appropriate frequency range by changing the frequency. In order to ensure the cut part of the stainless steel thick plate, the number of pulses must match the energy of a single pulse.