Views: 0 Author: HanTenCNC Publish Time: 2021-10-15 Origin: Site
The conventional marking sizes are 100*100mm, 150*150mm, 175*175mm, 200*200mm, 220*220mm, 300*300mm, so how do we choose many types of marking field lens?
1.working wavelength, entrance pupil, scanning range and focusing spot diameter.
2.Working wavelength: mainly depends on the wavelength of the laser, the lens of the field lens is coated at the given laser wavelength.If the field lens is not used within the given wavelength range, the field lens may be burned by the laser or the required laser transmittance is very low.
3.Entrance pupil: also called the maximum incident spot. If a single-piece mirror is used, the mirror is placed at the entrance pupil, and the diameter of the maximum usable beam is equal to the diameter of the entrance pupil. The larger the entrance pupil, the smaller the diameter of the focused spot focused by the focusing lens. Therefore, when special marking is required, we will consider using a field lens with a larger entrance pupil, such as fine marking and galvanometer welding.
4.Scanning range: The larger the range that the field lens can scan, the more popular it is of course. However, if the scanning range is increased, the focus spot becomes larger, and the distortion degree also increases. In addition, to increase the scanning range, the focal length and working distance of the field lens must also be increased. The lengthening of the working distance will inevitably lead to the loss of laser energy. Also, the diameter of the focused spot is proportional to the focal length, which means that if the scanning range is increased, the diameter of the focused spot will increase, and the spot will not be narrow enough, and the power density of the laser will drop very quickly (the power density is the second power of the spot diameter). Inversely proportional), which is not conducive to processing. Therefore, the user should choose the most suitable field lens according to different processing areas, or spare several field lenses with different scanning ranges.
5.Focal length: It has a certain relationship with the working distance, but it is not equal to the working distance. Focus spot diameter: For a scanning system with incident laser beam diameter D, field lens focal length F and beam quality factor Q, the focus spot diameter d = 13.5QF/D (mm). Therefore, a beam expander can be used to obtain a smaller focused spot.
Therefore, the larger the marking range is not the better, the larger the larger the focal length, the more laser loss, so you should choose the appropriate marking field lens according to the actual marking content.