The use environment of the cutting head of the laser cutting machine is very bad. Therefore, in order to protect the internal optical path and core components, especially the expensive components such as collimation and focusing lens, the cutting head must be equipped with upper and lower protective lenses. The dust and splash generated on the workpiece surface during the cutting process will cause serious damage to the focusing lens if it enters the cutting head, and the lower protective lens can prevent these dust and splash.
The cleanliness of the protective mirror directly affects the processing performance and quality of the laser cutting machine. If the lens is dirty, it will not only affect the cutting effect and efficiency, but also further cause the burning of the internal parts of the cutting head and the laser output head. Therefore, the protective mirror with good material, high transmittance and low thermal expansion coefficient should be used first. When the lens is dirty during processing, it needs to be cleaned or replaced.
There are special process requirements for the processing of protective lenses. There are different processing requirements from the selection of base materials, processing accuracy, surface defects, plating, stability, mechanical properties (specific gravity, brittleness, tensile strength, compressive strength, hardness), and preparation in the processing process → waste folding → sand hanging → grinding → coring → coating. The finished products can only be released to the market after strict quality inspection.
In order to reduce the cost, low-quality protective mirrors are made of ordinary substrate materials. The coating process is not guaranteed, and the transmittance is poor, heat resistant, easy to crack, and can not withstand the penetration of laser, resulting in lens holes, and the powder particles of broken lenses will pollute the entire cutting head, which will damage core high-value components, including focusing mirrors, sensors, and so on. The maintenance cost will reach 20-50% of the price of the new cutting head, and delay the terminal production and processing, Cause greater economic losses.
Therefore, we hope our customers can learn from this and purchase laser accessories from the manufacturer's regular channels to avoid losses!
The following are the adverse effects easily caused by poor quality protective glasses:
【1】 Focus drift of cutting head caused by thermal lens effect
The poor quality of the protective lens will increase the laser absorptivity. After a long period of continuous irradiation, the temperature rise will produce thermal deformation, which will cause the thermal lens effect to cause the focus drift of the cutting head. The higher the power, the more reflective materials are processed, the faster the thermal expansion of the optical elements, and the more obvious the thermal lens.
(1) When cutting stainless steel, the focus drift of thermal lens effect will cause inconsistent cutting section effect, more and more slag, and even continuous cutting problems.
(2) When cutting carbon steel, the thermal lens effect will cause more and more bottom slag and continuous cutting problems.
【2】 Burn point/burn through of protective mirror
During the processing of lower protective lenses with poor quality, the ability to prevent dust and splashes is poor, and the burning point is easy to occur; For the ten thousand watt ultra high power processing head, the protective lenses need to be carefully selected. Under the action of ten thousand watt laser, the protection lenses with poor quality will directly burn through in serious cases.
【3】 Focus mirror burning point
If the burning through of the protective mirror is not found in time, continue polishing, cut and generate particles of smoke and dust rising to pollute the installation components, sealing rings and the lower surface of the focusing mirror, and cause the burning point on the surface of the focusing mirror. It is necessary to deeply clean and replace the entire set of installation components and focusing mirror modules.
【4】 Laser output head burnt
For ten thousand watt laser equipment, once the protective mirror is burned through, under the action of ten thousand watt ultra-high power, it is very easy to burn the internal collimation and focusing mirror modules of the cutting head instantly. In the most serious case, when the optical elements inside the cutting head are damaged, the optical path will be abnormal, and the return light will cause abnormal heating of the window piece of the laser fiber output head, which will eventually burn out the QBH or LOE crystals, and the entire laser output head needs to be replaced.
The use of poor quality protective mirror not only affects the service life of the cutting head, causes various accidents, but also affects the processing progress and quality of the factory, thus increasing the processing cost and reducing the factory benefits. Here, we would like to inform the users that they must purchase protective glasses through regular channels and manufacturers. Don't lose too much for small!