The operating environment of the cutting head of the laser cutting machine is very harsh, so in order to protect the internal optical path and core components, especially the expensive parts such as collimation and focusing lens, the cutting head must be equipped with upper and lower protection lenses. The dust generated on the surface of the workpiece will cause serious damage to the focusing lens once entering the cutting head during the cutting process. So the lower protective lens can block these dust and splashes.

The neatness of the protective lens 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 will also further cause the internal parts of the cutting head and the laser output head to burn out. Therefore, it is necessary to use good materials and transparency. The protective lens with high light rate and low coefficient of thermal expansion needs to be cleaned or replaced when the lens is dirty during processing.

Protect lens processing has special technological requirements, from the selection of base material, processing accuracy, surface defects, coating, stability, mechanical properties (specific gravity, brittleness, tensile strength, compressive strength, hardness), preparation of materials in the processing process → There are different processing requirements for waste reduction→sand hanging→grinding→core taking→coating, and the finished products can only be put on the market after strict quality inspection.

In order to reduce costs, low-quality protective lenses use common base materials. The coating process is not guaranteed. The light transmittance is poor, heat-resistant, easy to break, and cannot withstand the penetrating power of the laser, causing the lens to blow holes, and the powder particles of the broken lens will contaminate the whole cutting head,which damage the core high-value components including the focusing lens and sensor. The maintenance cost will be as high as 20-50% of the price of the new cutting head, and it will delay the terminal production and processing, causing greater economic losses.

The following are the adverse effects that inferior protective glasses can easily cause:

The poor quality of the protective lens will increase the absorption rate of the laser. After a long time of continuous exposure, the temperature will increase and cause thermal deformation, which will cause the thermal lens effect to cause the focus of the cutting head to drift. The higher the power, the processing of high-reflective materials, and the thermal expansion of optical components the faster, the more obvious the thermal lens.

(1) When cutting stainless steel, the thermal lens effect focus drift will cause inconsistent cutting section effects, more and more dross, and even continuous cutting problems.

(2) When cutting carbon steel, the thermal lens effect will cause more and more slag at the bottom and continuous cutting problems.