This is a technique that operates with fine power and thickness management and requires no contact. A light dot is formed through laser beam focus possessing considerable power thickness. There are four methods of realizing cutting through laser and each of them is suitable for a particular situation.
Fusion Cutting Method
In this method the piece being cut is partly dissolved causing the dissolved part to be tossed out by airflow. This method is known as fusion for matter transformation is realized in its fluid state. A great pure inert gas accompanies laser beam leaving notch on materials.
This cutting method is of higher speed compared to gasification. And more energy is needed for the process of gasification in comparison with melting one. Laser beam absorption occurs partly in case of fusion cutting.
The upmost cutting rate rises parallel to the power rise and reduces if piece density and temperature of dissolution rises. In laser energy to some degree the restriction factor is the enforcement of air near the notch as well as the matter conductibility. This method of cutting is unable to make oxidation slot on iron steel or titanium. Laser energy thickness is not enough for these materials to achieve gasification. In case of steel substances the required range is 104W/cm2~105W/cm2.
Method of Vaporization Cutting
During gasification process the face temperature of substances reaches boiling point quickly and it is capable of escaping dissolution brought about by high temperature conduction. As a result the substance partly turns into vapor and partly tossed out by airflow from the slot base. At this point a considerable laser energy is necessary. To keep a substance from condensation its density should not surpass the beam diameter. This procedure is appropriate for operations that do not need to remove dissolved substance and is not suitable for wood or ceramic materials that possess no melting capability. In fact, it can be applied in not big spaces for ferrous alloys.
In case of laser gasification the success of beam focus is dependent on the substance density and the shaft property.
The utmost cutting rate is inversely proportionate to substance gasification heat in case of material density to some degree.
The necessary laser energy thickness exceeds 108W/cm2 and is dependent on the substance shaft focus property and how deep the cutting is.
Gas flow speed restricts the utmost cutting rate.
This method implies rapid and manageable cutting for fragile substances that are inclined to be damaged by heat.
Laser shaft affects a certain spot on fragile substance bringing about great heat grade and transforming the particular area. This in its turn causes the substance to be cracked.
If the heat grade is kept balanced, the fractures are possible to control in every course.
Such cutting is realized through inert gas and functions by making use of reactive gases like oxygen. Substances are lit as a result of laser shaft influence, a chemical reaction occurs producing heat, which affects the substance.
Oxidation Dissolving Cutting
In this case operation rate for steel materials with similar density surpasses the fusion cut rate. Actually it makes more broad seams, considerable crudity, more heat influenced area and not as good ridge property.
This method is not suitable for producing precise pieces or sharp angles. The thermal affect is restricted by pulse mode laser, cutting rate depends on the laser power. Oxygen supply and substance heat conductibility serve as a restricting factor.