Product parameters:
Applicable Wavelength/Applicable Wavelength 1064nm
Collimation focal length/Collimation Length 100mm
Focus Length/Focus Length 150mm/200mm
Focus Adjustment Range/Focusing Range
-15mm~+15mm (F150)
-30mm~+25mm (F200)
Focus adjustment speed/Focusing Speed 200mm/s-400mm/s
Auxiliary air pressure/Auxiliary Gas ≤3Mpa
Weight/Weight 5.5KG
As a new type of sheet metal processing equipment, laser cutting process and laser cutting machine equipment are being familiar and accepted by the majority of sheet metal processing enterprises through continuous technological updating and technological development, and gradually replace plasma cutting, water cutting, flame cutting CNC punch and other traditional plate processing means. According to different laser generators, there are three types of laser cutting machines on the market at present: CO2 laser cutting machines, solid state (YAG) laser cutting machines, and fiber laser cutting machines.
The quality of nozzle, focus lens and focus tracking system is related to the cutting quality
Among several key technologies of laser cutting machine, the quality of laser cutting head directly affects the quality of cutting. The common cutting head of laser cutting machine is composed of nozzle, focus lens and focus tracking system.
1. The function of laser head nozzle in laser cutting
Laser head nozzle is the most commonly used consumable part on the fiber laser cutting machine tool. With the development and wide application of fiber laser cutting technology, the demand for laser head nozzle has increased greatly in recent years. There are three types of nozzles: parallel, convergent and conical. The cutting quality is closely related to the nozzle type and nozzle size.
The first function is to collect the capacitance signal and transmit it to the signal processor through the ceramic ring. The signal processor sends the signal to the machine tool control center. The machine tool control center makes feedback based on the signal, adjusts the vertical position of the laser head, so as to maintain the distance tracking of the laser head to the workpiece during the cutting process;
The second function is to use its internal shape to guide the gas to pass through the cut workpiece smoothly and form high pressure near the nozzle outlet. The smaller the nozzle outlet diameter is, the higher the formed air pressure is. In case of oxidation cutting, after high-pressure oxygen passes through the nozzle, part of the working surface will provide heat through oxidation reaction with the cut part to accelerate cutting; The other part passes through the cutting surface at high speed to take away the slag and maintain proper pressure on the cutting surface to ensure smooth cutting.
The third function is to protect the lens inside the laser head. In the process of laser cutting, especially in the process of drilling, there is often molten slag sputtering. The high-pressure gas blown from the laser head nozzle can block most of the sputtering objects outside to protect the lens from damage.
2. Relationship between focusing lens and laser cutting
Focusing lens has the general characteristics of ordinary optical lens, but it has its unique features. It can be used to make a lens with ultra-short focal length, and also to form a real image on the end face, which is easy to obtain an upright real image of the same size as the object.
To use the energy of the laser beam to cut, the original beam emitted by the laser must be focused through the lens to form a high energy density spot. The transmission lens is very simple to use. When the laser beam passes through the lens, the lens focuses the laser beam on the workpiece along the axis. In common industrial laser systems, the nozzle has the function of gas washing, that is, introducing a gas jet at the nozzle to help improve the performance of the interaction between the laser beam and the material. At the same time, the high-speed air flow also plays the role of isolation from the optical system. The gas jet prevents material processing contaminants from entering the nozzle and contaminating the lens surface. The reflective focusing system uses additional beam deflector and rear focusing mirror. In this condition, there are two additional optical systems, namely zinc selenide window and beam deflector. The function of the window is to seal off the focusing system on the nozzle.
The transmissive focusing head has two main advantages, that is, the beam is easy to be adjusted and small deviation such as beam eccentricity is allowed, that is, the beam eccentricity or angle deviation is allowed to shoot into the lens. Reflective lens is suitable for high power applications. It is ideal for high-power laser systems. It produces less thermal lens effect and is durable in harsh welding environments. In theory, the parabolic mirror should focus the laser beam to the diffraction limit of the beam. The diffraction limit is the minimum focal spot that can be achieved for a specific laser beam diameter and mode quality. Parabolic mirror is one of the most difficult mirror systems to adjust. Therefore, in high power laser systems, it is usually difficult to achieve diffraction limit focusing. For welding, it is not always required to use small light spot, so the reflector is very suitable in this application.
In recent years, the market demand for high-power lasers has risen. There is a restriction between the depth of focus and the focal spot of traditional lenses. Increasing the depth of focus will inevitably lead to the expansion of the size of the focal spot. In many cases, it can not meet the requirements of laser processing. The focus lens with long depth of focus and high resolution has become a new market demand.
The focal length and focal position of the focus lens have an impact on the laser cutting quality. The short focal length lens is suitable for high-speed cutting thin materials, and the long focal length lens is suitable for cutting thick workpieces.
3. The role of focus tracking system in laser cutting
The focusing and tracking system of laser cutting machine is generally composed of focusing cutting head and tracking sensor system. The cutting head is composed of light guide focusing, water cooling, air blowing and mechanical adjustment parts; The sensor is composed of sensing element and amplification control part. The tracking system is different with different sensing elements.
At present, there are mainly two types of tracking systems. The first is the capacitive sensor tracking system, also known as the non-contact tracking system; The second is inductive sensor tracking system, also known as contact tracking system.
The working process of the laser head is as follows: the laser generates the laser and transmits it through the external optical path. After being focused by the focusing lens in the cutting head, it acts on the surface of the processed material to vaporize the material or form a molten pool with the help of the cutting gas (mainly oxidation). After the cutting auxiliary gas flows through the cutting head (including nozzle), a strong air flow is generated to blow off the generated slag, and at the same time, the material gasification is prevented from adhering to the surface of the focusing lens to damage it, so as to prevent the generation of plasma or the mixture of plasma and gas.
New requirements in the era of intelligent manufacturing: automatic focus cutting head is popular
Intelligent manufacturing technology is a subject that industrial automation must study. At present, there are not many real achievements in the market. Taking the auto-focusing cutting head as an example, the domestic laser cutting head manufacturers mainly based on Orsendec have been able to do so.
Focus control refers to that when the laser cutting machine cuts different materials and plates of different thickness, in order to achieve better cutting effect, the focus of the laser beam will be set at different places, which is called focusing. With the breakthrough of industrial control technology, automatic focusing cutting head is indispensable in laser cutting automation.
In the early days of laser cutting application, the main way of focusing is to rely on manual. Now with the development of laser technology, this manual focusing method has been gradually eliminated, and the automatic focusing function has begun to be realized slowly.
The bottom of the laser cutting head is a nozzle. During the cutting process, the nozzle height remains unchanged, so the focus cannot be adjusted by lifting the cutting head. The focal length of the focusing lens cannot be changed, so it cannot be expected to focus by changing the focal length. If you change the position of the focus lens, you can change the focus position: if the focus lens falls, the focus will fall, and if the focus lens rises, the focus will rise. This is a way of focusing. A motor is used to drive the focusing mirror to move up and down, which can realize automatic focusing.
Another method of auto-focusing is to set a variable curvature mirror before the beam enters the focusing mirror. By changing the curvature of the mirror, change the divergence angle of the reflected beam, and then change the focus position.
With the auto-focusing function, the machine can automatically adjust the focus to the most appropriate position when processing workpieces of different materials and thicknesses, which can significantly improve the processing efficiency of the laser cutting machine and greatly reduce the perforation time of thick plates. Therefore, for laser cutting machine, automatic focusing function is an important and indispensable function.
