2021 Ultimate Guide: Fiber Laser Cutting Heads

The laser head is an important part of the fiber metal cutting machine, used to generate the laser beam energy for cutting, similar to the human heart. Today, we mainly introduce the structure and types of fiber laser cutting heads.

 

Fiber laser cutting heads drawing

 

Fiber laser cutting heads structure

The laser cutting head generally consists of a nozzle, a focusing mirror, an auxiliary system and a focus tracking detection system.

 

1. Nozzle

The nozzle is usually coaxial with the laser cutting head and has various shapes: cylindrical, conical, zoom and so on. Principle of nozzle selection: Its aperture must be larger than the focused beam. In other words, the laser beam cannot hit its wall when passing through the nozzle.

 

Large-caliber nozzles do not have strict requirements for focusing laser beams, while small-caliber nozzles have higher requirements for focusing laser beams. Therefore, it is necessary to ensure that the collimation and diameter of the laser beam perfectly match the nozzle diameter. In practical applications, since the outlet of the auxiliary gas is also in the nozzle part, it is very important to choose a suitable caliber. If the diameter is too small, the gas field of the nozzle will be turbulent, and the nozzle will be partially deformed due to the high temperature.

 

The higher the height between the nozzle and the sub-material, the energy loss of the laser part will not achieve the expected cutting effect. On the contrary, the blown slag easily enters the cutting head, which will not only damage the lens, but also disturb the flow field and affect the focus position. But now, fiber laser head height trackers, such as LVDT height sensors and capacitive height sensors, are usually equipped with height adjustment functions.

 

2. Focusing lens

 

The focusing lens is located directly above the nozzle. Its main function is to focus the beam to obtain an energy-intensive spot. Focusing mirrors can be divided into two types: transmission and reflection. 

 

Among them, the transmissive laser head generally uses a projection mirror, and the reflective laser head generally uses a reflective mirror. There are many kinds of lens materials, and zinc selenide has become the first choice for lens materials with ultra-high light transmittance and lowest light absorption.

 

In general, the smaller the focal length of the focusing lens, the smaller the spot diameter after focusing (the more dense the energy from the focal point), and the shallower the focal depth. (The depth of focus refers to the distance between two light spots with a 5% change in diameter on both sides of the focal point, which is also called the effective cutting range in cutting.)

 

When cutting thick plates, shallow depth of focus will seriously affect the cutting quality, resulting in burrs and burrs. Moreover, the shallow depth of focus will shorten the distance between the fiber cutting head and the plate, and the molten slag will easily penetrate the laser head, which has a bad effect. Therefore, we should try to use a suitable focal length for the post-cutting process.

 

When the thickness of the sub-material is large, the weak state of the spot energy can be relieved by using a larger focal length and increasing the laser power. When the thickness of the sub-material is small, a smaller focal length can be used to achieve high-speed cutting.

 

3. Auxiliary system

 

The auxiliary system includes: water cooling system, auxiliary gas and protective air curtain.

 

The water cooling system is to protect the laser cutting head. It is cooled without affecting the processing efficiency and quality. The common uses of auxiliary gas are well known, so we won’t go into details here, but why do different plates make different gas choices?

 

In fact, the heat generated in the cutting process is not only the energy of the laser beam, but also the additional energy brought by the auxiliary gas. When cutting active metals, inert gas is usually used to prevent additional heat from affecting the cutting effect. On the contrary, active gas is used to increase the heat of cutting.

 

In addition, the auxiliary gas pressure for high-speed cutting of thin plates can be set to a high pressure to match the cutting speed (100-300 kPa). If cutting thick plates at low speed, low pressure is required to prevent splashing.

 

4. Focus tracking detection system

 

Focus tracking systems are usually designed to ensure a stable focus. According to different requirements, detecting devices with different functions are installed on the cutting head to keep the cutting error rate low.

 

The focus tracking system consists of a focus fiber laser cutting head and a tracking sensor system. When the shape of the laser cutting head changes and the surface is uneven, the sensor automatically detects the change, and automatically adjusts the height according to the change, so that the distance between the laser cutting head and the surface of the workpiece is always consistent.

 

According to different sensor elements, tracking systems are mainly divided into capacitive sensor tracking systems, also called non-contact tracking systems, and inductive sensor tracking systems, also called contact tracking systems.

 

The role of the laser cutting head

 

Fiber laser cutting machine is a kind of intelligent equipment for cutting metal quickly. The laser head is an important part of the fiber metal cutting machine, used to generate the laser beam energy for cutting, similar to the human heart.

 

The two main core components of the fiber laser cutting machine are the laser cutting head and the laser. The laser is like a cistern, cutting the head like a faucet. The fiber laser is emitted by the laser, and is emitted from the laser head through the optical path system. The laser cutting head continuously releases high-energy laser beams to irradiate the surface of the workpiece and cut metal plates, pipes and other materials.

 

Because it is a non-contact processing method, the fiber laser cutting machine cuts metal without burrs, and the cutting quality is very good.

 

Types of cutting heads

 

1. Planar fiber laser cutting head

The auto-focusing cutting head is suitable for the integration of large and medium-sized platform cutting machines. According to the selected laser power, it can cut 20 mm large stainless steel and aluminum and 40 mm large carbon steel with good cutting quality.

 

The planar fiber laser cutting head is extremely light weight and faster to carry. It is suitable for high-precision laser cutting, and is widely used in fields with extremely high precision requirements such as the aviation industry. It can be used for IPG, SPI, Rofin, Coherent, Raycus, Trumpf, Chuangxin and other lasers.

 

2. Laser cutting head

The carbon dioxide laser cutting head is the core component of the carbon dioxide laser cutting machine, mainly using laser carbon dioxide cutting technology. The laser tube is generally driven by a laser power source to emit light. Through the refraction of several mirrors, the light is transmitted to the laser head. 

 

Then the focusing mirror installed on the laser head converges the light into one point, which can reach a very high temperature, so that the material is instantly sublimated into gas, which is sucked away by the exhaust fan, so as to achieve the purpose of cutting.

 

3. YAG solid-state laser cutting head

 

YAG solid-state laser cutting speed is faster than carbon dioxide, and the wire cutting speed is more than 100 times. Its notch heat affected zone is small, will not be deformed, the notch is smooth, and no subsequent treatment is required.

 

YAG solid-state laser cutting performance is stable; suitable for continuous mass production. It also has the characteristics of high photoelectric conversion efficiency and small size. However, its energy pump has fast loss and high maintenance cost, which limits its application.

 

YAG solid-state laser cutting head is very cost-effective. The price of YAG solid laser cutting machine is only 1/3 of the carbon dioxide laser cutting machine with similar performance and 2/5 of the CNC punching machine with the same efficiency. Its cutting precision is high, it is suitable for cutting precision hardware accessories, and it can also cut hollow out various fine craftsmanship and calligraphy.

 

4. Three-dimensional fiber laser cutting head

 

This cutting head is specially designed for robot three-dimensional cutting. It is suitable for cutting square tubes, round tubes and three-dimensional stamping parts. The 3D fiber laser cutting head has a compact cutting structure, light weight, and reasonable water cooling distribution, focus rotation adjustment, built-in amplifier, diffusion in the gas path, eliminate swirling. Then cut with Laval nozzle to make the section more smooth and vertical.

 

The alignment of the X, Y, and Z directions can be adjusted, which can make the laser beam cut better and more vertical. The completely sealed optical path can protect the optical system from pollution, and it is easy and quick to observe or change the lens, resistant to high temperature, and not affected by plasma.

 

Which cutting head is the best？

 

Raytools

Raytools was established in January 2005, dedicated to the evaluation, production and application of industrial lasers.

Company achievements: special applications of diode-pumped solid-state lasers and unique applications of high-power laser diodes; related projects include the concept of modular laser light sources and machines, components and unique beam alignment technology.

 

Company advantage: An independent company with rich professional knowledge and engineering skills to meet customer needs.

 

Main product: Raytools laser cutting head

 

BM114 series Raytools 6kW auto-focus laser cutting head:

 

Features:

1. Optimize the optical structure, smooth and efficient streamline design;

2. Auto focus range +10~15mm, accuracy 0.05mm;

3. The maximum acceleration of the focus lens drive is 10m/s, and the minimum speed is 10m/min;

4. Protective glasses are added to the collimator lens to prevent the collimator lens from being damaged when it is dropped;

5. Drawer-type lens holder for quick and easy access to each glass cover;

6. Air cooling design is added to the nozzle to effectively protect the nozzle and ceramics from damage caused by high temperature; 

7. The collision protection function can prevent damage to the laser head when it collides; 

8. QBH, QD and other optical interfaces can be adapted to various fiber lasers.

 

BT243 series Raytools3KW laser cutting head:

 

Features:

1. Manual turntable focus adjustment, meticulous and flexible. The adjustment range is 20mm, and the accuracy is 0.05mm; 

2. The dust-proof design is upgraded with double protection, making it almost impossible for the lens to be contaminated;

3. The collimator lens, focusing lens and nozzle increase the water cooling design; 

4. The collision protection function can prevent the damage of the laser head when it collides.

 

Raytools-EMS-G5030 basic type:

Longmen single-drive linear motor laser precision cutting program

 

Features:

7×24h cutting, high efficiency, high quality, high material utilization, strong scalability and flexibility.

 

Application areas:

It can cut various metal sheets and tubes, especially suitable for cutting stainless steel, carbon steel, manganese steel, copper plate, aluminum plate, various alloy plates and rare metal materials, etc.

 

Product number:

Raytools laser cutting head:

BM114 series

BM110 series

BT243 series

BT220 series

BT240-cut series

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BLMA, as China best fiber laser cutting machine manufacturer, providing high-quality fiber laser cutter with Raytools laser. If you have any needs, please contact us!