12 questions about handheld laser welding?

February 19, 2024

1. What is laser welding? What type of welding process does it belong to?

We all know that welding can be divided into fusion welding, pressure welding, and brazing. Fusion welding is a method in which the workpiece interface is heated to a molten state during the welding process and the welding is completed without applying pressure. During welding, the heat source rapidly heats and melts the interface between the two workpieces to be welded, forming a molten pool. The molten pool moves forward with the heat source, and after cooling, a continuous weld is formed to connect the two workpieces into one body. Laser welding is a type of fusion welding.

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2. What components does the handheld laser welding machine consist of?

Handheld laser welding machines generally consist of lasers (generally equipped with 1000-2000W fiber optic continuous lasers), chillers, control software, laser welding heads, optical fibers, and other components.

3. What is a handheld laser welding machine and what can it do?

This is a new type of metal welding technology that requires low technical requirements for skilled workers. It only requires light grinding and polishing to produce beautiful results, which is strong and reliable. It is another new welding production operation method that reduces labor costs and increases production efficiency.

4. How big a product can hand-held laser welding be?

Generally, the standard configuration of optical fiber transmission cable is 10 meters, which can be used for welding operations within the diameter range. It also has auxiliary rolling wheels to enable large-scale mobile welding operations.

5. What materials can be welded by handheld laser welding?

The fiber laser handheld welding machine can weld 0.4-8.0mm thick stainless steel, galvanized sheet, iron sheet, copper, aluminum, and other metal materials due to the selected power. The details depend on the power/process. The greater the power, the stronger the welding ability.

6. How long is the service life of handheld laser welding?

Similar to laser cutting, the light source life is generally 100,000 hours;

7. Can the wire be fed during laser welding? And the specific choice of welding wire?

Can feed wire, standard automatic wire feeder, 1000 watts suitable for 0.8-1.0 wire, 1500 watts suitable for 0.8-1.6 wires, 2000-3000 watts suitable for 2.0 wires;

Specific selection of welding wire:

According to the different welding plates, we need to use different welding wires (gas-shielded solid core welding wire)

Stainless steel = stainless steel welding wire

Carbon steel/galvanized sheet=iron wire

Aluminum = aluminum wire (for aluminum welding wire, we recommend using alloy aluminum above 5 series, which has higher hardness and is not easy to get stuck)

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8. Does laser welding require protective gas? And the specific choice of protective gas for the welding process?

① There are two common types of nitrogen or argon. When welding stainless steel, we recommend using nitrogen for a better welding effect. Please do not use mixed/nitrogen dioxide gas.

②Air pressure requirements: the flow meter should not be less than 15, and the pressure gauge should not be less than 3;

9. What are the basic principles of the handheld laser welding process?

Follow the following principles when laser welding:

The thicker the plate, the thicker the welding wire, the greater the power, and the slower the wire feeding speed;

②The lower the power, the whiter the welding surface, And the greater the power, the weld seam changes from color to black, and single-sided forming is performed at this time;

③The thickness of the welding wire should be no larger than the plate thickness and biased towards the plate thickness. The welding wire affects the fullness of the weld;

④The thinner the welding wire, the lower the scanning width;

10. What are the consumable parts for handheld laser welding?

Similar to laser cutting, the commonly used welding nozzles and protective glasses generally have a service life of about a week, depending on the frequency of use and continuous operation time;

11. What are the precautions when using handheld laser welding?

Wear laser protective eyewear (PPE) to protect against laser radiation hazards.

Wear a welding mask/helmet to protect your eyes and head. Because welding may produce hot flying particles, strong light and ultraviolet radiation. Wear protective clothing and protective gloves.

12. What is the welding fastness of handheld laser welding?

First, we need to understand the factors that influence welding strength:

The main purpose of welding is to form a connection of sufficient strength between components. Welding strength is not only a basic issue using weldability analysis but also the basis for welding structural integrity analysis. The factors that affect welding strength mainly include mechanics and materials. Mechanical effects include welding defects, incomplete joint shape, residual stress welding deformation, etc. Material effects include structural changes caused by welding thermal cycles, material changes caused by thermoplastic strain cycles, post-weld heat treatment, and correction deformation. Material changes caused by etc.

Welding thermal process:

Welding is usually performed when the material connection zone (welding zone) is in a local plastic or molten state. For the material to reach the conditions for welding, a highly concentrated heat input is required. Therefore, the welding heat source must be used during the welding process of the material. The welding zone is heated so that it melts (fusion welding) or enters a plastic state (solid phase welding) and subsequently cools down to form the weld seam and welded joint.

The welding heat process is concentrated and instantaneous, which has a great impact on the microstructure of the material and also causes welding stress deformation of the component. This thermal effect is called the welding heat effect.

During the welding process, uneven heating and cooling of the weldment will produce uncoordinated strains inside the weldment, causing welding stress and deformation.

Stress concentration in welded joints

Stress concentration will occur in local areas of welded joints. The direct effect of stress concentration on the structure is the so-called notch effect. The notch effect has varying degrees of impact on the strength of the welded structure. A severe notch effect will significantly reduce the load-bearing capacity of the welded structure. Welding The notch effect of the joint can be visible, or it may not be directly reflected in the appearance. The former can be called the displayed notch effect, and the latter can be called the implicit notch effect. The notch effect is caused by the geometry or defects of the welded joint. It should be shown that the gap effect caused by the difference in material properties, especially the interface connection of dissimilar materials, exists implicitly.

The display notch effect is a stress concentration problem in a general sense. The local stress is analyzed only based on the structural geometry, without considering the differences in material properties.

Welding penetration

For some thicker workpieces, the welding strength is reflected by the weld penetration and whether spatter and pore inclusions are generated during the formation of the pool.

So what exactly is laser welding? Is it as awesome as the propaganda says? Simply put, laser welding is an efficient and precise welding method that uses high-energy-density laser beams as heat sources. Laser welding can be achieved using continuous or pulsed laser beams. The principles of laser welding can be divided into heat conduction welding and laser deep penetration welding.

The principle of thermal conduction laser welding is: that the spot power density of laser thermal conduction welding on the surface of the workpiece is low, generally less than 105W/cm2. The laser delivers energy to the surface of the welding workpiece, causing the metal surface to heat between the melting point and boiling point. The surface of the metal material converts the absorbed light energy into heat energy, causing the metal surface temperature to continuously increase and melt, and then transfers the heat energy to the interior of the metal through thermal conduction, so that the melting area gradually expands, and after cooling, a solder joint or weld is formed. This welding principle is similar to tungsten arc welding (TIG) and is called thermal conduction welding.

Laser deep penetration welding: When the laser power density acting on the metal surface is greater than 105W/cm2, the high-power laser beam acts on the surface of the metal material to cause local melting and form a "small hole". The laser beam penetrates deep into the melt through the "small hole". Inside the pool, the metal melts in front of the small hole, and the molten metal flows around the small hole to the rear, where it solidifies again to form a weld.

With the research and development of high-power lasers, laser welding technology has been widely used in many fields, mainly because of its following characteristics:

When using a laser welding machine to connect workpieces, there is almost no connection gap between the workpieces to be welded. At the same time, the welding aspect ratio is large, the post-welding deformation is small, the heat-affected zone is small, and the precision is high.

The welding device is simple and flexible, can be welded at room temperature or under special conditions, and has low requirements in the welding environment.

The laser welding machine has considerable penetration depth and high power density and can weld refractory materials, such as titanium alloy, No. 45 steel, etc.

In the early days, laser welding technology was first used in the field of military tank manufacturing. The standards of welding products in national defense were extremely high and the welding environment and welding processes were extremely demanding. Therefore, the lasers can provide welding strength and welding grade that are much higher than traditional welding technology. However, although it can provide welding strength that is much higher than traditional welding technology, its welding cost is only affordable in one country. Later, with the improvement of laser welding technology, the Volkswagen Group, which specializes in body manufacturing hard technology, applied the laser welding technology that was once outstanding in the military field to the automotive welding field in the 1990s. This has revolutionized the welding grade and strength of automobile structures and parts. It is enough to illustrate the advantages of laser welding.