Ultimate Guide to Laser Welding Applications

Ultimate Guide to Laser Welding Applications

The Application Field of Laser Welding

Laser welding is increasingly valued as a unique welding method due to its excellent capability in welding various materials. It has found widespread applications in industries such as automotive, steel, shipbuilding, aviation, and light industry, particularly achieving successful applications in the aerospace field. Table 1-1 presents some specific application examples of laser welding.

Table 1-1: Partial Applications of Laser Welding

Industrial SectorExamples of Application
AviationEngine casings, fan housings, combustion chambers, fluid ducts, wing spars, solenoid valves, diaphragm housings, etc.
AerospaceRocket casings, missile skins and frames, gyroscopes, etc.
MaritimeShip steel plate welding
PetrochemicalMulti-layer mesh for oil filtration devices
Electronic InstrumentsLead wires within integrated circuits, electron guns for cathode ray tubes, tantalum capacitors, voltage regulators, instrument filaments, optical fibers, etc.
MachineryPrecision springs, parts for needle printers, metal thin-walled corrugated tubes, thermocouples, electro-hydraulic servo valves, etc.
SteelWelding of silicon steel, high, medium, and low carbon steel, and stainless steel with a thickness of 0.2 to 8mm and a width of 0.5 to 1.8m, at a welding speed of 1 to 10m/min.
AutomotiveAutomobile chassis, transmission devices, gears, battery anode plates, and components such as igniter shafts and pawls.
MedicalPacemakers and the lithium-iodine batteries used in them.
FoodFood cans (where laser welding has replaced traditional soldering or high-frequency contact welding, offering non-toxic, fast welding, material-saving, aesthetically pleasing joints, and excellent performance).

Laser welding, although shallower in welding depth compared to electron beam welding, has a broader application outlook due to its ability to eliminate the constraints of vacuum chambers required for electron beam welding. It does not require welding under vacuum conditions, hence its prospects are more extensive. Since the 1980s, laser welding equipment has been growing at a rate of 25% annually in foreign countries.

Laser processing equipment is often combined with robots to form flexible processing systems, further expanding its application scope. In the construction of power plants and in the chemical industry, there are numerous pipe-to-pipe and pipe-to-plate joints, for which high-quality single-side welds and double-side formed welds can be achieved using laser welding.

In shipbuilding, welding thick plates (with added filler metal) using laser welding yields joint performance superior to conventional arc welding, reducing product costs, enhancing component reliability, and contributing to the extended service life of ships.

Laser welding is also applied in the welding of stator laminations for electric motors, the production of engine casings, wing spars, and other aircraft components, as well as in the repair of aviation turbine blades.

The application of laser welding in the automotive industry

The automotive and automotive parts manufacturing industry represents the most extensive and mature application of laser welding. Over 30% of high-end cars utilize laser welding for their welding processes. Laser welding has significantly elevated the quality of car manufacturing.

Presently, it’s not just European and American cars that extensively use laser welding; Japanese cars and domestically produced vehicles are also transitioning from arc welding to laser welding.

The process characteristics of laser welding in the automotive and parts manufacturing industry are as follows:

1) High power density enables fast welding speeds.

2) Narrow weld seams with high weld strength.

3) Small heat-affected zone.

4) Minimal welding deformation.

5) Excellent suppression performance.

6) Good coating ability.

7) Minimal assembly errors.

The application of laser welding in automotive manufacturing is depicted below.

Application Forms of Laser Welding in Automobile Manufacturing:

  • Galvanized Sheet Laser Spot Welding
  • Laser Wire Filling Brazing
  • Aluminum Alloy Body Laser Welding
  • Laser Stitch Welding
  • Laser Intermittent Welding
  • Laser Rapid Scan Welding
  • Plastic Laser Welding
  • Galvanized Sheet Laser Continuous Welding
  • Laser Hybrid Welding
  • Powertrain Components Laser Welding

Laser welding is widely used in the production of automobile bodies, where several pieces of steel with different materials, thicknesses, and coatings are welded together using laser to form a single integrated plate. This process meets the diverse material performance requirements of automotive components.

Since the mid-1980s, the use of welded plates as a new technology has gained widespread attention in Europe, the United States, and Japan. The process of welded plates primarily serves the automotive industry, particularly in the production, manufacturing, and design of automotive body components, offering significant advantages.

Laser welding can significantly reduce the number of automobile parts, reduce vehicle weight, optimize component tolerances, and lower costs, while ensuring vehicle performance. It represents the development direction of new automotive technologies.

Laser welding has other forms of applications, such as laser brazing, laser-arc welding, laser cladding, and laser spot welding. Laser brazing is mainly used for soldering printed circuit boards, while laser spot welding is primarily used for welding thin sheets or strips of steel.

Manufacturing industry

Laser tailored blank welding technology has been widely utilized in manufacturing. According to statistics, there are over 100 production lines for laser tailored blank welding globally as of 2000, with an annual production of 70 million welded blank car components, and this number continues to grow at a high rate. Domestically produced car models such as the Passat, Buick, and Audi have also adopted some welded blank structures.

In Japan, CO2 and laser welding have replaced flash butt welding in the steel industry for connecting rolled steel coils. In the research of welding ultra-thin sheets, such as foils with a thickness below 100 μm, it was found that they couldn’t be fusion-welded. However, successful welding was achieved using YAG laser welding with a special output power waveform, demonstrating the vast potential of laser welding.

Japan has also successfully developed, for the first time in the world, the use of YAG laser welding for the maintenance of steam generator tubes in nuclear reactors. In China, research institutions have also conducted studies on gear laser welding technology.

Powder Metallurgy

With the continuous development of science and technology, many industrial processes have special requirements for materials. Materials manufactured using foundry methods can no longer meet these needs. Due to the special properties and manufacturing advantages of powder metallurgy materials, they are gradually replacing traditional cast materials in certain fields such as the automotive, aerospace, and tool manufacturing industries.

As powder metallurgy materials continue to advance, the issue of their connection with other components is becoming increasingly prominent, thereby limiting their application.

In the early 1980s, laser welding entered the field of powder metallurgy materials processing with its unique advantages, opening up new prospects for the application of these materials.

For example, in the common method of brazing diamond with powder metallurgy materials, the low bonding strength, wide heat-affected zone, and especially the inability to meet high-temperature and high-strength requirements often lead to brazing material melting and detachment. Laser welding, on the other hand, can improve the welding strength and high-temperature performance.

Laser cladding welding (laser overlay) is illustrated in Figure 1-4.

Laser Cladding Welding
Figure 1-4: Laser Cladding Welding (Laser Overlay)

The relevant applications of laser technology

(1)Electronic industry

Laser welding has found wide applications in the electronics industry, particularly in the microelectronics sector. Due to its small heat-affected zone, rapid and concentrated heating, and low thermal stress, laser welding demonstrates unique advantages in the encapsulation of integrated circuits and semiconductor device housings.

In the development of vacuum devices, laser welding has also been utilized, such as in the welding of molybdenum focusing electrodes with stainless steel support rings and fast-heating cathode filament assemblies. For elastic thin-walled corrugated diaphragms in sensors or thermostats, with a thickness ranging from 0.05 to 0.1mm, traditional welding methods are difficult to apply.

TIG welding is prone to burn-through, and plasma welding exhibits poor stability with multiple influencing factors, while laser welding shows excellent performance, thus gaining widespread use.

In recent years, laser welding has gradually been applied to the assembly process of printed circuit boards. As circuit integration continues to increase and component sizes become smaller, the pin spacing also decreases.

Traditional tools have become inadequate for operating within these confined spaces. Laser welding, as it does not require contact with the components to achieve welding, effectively addresses this issue and has garnered attention from circuit board manufacturers.

(2)Biomedical

The application of laser welding in biological tissues began in the 1970s, as demonstrated by the successful work of Klink, Jain, and others in welding fallopian tubes and blood vessels, which prompted more researchers to attempt welding various biological tissues and to extend the practice to other types of tissues.

Research on laser welding in neurology has mainly focused on the laser wavelength, dosage, their impact on functional recovery, and the selection of laser welding materials. After conducting foundational studies on laser welding small blood vessels and skin, researchers have also investigated the welding of rat bile ducts.

When compared to traditional suturing methods, laser welding offers advantages such as faster apposition speed, no foreign body reaction during the healing process, preservation of the mechanical properties of the welded area, and the growth of repaired tissue according to its native biomechanical characteristics. These advantages are expected to lead to broader applications in future biomedical fields.

Additionally:

(3)The directional properties of lasers can be used for precise distance measurements.

(4)The monochromatic nature of lasers can be employed in optical fiber communication.

(5)The coherent properties of lasers can be used to create holographic images.

(6)In other industries, the application of laser welding is gradually increasing, particularly in the welding of special materials.

Many studies have been conducted domestically in China, such as on laser welding of BT20 titanium alloy, HE130 alloy, and Li-ion batteries.

Furthermore, the German glass machinery manufacturer GlamacoCoswig GmbH, in collaboration with the Institute of Joining and Welding (IFW), has developed a new laser welding technology for flat glass.

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