Laser welding is the best option if you want to scale up your welding process. Besides ensuring high precision, it ensures a finished outcome and allows the joining of dissimilar materials.
Nevertheless, laser welding has a few drawbacks; it is very expensive and requires a complex setup. Let’s get deeper into the pros and cons of the welding process to decide whether it’s an ideal choice for your project.
What Is Laser Welding?
In laser welding, laser beams join metal and thermoplastic parts. The rays are of high energy that melts the metal instantly as they are projected. Once the molten part is cooled, it solidifies, forming a strong connection between the metal parts.
It is a very fast process compared to traditional welding processes like gas metal arc welding (GMAW) or shielded metal arc welding (SMAW). Laser welding further ensures high precision and minimal error as this is mostly automated. As the process deals with no physical contact, the chance of contamination is also minimal. Nevertheless, you need a higher initial budget to set up and operate ladder welding stations.
9 Advantages Of Laser Welding
1. High Precision
Laser welding is done with high-tech machinery that uses focused laser beams for welding. It projects the rays on small spots that ensure heating up only the targeted zones. As a result, the surrounding area is barely affected.
Besides, the laser welding process offers you greater control over welding. You can adjust the power and intensity of welding depending on material type and requirements. This makes laser welding highly suitable for applications that demand precise welding like- watches, jewelry, medical devices, etc.
2. Narrow Weld & Minimal Heat-Affected Zone (HAZ)
Heat-Affected Zone or HAZ indicates the surrounding areas of the welding zone. When a powerful laser beam is projected on the welding zone, the increasing heat also impacts the surrounding area.
Compared to the traditional welding process, the heat-affected zone in laser welding is negligible. This is because the laser beams are very narrow and are focused on the targeted points. Thus, the surrounding areas of the welding point are barely affected or deformed while laser welding.
3. High Speed
The speed of the laser welding greatly depends on the material you are working on. Based on metal thickness, it usually ranges from 0.5 to 10 m/min. However, you can integrate laser treatment with robotic arms and automated setups to boost the speed. This way you can maximize the production for industrial applications.
4. Versatility
Laser welding is a suitable approach for a wide range of materials, including- steel, aluminum, copper, gold, silver, nickel, and more. Besides, they can join metal sheets as thin as 0.1 mm or thicker metals as used in ships. This enhances the versatility of laser welding, making them suitable for a greater sector of application. You can use them for welding metal parts of automotive, aerospace, medical devices, electronics, jewelry, and more.
5. Non-Contact Process
Unlike traditional welding, laser welding doesn’t come in physical contact. Therefore, there are minimal chances of contamination.
6. High Automation Potential
One of the best facts about laser welding is that you can automate it by integrating it with robotic arms and CNC machines. This reduces manual effort and also boosts your production speed. This allows higher scaling potential in manufacturing and industrial applications.
7. Ability to Weld Dissimilar Materials
Laser welding can join two completely different materials together. Welding processes like shielded metal arc welding (SMAW) do not support joining dissimilar materials. But with laser welding, you can join metals of different properties and melting points.
For instance, you can weld a steel part with aluminum. Thus, laser welding is used for weight minimizing and strengthening different parts in different industries like automobile or aerospace. However, while choosing the materials, the factors to consider include:
- Melting point
- Linear expansion coefficients
- Thermal conductivity
- Electromagnetic properties
- Electrochemical characteristics
8. Environmentally Friendly
In flux-based welding methods, greater smoke and fumes are emitted. This adversely impacts the environment. In contrast, laser welding uses no electrodes and produces minimal fumes. Moreover, the entire process doesn’t deal with any hazardous chemicals. This makes laser welding an environmentally friendly welding option.
9. Flexibility in Power Adjustment
The required power of the laser beam varies depending on the type and thickness of the metal. It offers you two beam modes – conduction mode and keyhole mode for power adjusting.
For applications where you need minimal laser depth, use conduction mode, and for greater depth, use keyhole more. You can also adjust both modes from time to time based on application and welding needs. This way, laser welding offers you greater control over the welding process.
8 Disadvantages Of Laser Welding
1. High Initial Cost
Laser welding requires advanced technology and expensive sources like laser generators, optics, cooling systems, and control units. These are very expensive, which ends up with a high initial cost.
2. Complexity & Initial Learning Curve
Operating laser welding requires skilled knowledge. You need to deal with parameter settings like power levels, pulse rates, and focus points. All these require learning curves. Additionally, automation of the process or robotic integration also needs technical knowledge and skilled operators to maintain.
3. Limited Thickness Range
Laser welding, though versatile, has limitations for thicker and heavy metals. The maximum depth laser weld penetrates usually maxes out at around 25 mm. For material thicker than this, multiple passes are required. This is why heavy industries, such as shipbuilding and large-scale construction, frequently use alternative welding technologies, such as arc welding, for thicker components.
4. Reflective Material Challenges
Running laser welding on reflective materials like aluminum, copper, and gold is very challenging. The reflection of the laser beam affects the laser optics, which leads to costly repairs. However, by using specific laser wavelengths (e.g., green or blue lasers), you can improve absorption for reflective metals.
5. Sensitivity to Joint Preparation
Pre-welding cleaning and preparation is a crucial step for laser welding. If there is any oil, oxidizes, dust, or any contamination, it leads to a weak weld. That is why you need to properly clean the welding space before laser welding. For convenience, you can adopt automated cleaning processes, but these add extra expense to your manufacturing.
6. Maintenance Costs
Laser welding requires regular maintenance and expert handling. You frequently need to service the laser optics, nozzles, and cooling systems. Besides, replacing the parts of the laser welding equipment and machinery is also expensive.
7. Safety Hazards
If the high-power laser beam comes in contact with your eyes or skin, it will cause severe damage. This brings a potential safety hazard. So, you should always use safety measures, such as laser enclosures and protective eyewear.
8. Limited Gap Tolerance
Laser welding has a narrow beam width. So, if there is a large gap between the joining materials, it results in weak or incomplete welding. Using hybrid welding techniques or filler materials, you can bridge gaps in certain applications. However, this has to be done while maintaining extremely tight tolerances, which will increase your production costs.
Process Of Laser Welding
The basic mechanism of laser welding deals with focusing laser beams into the joining section of two metal pieces that melt and join them together when cooled.
Key Components of a Laser Welding System
- Laser source (Fiber, CO₂, or diode lasers)
- Focusing optics
- Beam delivery system
- Worktable and fixturing
How Laser Welding Works?
Step 1: Heat Application
Laser rays from the beam delivery system are focused on the metal parts. The narrow beam heats up the specific portion and melts the metals from both sides, creating a molten pool.
Step 2: Beam Modes
Laser welding operates in two modes depending on the energy density applied to a particular metal thickness. These are:
Conduction Mode
The condition mode of the laser is suitable for applications where surface aesthetics is more important than depth. It runs the laser at a lower power density but covers a larger area. As a result, a shallow weld penetration occurs, which gives similar results as TIG welding.
This mode is ideal for visible joints/front-side welds and delicate materials that can’t tolerate heat. The greater advantage of using conduction mode is minimal splatter or distortion and a neat welding finish.
Keyhole Mode
Keyhole mode is designed for applications requiring deeper penetration through high laser energy density. It melts and vaporizes material to form a cavity or “keyhole.” As a result, the surrounding molten material flows into the deep keyhole, forming a strong joint once solidified.
This welding mode is suitable for thick metals and applications requiring high strength. It is also ideal for welding multiple layers or thick components. For example, use keyhole mode when welding automotive frames or aerospace components. Additionally, this laser mode is highly compatible with automated systems.
Note: You can easily switch between the two modes in a laser welding system by adjusting the power intensity and surface area.
Step 3: Cooling and Solidification
After using either of the modes for welding, you need to rest the metal piece to cool it. As the molten metal in the welding joints cools, it solidifies, forming a robust connection.
Traditional versus Laser Welding – Which is Better?
Laser welding is more advanced than traditional welding processes like- MIG, TIG, stick, etc. Traditional welding, like arc welding, deals with electrodes that produce fumes that are not suitable for the environment. Besides, they are not so suitable for joining dissimilar materials like laser welding. Though traditional welding is cheaper, it can’t beat the high precision of laser welding.
Criteria | Traditional Welding | Laser Welding |
---|---|---|
Precision | Moderate precision | Extremely high precision |
Heat-Affected Zone (HAZ) | Large | Minimal |
Welding Speed | Relatively slow; manual processes are time-intensive. | Very fast; ideal for high-speed manufacturing. |
Material Compatibility | Limited ability to weld dissimilar materials. | It easily welds a wide range of materials, including dissimilar ones. |
Automation Potential | Challenging; not compatible | Easily automated |
Aesthetics | Requires post-processing for smooth welds. | Produces clean, polished welds with minimal finishing. |
Initial Investment | Low to moderate | High initial cost |
Scalability | Low to medium | High |
Operating Costs | Low maintenance but higher consumable costs. | Low consumable use but higher maintenance costs. |
However, compared to traditional laser welding, traditional welding is less expensive and simpler to set up. Moreover, they are suitable for different metal thicknesses, whereas laser welding shows some limitations regarding thicker metals.
Therefore, while choosing between laser and traditional welding, consider the application. For fast speed, high preciseness, dissimilar material compatibility, automation, and scalability, laser welding is best. In contrast, if you want a cheaper and simpler option, going for traditional welding is ok.
Wrapping Up
Laser welding is a top-notch choice for precise welding finishes. It has low HAZ that focuses only on the welded joints without affecting the surrounding areas. As a result, you get a neat welding surface. Additionally, you can automate the laser welding process by integrating it with a CNC machine.
However, there is a limitation in using laser welding when it comes to heavy and thick metal. Yet, you can weld it using multiple lasers. Besides, it is expensive and needs a more complex setup than traditional welding. But as you consider precision and better results, laser welding is the best option.
FAQs
What materials can you weld using laser welding?
Laser welding supports a variety of materials, including steel, aluminum, copper, nickel, titanium, etc. Besides, you can use this welding method to join dissimilar materials like steel to aluminum, copper to aluminum, etc.
How precise is laser welding?
Laser welding offers high precision with tolerances as low as ±0.01 mm. So, you will get a neat and finished welding result using laser welding.
Can laser welding be automated?
Yes, laser welding uses advanced technology and can be automated by integrating with robotics and CNC machines.
Is laser welding environmentally friendly?
Yes, laser welding is environmentally friendly as it emits no toxic chemicals or fumes.
What are the safety requirements for laser welding?
Laser welding deals with high-power light rays that are highly sensitive to your eye and skin. So, always use an eye protector and a protected enclosure when dealing with laser welding.