To enhance weld quality and production speed, many manufacturers adopted laser welding.
Yet, many still doubt laser welding’s strength compared to traditional techniques like MIG and TIG as the latter’s investment cost is no joke.
In this article, we discuss how strong laser welding is and explain how it beats old-school techniques.
Factors That Determine Laser Weld Strength
Strength matters in laser welding. The stronger the laser weld, the more durable and safer the final product is. For this reason, operators pay attention to various factors that can affect the strength of a laser weld.
Material Type
The parent material’s chemical composition and properties hugely impact the strength of a laser weld. For instance, a metal may react adversely to laser’s heat due to its natural impurities.
Consider copper with a melting point of around 983° Fahrenheit (1084° Celsius). While this low melting point enables swift melting and fusion, it poses a risk of burning if the laser power is too high.
Meanwhile, some elements present in the materials, like phosphorous, can increase brittleness and decrease laser weld quality. On the other hand, sulphur can cause hot cracking even if it is present only in trace amounts.
So, which material types ensure strong laser weld? Most steels (carbon, alloy, and stainless) usually respond well to laser welding because they easily absorb heat and energy. Aluminum, thermoplastics, and ceramics can also create strong bonds through laser welding.
Laser Power and Focus
Laser power is proportional to the welding speed, heat input, and penetration depth. A laser in a high-power setting can swiftly penetrate thick material and form robust joints. However, laser power highly depends on the quality and capacity of the machine.
However, excessive laser power can result in material burn-through and undesirable final product. For this reason, your laser welding machine must have an easily adjustable power setting and specialized safety setting to prevent such risks even without an experienced operator.
Moreover, laser focus can augment the strength of the laser weld. A beam well-concentrated in a specific spot can penetrate quickly and form a narrow weld. An automated laser welding machine usually focuses better than an operated one.
Joint Design
The strength of the laser weld also depends on the joint geometry. Joints that directly align metal edges, like butt joints, usually work well with laser welding. Complex ones like T-joints are also quite compatibl,e but the operator must carefully align the beams to ensure that both sides of the joint are well-penetrated.
External Factors
Some factors beyond the machine and materials can influence the laser weld strength. For example, contaminants like oil and dust can negatively affect laser welding since they can absorb the beam’s energy and heat.
Is Laser Welding Stronger Than TIG and MIG?
Yes, laser welding is often stronger (and better) than Tungsten Inert Gas (TIG) and Metal Inert Gas (MIG) welding. Its strength advantage is primarily based on its better heat input, material compatibility, and speed compared to conventional methods.
Heat Input: Laser welding usually generates less heat than TIG and MIG but emits higher energy density. So, it’s more effective in penetrating materials with less distortion.
Material Compatibility: While MIG and TIG are considerably versatile, they’re still unsuitable in some materials. MIG works poorly in thin materials, while TIG usually struggles with thick sections of unalloyed and low-alloy steels. On the other hand, laser welding is suitable both for thick or thin metals or thermoplastics.
Speed: Laser welding is about four times faster than TIG and two times faster than MIG. Its high-density energy emission rapidly heats and melts metals, especially the thin ones. For this reason, laser welding is ideal for fast-track, high-volume production processes.
How Thick Can Laser Welding Weld?
Depending on the material type, the thickness laser welders can handle is generally from 0.1 to 8 millimeters. Of course, laser power, focus, and spot size may also affect its penetrative capacity.
Here are the average thickness laser welders (with power of about 1000 to 1500 watts) are capable of for common materials:
- Iron: 5mm – 4mm
- Aluminum: 5mm – 3mm
- Brass: 5mm – 6mm
- Carbon steel: 5mm – 4mm
- Stainless steel: 5mm – 4mm
Moreover, laser type also plays a role in the beam’s penetrative ability. For instance, Fiber lasers work well with thick aluminum and copper. CO2 laser (which is a bit weaker than Fiber laser) is effective with materials >0.5 in. And Nd: YAG Laser is highly powerful and versatile for spot welding.
Advantages and Disadvantages of Laser Welding in Strength-Critical Applications
As with any welding technique, laser welding has advantages and disadvantages. Every welder must consider these, especially in strength-critical production processes that require more robust and efficient welding methods.
Advantages
- Deep Penetration:Deep and narrow welds are essential when the joints’ structural integrity is paramount. Compared to MIG and TIG, laser welding can achieve deep penetration even with relatively low power density.
- Minimal Distortion: The laser beam is highly precise, which means that thermal stress is consistently applied only at the contact point. This leads to minimal (or even zero) distortion in the surroundings of the material’s surface.
- Strong Welds:The laser’s concentrated energy forms a strong and durable bond with most metals. This is crucial in industries such as aerospace, automotive, and medical, where the safety and reliability of tools and equipment are crucial.
Disadvantages
- Limitations in Material Compatibility:Some materials, such as low-melting or highly reflective metals, require strong welds, and laser welding is incompatible with them. Also, materials with an abundance of inherent impurities might be unsuitable for this technique.
- Initial Setup Cost: Laser welding requires sophisticated technology (and sometimes a skilled operator) to perform. So, it needs substantial capital to acquire. However, laser welding can be cost-effective in the long run because of its high welding speed (which means faster turnaround time) and minimal post-processing
Invest in a High-Strength and Reliable Welding Method: Laser Welding
High-power input, impressive versatility, and reliable spot focus – laser welding stands as the leading welding technique for strength-critical production lines. It’s even miles stronger compared to MIG and TIG welding options, making it a worthwhile investment for manufacturers seeking enhancements in their productions and operations.
For premier laser welding solutions, go to Denaliweld for CE and SSG-certified laser welding machines. Achieve superior laser welds with our products formulated by experienced engineers and design experts in the laser industry.
