Laser welding’s prominence across industries has grown exponentially over the past decade. As this technique ensures deep workpiece penetration, a minimal heat-affected zone (HAZ), and ultra-fast processing speeds, more manufacturers are opting for this solution over traditional ones.
But to optimize a laser welding process, you need careful control of specific parameters or factors that influence its performance. Read on and understand the factors that can guarantee top-notch weld quality.
What are the Main Factors Affecting Laser Welding?
Multiple factors influence laser welding performance. It is crucial to fine-tune these factors for a robust and reliable weld quality.
Laser Power
Often measured in Watts (W), laser power pertains to the laser beam’s penetration depth and heat input. Higher power is usually required when fusing thicker materials, while lower power is preferable for thinner materials to avoid unnecessary melting or material deformation.
For instance, a workpiece that is one millimeter thick needs 2 kW laser power for optimal fusion. Meanwhile, an 8-millimeter workpiece needs 8 kW for deep penetration and minimal weld spatter.
Welding speed
Fast welding speed provides lower heat input per weld’s length unit and is recommended when fusing thin materials to avoid overheating. Slower welding speed, on the other hand, concentrates heat input better, which is preferable in penetrating thicker materials.
Focus position and beam quality
The laser’s focus position refers to the location where the laser beam converges and hits the material’s surface. Typically, if the focus is too far from the metal workpiece, the energy density decreases, which results in shallow welds. Meanwhile, an excessively close focus can lead to excessive heat that can distort or damage the material.
Material type and thickness
There are various ways in which the material’s composition influences the weld quality. For instance, metals with high thermal conductivity, such as copper or aluminum, usually dissipate heat rapidly from the beam fusion zone. Hence, penetration is often tricky with these materials. In such cases, a higher laser power or slower welding speed is used to achieve proper fusion.
Shielding gas
A shielding gas acts as a protective barrier for the welding pool, shielding it from atmospheric contamination and helping to prevent defects such as oxidation or porosity. Different gases, such as argon or helium, can also affect the amount of heat transferred to the material, which in turn impacts the strength and appearance of the finished joint.
Pulse duration (for pulsed lasers)
This refers to the duration of each laser energy burst applied to the material. Rather than delivering a continuous stream, the laser sends out controlled, short pulses. The duration of these pulses can be adjusted, allowing for precise control over the amount of heat introduced and the depth of material melting.
For easy fine-tuning and optimization of the factors above, invest in a high-grade laser welding machine that offers intuitive adjustment tools. For instance, Denaliweld’s Air-Cooled Laser Welding offers consistent laser output and adjustable settings for speed, power, and beam focus. This machine comes with a user-friendly software for laser parameters adjustment and features an ergonomic design for easy maneuvering during the laser welding process.
What are the Considerations for Laser Welding?
Aside from the parameters and factors discussed above, manufacturers must also consider the following aspects for optimal results.
Match the laser’s power and speed to the material thickness
Thicker metals, such as those that are 10 mm thick, require high laser power and speed for deep and clean penetration. A laser power of 8 kW and a speed of around 1 meter per minute is recommended for these materials.
But for thinner metals, power and speed must be kept at a minimum (2 kW and 7 meters per minute, respectively) to prevent thermal damage to the material.
Prepare a Welding-Conducive Environment
The material’s surfaces must be thoroughly cleaned from rust, oil, or paint to avoid contamination or spatter formation. Good ventilation is also recommended to eliminate harmful fumes and provide fresh air to the welder. Stable lighting must also be ensured to help the operator see the welding pieces.
Use of Clamping Fixtures for Alignment and Consistency
Clamping fixtures are used in laser welding to maintain parts’ accurate alignment throughout the process. As these tools hold the components firmly, unwanted workpiece shifting or movement is prevented, which could cause uneven joints or gaps.
Post-Weld Cooling and Surface Finish Requirements
This step is crucial as it affects the final properties and appearance of the welded material. Controlled cooling helps prevent the formation of cracks or unwanted changes in the metal’s structure. If rapid cooling is employed, the welded joints may experience metallurgical stress, which can compromise their quality. Meanwhile, slow cooling may result in unwanted grain growth that can adversely affect the weld’s durability in the future.
What are the Defects of Laser Welding?
Say your laser welding parameters are poorly configured. What will happen to your fused workpieces?
All potential results are unfavorable.
- Porous material surfaces: Tiny holes or spaces are present in the metal’s structure. This occurs when trapped gases are present in the workpieces or when they are welded in a contaminated state.
- Presence of cracks: When the laser welding process involves rapid cooling, the material will exhibit numerous cracks, indicating poor fusion.
- Undercuts and spatters: The presence of these impurities indicates that the laser welder is using incorrect speed or power settings.
- Incomplete fusion: If there are sections in the weld that are not properly fused, the laser welder may be using a low power setting. Another potential culprit is poor focus beam alignment. This problem usually has no adequate remedy other than repeating the entire welding process with new materials.
Experience Premiere Laser Welding Process With a High-Grade Laser Welder
While laser welding is known for its high precision and efficiency, its final weld quality is only as good as the control over influencing factors. Laser power and speed, as well as the material thickness and type are all relevant in the achievement of an optimal weld quality.
Denaliweld is a leading global provider of CE/SGS/WPQR-certified laser welding solutions. Our laser welding machines feature advanced parameter control software to help operators adjust laser power, speed, and focus that fit the project needs and requirements. We are committed to bringing your business a laser welding solution that is precise, high-quality, environmentally friendly, and energy-efficient.
