In modern industrial production, welding technology, as an important connection process, is widely used in the processing and manufacturing of various materials. Especially in the application of flat panel solar collectors, the heat absorbing plates of flat panel solar collectors mainly use aluminum and copper sheets, while the flow channels are mostly made of copper tubes. In the practical application of these two welding methods, ultrasonic welding and laser welding, each has its own advantages. This article aims to explore in depth the differences between ultrasonic welding and laser welding, analyze their differences in working principles, application scope, operation methods, and advantages and disadvantages.
Laser Welding vs. Ultrasonic Welding
Laser technology utilizes polarized mirrors to reflect laser beams, concentrating them into a focused device to generate a high-energy beam. This beam, emitted in pulses, reaches temperatures exceeding thousands of degrees Celsius, melting and evaporating metal materials within milliseconds.
Laser welding is a non-contact welding method, capable of transmitting over considerable distances before providing welding, cutting, and heat treatment functions. Its advantages include minimal deformation and pressure required on the welded workpiece, resulting in minimal surface damage to absorber coatings. This has led to prevailing industry sentiment favoring laser welding over ultrasonic welding. However, laser welding alters the physical structure of the welded object, leading to decreased mechanical strength and some impact on thermal conductivity.
Ultrasonic welding utilizes high-frequency mechanical vibrations to generate high-density energy, inducing plastic deformation on the workpiece surface and disrupting surface layers under pressure, resulting in a physical connection between welded metals at room temperature. Although ultrasonic welding may damage coating layers by around 3%, its continuous non-melting welding process offers relatively good thermal conduction efficiency. Additionally, ultrasonic welding holds certain advantages in material costs and is suitable for thin products. On the other hand, laser welding is more suited for thicker materials. In reality, both welding technologies have their own merits, and enterprises should choose the most suitable one based on their specific circumstances, rather than making a blanket assessment of the superiority or inferiority of the two welding technologies.
Advantages of Ultrasonic Welding vs. Advantages of Laser Welding
The advantage of laser technology lies in the minimal deformation and pressure required on the welded workpiece, resulting in minimal surface damage to absorber coatings. However, laser welding also alters the physical structure of the welded object, and frequent cold and hot shocks at the weld points can lead to fractures and reduced strength.
Ultrasonic metal welding offers the advantage of non-melting welding, preserving the non-brittle metal properties. It has short welding times, high fusion strength, and approaches cold-state processing. However, it may damage absorber layers by around 3%, and it is not suitable for welding thick metals (taking the example of flat solar panels mentioned earlier, typically ?5mm, which becomes an advantage for flat solar absorber plate welding). Additionally, due to its continuous non-melting welding process, it exhibits relatively good thermal conduction efficiency. Some experiments have shown that under equivalent conditions, ultrasonic welding products have around 3% higher thermal conduction efficiency compared to laser welding.
Ultrasonic metal spot welding machines are used for similar metal welding and can handle thin materials of copper, silver, aluminum, nickel, and other non-ferrous metals. They can perform single-point, multi-point, or short-line welding and are widely applicable in welding various shapes such as fuse pieces in lithium batteries.
Ultrasonic metal spot welding machines utilize electronic program control, offering high power, efficiency, automatic control, easy operation, built-in electronic protection circuits for safety, and stable and reliable operation. Welded joints exhibit firm bonding, high strength, subjectivity, and environmental friendliness.
Ultrasonic welding machines are suitable for welding relatively thin products, as laser welding can pierce through thin materials directly. Another important aspect is that the price of laser welding machines is several times higher than that of ultrasonic welding machines.
Ultrasonic Welding vs. Laser Welding: Tips
Although ultrasonic welding and laser welding are effective connection techniques, they may both result in some welding defects in practical applications.
The main defects of ultrasonic welding include:
- Porosity: This is often caused by inadequate cleaning of the plastic surface before welding or using an inappropriate ultrasonic vibration frequency. Porosity can affect the strength and sealability of the weld.
- Weld lines: Refers to irregular lines generated during welding, which may be caused by insufficient ultrasonic vibration frequency or too low melting point of the plastic material, adversely affecting the appearance and strength of the product.
- Incomplete welding: This is usually due to improper ultrasonic vibration frequency or insufficient welding time, resulting in ineffective welding in some areas.
- Weak welding: It may be due to insufficient power of the ultrasonic welding machine, uneven pressure distribution, or mismatched vibration frequency with the material, resulting in inadequate welding strength or even fractures.
Potential defects in laser welding may include:
- Cracks: Often caused by thermal stress during welding or shrinkage stress during cooling exceeding the material’s tolerance.
- Undercut: In laser welding, welding undercut is mainly due to poor bonding between the weld and the base material, resulting in a groove.
- Shrinkage cavities: This is usually caused by too fast or uneven melting and solidification speeds in the welding area.
- Deformation: During laser welding, the weld joint may deform due to thermal deformation or unbalanced stress.
- Slag inclusion: This is often due to ineffective removal of oxides, impurities, etc., from the welding area during the welding process.
- Discoloration: Welding materials subjected to high temperatures and oxidation may experience surface oxidation and discoloration.
In order to avoid welding defects in ultrasonic welding and laser welding, it is necessary to accurately control welding parameters, ensure material cleanliness and sufficient preparation before welding, and select appropriate welding materials and equipment. In addition, strict monitoring and testing of the welding process, timely detection and handling of potential defects, are also key to ensuring welding quality.
BoYi – Manufacture High-Quality Welded Plastic and Metal Parts
Welding, as an effective technique for joining plastic and thin metal, plays a crucial role in the manufacturing industry. At BoYi, we specialize in providing professional rapid prototyping and manufacturing services to our clients. Equipped with state-of-the-art machinery, our factory is capable of efficiently and precisely welding plastic and metal components, ensuring product quality meets the highest industry standards. Additionally, we have a comprehensive inspection process in place, rigorously monitoring every step from raw material intake to finished product delivery, to ensure the quality and stability of welded components.
Conclusion
In summary, there are significant differences between ultrasonic welding and laser welding in terms of principles, application scope, operation methods, and advantages and disadvantages. The choice of welding method should be comprehensively considered based on specific application requirements, material types, production costs, and other factors
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