When discussing laser welding, it is often mentioned whether it is possible to weld certain highly reflective materials. Let’s first understand what is a highly reflective material? Is aluminum exactly the same as pure aluminum?
How to judge the high reflective material? We judge based on two criteria: high electrical conductivity and a very smooth surface. If a material has one of these qualities, it is considered highly reflective.
The main factor for judging is electrical conductivity. Materials with lower resistivity absorb less laser energy (high anti), while those with higher resistivity absorb more.
Some materials conduct electricity better than others. Stainless steel and carbon steel have poor conductivity, while copper and aluminum have good conductivity. Purple copper has the best conductivity. Copper wire is better than aluminum wire because it produces less heat. We can simply understand that the better the conductivity of the thing it is the more high anti.
The second criteria is that the surface should be smooth like a mirror. The flatter it is, the better the anti-reflective properties. Smooth materials absorb less laser energy. Very smooth surfaces, such as stainless steel, are ideal for laser processing. This is because they are resistant to the laser.
The rougher the material, the more the laser absorbs. If it’s very rough (like purple copper), it’s not good for laser processing because it doesn’t resist the laser well. Stainless steel is reflective when its mirror film is removed. Wood can also be reflective when its surface is very smooth. However, the level of brightness does not affect the material’s reflectiveness.
Surface microstructure
Is aluminum a highly reflective material? High reflection depends on the grade of aluminum. Grades vary greatly, with aluminum alloy and pure aluminum being very different.
Materials have different numbers, such as carbon steel. Different materials have different numbers, like carbon steel and aluminum plates.
The most common aluminum plate numbers range from 1 series to 7 series. Examples include 1001, 3001, 4043, 5052, 6061, 6063, and 7075. Pure aluminum reacts quickly, while the 7 series and 8 series aluminum have a slower reaction rate.
Pure aluminum has a high reaction rate. However, the 7 series and 8 series aluminum have a weaker reaction rate.
High reflection grades can vary greatly. Conventional aluminum alloys have lower reflection compared to pure aluminum or mirror stainless steel. The grade of the material affects its reflective properties.
Nowadays, fiber laser welding for highly reflective materials is well-developed. DenaliWeld laser, with a 976nm laser pump source, can weld various metals, such as copper.
In laser welding, high reflection is a relative concept determined by material resistivity, surface structure, and state. It helps decide if a material can be used for processing that requires high reflection. If you are still not sure about the specific material, you can contact us for consultation.
