When you have such concerns and want to ask your potential suppliers about this issue, generally speaking, I believe all suppliers will tell you the welding strength is quite reliable and firm, but is it true? Today we are going to look into the topic.
First of all, we have to figure out what laser welding technology is. Simply speaking, Laser welding is a high-efficient and precise welding method that uses a high-density laser beam as a thermal source. Laser welding can use continuous laser beams or pulsed laser beams, welding principle can be classified into thermal-conduction welding and laser deep-fusion welding.
Working principle of thermal-conduction welding: The power density of the laser spot working on the welded part surface is relatively low, generally less than 105W/cm2. The laser delivers energy to the welded part surface to heat the metal surface until between melting point and boiling point. Absorbed light energy will convert into thermal energy to make the temperature of the metal surface get higher and higher until it is melted, then thermal energy will be transmitted to the inner of the metal in a thermal conduction way to make the melted pool bigger, welding spots or welding seam will form after melted pool gets cooled. The welding principle is similar to TIG.
Working principle of deep-fusion welding: When the laser density of the laser spot working on the metal surface is more than 105W/cm2, the high-power laser beam can cause partial melting and form a “Keyhole”, the laser beam that can through the keyhole and arrive at the inner of welding pool. Metal is melted in front of the keyhole and melted metal bypass the keyhole and flows to the back, melted metal will form a welding seam after getting cooled.
With the development and design of high-power laser sources, laser welding technology is now being used in a lot of fields. Laser welding technology features the following characteristics:
- When welding with a laser welding machine, the connection gap between welded parts nearly doesn’t exist. Meanwhile, the depth/width ratio is big, with no deformation, and precision is high.
- The laser welding machine is easy and flexible and can be used at ambient temperature and under special conditions. No strict requirements for the welding environment.
- Laser welding machines can form quite deep fusion, laser density is big, can weld difficult-to-weld materials, like titanium alloy, #45 steel, etc…
- Red dot positioning method, positioning precision is much higher
- No environmental pollution, reducing the possibility of injury and occupational disease
- Fast welding speed, about 3-8 times faster than traditional welding
In the early days, laser welding technology was first used in the field of military tank manufacturing. The welding products for national defense have a high standard and are extremely harsh on the welding environment and welding process, welding strength, and welding grade of fiber laser are both much higher than traditional welding technology. Although it can realize high welding strength, the welding cost makes it even not a possibility in the metal processing field. Later, with the improvement of laser welding technology, the Volkswagen Group, which is good at car body manufacturing, applied laser welding technology to the field of automobile welding in the 1990s. The welding grade and strength of the structure and parts of the car have been revolutionized. It is enough to illustrate the welding strength of laser welding.