Choose the way to weld for the Seamless FCW
![image of welding section](../different-thinking_01.png)
Assumption according to the Patent of EP 0489167 B1
- Old patent that the laser welding has not yet introduced the the seam welding.
- Lots of heat generated from welding point enough to burn all surface of tube.
- To protect the flux, it need to secure some distance from heat source.
- Big tube make the manufacturing process complicate.