We are discussing vehicle construction in class and found these videos that demonstrate how some cars are laser welded from the manufacure.  It is amazing how fast these are being welded using these machines.  Take a minute to watch the videos below.

[youtube]http://www.youtube.com/watch?v=kL6pz5iziss[/youtube]

[youtube]http://www.youtube.com/watch?v=EkAs6UW53-4[/youtube]

Here is another video of a vehicle being spot welded from the manufacture. 

 [youtube]http://www.youtube.com/watch?v=F2TV2s7GYSc[/youtube]

This type of welding does not use any filler material when welded, which does not add any weight to the vehicle.  In the collision repair industry, we use a smaller version of a spot welding machine to reporduce these spot welds, or drill 8mm hole to produce a plug weld using a MIG welding machine.  This is the process of drilling the 8mm hole, placing the two pieces (or more) of metal being welded together, claming the metal secure, and filling in the hole with the MIG welder.  This fuses the two pieces of metal together.  Once welded, the plug weld can be ground smooth and prepared for paint.