I have spent more hours of my life than I now care to think about installing and getting equipment like that into production (assembling the body shell is called 'body-in-white' because no paint is involved yet). All those sparks are just for effect, if the welding guns are set up properly they don't spark - but the film-makers know that it looks boring and they always asked us to turn up the welding current until nice big satisfying showers of sparks were produced. Truth is quality control would reject a body that had been welded like that.
I can remember times when quality found marks (dings) on panels, especially 'skin' panels which show up when car is finished (and the marks look worse when they are painted) - we had to track back through the whole process to find out where the dings were happening - happy days
I felt bad about putting people out of jobs and replacing them with robots, and as some operators used to say 'you realise those robots won't be buying cars' - how can you argue with logic like that ?
