Was just looking at the welds too, wondering what they were for. Practice as you said? One box with an X for each body part lost to this machine? LoL I do like it though, it makes me curious as to what exactly it is, what it does and so on, but I like not knowing in this case, it makes it more interesting to me.
I've been staring at this trying to figure out why it doesn't work for me as a composition. My first gut reaction is that there are a lot of pieces that don't work together so I'm just looking all around the image for something to tie it together. The only specific reason that occurs to me is that there are several bars or arms or whatever that have very little detail and lead out of the frame, so perhaps my eye is moving along these looking for something and then ends up out of the frame and has to be brought back in. A type of composition that sometimes works better for machinery is a circular arrangement where there are points of interest which can be connected in a loop (need not actually be a circle) so that one's eye moves from one to the next, eventually returning to the starting point. In some cases, such an arrangement just isn't there to be photographed.
My guess on the welds is that they are surfacing welds...used on machinery that comes in contact wih other objects. The idea is these welds come in contact with with another object instead of the base metal...extending the life of your equipment