So I took apart my DVD burner today – no worries, it was already broken… ;]
I have to say, I was simply astounded at the complexity of the mechanism. I mean, sure, I knew that it was complex, but the intricacies of the mechanism floored me. I had no idea that such am everyday item possessed such engineering beauty!
First of all came the tray mechanism with all of its plastic-geared beauty… Well, maybe that bit wasn’t so beautiful after all… ;] However the worm gear drive and stepper motor was pretty cool.
The direct drive CD spinning motor was pretty cool, too – at least I think it is when you think about how fast it had to spin that little plastic platter.
The real marvel of the thing comes in the read-write head, however. That is a precision-cast little bit of aluminium (to keep it light, and yes, I am German, so I write and say aluminium correctly 😜) that is machined to some apparently pretty tight tolerances to keep the optical path accurate. This is wrapped in a miniature 3D circuit board whose equal I have yet to see elsewhere, including laptop designs. These were little bits of board connected with filigree ribbon (I hesitate to call them “cables”) that wrapped around all sides of the aluminium substructure.
Not stopping there, we have a wonderfully complex optical path that includes the laser diode, a detector and the lens that is suspended on the teeniest imaginable copper springs which also service as current-carrying conduits that energize the circuit boards on either side of the lens. These circuits create electric loops which then help to drive it up and down inside the strong magnetic field generated by the two tiny rare-earth magnets on either side.
All in all a complete engineering marvel that I picked up for a measly $40.
I think I’m beginning to understand why these things cost over $1,000 at inception… ;]