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High-Speed destruction : CD disintegration

CD smashed by hard-disc platter : cdsmash_disc_flat.m1v (3.9MB). 1000 frames/sec

Credit for the inspiration to try this goes to Dave Green of NTK , who had enquired if it might be possible to use the destruct-o-tron to destroy a Band Aid 20 CD in the name of charity at the December Dorkbot London meeting, where I was due to do a demo the day after the camera recording. 

The setup was a hard-disc platter on the coil, with a CD placed on top of it, inside the usual 10" gas-pipe containment vessel.(a CD on its own won't work as the metallisation is not conductive enough to carry the required current.
The results were utterly staggering - there was much jaw-dropping the first time we played it back.
If you only look at one of these movies, WATCH THIS ONE!!!!
The effect of the CD fragments spinning through the air, rebounding everywhere and sparkling as they catch the light is quite simply stunning.

Careful examination of the frames shows that the CD is actually smashed by the acceleration of the HD platter against the CD, not by the impact with the top of the containment tube, although the leatter may be responsible for further granulation...

The framerate on the movie is a bit odd as we'd not got the hang of making sure we had a full sequence coppied off at 25fps, but I extracted the frames below from a different section to get clean interlace-blur-free images.

wpe6F.jpg (18889 bytes)

The Disc starts to lift
wpe70.jpg (18923 bytes)

The CD is now in many pieces
wpe71.jpg (19519 bytes)

wpe72.jpg (20004 bytes)

wpe73.jpg (20061 bytes)

The fragments start bouncing off the walls & all hell breaks loose..!
wpe77.jpg (20737 bytes)

OK, now what if we have 2 CDs...  cdsmash_2cd.m1v (3.6MB)

This was done with a ring of brazed 1/4 inch copper refrigeration tube instead of the hard disc platter.

wpe78.jpg (19129 bytes)

wpe79.jpg (19298 bytes)

wpe7A.jpg (20038 bytes)

wpe7B.jpg (20894 bytes)

wpe7C.jpg (21699 bytes)

wpe7D.jpg (21699 bytes)

One CD with the copper ring. Movie runs forward and then backwards : cdsmash_tilt_2way.m1v (7.5MB)

This one used a much smaller ringm which broke the disc into much larger fragments : cdsmash_smallring.m1v (3.5MB)

One obvious difference is that the fragments move a lot more slowly, taking about 20ms to hit the top of the pipe.

wpe7E.jpg (19895 bytes)

wpe53.jpg (20828 bytes)

We chickenned out of trying to shoot the destruction end-on, i.e coming at the camera, as it wasn't our camera, and I wasn't confident enough that the big lump of perspex we were using as a shield wouldn't break, so we split the difference and tilted the coil and CD up to about 45 degrees. This was done with a hard-disc platter.
cdsmash_45deg_150k.m1v (387K)

wpe8B.jpg (19743 bytes)

You can just see something starting to happen at the bottom of the CD
wpe81.jpg (21168 bytes)

wpe82.jpg (20154 bytes)

wpe86.jpg (20799 bytes)

wpe89.jpg (21025 bytes)

wpe8A.jpg (21025 bytes)

Now let's try a different arrangement... Copper tube ring hitting CD edge-on. 1000 frames/sec
cdsmash_vert.m1v (3.3MB)

wpe8C.jpg (19628 bytes)

3mS after lift-of, the ring starts tearing into the CD
wpe8E.jpg (19796 bytes)

wpe54.jpg (19890 bytes)

wpe55.jpg (19676 bytes)

Sequence at 3000 frames/sec

wpe59.jpg (4514 bytes)
wpe5B.jpg (4213 bytes)
wpe5C.jpg (4169 bytes)
wpe5D.jpg (4068 bytes)
wpe5E.jpg (4018 bytes)
wpe5F.jpg (3966 bytes)
wpe60.jpg (4212 bytes)
wpe61.jpg (4188 bytes)
wpe62.jpg (4071 bytes)
wpe63.jpg (4008 bytes)


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