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View Full Version : It's me, the exploding CD guy :)



JamesStewart
02-11-2003, 11:41 PM
Hi. Well, I went down to Dick Smith's the same day that I recieved the e-mail saying that they will give me a new drive. I was (please note the WAS happy). Got home, had double the RW speed (from 12x to 24x) which was good. I put the drive in, XP found it ok. I burnt a CD of music (to test the drive) and put the CD in my CD player. The CD just would not play. I then put the CD into the computer and Windows media player would play it it. I know it isn't the CD's (because I have never had problems with Imation before with my old drive). I have gone through about 10 CDR's trying to burn working music (music that I have burnt with my old drive and it worked) and I have ended up with a CD that doesn't play or a CD that gets 1/2 way through burning and then fails and reboots my computer. I am using Nero 6 for burning.

Now, it was all good when Dick Smith said they would give me a new drive (I was quite happy) but this is just REALLY inoying and pissed the living %*$@ out of me. I have found my old drive on Price Spy for $70 ... do you think I should get DSE to take this drive back and give me the $70 for a new .. WORKING drive?

I know this is "pushing" my luck but you have to admit, they should replace my drive with one of equal or better ability and this certainly isn't up to scrach!

robsonde
02-11-2003, 11:52 PM
I would send a polite emial to DSE again and explane the you are very happy that DSE has replaced your drive but that the new drive is causing a few problems and would they exchange it?

JamesStewart
02-11-2003, 11:55 PM
You see, DSE are all good for phones, software, and hardware (such as screws, cables and such) but i wouldn't touch their real hardware (like Computers, drives, grahpics cards). It seems too ... cheap and nasty. Not taking anything away from DSE, they are (on the whole) are great company with extemely good PR. I love their "14 day no questions asked return" policy :)

00falcon
02-11-2003, 11:58 PM
I know this might be of the track... but...

When i first got my "puter" bout 18 months back i went to wright a music CD and wrote it in the wrong format...

Did nero 6 come with the new drive and so being new software your not familea with...

Try differant software...

Falcon

Chilling_Silently
02-11-2003, 11:59 PM
Have you tried burning it at 4x (or 2x if it'll let you.. dont think those speed Writers do 1x)? That might help?

PoWa
03-11-2003, 12:06 AM
Are you writing to a CD-R or CD-RW??? Most standalone players have trouble reading CD-RW discs due to the poor reflectivity.

JamesStewart
03-11-2003, 12:21 AM
To answer all the questions: I am burning at 48x (which is what the CDR not RW) can handle. I have always used Nero 5 or 6 (got Nero 6 about two weeks before this all happened). When I went into Dick Smith's, they only gave me a drive. No box, cables, software, manuals, nothing. Took the drive out of the box and handed it over.

Now, as for you saying try burning at 4x or 2x. That is not the point, the point is that I had a product that worded FINE at 48x and I have to settle for 4 or 2 times? I don't think so. If you have read my post carfully, you would note that I have never has this problem before with my old drive (I have always use Nero, 48x, and my Imation CD's).

And no, I am not writting in the wrong format, I do know what I am doing :). +Nero coverts .wma/.wav/.mp3 to .cda (the CD format) automatically if you select Audio CD. I have also gone through all the setting and tried to sus out the problem but I don't see why I should have to do that as I havn't changed any settings in Nero when I got the new drive.

PoWa
03-11-2003, 12:33 AM
Are you finalising the cd?

Try a different burning program for starters. Otherwise it might be an inferior drive. You get ones like that, that can't record bit patterns correctly.

JamesStewart
03-11-2003, 12:40 AM
I am doing everything physically possible short of pulling the drive apart and testing each piece of the drive myslef.

revspecies116
03-11-2003, 06:33 AM
Hi James

Quote: I am burning at 48x (which is what the CDR not RW) can handle.

There in lies the problem - most CD-R Discs
CANNOT cope with that (And if the lable on the
CD-R disc says it can cope - DO NOT BELIEVE
IT :)). I always burn my music CD's at x12 or x16
at the MOST. If this still causes a problem on
your end, then you can complain to DSE. Lower
the speed.

In fact For Everyones Information, Dedicated
Audio CD Players can only read at 1x speed, as
per CD Specifications. No wonder your x48 is not
working.

Hope that helps, James


Rev Species 116

ilikelinux
03-11-2003, 06:40 AM
have you tried reinstalling nero?

Some times programs stuff up and need to be reinstalled but they don't tell u.

(seeem s like windows.............)

somebody
03-11-2003, 07:47 AM
James did say that he's never had problems with burning at 48x though.

PoWa
03-11-2003, 09:48 AM
... except his cds exploding ;)

Yes I agree with RevSpecies and Chill, burning at 48x just isn't accurate enough for audio cds, theres a much higher error rate.

Graham L
03-11-2003, 02:51 PM
I would try reinstalling the software. There are so many things involved in writing CDs that installing almost certainly involves a lot of checking the actual drive the software has to work with.

I have to say that if a CD written on the drive can be read on the same drive, but can't be read on an audio player that means that the writer is OK. :D It's an "unfortunate" fact that audio players are designed for pressed CDs . Pressed CDs have a much greater difference between pit and no-pit than the dye-based layers on CD-R and CD-RW disks. The faster the recording is done, the less energy goes to record each bit.

Recording slower might help. A different brand of disk might help. But I don't think that DSE are to blame. A new drive "identical" to the one which exploded might have the same problem. :D

JamesStewart
03-11-2003, 03:06 PM
Well, ONCE AGAIN!!! Dick Smith's are ... beyond words and have said they will give me $99.00 for the drive as "it is not meeting your expectations". I have to say, these guys are bloody good. I do need to say though, that these Cyber Drives are not of ... "high" quality. I was extremly happy with my Aopen drive and this was a huge let down. Well, thanks for your ideas and help people (I will remember the 16x burning next time).

Thumbs up to DSE

James

Terry Porritt
03-11-2003, 05:15 PM
Yes, DSE are pretty good, but dont get carried away with your "need for speed". The microseconds you save burning at x48 dont really compensate for the possibility of exploding CDs destroying yet another new drive.

If I knew the elastic moduli and UTS of CD disks I could calculate the bursting speed of CDs and see what sort of safety margin is built in, probably not much.

It wouldnt require much of a homogeinity defect in the disk, a stress raiser, or a bit of out of balance to lead to catastrophe. Used to do these calcs for turbine disks, grinding wheels, and other high speed components once upon a time.

Graham L
03-11-2003, 05:25 PM
The material is polycarbonate, Terry ... I'm sure the properties will be available online. The peripheral speed is a bit frightening at 52x. I think the x1 speed is 300 rpm or thereabouts (so perhaps they should be "reinforced" with titanium dioxide, like the plastic spouting.) :D)

Terry Porritt
03-11-2003, 05:49 PM
Thanks Graham, I found the required data, albeit in psi and density in lb/in cubed etc, good job Im bilingual units-wise.

Unfilled polycarbonate is also said to not have good fatigue strength and also has poor notch strength, ie it shouldnt be played more than once :)

Terry Porritt
03-11-2003, 05:50 PM
........ but tonight is dog training so will give results tomorrow!

Graham L
03-11-2003, 05:57 PM
They probably rely on the strength of the screen-printed label on one side. :D

And Philips will have done the numbers for the audio CDs. That's what the standard is written for. I bet no-one has thought of recalculating the actual stress at the higher speeds. :D

I haven't looked, but I have an idea that CD-R and CD-RW won't have the Compact Disc logo, because they are not in comformance wuth the standard --- not least the bit/no-bit reflectances. Philips have said that any music distributers which use copy-protection are breaking the licence ... you can use the logo if the CD is according to the standard.

Graham L
03-11-2003, 06:19 PM
And while Terry is looking at the theory, Atlas Copco AB (the big Swedish engineering company) have done some experiments. The report is here (http://www.paintbug.com/cdexplode/), and there's even a movie (http://powerlabs.org/cdexplode.htm).

Scary.

Graham L
03-11-2003, 06:19 PM
And while Terry is looking at the theory, Atlas Copco AB (the big Swedish engineering company) have done some experiments. The report is here (http://www.paintbug.com/cdexplode/), and there's even a movie (http://www.powerlabs.org/cdexplode.htm).

Scary.

ilikelinux
03-11-2003, 06:40 PM
Boooo Hooooo

I get a messege saying "Forbiddon access or something" (p.s i'm in red hat linux)

Thomas
03-11-2003, 06:50 PM
Wonder what breed of dog Terry has and what is he training them for.If he had whippets like yours truly he wouldn't need to train them and he could get on with calculations;)

Terry Porritt
04-11-2003, 01:33 PM
Thin rotating disks are quite interesting. I first got involved with them in the earlier days of silicon wafer slicing. The need was for thinner diamond edged wheels so as to minimise the waste produced. Even so the wheels were thicker than the slices, and discs supported at the outer edge, with the cutting edge at a central hole were used for strength reasons. Discs with the diamond impregnation at the outer rim were more convenient to use, and made machine design somewhat easier.

The interesting thing is the travelling and standing wave patterns that can be seen with a stroboscope when passing through modal frequencies, of which more below. Disk instability, dynamic and buckling, was the limiting factor for external slicing discs.
My contribution was to stiffen thin cutting disks by enclosing them between pressurised water lubricated thrust bearings having a U shaped cut out at the outer edge to expose a small portion of the disc where the silicon crystal was cut.


Ive based the calculations on the dimensions of a CD. I dont know if other types of disk are different, they could be.

I also had to assume a value for Poissons Ratio, couldnt find that, so used 0.3.

Also I'm not too au fait with the behaviour of plastics beyond the region of elasticity, except that they will be highly plastic :D

For Polycarbonate the elongation at break is 60%, which is considerably more than steel.

The principle stresses are naturally enough tangential and radial, and as the CD is rotated the maximum tensile strength stress (9500 psi) will be reached first tangentially at the perimeter of the hole.

Just giving the result of calcs ( Ive based the calcs on "Roark" formulas for stress and strain , which will be familiar to mech. engineers), I wont bore anyone with maths.

The estimated bursting speed for a CD based only on simple stress with the CD remaining circular comes out at about 41,000 rpm.

However well before this speed is reached there will be considerable radial expansion of the CD in the elastic region followed by plastic deformation.
It is not possible for this deformation to take place perfectly symmetrically as it grows in diameter and the CD will tend to deform elliptically? and go out of balance creating yet higher stresses.

So the figure of about 27,000rpm measured in Grahams reference is not surprising.


There is though yet more considerations, real life is quite complicated, a disc experiences transverse vibrations as well as pure radial extension.

Well before the bursting speed, and in fact below the typical running speeds of 52x drives, the CD will go through its critical speed.

This is too complicated to go into except to say there is a forward natural frequency and a backward natural frequency, ( Another purpose of the hydrostatic water bearings was to supress transverse vibration), and calculation is difficult.

Based on calcs of the stationary natural frequency of a disk and making a guestimate, the critical frequency of a CD should be around 6500rpm.

There is yet another effect on a CD, and that is the aerodynamics of a disk in an enclosure, which will be quite different to a disc in free air of infinite extent.
For a disc in open air, the flow of air over the disc tends to provide a transverse stiffening effect.

In an enclosure like a CD drive the air will be turbulent, spinning to a certain extent with the disc, and/or will have vigorous vortices.
This may well generate aerodynamic instability, and add to stresses.

The reported low fatigue strength of Polycarbonate may well mean that re-writable discs could fail after 'x'?? number of re-writes.

Terry Porritt
04-11-2003, 01:42 PM
Oh, and I forgot Thomas, the dog is a Border Collie X, got him from the SPCA about 9 weeks ago.

Why dont Whippets need training, do they go too fast to sit and stay?

Thomas
04-11-2003, 01:45 PM
pheew,I am glad that is cleared up;)

Thomas
04-11-2003, 01:57 PM
I love the way Border collies look at you,sort of what can I do for you next.
Whippets just do what they are bread to do,run and woe betide a rabbit that takes them on,poetry in motion.

Terry Porritt
04-11-2003, 06:57 PM
If anyone is worried about exploding CDs, there is a utility called CD Speed that allows the maximum speed to be controlled.

It works with my writer, but only gave the choice of 1x or 52x with my Liteon 52x cdrom drive, nothing in between.

http://www.tonec.com/download.html