52X CD-RW could be dangerous acc to some major manufacturers

[VEFF]

I was checking out the PC World article Ian mentioned, in order to see exactly what it said about 4X DVD-R media possibly not being playable on DVD-ROM drives or home DVD players manufactured before THIS fall!

Anyway, while reading the article, I also noticed that Maxell was
going to introduce 48X CD-R media in 2003.
The article implies that the reason they aren't releasing 52X media is as follows (quoted verbatim from the article):

"Along with Sony, Yamaha, and Plextor, Maxell has decided that spinning a disc fast enough for 52X recording is dangerous, producing a level of stress that can damage the disc"

I am glad I read it, since:
1) I was planning on buying a lot of 4X DVD-R media when my 2X supply runs out.
2) I had been slightly tempted to get a 52X CD-RW (have a 48X, so I am not in a rush especially since I almost always burn below 48X for quality reasons anyway)

Thanks Ian!

[Ian]

The 52x writers are loud.. and spin the disc pretty fast. While I wasn't afraid of cracking or shattering a disc with a 48x writer, some of the 52x writers do make me think twice.

[VEFF]

The 52x writers are loud.. and spin the disc pretty fast. While I wasn't afraid of cracking or shattering a disc with a 48x writer, some of the 52x writers do make me think twice.

For the 5 - 8 seconds to be gained, and the less reliable burn quality of high speed burns in general, I'll probably stick with my 48X burner, especially now that I am burning more DVD-Rs.
In addition, even with my 48X writer, I rarely burn faster than 32X for VCD and 40X for non-important data, let alone critical data, which I back up much slower.

But then again, sometimes temptation gets the better of me LOL

[T-Man]

Ack...

I just ordered a Lite-On x52 drive. I wonder if I should return it to get a x48? I am also wondering if the manufacturers of these drives will offer firmware that will take these drives down to x48?

Just curious as to what other people think of this.....

[falcon]

From the reviews I've read, Maxell has just about the crappiest media and has problems with speeds over 40x....so it makes sense that they would be against 52x speeds.

[T-Man]

Well, If it was just Maxell that was making that statement, then it wouldn't bother me that much.

[lppnet]

So is the 52x cd-rw drive really that dangerous to use? Think of getting one lite-on 52x this weekend. Should I bought a 48x instead?

[coolestnitish]

Common guys, its a CD-RW drive not a bomb. It won't blow up your PC. I think 52x is fine and safe. It may worry people because the industry didn't suggest pushing CD reading more than 52x. I think if you follow some of these suggestions, you should be fine -
-don't burn 10 discs in a row at 52x
-make sure your computer atleast has average cooling.
-use quality media like TYs
If you follow those, i cant think of a reason why it should be unsafe. From 48x burners, its just a 4x faster one. If 48x is safe, then it makes sense that so is 52x. Now if we start talking 56x and + burners (which I think we won't see), then maybe you might want to have a fire extinguisher nearby while making a cd...
I am going to buy the LiteOn 52x soon, the 48x is a lot cheaper and I also prefer quality over speed, still I have this urge to have the fastest one out.

[cd pirate]

:-? So is the 52x cd-rw drive really that dangerous to use? Think of getting one lite-on 52x this weekend. Should I bought a 48x instead?

there wouldnt be much of an increase in rpm between 48x and 52x. so the 48x would be just as dangerous as the 52x. anyway, the 52x speed is a better choice, they have better media compatiblity and better write performance. read the cendyne lightning review here at cdrlabs if you dont believe me. by the way, the cendyne is a liteon 52x drive.

[lppnet]

Agree with you all. I like the lite-on 52x very much after reading Ian's review, except the rw issues. At my place can get the original lite-on for USD 77 (RM 290).

[Creig]

Just get the 52x. It has the newest mediatek 6 chipset which means it's more compatible with PC and audio discs, even those with copy protection. If burning at 52x makes you nervous, simply choose a lower speed to burn at.

[Creig]

Or if you want to save a few $$$$, just get a Cendyne LTR-48246S 48X drive which is identical to the 52x drive. All you have to do is flash it with the 52x bios. I currently have this drive and will reflash it if I need to. However I currently have a Memorex 40MAXX flashed to a Lite-On LTR-48125W 48x12x48 and now this LTR-48246S 48x24x48 so I don't really feel any need to go faster since I can now burn 2 discs in under 5 minutes.

Just make sure you look at the back of the box before you purchse a Cendyne. They stuff all SORTS of different drives in their boxes. It HAS to say LTR-48246S (the best one to get, has the Mediatek 6 chipset) or LTR-48125W (2nd best, with the Mediatek 5 chipset) in order to get a Lite-On. If it says 48x12x50 that's an AOpen. There's a few others as well.

[lppnet]

But from the Ian's review, the 52x have a good writes quality. So no doubt burning at 52x with good quality media as adviced by ~coolestnitish~.

[dodecahedron]

back to the original topic of this thread:

The 52x writers are loud.. and spin the disc pretty fast. While I wasn't afraid of cracking or shattering a disc with a 48x writer, some of the 52x writers do make me think twice.

:-? So is the 52x cd-rw drive really that dangerous to use?

i think it's just nonesense.
there have been 52x readers for a couple of years (?) and how often do we hear of a CD "exploding"? not that it doesn't happen, but it's rare. and the speed difference between a 48x drive and a 52x drive is 8.3% not that big a deal.
besides, although you might argue that a CDRW burner is more dangerous at 52x than a 52x reader, because the disc heats up from the laser burning, i think it's the other way around. in a CDRW drive you put (more often than not) a BRAND NEW DISC. whereas into readers go used and old discs, more suceptible to be shattered. and like i already said, we've been using 52x readers for a long time...

[cfitz]

the speed difference between a 48x drive and a 52x drive is 8.3% not that big a deal

If I have successfully resurrected my high-school physics, centripetal force goes as the square of the velocity, not linearly with velocity, so an 8.3% speed increase translates to a 17% increase in the radial forces trying to tear apart the CD. If you want to make it look worse, you can compare 52x to 40x - an increase in speed of 30% and an increase in radial forces of 70%!

Personally, I hope that margins aren't being cut so close that a 17% increase in forces will result in a significant increase in catastrophic failures. If that was truly the case, then I wouldn't be comfortable burning at 48x either. I probably would want to burn at 36x for a safety factor of two. Of course, one does have to draw the line somewhere, and maybe that line does belong between 48x and 52x. But, I can't imagine that the line is hard enough that people who buy 52x burners will be dodging fragments of polycarbonate shrapnel on a regular basis.

In my opinion, this is an issue to be decided by personal levels of comfort. The bold and free-spirited will say, "Damn the torpedoes! 52-speed ahead!" while the conservative and wary will say "Better safe than sorry." Neither position is definitively correct or incorrect.

cfitz

[Inertia]

the speed difference between a 48x drive and a 52x drive is 8.3% not that big a deal

If I have successfully resurrected my high-school physics, centripetal force goes as the square of the velocity, not linearly with velocity, so an 8.3% speed increase translates to a 17% increase in the radial forces trying to tear apart the CD.

cfitz - This "not a big deal" argument comes up often, so you have raised a very important point in that the actual physical force increase is not linear.

Not so long ago, 32x was the maximum speed for a fast ATAPI device. 52x is "only" 62.5 % faster. However, compared to the force on a disc at 32x, the force acting on a disc at 52x is increased by 164% .

[alchip80]

on the topic of flying debris, here is some further reading on that subject.
I don't have time right now to add more. as I have a flight to catch. anyway check this out.

http://www.techwarelabs.com/cdexplode/
http://www.guru3d.com/tech/aopen-explode/
http://www.rm.com/safety/FAQBackground.asp

[cfitz]

Thanks for the interesting links, alchip80. I wouldn't attach a lot of importance to the first link. Despite the "scientific" appearance of the report, I think these guys were having fun destroying discs more than they were conducting a real inquiry. In any event, they were breaking discs at ~27,000 rpm, almost three times faster than discs actually spin in high-speed CD-R drives and stressing the discs with almost nine times the actual forces experienced in normal operation!

The second link is just an anecdotal account of one failure, so it isn't very informative.

The third link is the most relevant for those actually concerned about high speed drives. It represents a pretty thorough investigation by a an organization with a lot of experience supporting a lot of CD-ROM drives. Among the salient points contained within:

We have found that in very rare circumstances, some high speed CD ROM drives (48X or higher speed) can become dangerous when used with CD ROM disks with small cracks. The result is that the disk can be damaged further or shattered and, in very exceptional circumstances, fragments of the broken disk can be expelled through the front cover of the drive at high speed. This could cause serious physical injury. We have confirmed that the problem can only occur when a damaged CD ROM disk is used in the CD ROM drive.

(emphasis is mine)

This is a very rare event. On one hand, the rate of items being ejected from drives that have not been flashed or shielded is only once every 13,000 years of computer operation.

("flashed or shielded" refers to RM's safety-oriented remediation of flashing firmware to limit drive speed to 32x and adding physical shielding material to the drive door to catch any fragments if a disc does break apart. In other words, based on RM's experience, a single, unmodified 48x-52x drive will break a disc and expel fragments at a rate of once every 13,000 years under normal usage patterns.)

At a speed of 10500 rpm (corresponding to a 52X drive) stresses are well below the yield stress of CD material, so that failure of an uncracked disk by yield is unlikely.

we can obtain an estimate of critical crack length ...to be... 12.5 mm. This compares with RM experience which suggests that cracks of approximately 6mm long may be critical.

("critical crack length" is the length of a crack required to be pre-existing in a CD in order for that CD to fail within a 52x drive)

Here is a picture that www.rm.com posted of a CD with a crack of critical length:



The general recommendation is to check all CD's for cracks before putting them into a drive, and not to use them if you find any cracks.

For those of you with particular concerns, RM suggests limiting top speed to 32x, although they do state:

Our research to date has shown that it is extremely unlikely that a disk will shatter in a 40X drive.

cfitz

[T-Man]

Thanks for the great info guys. Just looks like a little common sense is all that is needed here. Put simply, if the disk is in any way cracked or damaged, don't use it.

[cfitz]

Do you think there is a posibility that, constantly reading a disk at 48X speeds and over, puts such stress on the disks, that they start to become distorted or damaged in the long term?. <snip> Can they become damaged at lower speeds, but in an extended period of use?.

The independent study contained in the third link alchip80 kindly provided contains the following tidbit:

the specific rotational speed in a 52X drive (10500 rpm = 1099 rad/s) allows us to calculate the value of the maximum stress, which is 5.04 MPa. This may be compared to the quoted yield strength for the material of 60 MPa. It is clear that the material is still a long way from reaching its yield strength, so that our initial assumption that the disk remains elastic is correct.

What does this mean? The polycarbonate substrate of the CD-R remains within the elastic deformation limits when exposed to the forces of a modern, high-speed CD-R drive. In other words, even though the disc will deform a small amount when exposed to the spinning forces of the drive, it will snap back, like an elastic rubber band, to its original shape and dimensions after the spinning stops. You don't need to worry about long-term deformation.

cfitz

[cdrfreak2003]

i have a question..

how do cd-r's or cd-rw's brake in a cd burner?.. its not touching anything or getting hit by something

[jase]

It's as has been said, the centripetal forces (NOT centrifugal, such a force does not exist, at least that's what my physics teacher taught me!!) acting on the disc cause it to break (although if I remember correctly doesn't centripetal force act inward and not outward, so in effect the disc is being pushed inward from the outside?).

The disc can and does hit the top and bottom of the transport sometimes (esp warped ones, you can hear the helicopter effect). If that is added to the other forces it could cause a disc to break.

Now, what I'd like to know then is, are discs from MBI (Moser Bayer India) less likely to shatter? They use a special plastic from the German Bayer company which is far more elastic than the usual material other manufacturers use. Could this be a crucial advantage for them if we move to 56x in the future?

[cdrfreak2003]

does the amount of buffer have anything to do with how good a cd burner reads scrathed cd's?? or is it my imagination

[cfitz]

does the amount of buffer have anything to do with how good a cd burner reads scrathed cd's?? or is it my imagination

It's your imagination.

cfitz

[cdrfreak2003]

o.
< feelin stupid