What is a CD made of?
What CDs Are Made Of. In fact, a CD is almost pure polycarbonate plastic. There is a spiral track molded into the top of the plastic. The surface of a CD is reflective because the disc is coated with a thin layer of aluminum or sometimes gold. The shiny metal layer reflects the laser that is used to read or write to the device.
What is the difference between a CD and a glass substrate?
Glass substrates, noticeably larger than a CD, are round plates of glass approximately 240 mm in diameter and 6 mm thick. They often also have a small, steel hub on one side to facilitate handling.
What is the process of CD creation?
The process of CD creation begins with a single master disc. This original disc is made of glass and is designed to withstand the pressures of replication. This disc is cleaned with deionized water and a fine brush, then it is left to dry before photo resistant chemicals are spread on its surface.
Why is the surface of a CD reflective?
The surface of a CD is reflective because the disc is coated with a thin layer of aluminum or sometimes gold. The shiny metal layer reflects the laser that is used to read or write to the device. A layer of lacquer is spin-coated onto the CD to protect the metal.
What are CDs made out of?
A CD is made from 1.2-millimetre (0.047 in) thick, polycarbonate plastic and weighs 14–33 grams. ... A thin layer of aluminum or, more rarely, gold is applied to the surface, making it reflective.More items...
Are CDs plastic?
Despite the fact that CDs and DVDs are made of plastic, your local curbside recycling program is unlikely to accept them. That's because most of these media discs are made of a mixture of plastic resins.
What type of plastic are CDs?
polycarbonateThese media are made of plastic, but not the same kind of plastic as bottles and food containers. In fact, they are a mixture of different plastic resins. CD cases are polystyrene (#6 plastic), while the discs themselves are polycarbonate (#7 plastic).
What are CDs and DVDs made of?
The discs are made of plastics and metals. The largest ingredient is polycarbonate plastic derived from oil. Can be processed from oil drilling or mined from oil sand or oil shale. The most important part of the disc is the thin metal layer that reflects laser beams used to read the information on the disc.
How do you destroy old CDs?
The best way to totally destroy a CD/DVD is to incinerate it. You need quite a hot fire and good ventilation if you don't want to end up with lumps of melted plastic or your lungs filled with noxious fumes. Despite these drawbacks, things don't get much more secure than burning.
Should I throw away my CDs?
You should never throw away old CDs. If they end up in the landfill, it's estimated that they could last for up to 1 million years. If they end up in an incinerator, they can release hydrochloric acid, sulfur dioxide, and dioxins into the atmosphere.
Do old CDs have any value?
Sell them to stores: Surprisingly, many record shops still buy and sell used CDs, as does Half-Price Books. The Electric Fetus' general manager, Bob Fuchs, said used sales have held strong even while new CDs have tanked, because “they're so cheap now, you can go home with four or five new albums for about $20.”
Can you melt CDs?
Take some old CD's that you don't want anymore and preheat your oven to 325*. Wad up a ball of aluminum foil, and place it on a covered cookie sheet. Place your old CD on top of the ball of aluminum foil and place it in the oven to melt down. No- it will not catch on fire!
How long does it take for a CD to decompose?
1 million yearsIt is estimated that it will take over 1 million years for a CD to completely decompose in a landfill. More than 5.5 million boxes of software go to landfills and incinerators, plus people throw away millions of music CDs each year!
Do CDs contain gold?
CD-ROM, DVD and Other Drives The value in those drives resides in the printed circuit boards that they contain, which hold small quantities of gold in the “fingers” at their edges where cables attach.
What are the 3 types of CDs?
CD-R (Compact Disc – Recordable): This type of compact disc can be written only once and can not erased. CD-ROM (Compact Disk-Read Only Memory): This disks are read once, after read it is use as a ROM, that is cannot be updated later.
Why do CDs look Colourful?
The colors that you see on the CD are created by white light reflecting from ridges in the metal. When light reflects off or passes through something with many small ridges or scratches, you often get rainbow colors and interesting patterns. These are called interference patterns.
Are CDs biodegradable?
Because CDs are not biodegradable, it is estimated that it will take over 1 million years for a CD to completely decompose in a landfill. More than 5.5 million boxes of software go to landfills and incinerators, in addition to the millions of CDs people throw away each year.
Are CDs toxic?
Over time, CDs can release Bisphenol A (BPA), which can cause health implications in humans. Burning CDs releases toxic fumes into the air we breathe, and they require a special recycling process that isn't accepted in single-stream recycling bins.
Can you melt CDs?
Take some old CD's that you don't want anymore and preheat your oven to 325*. Wad up a ball of aluminum foil, and place it on a covered cookie sheet. Place your old CD on top of the ball of aluminum foil and place it in the oven to melt down. No- it will not catch on fire!
Are CDs polycarbonate?
CD's consist of 99% clear polycarbonate plastic. The reflective layer, protective layer and screen print comprise the remaining 1% of the disc.
What is a CD?
Anne Marie Helmenstine, Ph.D. Updated July 03, 2018. A compact disc or CD is a form of digital media. It is an optical device which can be encoded with digital data. When you examine a CD you can tell it is mainly plastic. In fact, a CD is almost pure polycarbonate plastic. There is a spiral track molded into the top of the plastic.
Why is a CD reflective?
The surface of a CD is reflective because the disc is coated with a thin layer of aluminum or sometimes gold. The shiny metal layer reflects the laser that is used to read or write to the device. A layer of lacquer is spin-coated onto the CD to protect the metal.
Is a scratch on the label side of a CD better than on the other side?
Scratches Are Worse on One Side than the Other. Pits are closer to the label side of a CD, so a scratch or other damage on the label side is more likely to result in an error than one occurring on the clear side of the disc. A scratch on the clear side of the disc often can be repaired by polishing the disc or filling the scratch ...
What does a compact disc look like?
On the surface, a compact disc looks like a gleaming mirror on one side, and some ornamental painting on the other side . I was intrigued by the amount of music a small disc could hold when I received my first CD player as a Christmas gift. Since then I have always wanted to know what makes a CD sound. Searching the Internet one would not be difficult to find literatures on this area. Unfortunately most are written in the language difficult to be understood by the laymen -- the outsiders of the CD and DVD replication industry.
What is the metal mold used for glass master?
Since the glass master is too fragile to be used as an injection mold, a metal mold called a stamper is usually used.
How to polish glass substrate?
The glass substrate is first cleaned with ultrasound. For making sure there will not be dirt during the polishing process, the glass substrate needs to be electrostatics free. Once the de-statics is done, the glass substrate will undergo the polishing in a controlled environment. Using SiO 2 with Ra ≤ 0.5μm as the abrasive agent, the glass substrate will be buffed to the desire smoothness, i.e. Ra ≤ 10μm.
What is a glass master mold called?
Since the glass master is too fragile to be used as an injection mold, a metal mold called a stamper is usually used. Making a stamper from the glass master involves the metallization of the glass master and later galvanizing it with electroforming.
How to metalize glass master?
To metalize to glass master the glass substrate is loaded into a “Load Lock Chamber” and the chamber should be in class one vacuum. The Load Lock Chamber is for preparation only. The main work is done in the Process Chember where class 2 vacuum is required. The material of the coating is usually Ni-V alloy target.
Can a CD be silkscreened?
With all the steps so far a working CD has been made. The CD can then be silkscreen or offset printed with artwork. Silkscreen is normally used for vector graphics for better color matching. Offset is used for photographic artwork using CMYK as the basic color elements.
Can a father stamper be used for disc injection?
Mother stampers cannot be used for disc injection. Mother stampers are used to create the Son stampers which have the same pits and lands as the father stamper.
How are CDs printed?
After metalisation, the discs pass on to a spin-coater, where UV curable lacquer is dispensed onto the newly metallized layer. By rapid spinning, the lacquer coats the entire disc with a very thin layer (approximately 5 to 10 μm ).
What is CD manufacturing?
Compact disc manufacturing is the process by which commercial compact discs (CDs) are replicated in mass quantities using a master version created from a source recording. This may be either in audio form ( CD-Audio) or data form ( CD-ROM ). This process is used in the mastering of read-only compact discs. DVDs and Blu-rays use similar methods (see Optical Disc § Optical Disc manufacturing ).
What is CD pressing?
All CDs are pressed from a digital data source, with the most common sources being low error-rate CD-Rs or files from an attached computer hard drive containing the finished data (e. g., music or computer data). Some CD pressing systems can use digital master tapes, either in Digital Audio Tape, Exabyte, Digital Linear Tape, Digital Audio Stationary Head or Umatic formats. A PCM adaptor is used to record and retrieve digital audio data into and from an analog videocassette format such as Umatic or Betamax. However such sources are suitable only for production of audio CDs due to error detection and correction issues. If the source is not a CD, the table of contents for the CD to be pressed must also be prepared and stored on a tape or hard drive. In all cases except CD-R sources, the tape must be uploaded to a media mastering system to create the TOC (Table Of Contents) for the CD. Creative processing of the mixed audio recordings often occurs in conventional CD premastering sessions. The term often used for this is "mastering," but the official name, as explained in Bob Katz book, Mastering Audio, edition 1, page 18, is 'premastering' because there still has to be the creation of another disc carrying the premastered audio which supplies the work surface on which the metal master (stamper) will be electroformed.
Why use a spin coater on a glass master?
Once the glass substrate is cleaned using detergents and ultrasonic baths, the glass is placed in a spin coater.
What class is glass mastering?
Glass mastering is performed in a class 100 (ISO 5) or better clean room or a self-enclosed clean environment within the mastering system. Contaminants introduced during critical stages of manufacturing (e.g., dust, pollen, hair, or smoke) can cause sufficient errors to make a master unusable. Once successfully completed, a CD master will be less susceptible to the effects of these contaminants.
What is replication in CD?
Replication differs from duplication (i.e. burning used for CD-Rs and CD-RWs) as the pits and lands of a replicated CD are moulded into a CD blank, rather than being burn marks in a dye layer (in CD-Rs) or areas with changed physical characteristics (in CD-RWs). In addition, CD burners write data sequentially, while a CD pressing plant forms the entire disk in one physical stamping operation, similar to record pressing.
What is a CD used for?
A CD can be used to store audio, video, and data in various standardized formats defined in the Rainbow Books. CDs are usually manufactured in a class 100 (ISO 5) or better clean room, to avoid contamination which would result in data corruption.
