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Encyclopedia > CD manufacturing

CD manufacturing is the process by which commercial discs are mechanically duplicated in mass quantities using a master created from a digital source. This method is used in the mastering of CDs, and does not include blank CD-Rs or DVDs, although these are made using similar methods. January 2006 : January - February - March - April - May - June - July - August - September - October - November - December- → 31 January 2006 (Tuesday) U.S. President George W. Bush delivers the State of the Union Address to a joint session of the U.S. Congress (the House of Representatives and the Senate). ... Commercial may mean: as a noun: a form of advertising, as in a television commercial as an adjective: referring to commerce or for-profit activities or trade (compare with non-profit organization) a breed of cattle, Commercial This is a disambiguation page — a navigational aid which lists other pages that... A digital system is one that uses numbers, especially binary numbers, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (an analog system) or non-numeric symbols such as letters or icons. ... A master recording is an original recording, from which copies may be made. ... The Compact Disc logo was inspired by that of the previous Compact Cassette. ... A CD-R (Compact Disc-Recordable) is a variation of the Compact Disc digital audio disc invented by Philips and Sony. ... DVD-R writing/reading side DVD (also known as Digital Versatile Disc or Digital Video Disc) is an optical disc storage media format that can be used for data storage, including movies with high video and sound quality. ...


A compact disc (CD) can be used to store audio, video, and data in various formats which are defined in the Rainbow Books. A CD is usually manufactured in a class 100 or better clean room, kept clean of manufacturing. A CD can usually be manufactured within strict manufacturing tolerances for US$2 or less. Audio can mean: Sound that can be heard. ... Look up Video in Wiktionary, the free dictionary Video is the technology of capturing, recording, processing, transmitting, and reconstructing moving pictures, typically using celluloid film, electronic signals, or digital media. ... The Rainbow Books are a collection of standards defining the allowed formats of compact discs. ... In manufacturing, a clean room is an enclosed area protected against dust that might interfere with the manufacturing process. ...


CD mastering differs from burning in that the pits and lands of a mastered CD are etched into the CD, rather than being simulated by a CD burner. A CD burner, CD recorder or CD writer is an internal or external writable Compact Disc drive that can be attached to a computer. ... A CD burner, CD recorder or CD writer is an internal or external writable Compact Disc drive that can be attached to a computer. ...

Contents


Premastering

All CDs are pressed from a digital source, the most common CD sources are low error-rate CD-Rs or files from an attached computer hard drive containing the finished product. Some CD pressing systems can use digital master tapes, either Digital Audio Tapes, Exabytes or Umatics, however such sources can only be used for production of audio CDs. If the source is not a CD, the table of contents for the CD to be pressed must also be prepared and stored on the tape or hard drive. A digital system is one that uses numbers, especially binary numbers, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (an analog system) or non-numeric symbols such as letters or icons. ... An illustration of a modern personal computer. ... Typical hard drives of the mid-1990s. ... A digital system is one that uses numbers, especially binary numbers, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (an analog system) or non-numeric symbols such as letters or icons. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... CD re-directs here; see Cd for other meanings of CD. Image of a compact disc (pencil included for scale) A compact disc (or CD) is an optical disc used to store digital data, originally developed for storing digital audio. ... A table of contents is an organized list of titles for quick information on the summary of a book or document and quickly directing the reader to any topic. ...


Mastering

Glass mastering

Glass mastering is performed in a Class 100 clean room. Dust, pollen, hair and smoke particles can all affect the quality of a CD glass master whilst it is being prepared. Once completed, a CD will resist effects caused by any of these contaminants however during critical stages of CD manufacturing these pollutants can render a CD glass master unusable. This article refers to the material. ... After just three years of use dust has blocked this laptop heat sink, making the computer unusable Dust is a general name for minute solid particles with diameter less than 500 micrometers (otherwise see sand or granulates) and, more generally, for finely divided matter. ... SEM image of pollen grains from a variety of common plants: sunflower (Helianthus annuus), morning glory (Ipomea purpurea), hollyhock (Sildalcea malviflora), lily (Lilium auratum), primrose (Oenothera fruticosa), and castor bean (Ricinus communis). ... Young Girl Fixing her Hair, by Sophie Gengembre Anderson Hair is a filamentous outgrowth skin found only in mammals. ... Smoke from a wildfire Smoke is a suspension in air (aerosol) of small particles resulting from incomplete combustion of a fuel. ...


Glass mastering is so-called because glass is used as a substrate to hold the CD master while it is created and processed. Glass substrates are a round plate of glass typically 240mm in diameter and 6mm thick. They can also have a small, steel hub on one side to facilitate handling. The substrates are created especially for CD mastering and one side is polished until it is ultra smooth. Even minor scratches in the glass will affect the CD quality. Glass substrates are noticeably larger than a CD. The extra area on the substrate allows for easier handling of the glass master. Glass substrates can be reused hundreds of times if maintained however before reuse they must be cleaned of contaminants from the previous cycle. The word substrate can mean the following: In biochemistry, a substrate is a molecule which is acted upon by an enzyme. ... The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ... Look up scratch in Wiktionary, the free dictionary. ...


Once the glass substrate is cleaned using scratch-less materials, detergents and ultrasonic baths the glass is placed in a spin-coater. The spin coater spins the glass and rinses it first with a solvent and then applies the resist (photo or non-photo). The rotation of the glass forces spreads the resist out across the face of the glass in an even coating. The substrate is removed and baked to dry the resist and the glass substrate is ready for mastering. A detergent is a compound, or a mixture of compounds, intended to assist cleaning. ... An ultrasonic bath is a method used for mixing liquid chemicals. ... A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... Wikibooks Cookbook has more about this subject: Baking Baking is the technique of cooking food in an oven by dry heat applied evenly throughout the oven. ...


Mastering is performed by a Laser Beam Recorder (LBR) machine. These are manufactured by a small number of companies and use one of two recording methodologies for CD mastering, photo resist and non-photoresist mastering. Photoresist also comes in two variations positive photoresist and negative photoresist. Lasers range in size from microscopic diode lasers (top) with numerous applications, to football field sized neodymium glass lasers (bottom) used for inertial confinement fusion, nuclear weapons research and other physics experiments. ...


Photoresist mastering

Photoresist mastering uses a light-sensitive material (photoresist) to create the pits and lands in the CD master. Photoresist is a light sensitive material used in several industrial processes, such as photolithography and photoengraving to form a patterned coating on a surface. ...


A laser beam recorder (LBR) uses a deep blue or ultraviolet laser to write the master. When illuminated by the laser light, the photoresist undergoes a chemical reaction which hardens it. The exposed area is then soaked in a developer solution which removes the exposed positive photoresist or the unexposed negative photoresist. Blue lasers have applications in many areas, from opto-electronic data storage at high-density, to medical applications. ... Ultraviolet (UV) radiation is electromagnetic radiation of a wavelength shorter than that of the visible region, but longer than that of soft X-rays. ... Lasers range in size from microscopic diode lasers (top) with numerous applications, to football field sized neodymium glass lasers (bottom) used for inertial confinement fusion, nuclear weapons research and other physics experiments. ...


Once the mastering is complete, the glass master is removed from the LBR and it is etched with chemicals to dissolve the photoresist that has been exposed to the laser light. Because the intensity of the laser spot used to write the master is not "ideal" etching can be an art. Care must be taken not to "over etch" the pits or they will become oversized and deformed or "underetched" causing the pits to be too shallow. Diffraction is used to determine the ideal pit depth while the etching is underway. To meet Wikipedias quality standards, this article or section may require cleanup. ...


Once etching is complete the glass master must be metalized to provide a surface for the moulding parts to be formed on and more importantly so that the quality of the master can be ascertained via playback testing. This is a drawback of the photoresist method, since many steps must be taken before the master can be tested. Metallizing is the general name for the technique of coating metal on the surface of non-metallic objects. ... Moldy cream cheese Molds (British English: moulds) are various fungi that cover surfaces as fluffy mycelium and usually produce masses of asexual, sometimes sexual spores. ...


Non-photoresist or NPR mastering

Once the glass is ready for mastering, it is placed in a Laser Beam Recorder. LBRs are capable of mastering at greater than x1 speed but due to the weight of the glass substrate and the requirements of a CD master they are typically mastered at no greater than x6 playback speed. The LBR uses a deep blue or ultraviolet laser to write the information. When the blue laser is fired at the non-photoresist the pink colour of the NPR absorbs a large quantity of the energy of the laser causing the NPR to vapourise and forming a pit in the surface of the NPR. This pit can be scanned by a red laser, several revolutions later and the quality of the recording can be directly and immediatetly assessed, the audio can also be played straight from the glass master as it is being recorded. The pit geometry and quality of the playback can all be adjusted as the CD is being mastered as the blue writing laser and the red read laser are connected and a feedback system is used to optimise the recording. Ultraviolet (UV) radiation is electromagnetic radiation of a wavelength shorter than that of the visible region, but longer than that of soft X-rays. ...


This type of mastering is called Direct Read After Write or DRAW and is the main advantage of the non-photoresist recording system. Any problems with the quality of the glass substrate, scratches or an uneven coating of the NPR are immediately detected and if required the mastering can be abandoned at very little cost in time or materials.


Post-mastering

After mastering, the glass master is baked to harden the non-photoresist and it is ready for metalisation. Metalisation is a critical step prior to the electrogalvanic manufacture (electroplating) of the masters used in the injection moulding process of the CD manufacture. Electroplating is the coating of an electrically conductive item with a layer of metal using electrical current. ...


The mastered discs are placed in a vapour deposition metaliser which uses a combination of mechanical, turbo and cryo pumps to lower the pressure inside a chamber to extremely high vacuum. A piece of nickel wire is then heated in a tungsten boat to white hot temperature and the nickel vapour is deposited onto the rotating glass masters. The glass masters are coated with the nickel vapour up to a typical thickness of around 400nm (the wavelength of blue light) before they are removed. General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic Atomic mass 58. ...


The glass masters are removed and inspected for stains, pinholes or incomplete coverage of the nickel coating.


Electroforming

Electroforming occurs in Matrix, the adopted name for the electroforming process area and is still a class 100 cleanroom. The information contained on the metalised glass master is extremely fragile and it must be transferred to a more resilient form for use in the injection moulding equipment. Electroforming is a highly specialized process of metal part fabrication using electrodeposition in a plating bath over a base form or mandrel which is subsequently removed. ...


The metalised master is clamped in a conductive plating frame with the information side facing outwards and lowered into a plating tank. The tank contains a nickel salt solution (Nickel Sulfamate) at a specific concentration. The solution is carefully buffered to maintain the pH and detergents are added to maintain a specific surface tension. If the surface tension is too high, the solution cannot flow around the features on the surface sufficiently to deposit nickel evenly. The bath is heated to approximately 40degC. Electrical conductivity is a measure of how well a material accommodates the transport of electric charge. ... The correct title of this article is pH. The initial letter is capitalized due to technical restrictions. ... In physics, surface tension is an effect within the surface layer of a liquid that causes the layer to behave as an elastic sheet. ...


The glass master is rotated in the plating tank while a pump circulates the nickel solution over the surface of the master. As the electroforming progresses, nickel is drawn out of the solution and must be replenished. This is done using "bright", pure nickel pellets suspended in the solution in a non-conductive polypropylene bags called and anode bags. The plating solution flows through the bag and over the glass master. The anode bags stop sediment formed during the nickel decomposition from been plated on to the part. The nickel is packed firmly into the bag and forms part of the electric circuit. General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic Atomic mass 58. ... Polypropylene lid of a Tic Tacs box, with a living hinge and the resin identification code under its flap Polypropylene or polypropene (PP) is a thermoplastic polymer, used in a wide variety of applications, including food packaging, textiles, laboratory equipment, automotive components, and polymer banknotes. ... Diagram of a zinc anode in a Daniells cell. ...


A DC current is applied to the glass master travelling through the nickel contained in the anode bags, through the solution and into the nickel surface of the glass master. The electrons flow in the opposite direction to the current, from the cathode to the anode via the solution. The electrons are stripped from the nickel in the anode bag, travelling through the external circuit before combining with the Nickel ions in the solution at the cathode end and forming metallic nickel on the surface of the glass master. Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ... Properties The electron is a lightweight fundamental subatomic particle that carries a negative electric charge. ... Diagram of a copper cathode in a Daniells cell. ... // An ion is an atom, group of atoms, or subatomic particle with a net electric charge. ...


The to facilitate the electroplating the current must start off quite low and be increased slowly and evenly to prevent the metalised surface from overheating and burning like an electrical fuse. As the thickness of the nickel on the glass master increases the voltage can be increased. After approximately 1 hour the electroplating is complete. Typical metal parts are 0.25 - 0.5mm thick. The part is are removed from the tank and the metal part peeled off the glass substrate. The metal part now called a Father as the information side are a series of bumps not pits, is washed with deionised water and acetone to remove any trace of resist. The glass is sent for reclaiming and will be cleaned and checked before it is used again. Glass substrates, if handled carefully can be used for hundreds of glass masters. The word burn has many meanings: Look up burn in Wiktionary, the free dictionary. ... Look up Fuse on Wiktionary, the free dictionary The word fuse has several meanings: To fuse is to combine in a process of fusion. ...


Once cleaned of any loose nickel and resist, the father is electrolysed, washed and clamped back into a frame and returned to the plating tank. This time the metal part that is grown is the mirror image of the father and is called a Mother. From the mother all the stampers used to manufacture the CDs are made. Mothers can be regrown form Fathers if they become damaged however if handled correctly, 10 - 20 stampers can be grown from a Mother before the quality of the stamper is called into question. Mothers are regrown from the Father if it still exists otherwise a new glass master is made.


If the recording is going to be part of a long production run, the father may be archived however it is generally cut down and used as a stamper for moulding runs. Stampers and Fathers are the same "polarity", the information surface is made up of a series of bumps. Mothers are the reverse and are made up of pits. For other uses of the word Archive, see Archive (disambiguation) Archives refers to a collection of records, and also refers to the location in which these records are kept. ...


A Father, Mother and a collection of stampers (sometimes called "sons) are known collectively as a "family". Fathers and Mothers are the same size as a glass substrate, typically 300mm in diameter and are not cut down. Stampers do not require the extra space around the outside of the play area and they are punched to remove the excess nickel from the outside and inside the information area.


Replication

CD moulding machines are specifically designed, high temperature, polycarbonate injection moulders. They have a typical throughput of 500-700 discs per hour, per moulding line. A typical arrangement has two moulding systems sharing raw material feed, metaliser and lacquer/cure system. Clear polycarbonate pellets are fed into the one end of the moulder and are transported slowly to the injection chamber via a heated auger. The auger melts the polycarbonate slowly until it reaches the chamber. When the mould is closed the auger forces the molten plastic into the injection chamber. When the mould is full, cool water running around the outside of the mould cools the plastic so it solidifies. The entire process from the mould closing, injection and opening again takes approximately 3 seconds. Polycarbonates are a particular group of thermoplastics. ... An auger is a device for moving material or liquid by means of a rotating helical flighting. ... In jewelry, a solid gold piece is the alternative to gold-filled or gold-plated jewelry. ...


The moulded "disc" is removed from the mould via vacuum pickup "hands" and moved onto storage spindles to cool before they are metalised. As this point the discs are clear and contains all the digital information however it cannot be played. The discs then pass, one at a time into the metaliser, a small chamber capable of being evacuated. The metaliser contains a metal "target" made of an alloy of aluminium and silver. When the disc is in position underneath the target, the chamber is evacuated and an electrical current is sent through the metaliser target causing the outer layer over the disc to be boiled off coating the disc in a very thin layer of metal. The metal coats the information side of the disc and covers the pits. This metal layer is the reflective surface you see when you turn over a CD. This thin layer of metal is unstable and will corrode if it is not protected. Look up Vacuum in Wiktionary, the free dictionary For other uses, see vacuum (disambiguation) A vacuum is a volume of space that is empty of matter, including air, so that gaseous pressure is much less than standard atmospheric pressure. ... The term reflection (also spelt reflexion) can refer to several different concepts: In mathematics, reflection is the transformation of a space. ...


After metalisation the discs pass onto a spin-coater. UV lacquer is dispensed on to the metal layer and spun so the lacquer coats the entire disc without running over the edges. The lacquer layer is very thin but must cover the metal layer completly. After the lacquer is applied it passes under a high intensity UV lamp which sets lacquer. The lacquer also provides a surface for the screen printing ink to adhere to. Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... Screen-printing, also known as silkscreening or serigraphy, is a printmaking technique that traditionally creates a sharp-edged single-color image using a stencil and a porous fabric. ...


Testing

If the recording has not been manufactured before, both the stamper and the moulded discs are tested before a run of discs are made otherwise samples of the disc are taken during long production runs. The pressed discs and the stamper are tested on a machine such as the CD-CATS equipment manufactured by AudioDev. The metal stamper can be played on this machine however a small quartz window must be installed in the optical path of the playback system in order to correct the optics of the device. The machine will "play" the disc and stamper in real (x1) time and will measure various parameters, such as BLock Error Rate (BLER) - the "healthiness" of the disc surface, Jitter - ensuring that changes in the digital signal occur "on time" and decoder errors (E11, E22 and E32) - correctable and uncorrectable errors in the bit stream. Errors can be introduced by the moulding process however by testing both the CD and the stamper the source of the errors can be located. Any uncorrectable errors, regardless of their source will be cause to reject the pressing.


If no defects are found the CD continues into printing to have a label screen printed on the back of the disc and then onward to be packaged, shrink-wrapped and distributed. A label is any kind of tag attached with adhesive to something so as to identify the object or its contents. ...


References


 
 

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