CD Replication – A Service User’s Point Of View

A Sudden Requirement for a Large Run of CDs – This Calls For CD Replication

Tim Burgess works at a recording studio where he manages bands and organises gigs and promotion. One of the activities he provides for the bands he manages, is the ordering of CDs for selling at gigs and for sending on to various radio stations and record companies to try and get some air time. Most of the jobs are short runs of up to 1000 CDs and so he has always used a trusted supplier who provides a CD duplication service. Tim’s team produce their own artwork in house using CD and packaging templates supplied by the manufacturer who then print, duplicate and package the CDs. However, they recently started working with a band who came to them to record their debut album and they had an absolutely huge following because they were working so hard with their live performances and with social media. Tim knew that a short run of CDs just wouldn’t be enough to satisfy the expected demand for their CD at gigs and for sale online. He estimated that they would need at least 12,500 discs which was a much larger quantity than they were used to working with.

He calls their usual supplier of CD duplication services to ask for their advice and speaks to the project manager who they normally deal with, a gentleman called Dean. He suggested that they go for CD replication as a manufacturing method rather than CD duplication.

CD Replication and CD Duplication – What’s the Difference?

Tim had previously heard the term “CD replication” before but just assumed that it was the same as duplication, just as the term “CD pressing” is used to generally describe the manufacturing of CDs. He didn’t realise that the two terms are actually completely different processes. CD duplication is the act of burning information with an optical drive onto pre-manufactured, “write once” discs. CD replication is the act of physically moulding an exact replica of the master disc. Dean quickly filled Tim in on the basics of CD replication and then informed him that he was due to visit a supplier at the end of the week who specialised in this manufacturing process. He asked Tim if he would like to observe the manufacturing process and he agrees

A Trip to See the CD Replication Process

Dean picked Tim up the next morning and they travelled together to the factory. Tim’s first impression of the plant was that it was much more of a mass production environment. An engineer joined them for the tour to explain each stage of the process and to allow them to see CDs being made.

Stage 1 – Glass Mastering

The first stage of the replication process is to produce a glass master of the CD which will be used as the template for all CDs in the manufacturing run. To observe this process the engineer took Tim and Dean into a clean room environment where they had to put on protective clothing, hats and gloves to prevent any dust particles or hairs falling from them and interfering with the complex and intricate manufacturing process. Glass is used as the substrate to make a disc which is about twice the diameter and thickness of a CD, one side of this glass disc is then highly polished. Even tiny scratches that cannot be seen with the naked eye can seriously affect the final product quality of the final CDs, hence the need for the clean environment. The glass master is then coated with a photoresist or dye-polymer and baked in an oven to dry the coating and prepare the glass disc for mastering. A laser is used to burn “pits” into the dried coating and these pits are the physical interpretation of the audio or software data from the master recording which is to be reproduced.

Stage 2 – Manufacture of the Nickel Stamper using the Glass Master

The next stage of the process involves baking the coating on the glass master until it’s hard and then metalising the glass master using nickel vapour. The nickel coated master is then closely inspected for any defects or uneven areas in the coating. As the nickel coated master surface can be very easily damaged, several processes then take place using this original glass master to produce “Father”, “Mother” and “Son” stampers which are very much more robust. The “Son” stamper is the one usually used in the injection moulding process of the end products.

Stage 3 – Injection Moulding of the CDs from Polycarbonate

The injection moulding machines used to produce the finished product are high temperature polycarbonate injection moulders capable of producing nearly 1000 discs per hour. For very large runs of discs, several moulds are produced and the machines run simultaneously. Polycarbonate pellets are fed into the machine via a hopper and these are heated and the polycarbonate liquid is injected into the mould under pressure to form the disc. The clear discs are then removed by a high speed automated system. All the required information is contained on the clear disc but they cannot be read with an optical drive as there is no reflective layer as yet. Adding the reflective layer is the next step in the process.

Stage 4 – Metallizing and Lacquering of the Manufactured CDs.

The CDs pass into a metalising chamber where a very thin layer of aluminium alloy is applied. This metallic layer is then protected with a very thin layer of lacquer to prevent corrosion from contact with moisture in the air or other potential contaminants such as grease from skin contact. The completed discs are then stored on spindles and are made ready for the CD printing process.

Printing and Packaging the CDs

Tim is familiar with this side of the manufacturing process as it is the same as that used for CD duplication. The CDs can be screen printed or lithographically printed:

  • Screen Printing – If the artwork is made up of solid, block colours or text then this printing method is ideal for producing stunning printed CDs. It’s also a good printing method to go for if the budget is tight as you can still end up with a fantastic looking end product if you only use 1 or 2 different colours in the design and let the silver surface show through in some areas such as allowing text to show as silver. This way you only pay for a film and screen for each colour of ink. Saving money like this is only really useful though for short runs of discs.
  • Lithographic Printing - When the artwork is a photographic image or is made up of complex colour gradients, then this is the printing process to use. Extremely high resolution images can be printed using this method. It is not, however, a good idea to mix solid block colours and photographic images because lithographic printing is not a reliable method of printing consistent solid colours. It is also important not to use dark photographic images as they are notoriously difficult to print.

Printing and packaging assembly are carried out in the same plant and we use a variety of packaging types from card wallets and standard jewel cases to jakeboxes and metal tins for special edition release CDs.

The Manufacturing Time Disadvantage of CD Replication

The CD Replication process has the advantage of a cheaper unit cost when printing a large run of CDs and especially when there is a requirement for repeated larger runs as, once the glass mastering process is completed and the moulds are made, they have a long life and are capable of producing millions of copies of the CD before they might need replacing. The disadvantage of CD replication is that the initial glass mastering process is complex and time consuming and the initial order may take 10 to 14 working days to complete. This is fine as long as you plan for the longer manufacturing process and don’t leave it until the last minute to place your order or you don’t have a requirement that needs instant supply of CDs.


Tim found the CD replication plant visit of great benefit in understanding a bit more about the different CD manufacturing processes and as a result he can now offer a further service to clients that he manages and perhaps start managing some more bands with larger followings. Hopefully this information might be of use to others looking to expand their service capabilities within the music industry. Tim’s client has been really pleased that they could confidently keep all their management activities under one roof and he now has another 2 bands potentially coming to them through word of mouth.

Post time: 03-04-2017