A record press is a machine for manufacturing vinyl records. It is essentially a

hydraulic press A hydraulic press is a machine press using a hydraulic cylinder to generate a compressive force. It uses the hydraulic equivalent of a mechanical lever, and was also known as a Bramah press after the inventor, Joseph Bramah, of England. He inve ...

fitted with thin

nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...

stampers which are negative impressions of a master disc. Labels and a pre-heated vinyl patty (or "biscuit") are placed in a heated mold cavity. Two stampers are used, one for each of side of the disc. The record press closes under a pressure of about 150 tons. The process of

compression molding Compression molding is a method of molding in which the molding material, generally preheated, is first placed in an open, heated mold cavity. The mold is closed with a top force or plug member, pressure is applied to force the material int ...

forces the hot vinyl to fill the grooves in the stampers, and take the form of the finished record.

Vacuum molding

In the mid-1960s, Emory Cook developed a system of record forming wherein the mold pressure was replaced by a

vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often dis ...

. In this technique, the mold cavity was evacuated and vinyl was introduced in micro-particle form. The particles were then flash-fused instantaneously at a high temperature forming a coherent solid. Cook called this disc manufacturing technology ''microfusion''. A small pressing plant in Hollywood also employed a similar system which they maintained fused the particles more evenly throughout the disc thickness calling their product ''polymax''. Both claimed the resultant disc grooves exhibited less

surface noise In sound and music production, sonic artifact, or simply artifact, refers to sonic material that is accidental or unwanted, resulting from the editing or manipulation of a sound. Types Because there are always technical restrictions in the way a ...

and greater resistance to deformation from stylus tip inertia than convention pressure molded vinyl discs.

References

Audio storage Machines Plastics industry

External links

{{Commons category, Record press
List of vinyl press manufacturers