A Yankee machine is a paper machine with a single large drying cylinder which crepes the paper or produces a glazed surface on one side.
A tissue Yankee cylinder is a large diameter drum which is pressurized with steam to provide a hot cylinder surface used for soft tissue products, such as facial tissues, toilet tissues, and kitchen roll towels by a process called creping, which is achieved by using a doctor or creping blade to aid release of dried tissue from adhering to the Yankee cylinder.
A MG (stands for Machine Glaze) cylinder is also a Yankee cylinder, but used on other grades of paper. The paper sheet, in contact with the large hot highly polished dryer surface, for a long dwell time, will start to slip and plasticize the surface fibres, improving gloss & glazed properties on one side of the paper, e.g. manila envelopes.
On the Yankee dryer, the paper goes from approximately 42–45% dryness to just over 89% dryness. In industry, MG cylinders or Yankee dryers are primarily used to remove excess moisture from pulp that is about to be converted into paper. The Yankee cylinder can be equipped with a doctor blade and sprayed with adhesives to make the paper stick. Creping is done by the Yankee’s doctor blade that is scraping the dry paper off the cylinder surface thereby crêping the paper. The crinkle (crêping) is controlled by the strength of the adhesive, geometry of the doctor blade, speed difference between the yankee and final section of the paper machine and paper pulp characteristics