Shrink ring for extrusion die, and extrusion die comprising same

An extrusion die comprising:

• a cylindrical mandrel, the mandrel having a circumferential groove formed therein, the circumferential groove being formed in a cylindrical surface of the mandrel at a rear face of the mandrel;
• a cylindrical die plate, the mandrel and the die plate being coupled together;
• and
• a shrink ring separate from the cylindrical die plate and disposed in the circumferential groove of the mandrel, the shrink ring having a radially innermost surface abutting the circumferential groove,
• wherein the shrink ring has an additional circumferential groove formed therein,
• wherein the die plate has a circumferential tab formed therein, the circumferential tab engaging the additional circumferential groove of the shrink ring.

An extrusion die comprising:

• a cylindrical mandrel having a unitary, single-piece construction, the mandrel having a circumferential groove formed therein;
• a cylindrical die plate, the mandrel and the die plate being coupled together;
• and
• a shrink ring disposed in the circumferential groove of the mandrel,
• wherein the shrink ring is separate from the cylindrical die plate and is coupled to the mandrel by interference fit,
• wherein the shrink ring has a radially innermost surface abutting the circumferential groove,
• wherein the circumferential groove is formed in a cylindrical surface of the mandrel at a rear face of the mandrel,
• wherein the shrink ring has a rear surface that is coplanar with the rear face of the mandrel, and
• wherein the shrink ring abuts the die plate.