METHOD OF MANUFACTURING A HIGH PRECISION SLUG

摘要

A method is provided for the formation of high precision metal slugs by cold forming. A metal column starting material is subjected to a preforming step in which the starting material is cold forged with a pair of upper and lower metal dies provided with concave recesses to produce a primary product having a barrel shape having a high degree of parallelism on the ends. The resultant primary product is subjected to an upsetting step in which the barrel shape is crushed while maintaining parallelism to obtain a secondary product. The resultant secondary product is then subjected to an ironing step in which the outer diameter of the secondary product is reduced to obtain a high precision slug having an outer diameter which is substantially the same as the outer diameter of the desired final product for which the slug will be utilized.