Process and means for making metal inking rolls
OwnerRenato Della Torreinventor
Life of this patent
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Abstract
A process for making metal inking rolls, particularly for flexographic printing, having: A roll structure composed of an ammonia hardenable steel, in particular stainless steel, the selection of a roll wherein the minimum thickness of the wall, if tubular, is a direct function of the diameter and an inverse function of the length of the roll, so that, when the roll is supported at its ends and stressed in the middle, on a surface relatively distributed, it may be permanently distorted in the axial direction but without distorting its cross-section; a post-engraving ionic nitriding treatment to increase the surface hardness of the screen to at least 60 HRC and a final straightening step, to reduce the screen eccentricity at least 0.02 mm.
Claims14
A process of making a metal inking roll for flexographic printing wherein said roll is made from a nitridable steel containing chromium and is not metal plated, comprising the steps of:
- selecting a structure made of nitridable hardenable steel containing chromium wherein said structure is not metal plated;
- turning said structure to form a cylindrical roll of predetermined diameter;
- said turning step further comprising a rough-turning step which occurs prior to achieving said predetermined diameter;
- mechanically engraving said cylindrical roll with a die to produce a screen on a surface of said cylindrical roll;
- ionic nitriding the surface of said cylindrical roll after engraving to attain a surface hardness of at least 60 HRC;
- and
- straightening said cylindrical roll to correct an eccentricity of said roll to less than 0.02 mm.
Dependencies are inferred from the claim text.