GB814565A - Improvements in or relating to the production of matched embossing rolls - Google Patents

Abstract

814,565. Making embossing rolls. MODERN ENGRAVING & MACHINE CO. Dec. 11, 1957 [June 27,1957], No. 38559/57. Class 83 (2). A method of producing hardened metallic matched embossing rolls comprises hardening a pair of steel rolls 6 and 8 and applying an acidresistant coating thereto, rolling a co-extensive master pattern roller 18 on a first one of the rolls to remove the coating from predetermined areas thereof, etching the said first roll to remove metal from said areas, removing the remainder of the coating, rolling the now embossed roll on the second roll to remove its coating from complementary predetermined areas and then etching the second roll. The master roller 18 is made by a series of steps. The pattern of a die roll 10 is first rolled into a comparatively soft roll 14 which is then hardened and used to engrave the pattern on the roller 18, the roll 14 being fed axially across the roller 18 for this purpose. The rolls 6 and 8 are etched by dipping in a suitable etching fluid, such as nitric acid and the remaining coating and the acid are removed by a rinsing operation. The coating and etching steps may be repeated as often as necessary to produce the required depth of pattern. When the rolls 6 and 8 are to be used to emboss heavy gauge material, a clearance between the pattern projections of the rolls may be desirable and may be accomplished by making the first roll of slightly larger diameter and etching it to a greater depth after it has transferred the pattern to the second roll.