High wear durabilitly aluminum gravure cylinder with environmentally safe, thermally sprayed pre-coat layer

Abstract

The present invention describes a method for manufacturing rotogravure cylinders with a cylinder base made of a light weight material like aluminum. The method involves the surface treatment of the cylinder with mechanical means, the copper plating in an appropriate solution, the engraving of the cylinder, and the hardening of the cylinder by chromium plating. The advantage of this method is that the chemical treatment for the preparation of the cylinder surface which generates hazardous waste is replaced by a mechanical process. In addition, the reduction of the cylinder weight considerably (e.g. for aluminum base cylinder the weight reduction is two thirds of the weight of a steel base cylinder) reduces significantly the transportation costs. Moreover, the adhesion of the copper layer to be engraved is improved and the cost and time of manufacturing reduced.

1 . A gravure cylinder characterized by high wear durability prepared by a process comprising the steps of:
 roughening the surface of a base cylinder made of aluminum or aluminum alloy; and   using a thermal spraying process to create a pre-coat layer of copper or copper-based alloy of approximately 10 to 50 μm thickness over the roughened surface, the thermal spraying process having been performed in an environmentally safe manner and configured to achieve the adhesion thereto of an electroplated copper or copper-based alloy layer.   
     
     
         2 . The gravure cylinder prepared by the process of  claim 1 , further comprising forming the electroplated copper or copper-based alloy layer to a thickness of 100-300 μm. 
     
     
         3 . The gravure cylinder prepared by the process of  claim 2 , further comprising electroplating a further copper or copper-alloy layer over the electroplated copper or copper-based alloy layer. 
     
     
         4 . The gravure cylinder prepared by the process of  claim 2 , wherein the electroplated copper or copper-based alloy layer formed over the pre-coat layer does not include a hardener. 
     
     
         5 . The gravure cylinder prepared by the process of  claim 4 , further comprising electroplating a copper or copper-alloy layer which includes a catalyst for hardness over the electroplated copper or copper-based alloy layer. 
     
     
         6 . The gravure cylinder prepared by the process of  claim 5 , wherein the electroplated copper or copper-based alloy layer with catalyst for hardness is formed to a thickness of at least 200 μm. 
     
     
         7 . The gravure cylinder prepared by the process prepared by the process of  claim 6 , wherein the electroplated copper or copper-based alloy layer formed over the pre-coat layer is formed to a thickness of 100-300 μm. 
     
     
         8 . The gravure cylinder prepared by the process of  claim 1 , wherein the thermal spraying process is combustion wire thermal spraying. 
     
     
         9 . An engraved gravure cylinder characterized by high wear durability prepared by a process comprising the steps of:
 roughening the surface of a base cylinder made of aluminum or aluminum alloy;   using a thermal spraying process to create a pre-coat layer of copper or copper-based alloy of approximately 10 to 50 μm thickness over the roughened surface, the thermal spraying process having been performed in a environmental safe manner and configured to achieve the adhesion thereto of an electroplated copper or copper-based alloy layer;   forming the electroplated copper or copper-based alloy layer over the pre-coat layer;   electroplating an engraving layer over the electroplated copper or copper-based alloy layer; and   engraving an image on the engraving layer.   
     
     
         10 . The engraved gravure cylinder prepared by the process of  claim 9 , further comprising adding a chromium-based layer over the engraved engraving layer. 
     
     
         11 . The engraved gravure cylinder prepared by the process of  claim 9 , wherein the engraving layer is an electroplated copper or copper-based alloy layer formed to a thickness of at least 200 μm. 
     
     
         12 . The engraved gravure cylinder prepared by the process of  claim 11 , wherein the pre-coat layer is formed to a thickness of 100-300 μm. 
     
     
         13 . The engraved gravure cylinder prepared by the process of  claim 12 , wherein the electroplated copper or copper-based alloy layer formed over the pre-coat layer does not include a hardener. 
     
     
         14 . The engraved gravure cylinder prepared by the process of  claim 13 , wherein the thermal spraying process is combustion wire thermal spraying. 
     
     
         15 . The engraved gravure cylinder prepared by the process of  claim 11 , wherein the engraving layer includes a catalyst for hardness. 
     
     
         16 . A method of manufacturing a gravure cylinder characterized by high wear durability comprising:
 roughening the surface of a base cylinder made of aluminum or aluminum alloy; and   using a thermal spraying process to create a pre-coat layer of copper or copper-based alloy layer of approximately 10 to 50 μm thickness over the roughened surface, the thermal spraying process having been performed in a environmental safe manner and configured to achieve the adhesion thereto of an electroplated copper or copper-based alloy layer.   
     
     
         17 . The method of  claim 16 , further comprising forming the electroplated copper or copper-based alloy layer to a thickness of 100-300 μm. 
     
     
         18 . The method of  claim 17 , further comprising electroplating a further copper or copper-alloy layer over the electroplated copper or copper-based alloy layer. 
     
     
         19 . The method of  claim 18 , wherein the electroplated copper or copper-based alloy layer formed over the pre-coat layer does not include a hardener. 
     
     
         20 . The method of  claim 19 , further comprising electroplating a copper or copper-alloy layer which includes a catalyst for hardness over the electroplated copper or copper-based alloy layer. 
     
     
         21 . The method of  claim 19 , wherein the electroplated copper or copper-based alloy layer with catalyst for hardness is formed to a thickness of at least 200 μm. 
     
     
         22 . The method of  claim 21 , wherein the electroplated copper or copper-based alloy layer formed over the pre-coat layer is formed to a thickness of 100-300 μm. 
     
     
         23 . The method of  claim 19 , wherein the thermal spraying process is combustion wire thermal spraying. 
     
     
         24 . An engraved gravure cylinder characterized by high wear durability prepared by a process comprising the steps of:
 roughening the surface of a base cylinder made of aluminum or aluminum alloy;   using a thermal spraying process to create a pre-coat layer of copper or copper-based alloy layer of approximately 10 to 50 μm thickness over the roughened surface, the thermal spraying process having been performed in a environmental safe manner and configured to achieve the adhesion thereto of an electroplated copper or copper-based alloy layer;   forming the electroplated copper or copper-based alloy layer over the pre-coat layer;   electroplating an engraving layer over the electroplated copper or copper-based alloy layer; and   engraving an image on the engraving layer.   
     
     
         25 . The engraved gravure cylinder prepared by the process of  claim 24 , further comprising adding a chromium-based layer over the engraved engraving layer.