GB2212172A

GB2212172A - Wear-resistant coated article

Info

Publication number: GB2212172A
Application number: GB8726842A
Authority: GB
Inventors: John Foster
Original assignee: Baj Ltd
Current assignee: Baj Ltd
Priority date: 1987-11-17
Filing date: 1987-11-17
Publication date: 1989-07-19
Anticipated expiration: 2007-11-17
Also published as: GB2212172B; GB8726842D0

Abstract

A method of manufacturing a wear-resistant coated article, for example an intaglio printing roll, comprises providing a conductive layer on the surface of a fibre-reinforced article, electrolytically depositing a layer of metal on the conductive layer, and depositing on the metal layer by thermal spraying a layer of a refractory material. The electrolylcally deposited metal may be copper or nickel and the refractory material may be chromium oxide. An intaglio pattern may then be engraved or etched in the refractory material. The preferred printing roll is in the form of a glass fibre reinforced sleeve having a tapered bore. A printing roll is thus provided which is light-weight, readily transportable, and which can be telescoped over a fixed steel mandrel on site.

Description

Articles of Fibre-Reinforced Plastics Materials This invention relates to articles made of fibre-reinforced plastics materials and particularly, but not exclusively, to articles made of glass fibre reinforced plastics (GRP) materials. The invention has particular application to the manufacture of intaglio printing rolls and will be described primarily in relation to such rolls but has wider applications.

Intaglio printing rolls are usually made of steel with a coating of copper in which the design to be reproduced is etched, sometimes with an outer layer of chromium to reduce wear. Steel rolls are employed for their strength, rigidity and length of life. However, such rolls are very heavy so they are expensive to transport and difficult to handle.

According to the present invention, a wear-resistant coating is applied to a surface of a fibre-reinforced article, particularly a printing roll, by 1) providing a conductive layer on the surface, 2) electrolytically depositing a layer of metal on the conductive layer and 3) depositing on the metal by thermal spraying a layer of a refractory material.

Where the article is a printing roll, the intaglio pattern will be engraved or etched in the refractory material. The refractory material, which may be chromium oxide, may be applied by flame spraying or plasma spraying. Thermal spraying inevitably applies heat to the article sprayed and it is therefore considered to be unsuitable for coating plastics materials. However, it has been found that by providing an electrolytically deposited metal layer over the plastics material the heat is dispersed by the highly conductive metal and excessive local heating of the plastics material is avoided. The preferred metal is copper which can be electrolytically deposited easily and which has a high thermal conductivity but other metals may be used, one suitable alternative to copper being nickel.

By use of the invention it is possible to produce rolls used in the printing industry which are wear resistant, yet light in weight, so that they can be readily transported and, for example, exported to places where local manufacture would previously have been necessary. To provide the necessary rigidity the rolls may be in the form of sleeves, possibly with tapered bores, intended to be telescoped over steel or other rigid cores or mandrels.

In one particular example, a printing roll comprises a steel mandrel with a very gently tapered outer surface and a glass fibre reinforced sleeve having an internal taper to match the taper on the mandrel. The outer surface of the sleeve is prepared as follows. The cylindrical surface of the sleeve is prepared using the following steps and treatment mediums: soak clean, rinse, etch, rinse, neutralizer, rinse, conditioner, post conditioner, rinse, activate, rinse, post activator and rinse. The prepared surface is then given a conductive flash of copper by immersion in an electroless plating bath. The sleeve is then given an electrolytic coating of copper to a depth of between 0.01 and 0.015 inch (0.254-0.381 mm), the coating is grit blasted and then a layer of chrome oxide to a depth of 0.015 to 0.017 inch (0.381-0.432 mm) is applied by plasma spraying. The roll is then ground to provide a smooth outer surface to leave a depth of chrome oxide of approximately 0.01 inch (0.254 mm). A pattern is then engraved in the chrome oxide to a depth of approximately 0.005 inch (0.127 mm). The sleeve can then be removed from the mandrel and shipped to wherever it is required where it is placed on a similar mandrel of the printing press in which it is to be used.

Claims

Claims:

1 c A method of manufacturing a wear-resistant coated article comprising providing a conductive layer on the surface of a fibre-reinforced article, electrolytically depositing a layer of metal on the conductive layer, and depositing on the metal layer by thermal spraying a layer of a refractory material.

2. A method as claimed in claim 1 in which the electrolytically-deposited metal is copper.

3. A method as claimed in claim 1 in which the electrolytically-deposited metal is nickel.

4. A method as claimed in any one of the preceding claims in which the refractory material is chromium oxide.

5. A method as claimed in any one of claims 1 to 4 in which the metal coating is blasted to roughen it prior to thermal spraying of the refractory material.

6. A method of manufacturing a printing roll comprising manufacturing a coated article as claimed in any one of the preceding claims, and forming a printing pattern in the refractory material.

7. A method as claimed in claim 6 in which the printing pattern is an intaglio pattern engraved or etched in the refractory material.

8. A method a claimed in claim 6 or claim 7 in which the refractory material is ground smooth prior to formation of the printing pattern.

9.- A wear-resistant coated article comprising a fibre-reinforced support and, in order, a conductive layer, an electrolytically-deposited metal layer and a thermally-sprayed refractory layer.

10. An article as claimed in claim 9 in which the electrolytically-deposited metal layer is copper.

11. An article as claimed in claim 9 in which the electrolytically-deposited metal layer is nickel.

12. An article as claimed in any one of claims 9 to 11 in which the refractory material is chromium oxide.

13. An article as claimed in any one of claims 9 to 12 comprising a printing roll.

14. An article as claimed in claim 13 in which the roll is an intaglio roll.

15. An article as claimed in claim 13 or claim 14 in which the roll is in the form of a sleeve.

16. An article as claimed in claim 15 in which the sleeve has a tapered bore.

17. A method of manufacturing a wear-resistant coated article, substantially as described.

18. A wear-resistant coated article substantially as described.