Metering Roll Thermal Spray Coating Wear
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Solution Overview
Problem
Existing metering rolls face challenges with mechanical wear and corrosion resistance, particularly when exposed to aggressive cleaning products, and require costly chrome plating for surface hardening, while maintaining ease of engraving.
Innovation Solution
A peripheral coating made of an iron base containing elements like chrome, nickel, boron, and carbides, applied through thermal spraying methods such as flame or plasma spraying, providing a thickness of 50-400 micrometers and enhanced resistance to wear and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a ceramic coating is used on the metering roll, then the hardness and mechanical wear resistance are improved, but the corrosion resistance deteriorates because the porous structure allows aggressive cleaning liquids to penetrate to the lower layers
Solution Approach 1:
The patent applies a composite coating structure consisting of a ceramic layer (for hardness and wear resistance) combined with a metallic layer containing corrosion-resistant elements (such as chrome, nickel, or their alloys) applied by thermal spraying. This composite structure allows the ceramic to provide mechanical wear resistance while the metallic layer provides corrosion resistance by forming a dense, non-porous barrier against aggressive cleaning liquids.
Solution Approach 2:
The patent addresses the porosity issue of ceramic coatings by applying a metallic layer over the ceramic surface. This metallic layer fills and seals the porous structure of the underlying ceramic coating, preventing penetration of corrosive liquids while maintaining the hardness and wear resistance properties of the ceramic base layer.
2Ease of manufacture
If a soft metal surface layer (such as copper or tin) is used, then the ease of engraving is improved, but the mechanical wear resistance and surface hardness deteriorate, requiring additional chrome plating
Solution Approach 1:
Instead of applying a soft metal layer over a hard ceramic base (the conventional approach), the patent inverts the structure by applying a hard ceramic layer first and then coating it with a metallic layer containing corrosion-resistant elements. This inverted structure maintains the engraving properties of the ceramic surface while adding wear and corrosion resistance through the metallic coating.
Solution Approach 2:
The patent creates a composite coating system where the ceramic base layer provides engraving capability and hardness, while the thermal-sprayed metallic layer (containing chrome, nickel, or their alloys) provides enhanced wear and corrosion resistance, eliminating the need for additional chrome plating of soft metal layers.
3Object-affected harmful factors
If a thick protective coating is applied to improve corrosion and wear resistance, then the protection is improved, but the complexity of the manufacturing process increases
Solution Approach 1:
The patent replaces complex multi-step manufacturing processes (such as multiple ceramic coating applications, intermediate treatments, and chrome plating) with a single thermal spraying process that deposits a metallic layer containing corrosion-resistant elements directly onto the ceramic surface in one operation, simplifying the overall manufacturing process while maintaining protective performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution offers improved mechanical wear resistance and corrosion protection at lower costs, with the coating remaining easy to engrave and maintaining high hardness, extending the life of the scraper and roll surface.
Implementation Method 1
the peripheral coating being provided by thermal spraying including at least one of the following methods: flame spraying, electrical arc spraying, plasma spraying, high velocity oxy flame spraying or cold gas spraying
Implementation Method 2
flame spraying
Implementation Method 3
electrical arc spraying
Implementation Method 4
plasma spraying
Implementation Method 5
high velocity oxy flame spraying
Data Source
AI summary
The invention concerns a process for manufacturing a metering roll especially usable in flexographic printing presses, in varnish stations for offset presses and/or in short ink train dry offset presses for example, comprising a central cylindrical core and at least one layer of a hard material peripheral coating that is engraved by use of a laser beam. The peripheral coating is made of an iron base containing at least one of the elements of the group consisting of chrome, nickel, boron, carbon, molybdenum, silicon, manganese, cobalt and/or at least one of the components of the group consisting of chrome carbide (Cr3C2); nickel chrome (NiCr); cobalt chrome (CoCr); tungsten carbide (WC).