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Improvement of extrusion tools for ceramic tiles and bricks by the application of physical vapour deposition coatings

Development of new types of coatings to be applied to extrusion tools for bricks and tiles. This will increase the life of tools, improve the efficiency of the extrusion process and thus reduce the associated costs.

The loss in potential production volume due to the need to stop the operation of extrusion presses for three to four hours every few days, in order to replace the worn extrusion tools, represents a significant cost component for every brickyard. The recent development of PVD (Physical Vapour Deposition) coatings with excellent wear resistance, moderate friction and high mechanical strength offers a possibility to increase the life of these tools considerably, as well as to improve the overall efficiency of the extrusion process, and thus reduce the associated costs. The proposed project aims at developing new types of coatings, as defined by coating material, thickness and application process, especially suitable for application on extrusion tools for bricks and tiles. The extrusion tools will also be redesigned to allow for easy and practical application of the coatings and to ensure maximum strength. At the beginning of the project, the extrusion processes applied to the production of both bricks and tiles will be analysed, in order to identify the most important factors affecting tool life and process efficiency. The composition of clay material, the relation between extrusion speed and power, the flow pattern through the tools, the nature and frequency of tool damage, the progress of wear with time and its distribution over the tool surface will be studied and evaluated. Based on this analysis a FEM (Finite Element Method) simulation model for the stress-strain distribution in the coating material and the substrate will be developed. The study of the influence and relative importance of the coating parameters as well as of the geometric characteristics of the tools through this simulation model and through tests conducted in the laboratory of the participating university institution will lead to basic guidelines for an improved design of the extrusion tools and to the choice of the appropriate coating parameters. According to these guidelines three basic tool designs -one for tiles, whose size does not vary significantly, and one for each of two typical sizes of bricks, which are produced by the main participant in very different sizes- will be developed and a number of different coating materials and thicknesses (and other coating parameters, if necessary) will be specified for each of the three tools. For each such combination of tool design and coating parameters, the respective tool will be built and then coated by the coatings producer who participates in the project. These tools will then be tested in the extrusion presses of the main participant's production lines. Progress of wear with time, tool life and power consumption for the new tools will be measured and compared with those for the old tools. Higher extrusion speeds will also be tested, and their effect on product quality will be assessed with the help of a hydraulic compression tester. According to the tests findings the design and coating parameters of the tools will be modified and a new series of tools will be built and tested in the extrusion presses. The conclusions of the project will be summarised in a final report containing the detailed drawings and coating specifications for the developed tools. Keywords: coatings, extrusion tools, bricks and tiles.
Acronym: 
CERTO
Project ID: 
2 875
Start date: 
01-07-2002
Project Duration: 
45months
Project costs: 
290 000.00€
Technological Area: 
Coatings
Market Area: 

Raising the productivity and competitiveness of European businesses through technology. Boosting national economies on the international market, and strengthening the basis for sustainable prosperity and employment.