Résumé des résultats (Abstract)
(Anglais)
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In the wood industry, the improvement of performances observed during the last few years is mainly due to the use of new technologically developed machines and to the automation of the process production (computer aided machining, computer aided control, etc.). Nevertheless, the cutting tools were not developed and the functioning of the machines are at present time limited by tool potential (eating speed, power consumption, delays due to tools modification, high vibrations, noise, etc.). This causes an immediate production decrease, with an increase of waste, dust and labor costs. Those problems are more significant in primary transformation of wood (sawmills, veneer manufacturers) where steel knives are used. The widespread use of steel knives is due to large dimensions of processed raw materials and the balance between their hardness and resistance to shocks. Furthermore, in the secondary wood transformation, steel knives are also used for specific operations like planning and shaping because of their low price and facility of re-sharpening.
The SMEs, working in the primary transformation of wood, cut raw materials that contain a lot of knots, dust, sand, stones etc. Therefore the SMEs use large quantities of knives so they face the problem of knives blunting ; which is mainly due to abrasion and the breaks of the knife-edge on contact with raw materials and shocks. They are seeking for solutions and are asking tool manufacturers to solve their problems.
The SMEs involved in the project work in the different activities of wood processing, so they are representative of all steel knives users: (1)- canter and chipper (primary transformation of softwood), (2)- knives for chipping of green or live wood (primary transformation of wood), (3)- knives for wood peeling (primary transformation of logs), (4)- steel knives in the secondary transformation. Thus they are interested to have improved knives. Those improved knives are also interesting for other sectors within the wood industry like: panel production (particle boards, fiber boards, Medium Density Fiberboard (MDF), …), paper production (for pulp preparation chipper), decorative veneer production (veneer slicing), furniture and packaging industry.
Similar problems have been solved in the past for metal cutting industry by the use of hard coatings deposited by Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD) methods on tools. In fact, these hard coatings are widely used in the metal cutting industry owing to their mechanical properties. So the main objective of this project is to apply these new generation of multi-functional coatings in order to protect the cutting tools used in the wood industry against deterioration. Indeed, tools modified with hard coatings are more resistant to blunting and provide advantages such as better work quality, lower vibration, noise and power consumption. Up to now these technologies are still not applied and optimized to the wood machinery and wood-based material.
The targeted gains can be defined as follows:
Economic gains resulting from the reduction of the intervention frequency, minimization of sawdust quantity , elimination of waste ends, reduction of the amount of knives used and reduction of power consumption.
Industrial gains due to improvement in cutting-edge quality (surface condition of the product) and increase in cutting capacity.
Environmental gains linked to the reduction of waste (sawdust and waste ends) as well as noise reduction.
Improvement of working conditions due to the reduction in the number of interventions for knife change and due to the noise reduction.
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