Coated woodworking tool

Abstract

The invention relates to a coated woodworking tool, in particular a cutting tool comprising a tool body having a cutting part, on which cutting part a cutting edge is formed. At least the rake face or the rake and flank faces, and the cutting edge of the cutting part are coated with at least one hard-material layer and one sliding layer arranged above the at least one hard-material layer. The sliding layer may be made substantially of sulphides, tellurides or selenides having a transition metal of subgroup Va and VIa of the periodic table, in particular having Mo, Nb, Ta, W, Nb, Ta.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a national phase entry under 35 U.S.C. §371 of PCT / CH2012 / 000120 filed May 25, 2012, which claims priority to Swiss Patent Application No. 911 / 11 filed May 27, 2011, the entirety of each of which is incorporated by this reference.[0002]The present invention relates to a coated woodworking tool as per claim 1 and a method for producing such coated woodworking tool as per claim 12.PRIOR ART[0003]Cutting tools are characterised by one or a plurality of wedge-shaped cutting edges arranged on a shaft or blade which are used to shape a workpiece by cutting. Depending on the nature of the cutting process, a distinction is made between machining tools for manufacturing processes involving machining and cutting tools for manufacturing processes involving cutting (see www.wikipedia.de, keyword, cutting tool).[0004]Depending on the type of material to be machined, the cutting tools used need to meet different requirements. When c...

AI Technical Summary

Benefits of technology

The invention relates to a coated woodworking tool that has a sliding layer containing sulphides, tellurides or selenides, in particular, sulphides, tellurides or selenides of transition metals such as Mo, Nb or Ta. The sliding layer leads to a longer service life of the tool, even in oxygen-sensitive environments. The coated tool also results in better surface quality of wood workpieces, particularly solid wood, and produces fewer fine dust particles during use. The thickness of the hard-material layer on the rake face of the tool is important, with a lower limit of 0.5 μm and an upper limit of 7 μm. The hard-material layer consists of compounds of metals in groups IVa, Va, VIa of the periodic table or mixed compounds of two or more of these metals. Molybdenum disulphide can be formed by evaporation of molybdenum and simultaneous admission of a gas containing sulphur or by sputtering a MoS2 target.

Problems solved by technology

This results in wear on the cutting surfaces, comb cracks, cutting edge chipping, plastic deformation, erosion of the cutting tip (crater wear) etc.

In contrast with metal working tools, wear in woodworking tools is caused primarily by wear, however corrosion and gumming of the blades also play a major role.

It is therefore obvious to a person skilled in the art that, due to the different requirements in respect of woodworking and metal working tools, knowledge from the manufacture of metal working tools is not easily transferred to woodworking tools.

The machined wood surface looks good at first, but when it is painted, the compressed fibres spring back up which produces an unusable result on the surface.

In addition, working with a blade that is no longer ‘sharp’ creates much more dust with a particle size<100 μm, since the fibres are broken apart, not cut.

Since woodworking tools are not cooled during the cutting process and therefore can become extremely hot, molybdenum disulphide has not been considered previously as a sliding layer for woodworking tools.

According to EP-A-2 279 837, corrosion resistance is one of the main problems in coated woodworking tools along with wear resistance.

The use of a solid lubricant layer consisting of MoS2 is advised against since it lacks the required hardness and adequate adhesive force.

This is not possible, however, when working with wood.

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