On October 23rd, 2014, we updated our
By continuing to use LinkedIn’s SlideShare service, you agree to the revised terms, so please take a few minutes to review them.
” Efficiency of tools from diamond and cBN : The compromise of contradictory trends ” Quality of the generated surfaces Durability Productivity - The contribution of productivity, durability and quality of a surface to an end result Perfect balance Real situation - Problems and losses = not used possibilities Raise of durability of the tool on 30 % yields 1 % of economy of the cost price, Productivity raise on 20 % yields 10-13 % of economy of the cost price of process of machining The potential performance level of the up-to-date grinding equipment, as a rule, surpasses the level of possibilities given by the tool. The disbalance parent - extreme character of the physicochemical processes in a band of dynamic contact of the instrumental and handled materials. . Productivity Quality of the generated surfaces Durability
High density of the energy dispersed in contact beds of the tool and a detail in a band of abrasive cutting - a natural barrier to growth of productivity of grinding The instantaneous nucleation site for of contact: Life time 10 -4 - 10 -6 s Temperature to 1500 о С Pressure to 10 kbar Extent of plastic deforming of 500 % and more . Handled material
The cost of restraint of temperature in a cutting band for traditional composite:
Decrease in rigidity and wear hardness of the tool
The complicated and ecologically harmful measures on intensive cooling
The factors limiting raise of productivity:
Surface layer temperature - the contribution of 70-95 %
Power parametres of cutting - the contribution of 5-30 %
Excess of admissible temperature in a cutting band result in to an unacceptable fault of the handled surface.
Growth of power parametres worsens indexes of a roughness and parametres of basic curves and, as a result, worsens all complex of properties of products.
The traditional point of view:
The heat evolution parent - the cross intensification of thermal oscillations of atoms in contacting surface layers - uncontrollable, fatally inevitable phenomenon.
The alternative up-to-date point of view:
The heat evolution parent – the non-emissive relaxation of electron excitation in nucleation site of a contact;
The emissive relaxation of electron excitation generates a triboluminescence i.e. non-thermal dissipation of energy. The quicker shearing in the contact spot shifts the balance for benefit of the emissive relaxation.
Contact spot Nucleation sites
Demands of high efficiency and high durability clash, forming "vicious circle". Nevertheless, High durability is dictated by demands of the up-to-date equipment; shape retention of an effective surface of the tool directly influences accuracy of geometry and a state of a surface of finished parts Allocation of internal stresses in surface layer of H10F cemented carbide Tool adaptability results in better durability of sharpened hard alloy cutter Effect of productivity of grinding on ultimate bending strength of samples H10F cemented carbide Evolution of t he shape of a profile of an abrasive wheel from traditional abrasive composite in process of grinding Evolution of t he shape of a profile of an abrasive wheel from adaptable abrasive composite in process of grinding Abrasive composite adaptability minimizes the distortion of handled material structure Effect of productivity of grinding on sizes of blocks of a mosaic and magnitude of distortions of a crystal lattice of grains of tungsten carbide Compression tension raise fatigue strength of a material
Self-tuning of microgeometry of the adaptable grinding tool cutting profile Deforming abrasive grain Basic curve surfaces of the gas distribution valve of the engine after grinding: 1, 2 - a traditional cBN composite, 3 , 4 - adaptable cBN composites Resource of operation of gas distribution valve on the relative basic area at level of 2 microns 1, 2 - a traditional cBN composite, 3 , 4 - adaptable cBN composites Cutting abrasive grain Isolines of mechanical stress, caused by adaptive structural transform