Rezumat
Investigation of the influence of different factors on the strength of instrument is carried out. It is found that in the conditions of plastic current of the material of blank around the instrument surface a relief with protrusions of limited length in the shape of spherical segments is preferable. If a relative thickness of the coating increases then its supporting power increases. At decreasing of the thickness of coating or increasing of the thickness of the sheet blank it is necessary either to decrease the operating load or to increase strength properties of the surface layer of material. A negative influence of heat effects at the place of contact instrument–blank can be compensated by changing its thermophysical properties. Solution of this complex of problems is best achieved by electrospark deposition.