No abstract

As it has turned out from statistical surveys, carried out in workshops, the greatest part of industrial machining is hole making operation. By this fact can be explained that the tool manufacturing companies pay a special attention to the development of drilling tools. The features of an advanced construction can be charaterised by the curved main edge, the missing chisel edge, the flank land, produced by three-plane sharpening, the chamfer, optimized to the task and the coolant bores as well [1, . The load carrying capacity of the micro-grained carbide base materials can be developed further by the considerable hardness and heat resistance of coatings and by their low friction coefficient. The synergic effect of all these developments makes the drilling tools suitable for carrying out high perfomance machining tasks: the reliability of the operations - simultaneously with the fulfillment of quality expectations - is increasing, in this way the requirement of cost efficiency can be achieved as well.

Nowadays adhesive bounding becomes more and more popular in jointing of machine elements. It is important to know, how surface finishing and microgeometric preparation influence the jointing strength. In present study, shearing strength was examined using different type of adhesives of Loctite and Teroson (epoxy, acril, cianacrilat, MS polymer) and different surface roughness, but same layer thickness. After defining the optimal surface roughness the connection between layer thickness and jointing strength was investigated. Based on more than hundred tests, conclusions about the importance of surface roughness were drawn. It was proved that, surface roughness highly influence the adhesive bounding and the optimal layer thickness -connected to the bonding material -also has great influence to joint strength.

Surface roughness and the quality of surfaces of machine elements play important role in safety and reliable operation of technical devices. Present study shows that different machining processes results dissimilar microgeometry with variety of surface parameters. Formation mechanisms of surface roughness are analysed based on turning and milling tests. It is indicated that significant changes occur in amplitude, average and shape of cut surface during wear and cutting edge degradation processes of tools. In case of milling, behind the cutting parameters and geometric data the run-out has significant effect for the roughness of milled surface.