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The reliability of the products, determined by measuring and estimating quality characteristics, plays a decisive role in the strategy of the economic evolution. In the execution of rigid road clothing, traditional materials are used, which are found in nature (stone, sand, cover aggregate etc.). Blended with binders, the resulting structures must respect specific wellestablished resistors, obtained in special production stations. In order to determine the quality of any material used in practice, first of all, it is necessary to run tests on it in laboratories equipped with specific apparatus. This paper presents a comparative study on the bending behaviour of the road concrete class BcR-4.5 and BcR-5.0, on the KD-KL 300/R hydraulic dual piston test machine. The bending strength was calculated, under the action of different forces, comparing the experimental values with the values obtained from a finite element analysis. [ABSTRACT FROM AUTHOR]

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Dimensional accuracy of the cast parts strongly depends on cooling history which is mainly related with casting parameters. Cooling history refers also to heat transfer coefficient through cast/mold interface. This is a very difficult task for researchers to deal with, considering the difficulty in estimating and controlling the heat quantity which crosses the interface and mold wall going to ambient. The paper presents the estimation of heat transfer coefficient evolution during solidification of a hollow cylinder cast part. Artificial neural networks are very useful and reliable tools in prediction and estimation of casting parameters. Even if there are many previous relevant studies concerning the heat transfer coefficient determination at the cast/mold interface, researchers still deal with many uncertainties related to application of numerical developed models to a variety of dimensions and geometry. [ABSTRACT FROM AUTHOR]

Hydraulic cylinders are subassemblies of hydrostatic equipment which convert the hydrostatic energy to mechanical energy. This is possible by transforming the hydraulic parameters such as pressure and flow of the incoming fluid to parameters associated with translation, force and speed. The hydraulic cylinders usually have, as active element, a subassembly composed from a rod and one or more pistons which translates inside a working cylinder. This paper presents the functioning analysis at parallel hydraulic coupling of 3 single-rod double-acting hydraulic cylinders with different diameters and strokes. This is made in order to calculate the corresponding forces and speeds for both displacement directions of rod-piston subassembly. [ABSTRACT FROM AUTHOR]

The modelling of a curl of surfaces associated with a pair of rolling centrodes, when it is known the profile of the rack-gear's teeth profile, by direct measuring, as a coordinate matrix, has as goal the determining of the generating quality for an imposed kinematics of the relative motion of tool regarding the blank. In this way, it is possible to determine the generating geometrical error, as a base of the total error. The generation modelling allows highlighting the potential errors of the generating tool, in order to correct its profile, prior to using the tool in machining process. A method developed in CATIA is proposed, based on a new method, namely the method of "relative generating trajectories". The analytical foundation is presented, as so as an application for knows models of rack-gear type tools used on Maag teething machines. [ABSTRACT FROM AUTHOR]

The compressor rotors usually are helical surfaces with constant pitch and are composed of crossing profiles. Frequently, for repair operations, the reconstruction necessity occurs for one or both of the worms, drive and driven, from the helical compressors gear. The theoretical helical surface of the worm is being substituted by an assembly of helical lines which together with crossing profiles forms points cloud resulted from measuring leads to a polyhedral expression of the flank rotor. Numerically, this surface type is expressed by a coordinate array which shows its discrete image. The profiling of cutting tool bounded by a revolution surface reciprocally enveloping with the substitutive surface of the helical one represents a special problem. In this paper is proposed an algorithm for polyhedral expression of the helical surface previously determined by reverse engineering methods and an algorithm for the determination of the specific enveloping condition at contact with a discrete surface. It is presented an example for a compressor rotor measured on a 3D measuring machine, the algorithm for the transformation of the gathered points cloud in a surface with polyhedral expression. Given these conditions there were determined the enveloping condition and the axial section of the side mill. [ABSTRACT FROM AUTHOR]

In this paper, we present a graphical method, developed in CATIA environment, based on the method of substituting circles family and dedicated to profile pinion cutters for generating interior surfaces. Hereby, the family of substituting circles associated to the worked piece (the profile to be generated) is determined at the same time to the curve transposed, in the rolling motion, to the tool centrode. After finding the position of the contact points between the generated profile and the family circles, we can determine, in the transposed family, the locus of the points from the reciprocal enwrapping profile -- the pinion cutter profile. The paper also includes two method applications, for generating a hole with square transversal section, and a pump stator with trapezoidal profile. Comparisons between the profiling results when using the graphical method, versus an analytical method have also been realized. The results are proving the coincidence between the two profiles determined as above, on one hand, and both rapidity and precision of the graphical method, on the other hand. [ABSTRACT FROM AUTHOR]

Decrease of the unitary energetic load along the cutting edge with variable working angle, by increasing of the number of cutting edges in the construction of the helical drill, and, in the same time, the accomplishment of an evenness unitary energetic load may be assumptions for decreasing of the temperature of the tool cutting edge at its periphery. This will leads to the decreasing of the tool wear rate, hence the increasing of the tool's durability. In this paper, we present experimental research on curved cutting edge drills, regarding the speed-durability dependence in processing carbon steel. We observed that durability of curved cutting edge drills is superior to durability of standard drills for the same working conditions. [ABSTRACT FROM AUTHOR]

In the paper, for a specific profile, the localization of contact points in multipoint forming is analysed. For this, some simulation models using the finite element method were developed. A program for contact points calculation between the part and the tool active elements was designed. For a configuration of the multipoint deformation tool without interpolator, the correlation between the contact points distribution and the localized deformation is discussed. Then in the case of the multipoint deformation tool with interpolator, the part quality is analysed in terms of surface quality, part profile deviation and elastic recovery. The results show, in the cases of studied profiles, the presence of the spring-forward which increase when the part profile angles are increasing, to the same interpolator thickness. [ABSTRACT FROM AUTHOR]

In defining the process -- the complete combination through which the hired personnel, the methods, tool machines and cutting tools are involved in providing a product or service, we have to adjust quality indications regarding function performance of the cutting tool in its operational environment. The paper presents aspects on how to establish the precision with which a CNC machining center executes movements on the X and Y axis, while processing square plates, by drilling approximately 900 holes, on a total processing length of 45m, using drills with different diameters and variable cutting parameters (cutting speed and feed). [ABSTRACT FROM AUTHOR]

This paper presents a simplified algorithm for the profiling of the rack gear tool to generate the active profile associated with rolling centrodes. The algorithm is based on the enveloping surfaces principles and reduces the computational problem by proposing an approximate representation of tool’s profile using only three or four points on the profile to be generated by using Bezier representations of the surfaces. The algorithm computes the coefficients of a Bezier substitution polynomial instead of computing hundreds of points on the active profile. This simplifies the solution methodology and requires only a limited number of points along the profile to be generated. The algorithm is computationally efficient and can also be used in the case when the active profile to be generated is physically measured at a few points. Examples include mill tools, splined shafts, and gears. [ABSTRACT FROM AUTHOR]