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In most situations, for the proper design of a gerotor pump, numerous parameters must be taken into account: the pump geometry, the properties of the materials from which the pumps are made (Young's modulus, Poisson's coefficient, friction coefficients, etc.), the hydraulic characteristics of the circulated fluids (fluid density, kinematic viscosity, etc.), the working performance of the pump (speed ranges, pressure, flow rate, etc.), with greater or lesser influence on volumetric efficiency, work capacity, or energy consumption. The paper presents a study regarding the inspection of the reciprocally enwrapping surfaces of the gerotor pumps using a three-dimensional measurement technique specific to reverse engineering, which involves 3D scanning of the pump components in gearing movement. The components were measured by means of a specific software (GOM Inspect) and compared, by overlap, with the CAD models made with the help of CATIA software (CATIA V5R21). At the same time, an analytical calculation algorithm was developed for the complementarity of virtual representations. Finally, the advantages of the reverse engineering technique compared to the developed theoretical algorithm and traditional CAD design are presented. [ABSTRACT FROM AUTHOR]

In industrial practice, is sometimes needed to manufacture specific parts without blueprints. This part of engineering process is known as reverse engineering. Usually, this assumes that an existing piece is measured or scanned and based on this result is made a new part. If the part can be machined with universal cutting tools the manufacturing process don't rise problems, but in case of parts which needs specific tools, these must be designed to be suitable for machining the piece. In this paper, a tool profiling algorithm is proposed, which is based on the capacity to measure and represent some surfaces in a methodical cloud of points form. The proposed profiling algorithm is based on the "virtual pole" method. This method is used together with the intermediate surface theorem for profiling tools characterized by a helical primary peripheral surface. This article will represent a continuation of a research which was been published in 2021, in Bulletin of Polytechnic Institute from Jassy. In that published article, the profiling of the hob mill tool was presented in a theoretical way and the "virtual pole" theorem was applied for an any type of profiles. The proposed algorithm allowed the determination of the tool's profile reciprocally enveloping with a piece's profile known in discrete form. Now, in this paper, the discrete form profile will represent exactly a cycloidal disk from a cycloidal reducer whose coordinates were determined using specific reverse engineering processes. Considering that the determination of the relative movements between the tool and the part, as well as the determination of the enveloping condition are relatively complicated and can be a source of errors, the purpose of this work is to highlight the advantages of the "virtual pole" method compared to the other specific methods of tool profiling that generate by enwrapping. At the same time, it is investigated if the "virtual pole" method can provide a support for the identification of the intermediate surface, with the help of graphic design environments, for profiling, in this case, the worm tools, since the "virtual pole" method cannot be applied as such in the case of disk-type tools, worm tools and cylindricalfrontal tools, due to the fact that the theorem is intended for the study of planar gearing. The advantages of using the "virtual pole" method are obvious compared to the classical tool profiling methods. The results demonstrated the accuracy of the method, by the fact that, using the "virtual pole" method, the calculation time for profiling the hob mill tool for generating a profile known in discrete form, namely the profile of the cycloidal disk, is significantly reduced. [ABSTRACT FROM AUTHOR]

Recently, 3D measurement systems have developed more and more in various fields. With the help of 3D measuring systems, the measurement time in design, manufacture, assembly and production is substantially reduced. In this paper, it is proposed to redesign two pieces of a helical pump (driver and driven screws) based on numerical models obtained by scanning. These models are obtained based on the processing of point clouds resulting from the 3D scanning of the respective pieces. After completing the actual scanning process, the numerical models were measured using specific software to determine the dimensional characteristics and their modeling was performed in a computer-aided design program. Subsequently, the inspection was performed by overlapping the scanned model and the CAD model of each piece, in order to be able to compare the analytical models with the real pieces. This comparison allows to appreciate the degree to which the analytical model obtained by redesign corresponds to the real piece. In this way, the ability of future pieces obtained based on the analytical model to be able to accomplish the desired functional role can be appreciated. [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]