INNOVATIVE THREAD METHOD THROUGH CYLINDRICAL HOLES

Innovative activity in the field of engineering and technology, based on the use of best practices, contributes to scientific and technological progress in production. The latest projects in the field of technology significantly increase the technical and economic performance of enterprises. Innovative technical solutions of production nature significantly improve the structure and quality of production. Given the level of the proposed technological changes in the manufacture of threads in through holes, these innovations cover the field of combinatorial and partial. Today mechanical engineering is characterized by mechanization and automation of technological processes, a wide range of products of various parts. Among the non-detachable and detachable joints of parts, the threaded connection is the most common. Simplicity, reliability, the ability to adjust the force with which the conjugate surfaces come into contact, the possibility of repeated cycles of disassembly and assembly, etc., make this type of connection the most commonly used in mechanisms and machines of modern engineering. With the simplicity of the contact pair of threaded joints, where one of them contains the outer and the other the inner screw surface, during their manufacture there are problems that significantly inhibit production. The subject of research of this article is the solution of difficulties of manufacturing of an internal cut in through openings of small diameter by means of a tap. According to various sources, up to 80% of marriage is due to breaking taps. Studies by a group of scientists has found that more than 75% of taps break when the reverse (reverse) stroke of the tap, when the torque reaches its maximum value. The reverse scheme of production of a screw profile of a cutting surface by means of the mechanized devices and their alternative analogs, and also machines of drilling group, is offered.

Induction brazing technology for pipeline connections of an automated gas metering unit

The article discusses the connection of pipelines of an automated gas metering installation. Welding is considered as the main method of connecting pipelines and an induction pack of heating methods as proposed by the authors. In the work, a threaded connection is calculated according to the method of Anuryev V.I. On the basis of the calculations carried out by the authors using formulas from the designer’s handbook, a schematic diagram of the pipe fastening in the process of induction soldering is developed. A schematic diagram of a pipe bend is also being developed. The approach proposed by the authors will repeat the connection of pipelines of oil and gas equipment using induction packs and increase the reliability of brazed structures.

New Concept and Apparatus for Cytocentrifugation and Cell Processing for Microscopy Analysis

Cytocentrifugation is a common technique for the capture of cells on microscopic slides. It usually requires a special cytocentrifuge or cytorotor and cassettes. In the study presented here, we tested the new concept of cytocentrifugation based on the threaded connection of the lid and the sample holder to ensure an adjustable flow of solutions through the filters and the collection of the filtered solutions in the reservoir during centrifugation. To test this concept, we developed a device for the preparation of cell samples on circular coverslips. The device was tested for the capture and sample processing of both eukaryotic and prokaryotic cells, cell nuclei, and mitochondria for microscopy analysis including image cytometry. Moreover, an efficient procedure was developed for capturing formaldehyde-fixed cells on non-treated coverslips without cell drying. The results showed that the tested arrangement enables the effective capture and processing of all of the tested samples and the developed device represents an inexpensive alternative to common cytocentrifuges, as only the paper filter is consumed during sample processing, and no special centrifuge, cytorotor, or cassette is necessary. As no additional system of solution removal is required during sample staining, the tested concept also facilitates the eventual automation of the staining procedure.

REGARDING THE QUALITY OF ASSEMBLY OF THE SCREW CONNECTIONS OF THE MOUNTING ASSEMBLY OF BALL BEARINGS

Application of method of vibrodiagnostics is based on the presence of cross-correlation dependences of dynamic descriptions of all knots from contact pressure in connection through the change of inflexibility of joints. The change of inflexibility of separate elements causes the change of the resulted inflexibility of knot, and at the same time and characteristic it to dynamic descriptions of the artificially created oscillation field: frequencies and amplitudes of resonance vibrations, indexes of damping, phase correlations. There is a task of determination of method of control of the most responsible technological frame-clamping operations at making of such objects: quality of contact connections, ball-bearing knots, fixing of previous pull of ball-bearings and control of isotropicness, inflexibility and dissipative descriptions of the system of pendant of rotor at all stages of drafting, including in the functional state. The primary objective of this work is research of question of influence of non-perfect resiliency and different inflexibility of the supporting bearings on the dynamic reaction of object at external oscillation excitation, determination of estimation of the different inflexibility bearings, determination of accordance of axial inflexibility of ball-bearings supports, them by a basic value. The dynamic model of knot and certain functions of influence of parameters of the system is considered on high-quality indexes. The dynamic model of precision rotor system (PRS) is investigated. Vibration tests at the stage of assembling the structure of the ORS showed that in the process of assembling the elements change the natural frequencies of the system and the quality factor of the oscillating circuits. The resulted dependences allow giving an estimation degree of non-linearity of resilient description and, as a result, different inflexibility of bearings supports as a result of oscillation researches. The sensitivity functions of the design parameters of the complex press-threaded connection in relation to the vibration dynamic parameters – frequencies and amplitudes of resonant oscillations – do not differ qualitatively from those obtained previously.

Research on the Shock Response Characteristics of a Threaded Connection Using the Thin-Layer Element Method

Nonlinear factors such as the contact stiffness and friction damping at the threaded interface of a projectile–fuse system significantly affect the dynamic response characteristics. To obtain the dynamic response of the fuse body accurately during penetration, it is necessary to characterize these nonlinear factors reasonably. Because the existing structural dynamics software cannot effectively deal with nonlinear factors, the thin-layer element method was used to represent the nonlinear factors in this study. By combining the thread elastic model with thin-layer element principles, an effective method for determining the material parameters of the thin-layer element was established theoretically, which provided a different method of determining material parameters, not just relying on experiments. The accuracy of the material parameters was verified based on modal experiments with threaded tubes having different specifications. The errors were within 5%, indicating the reliability of the theoretical determination method for the material parameters. In addition, projectile penetration into a semi-infinite concrete target was tested to verify the accuracy of the thin-layer element modeling. Compared with the ‘TIED’ constraint method, the resonant frequency obtained with the thin-layer element method was in better agreement with that of the experimental data. The maximum error decreased from 15.7 to 7.8%, indicating that the thin-layer element method could accurately represent the nonlinear factors. Thus, this study serves as a reference for accurately evaluating the dynamic response of the fuse body of a penetrator.

TECHNOLOGICAL PROVISION OF THE ACCURACY FOR THE THREAD FORM OF ROD PUMPS

Aspects of thread manufacturing used in downhole rod pumps are considered. Technological defects of distortion of lateral surfaces of a thread profile arising in the course of processing on CNC machines are described, and the factors which most influence formation of these defects are established. The influence of profile defects on the reliability of the threaded connection during the operation of rod pumps is analyzed, as well as the research on the dynamics and oscillations of machine systems is analyzed. With the performed analysis the mathematical model of real technological system in the course of machining process is created and investigated. The main technological factors that have the greatest influence on the occurrence of error in the shape of the thread surface are identified. With the help of software for analysis of dynamic systems, the necessarily calculations were performed and the behavior of the dynamic system in the process of forming the thread profile was considered. Based on the analysis of the obtained results, a system for managing the parameters of the technological process of threading and technological solutions formulated. The introduction of which had a positive impact on the stability of the machining process and reduce the frequency of the above defect.

Thread Couplings Stress Analysis by Radial Basis Functions Mesh Morphing

Traditional analytical methods are approximate and need to be validated when it comes to predict the tensional behavior of thread coupling. Numerical finite element simulations help engineers come up with the optimum design, although the latter depends on the constraints and load conditions of the thread couplings which are often variable during the system functioning. The present work illustrates a new method based on Radial Basis Functions Mesh Morphing formulation to optimize the stress concentration in thread couplings which is subject to variable loads and constraints. In particular, thread root and fillet under-head drawings for metric ISO thread, which are the most commonly used thread connection, are optimized with Radial Basis Functions Mesh Morphing. In metric ISO threaded connection, the root shape and the fillet under the head are circular, and from shape optimization for minimum stress concentration it is well known that the circular shape becomes seldom optimal. The study is carried out to enhance the stress concentration factor with a simple geometric parameterization using two design variables. Radial Basis Functions Mesh Morphing formulation, performed with a simple geometric parameterization, has allowed to obtain a stress reduction of up to 12%; some similarities are found in the optimized designs leading to the proposal of a new standard. The reductions in the stress are achieved by rather simple changes made to the cutting tool.

Protection enhancing of threaded connections of light-alloy drill pipes against contact corrosion

When using light-alloy drill pipes (LAIDP) with steel tool joints, the development of contact corrosion is observed under certain operating conditions. The value of corrosion mainly depends on the difference in electrochemical potential (ECP) of the contacting metals. One of the effective methods for increasing the corrosion resistance of aluminum alloys is the micro-arc oxidation (MAO) method. This is an electrochemical process in combination with micro-arc-discharges phenomena at the anode-electrolyte border, which allows forming ceramic coatings of aluminum oxides on the surface, including its high-toughness and wear-resistant phase - α-Al2O3 (corundum). MAO-technology is a highly efficient and environmentally friendly process. At the forming of such a coating on the threaded part and in the tool joint zone of the pipe, a barrier for contact corrosion between the steel tool joint and the surface of the aluminum pipe is created. In this work, contact corrosion on samples in a pair of 1953T1 aluminum alloy - 40KhN2MA steel in a 5% NaCl solution at 80 °C was investigated. The data obtained showed the effectiveness of using protective MAO-coating to reduce contact corrosion and increase the reliability of the tool joint threaded connection of LAIDP.