Mechanical Assembly Research Articles

Assembly Monitoring Using Semantic Segmentation Network Based on Multiscale Feature Maps and Trainable Guided Filter

Timely detection of errors in assembly process is important for ensuring assembly quality and efficiency. Image segmentation technology can be used to monitor mechanical assembly for missing assembly, wrong assembly, assembly sequence, and assembly pose. However, unclear segmentation boundaries and low segmentation accuracy of small parts is the main limit of assembly depth image segmentation. Therefore, this study proposes a skip Fully Convolutional Network (FCN) with Multi-scale Feature maps (MF) and a Trainable Guided Filter (TGF) (skip FCN with MF&TGF for short) for depth image segmentation of mechanical assembly. By adding skip connections in the second maximum pooling layer of FCN, additional low-level features can be obtained, which compensates the problem of insufficient detailed information in feature map prediction. The problem of image segmentation edge blur is mitigated by the integration of a trainable guided filter. Moreover, this study establishes a mechanical assembly depth image dataset. The experimental results show that skip FCN with MF&TGF enhances the segmentation precision of mechanical assembly and significantly improves the segmentation edges of depth images. Furthermore, it shows significant improvement in segmentation performance when segmenting small parts. Finally, compared with other semantic segmentation networks, skip FCN with MF&TGF achieves the best segmentation performance on the mechanical assembly depth image dataset.

Моніторинг технічного стану ЗПРК за керівними матеріалами на їх експлуатацію

The efficiency of use and increase the reliability of agricultural machinery depends on the regulatory and technical documentation governing the requirements for its technical condition and operation. The analysis of the existing normative-technical and guiding documents on ensuring the reliability of means for preparation and distribution of fodder is given. To effectively carry out maintenance and repair of means for the preparation and distribution of feed should know: the criteria for disability; maximum and permissible parameters of technical condition; indicators of the transition of equipment from working to inoperable condition. The article presents the monitoring of instructions for maintenance and operation of machines, guide materials for use from the standpoint of their informativeness on the implementation of reliability requirements. Monitoring of technical condition was carried out for foreign samples of means for preparation and distribution of feed with horizontal mixing and grinding mechanisms. The mechanisms are analyzed from the standpoint of the availability of information about the features of the structure, the characteristic faults and failures, the main ways to restore efficiency. Ensuring reliability includes several activities throughout the life cycle. The main provisions for assessing the technical condition and improving the reliability of machines when using guide materials. The provisions include: information on the reliability of machines, mechanisms, working bodies; periodicity of maintenance and repair of machines, restoration of working bodies; information on the complexity of maintenance and repair of machines, restoration of working bodies; schemes of assembly and disassembly of mechanisms; information on typical failures and the sequence of their elimination; information on the limit state criteria; technologies for the restoration of working bodies; information on installation requirements. The current normative documents of the system of general technical requirements for the means for the preparation and distribution of feed do not fully meet the organizational and methodological aspects of ensuring their reliability.

Wasserstein generative adversarial networks for form defects modeling

Geometric deviations of mechanical products are specified by tolerancing in the design stage for a functional purpose. In order to verify the impact of geometric deviations on functional surfaces while considering the manufacturing process, form defects have been considered in tolerance analysis in recent years. As a digital representation of geometrical defects in mechanical parts and assemblies, Skin Model Shapes enables the rapid and comprehensive generation of non-ideal shapes from either measurement or via data augmentation using simulation approaches. This paper presents a novel method for form defects modeling using Generative Adversarial Networks (GAN). The form defects of cylindrical surfaces considering machining process are represented and used for training a Wasserstein GAN. The pre-trained network is able to generate realistic form defects for cylindrical Skin Model Shapes rapidly and automatically without explicitly formulated representations. Manufacturing errors in turning process are considered in this approach and the generated samples from WGAN can be re-used for generating new cylindrical surfaces with a mapping strategy considering specification. A case study of a cylindricity specification is used in the paper to illustrate the effectiveness of the proposed method.

Development of a No-till Transplanter for Walk-behind Tractors

Highlights Walk-behind tractor. No-till vegetable transplanter. Small local garden type farming. Transplanting precision. Abstract. A no-till vegetable transplanter powered by a walk-behind tractor was developed to reduce heavy physical labor, that is often required on small scale farming operations. Currently, there are no existing commercially available no-till transplanters made for walk-behind tractors. This concept can be an important factor in improving field transplanting operations by reducing time and human labor. The original patented concept was heavy (103 kg) and included complex mechanical assemblies to be powered by the tractor’s PTO (power-take-off). It was designed for walk-behind tractors not equipped with a battery and alternator to charge the battery in which newer walk-behind tractors are equipped. Therefore, the original functional idea of the transplanter did not change, but the transplanter’s components were modified and simplified by substituting mechanical drives and control mechanisms with a single 12-V electric motor allowing variable rpm (infinitely variable spacing) and reversible direction of rotation. The improved version of the transplanter has fewer components and weighs only 83 kg, a decrease of 20 kg. Powering the transplanter electrically (not mechanically) reduced overall weight by 19%. This new version of a modular design allows easier and faster transplanter fabrication, giving farmers an option to fabricate their own transplanter to reduce costs and increase adoption of no-till vegetable systems with cover crops. Keywords: 12-V DC variable speed reversible electric motor, No-till transplanter, Power take-off (PTO), Walk-behind two-wheel tractor.

Conveyor belt regulator through silo operation

Conveyor belts are used in industries such as electro-mechanical and mechanical assembly to transfer goods from one position to another or from one procedure to another. In coal mining industries, controlling the speed of a conveyor can be achieved by controlling the speed of its drive unit. The Programmable Logic Controller (PLC's) commonly used programming language has the trapezoidal chart language, Ladder Diagram (LD), the Smooth Functional Diagram (SFC), and the Function Block Language (FBD). The four-level leather belt conveyer control system belongs to the model of sequential control and therefore mainly uses the SFC to program. A Programmable Logic Controller (PLC) is used to implement the control strategy. A PLC is a microprocessor-based control device with the original drive of complementing relay logic. The latest PLCs have progressed past just a robust stage into a new realm of high computational control and processor speediness. These, along with the PLC's extremely elastic arrangement, make it an ideal stage for uses far beyond its conventional ones. The main aim of this paper is to design a PLC conveyor belt control system for silo operation that has three various modes, namely continuous mode, manual mode, and fill by pass mode. The conveyor belt plays a very effective role as it reduces the time required to complete a large amount of work and increases productivity with high efficiency. It also saves money and costs, reduces the required manpower, is characterized by ease of maintenance and handling, and offers many other benefits.

Bonding of composite parts: advantages and benefits of Structural Adhesives and Self-adhesive Tapes

The bonding process of composite materials is a challenging method in growing markets like Transportation and Construction. Differents methods exist today for the assembly of composite materials: mechanical fixing, ultrasonic welding, structural adhesives and acrylic foam tapes. Each method has its own advantages and drawbacks, but bonding with structural adhesives or acrylic foam tapes offer important benefits compared to mechanical assemblies. Adhesives and tapes allow to bond dissimilar substrates while keeping mechanical performance and improving aesthetics of composite materials. The Transportation market is leading the increasing demand of composite materials and design engineers look for detailed information on bonding methods and the performance of adhesives for the designed vehicles: mechanical and vibrations resistance, tenacity and elasticity, durability and capability to withstand extreme conditions. Design engineers require more than a bonding solution, they need technology partners like 3M providing technical support for project development, materials and adhesives testing, and process consultants for the optimization and automation of bonding processes. Los ingenieros quieren algo más que una solución adhesiva, y buscan socios tecnológicos como 3M. The purpose of this article is to create awareness on 3M new adhesive and tape technologies for multi-material bonding integrating a composite material. Assembly types and solutions allow to find the best adhesive technology for optimal bond design and manufacturing process.

The Future of Machine Vision in Industries- A systematic review

The Machine vision is the substitution of the human visual sense and judgment capabilities with a video camera and computer to perform an inspection task. It is the automatic acquisition and analysis of images to obtain desired data for controlling or evaluating a specific part or activity. Inspection of components using machine vision technologies provides solution for quality and process control. Now a days, Industry has huge demand for productivity improvement with the implementation of computer control automation. Machine vision reduces the scrap production due to non- conformity by controlling the manufacturing process through machine vision and to prevent the value addition for scrap product in subsequent stage of manufacturing process. The factory vision based industrial robot change the traditional way of mechanical assembly, quality control of product and rapid manufacturing. The various applications of machine vision technologies are automotive pharmaceutical, food and beverage, electronics, packages, and process control.

State of the art of fatigue strength of materials & structures from additive manufacturing – The pivot, A CETIM development.

Additive manufacturing is a subject at the heart of innovation in many fields of mechanics. It allows, through different techniques, to produce increasingly complex parts. It also offers greater design freedom, often with shorter times than conventional manufacturing. These techniques having a multitude of parameters and finishing methods, Cetim wishes to study their influence on fatigue resistance through tests on standardized samples and on mechanical parts.The pivot is an example of study part developed at CETIM. It is at the crossroads of technical art and technological developments. This part, resulting from a mechanical assembly of cable reels for industry, has been specially developed for additive manufacturing. It incorporates all the constraints and advantages of current technology. This part is stressed in fatigue during operation in combined rotations. It is subjected to alternating loads linked to centrifugal forces.The design optimizes the constraints and design opportunities linked to additive manufacturing (topological optimization, supports optimizations). It also integrates metallurgical considerations and geometric constraints necessary for the finish. A specific range of surface finishes was produced for this part, driven by the reduction of two key roughness values, the Ra and Rz of the surfaces.The validation of the mechanical properties was carried out on several production batches characterize the alloy behavior (metallurgically, mechanically and in fatigue). The parameters obtained during the first test phase (static and Manson-coffin) were incorporated into the simulations and dimensioning of the fatigue tests of the part. The pivot had several metrological checks with no-contact methods (tomography, scan, CMM, etc.) to check the dimensions and whether any defect was present. Then, the part was placed under a test bench to validate its mechanical performance and industrial expectations.This study therefore proposes a direct correlation between the difficulties linked to the development of parts of additivemanufacturing structures. The various technical problems from the microstructure to the structure of the part were removed step by step.

МОДЕЛИРОВАНИЕ СИСТЕМ УПРАВЛЕНИЯ ОРГАНИЗАЦИОННО-ТЕХНОЛОГИЧЕСКИМ ОБЕСПЕЧЕНИЕМ МЕХАНИЧЕСКОЙ СБОРКИ НА ПРЕДПРИЯТИЯХ АВТОМОБИЛЕСТРОИТЕЛЬНОГО КЛАСТЕРА

A system for providing mechanical assembly based on threaded joints used at enterprises of the automotive cluster. This system combines a subsystem of assembly equipment, a subsystem of spare tools. The model of the mechanical assembly support system can be based on a set-theoretic approach as a set of subsystems of organizational and technological support for mechanical assembly at automotive cluster enterprises. Subsystems of organizational and technological support of mechanical assembly for automotive cluster enterprises can be described from the standpoint of management theory. In each control system being formed, an object, a control subject, a feedback mechanism is allocated, and it is also assumed that the PMD will interact with the subsystem of organizational and technological support for mechanical assembly through the information system database being formed. The task of managing the organizational and technological system for providing mechanical assembly involves solving particular problems, including those of managing the subsystem of assembly equipment, also the subsystem of controlling and testing, the subsystem of spare tools, instruments and devices. The criteria of optimal control of the generated control tasks are presented.

On the broadband vibration isolation performance of nonlocal total-internal-reflection metasurfaces

The concept of a nonlocal elastic metasurface has been recently proposed and experimentally demonstrated in Zhu et al. (2020). When implemented in the form of a total-internal-reflection (TIR) interface, the metasurface can act as an elastic wave barrier that is impenetrable to deep subwavelength waves over an exceptionally wide frequency band. The underlying physical mechanism capable of delivering this broadband subwavelength performance relies on an intentionally nonlocal design that leverages long-range connections between the units forming the fundamental supercell. This paper explores the design and application of a nonlocal TIR metasurface to achieve broadband passive vibration isolation in a structural assembly made of multiple dissimilar elastic waveguides. The specific structural system comprises shell, plate, and beam waveguides, and can be seen as a prototypical structure emulating mechanical assemblies of practical interest for many engineering applications. The study also reports the results of an experimental investigation that confirms the significant vibration isolation capabilities afforded by the embedded nonlocal TIR metasurface. These results are particularly remarkable because they show that the performance of the nonlocal metasurface is preserved when applied to a complex structural assembly and under non-ideal incidence conditions of the incoming wave, hence significantly extending the validity of the results presented in Zhu et al. (2020). Results also confirm that, under proper conditions, the original concept of a planar metasurface can be morphed into a curved interface while still preserving full wave control capabilities.

Synthesis of Tostadas‐Shaped Metal‐Organic Frameworks for Remitting Capacity Fading of Li‐Ion Batteries

AbstractElectrode design strategies that aim to increase the electrochemical performance of Li‐ion batteries (LIBs) play a key role in tapping into the power of the energy transformations involved. Metal‐organic frameworks (MOFs) have attracted scientific interest as electrode materials for LIBs, while the utilization of pristine MOFs is hindered by limited conductivity and stability, partly due to their lack of hierarchically structured pores. Herein a hydrothermal‐mechanical synthesis is reported by combining the one‐pot chemical fabrication of Ni3(2,3,6,7,10,11‐hexaiminotriphenylene)2 sheets and particles, and the mechanical assembly of these building blocks to improve electrical conductivity is also described. The as‐prepared ensemble (denoted as NHM) exhibits a Tostadas‐shaped structure with enriched ultramicropores and micropores. The charge‐discharge profile of NHM gives a superior reversible capacity of 1280 mA h g−1 after 100 cycles at the rate of 0.1 A g−1, surpassing the state‐of‐art pristine MOFs‐based anodes. Moreover, NHM is capable of maintaining 392 mA h g−1 at 1 A g−1 after 1000 cycles, the completion of a stability test in coin cell‐powered light emitting diodes further visualizes the remitted capacity fading of NHM. This work breaks through the limitation of capacity for pristine MOFs, providing a new pathway for achieving better energy conversion and storage.

Synergistic effects of chlorine substitution in sulfide electrolyte solid state batteries

All-solid-state battery is considered as one of the most promising competitors to Li ion batteries. Two widely known performance metrics for solid electrolytes, among others, are ionic conductivity and stability. Here it is found that both can be improved by the synergistic effects of chlorine substitution in sulfide-based solid electrolytes. Particularly, instabilities arising from both bulk decompositions and interfacial reactions to electrodes can be better inhibited in the chlorine substituted sulfide solid electrolytes through the increased susceptibility to the mechanical constriction induced enhancement of voltage stability. As a result, the stability window of some chlorine-rich Li-argyrodites can be systematically higher than some other chlorine-deficient or chlorine-free electrolytes, especially under the implementation of the mechanical constriction battery assembly and test conditions. Thus, a solid-state battery system of 4 V to 5 V-class cathodes paired with lithium metal anode is demonstrated using these chlorine-rich Li-argyrodites without additional coatings. Furthermore, since Cl composition modulates the stability and instability of Li-argyrodite at low voltages, it allows us to design a multilayer configuration with a hierarchy of Li metal stabilities to demonstrate the stable cycling at relatively high current densities for solid-state batteries. It is found that a moderate Cl composition in the electrolyte is the best to inhibit Li dendrite penetration as the central electrolyte layer, emphasizing a slightly increased “instability” as the hidden performance metric of relevance here, in addition to the two well-known metrics of stability and ionic conductivity. The understanding of the chlorine substitution effect in sulfide electrolytes provides an important design principle for all-solid-state batteries.

Case Study of Strength Calculation and the Possible Repair Options for Screw Thread Damages

Abstract: Thread Strength and repair capability are critical to successful screw joints for any mechanical assembly. This paper explores the effect of the thread damage utilizing hand calculations, the margin of safety (MOS) for internal & external threads and compares with the required design criteria limit. Hence, the reduction in thread capability is analyzed in terms of shear and bearing strength of threads. This paper also emphasizes the Industry-standard repair techniques such as Helical inserts, Oversize inserts, and Twinserts with limitations and expected process/techniques. Advanced thread repairs in the market such as solid-body thread inserts (key-style, Time-sert, Big-sert) are also discussed Keywords: Thread damages, Shear strength, bearing strength. STI (Screw thread insert)

Prediction of fatigue crack growth rate in aircraft aluminum alloys using optimized neural networks

In aerospace industry, Fatigue Crack Propagation pose a serious threat to the professionals involved in designing mechanical assembly of the aircraft structures. In these structures crack growth is a problem that needs to be handled seriously, as human life risk is concerned in addition to economic loss. Fatigue Crack Growth (FCG) Rate is the rate at which crack grows with number of cycles subjected to constant amplitude loading. FCG curve is drawn between crack growth rate on y-axis and Stress Intensity Factor (SIF) range on x-axis. It needs to be predicted accurately to avoid losses. Upon analyzing the curve, it becomes obvious that the correlation between Stress Intensity Factor (SIF) ranges “ΔK” with FCG rate “da/dN” is deviating linear relationship considering region II of the curve that is also called Paris Region. Empirical formulation methods cannot deal with linearity factor satisfactorily. Other hybrid techniques are also found incapable of dealing with non-linearity suitably. In contrast to the prior methods, machine learning algorithms are capable to deal with the non-linearity issue in a much better way owing to their admirable learning ability and flexible nature. In this research work three distinct MLA based Optimized Neural Networks are utilized for prediction of FCG rate. The used algorithms include Genetic Algorithm based Optimized Neural Network, Hill Climbing based Optimized Neural Network and Simulated Annealing based Optimized Neural Network. The algorithms presented in the proposed technique are validated by testing on different aluminum alloys used for aerospace industry that includes 2324-T39, 7055-T7511 and 6013-T651 aluminum alloys. The least predicted MSE for 2324-T39 aluminum alloy is achieved by Hill Climbing based Optimized Neural Network that is 3.1069×10-8. For 7055-T7511 alloy, minimum predicted MSE is 1.4284×10-9 which is achieved by Hill Climbing based Optimized Neural Network. Finally, the least predicted MSE for 6013-T651 is 1.0559×10-9 that is achieved by Simulated Annealing based optimized Neural Network. Taking all alloys on which experiments were held with used algorithms, the least predicted MSE that is attained is 1.0559×10-9 for 6013-T651 Aluminum Alloy with Simulated Annealing based Optimized Neural Network. Moreover, the results demonstrate an exceptional conformity to the data conceived during experimentation process.

Cognitive Ergonomics of Assembly Work from a Job Demands-Resources Perspective: Three Qualitative Case Studies.

In manufacturing companies, cognitive processing is required from assembly workers to perform correct and timely assembly of complex products, often with varied specifications and high quality demands. This paper explores assembly operators’ perceptions of cognitive/mental workload to provide a holistic understanding of the work conditions that affect cognitive demands and performance. While the physical loading aspects of assembly work are well known, most empirical literature dealing with cognitive/mental loading in manufacturing tends to examine a few particular aspects, rather than address the issue with a holistic system view. This semi-structured interview study, involving 50 industrial assembly operators from three Swedish companies, explores how assemblers perceive that their cognitive performance and well-being is influenced by a wide variety of factors within the context of mechanical product assembly. The interview transcripts were analysed using a priori coding, followed by bottom-up Thematic Analysis. The results indicate that a variety of systemic effects on assemblers’ cognitive performance can be classified as job demands or resources. Quite often, the absence of a resource mirrors a related demand, and “good assembly conditions”, as described by the interviewees, often re-frame demands as desirable challenges that foster motivation and positive feelings towards the work. The identified demands and resources stem from task design, timing, physical loading, intrinsic and extrinsic motivators, social teamwork and the product’s “interface” design. Despite organisational differences and conditions between the three companies that took part in the study, the results are largely consistent.

Assembly variation analysis of the non-rigid assembly with a deformation gradient model

PurposeThis paper aims to develop a mathematical method to analyze the assembly variation of the non-rigid assembly, considering the manufacturing variations and the deformation variations of the non-rigid parts during the assembly process.Design/methodology/approachFirst, this paper proposes a deformation gradient model, which represents the deformation variations during the assembly process by considering the forces and the self-weight of the non-rigid parts. Second, the developed deformation gradient models from the assembly process are integrated into the homogenous transformation matrix to model the deformation variations and manufacturing variations of the deformed non-rigid part. Finally, a mathematical model to analyze the assembly variation propagation is developed to predict the dimensional and geometrical variations due to the manufacturing variations and the deformation variations during the assembly process.FindingsThrough the case study with a crosshead non-rigid assembly, the results indicate that during the assembly process, the individual deformation values of the non-rigid parts are small. However, the cumulative deformation variations of all the non-rigid parts and the manufacturing variations present a target value (w) of −0.2837 mm as compared to a target value of −0.3995 mm when the assembly is assumed to be rigid. The difference in the target values indicates that the influence of the non-rigid part deformation variations during the assembly process on the mechanical assembly accuracy cannot be ignored.Originality/valueIn this paper, a deformation gradient model is proposed to obtain the deformation variations of non-rigid parts during the assembly process. The small deformation variation, which is often modeled using a finite-element method in the existing works, is modeled using the proposed deformation gradient model and integrated into the nominal dimensions. Using the deformation gradient models, the non-rigid part deformation variations can be computed and the accumulated deformation variation can be easily obtained. The assembly variation propagation model is developed to predict the accuracy of the non-rigid assembly by integrating the deformation gradient models into the homogeneous transformation matrix.

Discovery of key function module in complex mechanical 3D CAD assembly model for design reuse

PurposeComplex mechanical 3D computer-aided design (CAD) model embodies rich implicit design knowledge. Through discovering the key function parts and key function module in 3D CAD assembly model in advance, it can promote the designers’ understanding and reuse efficiency of 3D assembly model in design reuse.Design/methodology/approachAn approach for discovering key function module in complex mechanical 3D CAD assembly model is proposed. First, assembly network for 3D CAD assembly model is constructed, where the topology structure characteristics of 3D assembly model are analyzed based on complex network centrality. The degree centrality, closeness centrality, betweenness centrality and mutual information of node are used to evaluate the importance of the parts in 3D assembly model. Then, a multi-attribute decision model for part-node importance is established, and the comprehensive evaluation for key function parts in 3D assembly model is accomplished by combining Analytic Hierarchy Process and Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS). Subsequently, a community discovery of function module in assembly model-based Clauset–Newman–Moore (CNM)-Centrality is given in details. Finally, 3D CAD assembly model of worm gear reducer is taken as an example to verify the effectiveness and feasibility of proposed method.FindingsThe key function part in CAD assembly model is evaluated comprehensively considering assembly topology more objectively. In addition, the key function module containing key function part is discovered from CAD assembly model by using CNM-Centrality-based community discovery.Practical implicationsThe approach can be used for discovering important design knowledge from complex CAD assembly model when reusing the assembly model. It can help designers capture and understand the design thinking and intent, improve the reuse efficiency and quality.Originality/valueThe paper first proposes an approach for discovering key function module in complex mechanical 3D CAD assembly model taking advantage of complex network theory, where the key function part is evaluated using node centrality and TOPSIS, and the key function module is identified based on community discovery.

Experimental Validations of Hybrid Excited Linear Flux Switching Machine

Linear Flux Switching Machines (LFSMs) possess the capability to generate adhesive thrust force, thus problems associated with conventional rotatory electric machines and mechanical conversion assemblies can be eliminated. Additionally, the unique features of high force/power density, efficiency, and a robust secondary structure make LFSMs a suitable candidate for linear motion applications. However, deficiency of controllable air-gap flux, risk of PM demagnetization, and increasing cost of rare earth PM materials in case of PMLFSMs, and inherent low thrust force capability of Field Excited LFSMs compels researchers to investigate new hybrid topologies. In this paper, a novel Double-Sided Hybrid Excited LFSM (DSHELFSM) with all three excitation sources, i.e., PMs, DC, and AC windings confined to short moving primary and segmented secondary providing short flux paths is designed, investigated, and optimized. Secondly, unequal primary tooth width optimization and additional end-teeth at all four corners of the primary equip proposed design with balanced magnetic circuit and reduced end-effect and thrust force ripples. Thirdly, the measured experimental results of the manufactured proposed machine prototype are compared with corresponding simulated model results and shows good agreements, thus validating the theoretical study.

Research on reliable sealing technology of spacecraft rectangular hatch based on boundary control

In view of the large size of the sealing surface of the space large diameter rectangular cabin door, the large number of locking mechanisms and long service life, it is difficult to adjust the multi degree of freedom attitude in the assembly process, the complex assembly and adjustment of the mechanism, the synchronization accuracy is not easy to ensure, the consistency of the multi-point seal compression rate is high, and it is not easy to control. Based on the rotation law of the spatial linkage mechanism, the precise dimension chain control of the hatch is carried out, and the attitude of the multi degree of freedom linkage is adjusted to realize the synchronous compression of multiple compression units of the compression mechanism; Based on the minimum and maximum operating force as the boundary, through the sealing stress simulation, the “boundary control” coupling assembly and adjustment technology is proposed to optimize the sealing structure and realize rapid and efficient assembly. The results show that the vacuum leakage rate is still less than 2.5×10−3 PaL/s after 2000 door opening and closing tests and sealing compression ratio are better than 15%. The long-life test verifies the feasibility and effectiveness of this method, and forms a set of high reliable and long-life sealing assembly and adjustment method of space hatch, which provides technical guidance and reference for the subsequent assembly of similar space hatch mechanisms.

Possible use of precipitation for water recirculation system of a machine building site: analysis

An urgent task for industrial enterprises of metallurgical complexes is to create a rational and most environmentally friendly cycle of recycling water supply. One of the options for optimizing the efficiency of the water supply system is the collection and use of precipitation. This article presents the conducted studies of the chemical composition of atmospheric precipitation collected from the roof of the mechanical assembly shop of a machine-building enterprise in the Moscow region, as well as the possibilities of their further use in the circulating water supply cycle of this enterprise. At the first stage of the experiments, a primary assessment of the chemical and microbiological indicators of the quality of atmospheric precipitation was carried out depending on the season, and the data obtained were compared with the requirements of regulatory documents. In order to inhibit biological processes occurring during the collection and accumulation of atmospheric precipitation, a technology for the disinfection of effluents was proposed, based on the use of hydrodynamic cavitation devices. A method for calculating the applied hydrodynamic devices is presented. The technology of ultrafiltration purification through ceramic membrane filters was proposed as the final stage of additional purification of atmospheric precipitation but with standard values. This stage allows with a high degree of efficiency to remove from the water micro-impurities of suspended solids, as well as formed in the process of hydrodynamic treatment of insoluble compounds. The proposed technology of hydrodynamic treatment of atmospheric water with subsequent ultrafiltration was subsequently successfully tested in real conditions. The calculation of the expected volumes of formation and collection of atmospheric precipitation was carried out with an assessment of the possibility of reducing the volume of water consumption from an artesian well. The high prospects of using atmospheric precipitation for feeding individual operations (galvanic processes, boiler water) have been confirmed. This research was carried out under a programme aimed at giving support to young research and teaching staff of D.Mendeleev University of Chemical Technology of Russia; Application No. К-2020-015.