Assembly Machine Research Articles

Design and Implementation of Control System in Ultrasonic Detection Machine for Shaft-Tube-Like Part

Nondestructive inspection should be carried out before a shaft-tube-like part of an important machine assembly. The Ultrasonic Detection Machine was typically designed to detect if a shaft-tube-like part has some imperfection. There are three work posts in this equipment, they work continuously. This approach makes it very easy to split up a complex transformation into a series of simple transformations arranged in a pipeline. The machine includes control system built with SIEMENS CPU224 programmable logic controller (PLC), hydraulic driving system and the ultrasonic detection. Practices show that the prototype built can detect a key part quickly and efficiently before assembled, which is used in military, high pressure vessel, aerospace field and huge bridge, etc.

Crystal Structure of BamB from Pseudomonas aeruginosa and Functional Evaluation of Its Conserved Structural Features

The assembly of β-barrel Outer Membrane Proteins (OMPs) in the outer membrane is essential for Gram-negative bacteria. The process requires the β-Barrel Assembly Machine (BAM), a multiprotein complex that, in E. coli, is composed of the OMP BamA and four lipoproteins BamB-E. Whereas BamA and BamD are essential, deletion of BamB, C or E produce membrane permeability defects. Here we present the high-resolution structure of BamB from Pseudomonas aeruginosa. This protein can complement the deletion of bamB in E. coli indicating that they are functionally equivalent. Conserved structural features include an eight-bladed β-propeller fold stabilized by tryptophan docking motifs with a central pore about 8 Å in diameter at the narrowest point. This pore distinguishes BamB from related β-propellers, such as quinoprotein dehydrogenases. However, a double mutation designed to block this pore was fully functional indicating that the opening is not essential. Two loops protruding from the bottom of the propeller are conserved and mediate binding to BamA. Conversely, an additional loop only present in E. coli BamB is not required for function. A cluster of highly conserved residues in a groove between blades 6 and 7 is crucial for proper BamB folding or biogenesis. It has been proposed that BamB may bind nascent OMPs by β-augmentation to its propeller outer strands, or recognize the aromatic residue signature at the C-terminus of OMPs. However, Isothermal Titration Calorimetry experiments and structural analysis do not support these proposals. The structural and mutagenesis analysis suggests that the main function of BamB is to bind and modulate BamA, rather than directly interact with nascent OMPs.

Research on Complex Precision Mechanical System Assembly Parallel Control System

To achieve the assembly process control of aerospace complex precision mechanical systems and ensure its dynamic characteristics, parallel control theory and methodology is used in the assembly process. The main point is: assembly parallel control system is built corresponding to the actual assembly ones. The ultimate quality of assembly is guaranteed via alignment influence analysis on the dynamics characteristics of the assembly joint structural and the assembly machine and the dynamic characteristics-oriented alignment process optimization and decision-making to carry out computing operator and process decision-making in the assembly process. The dissertation ,regarding space sophisticated mechanical system assembly and its dynamic characteristics as study object, introduced the parallel control thought, presented the overall framework of assembly parallel control, built the assembly parallel control system(APCS) and given the main process and implement of assembly parallel control.

Research on the Material Tracking Management System in the Magnetic Pump Assembly Process

The material tracking management system in the magnetic pump assembly process is studied to the machine shop and assembly shop of a pump company as an example. The system mainly includes production line management module, assembly process management module, material tracking management module and work in process (WIP) tracking management module. In this system, the workshop visual management, real-time status information collecting on-site, materials status monitoring, and product life cycle file establishing are implemented. The functions of product assembly processes tracking can be realized, so that the traceability of the parts, components, WIP and products in the process can be achieved. The system ensures the material supply timely and equipment operation normally in the production processes.

Research on Automatic Judgement of Wheelset Press-Fit Curve

This paper presents an automatic judgement method for wheelset press-fit curve, in which thirteen technical conditions are examined for qualified wheelset assembly or not. In order to meet the requirements of Criterion of inspection and repair - railway vehicles [2007]95, some algorithms are designed to identify several traits on press-fit curve, such as force zoom, force decrease, flat line, concave-up shape and so on. In accordance with the Criterion 95 and the algorithms, a quality judgement software attaching to the computer control system in a wheelset assembly machine is developed. The practical application shows that the software’s judgement accuracy is up to 99.4%. Compared with artificial approach, the accuracy, reliability and efficiency of the new judgement method all improve greatly. It also avoids influences of personal factors and makes great sense to the assurance of press-fit quality and transportation security.

1,25-Dihydroxyvitamin D3 Suppresses Telomerase Expression and Human Cancer Growth through MicroRNA-498

Telomerase is an essential enzyme that counteracts the telomere attrition accompanying DNA replication during cell division. Regulation of the promoter activity of the gene encoding its catalytic subunit, the telomerase reverse transcriptase, is established as the dominant mechanism conferring the high telomerase activity in proliferating cells, such as embryonic stem and cancer cells. This study reveals a new mechanism of telomerase regulation through non-coding small RNA by showing that microRNA-498 (miR-498) induced by 1,25-dihydroxyvitamin D3 (1,25(OH)(2)D(3)) decreases the mRNA expression of the human telomerase reverse transcriptase. MiR-498 was first identified in a microarray analysis as the most induced microRNA by 1,25(OH)(2)D(3) in ovarian cancer cells and subsequently validated by quantitative polymerase chain reaction assays in multiple human cancer types. A functional vitamin D response element was defined in the 5-prime regulatory region of the miR-498 genome, which is occupied by the vitamin D receptor and its coactivators. Further studies showed that miR-498 targeted the 3-prime untranslated region of human telomerase reverse transcriptase mRNA and decreased its expression. The levels of miR-498 expression were decreased in malignant human ovarian tumors as well as human ovarian cancer cell lines. The ability of 1,25(OH)(2)D(3) to decrease human telomerase reverse transcriptase mRNA and to suppress ovarian cancer growth was compromised when miR-498 was depleted using the sponges in cell lines and mouse tumor models. Taken together, our studies define a novel mechanism of telomerase regulation by small non-coding RNAs and identify miR-498 as an important mediator for the anti-tumor activity of 1,25(OH)(2)D(3).

The Roller Disassembly and Assembly Machine Controlled by PLC

This paper provides a kind of roller maintain machine. It introduced the structure and the working principle of the roller disassembly and assembly machine. According to the work requirements, selected the PLC Toshiba's F1-20MR，to realize the switching sequence control function. Analyzed machine's work flow, Designed the PLC control program. Point out the advantage that using PLC replaced the original relay logic control systems: flexible application and good generality, high reliability and environmental adaptability; the program is simple to grasp easy.

Application of Virtual Assembly Technology in the Design of Shaper

Using functions of the parametric design and assembling in Pro/E, the parametric model for parts of shaping machine was established and the virtual assembly of shaping machine was achieved according to the parts of the assembly relationship in Pro/E assembly environment. Using functions of gap analysis and interference check in Pro/E,it can check interference to find and amend parts structure of shaping machine and can analyse gap to find the assembly relationship of shaping machine. Through the motion simulation, it can simulate movement of various parts of shaping machine in virtual environment. Using the method of virtual assembly ,it can met the design requirement of shaping machine, reduce the design cost of shaping machine, shorten the product development cycle, improve the design efficiency. It has offered a kind of new design method and implementation way for research of the model.

Digital Design and Manufacturing of Zero-Tooth-Difference Mechanism Based on UG

Digital design and manufacturing is the development direction of CAD/CAM technology. Using the powerful CAD/CAM function of UG software , analyze the tooth profile curve of involute internal gear with , which is a part of electric submersible progressing cavity pump, and realize virtual assembly and wire cut electrical discharge machining. The application based on UG digital design and manufacturing technology can improve production effectiveness, boost production development, save energy and powerfully，and impel the development process of manufacturing industry.

Application of a new type feedforward‐feedback controller in assembly machine for assembled camshaft

PurposeAiming at the positioning accuracy control problem in the running of the assembly machine for assembled camshaft, a kind of position controller based on the feedforward‐feedback control of speed and acceleration is designed.Design/methodology/approachIt combines feedforward‐feedback control with the quartic displacement curve acceleration/deceleration algorithm.FindingsThe axial dimension and the phase angle of the cam obtained after being assembled is checked. The result shows that for each type of camshaft, the error of the axial dimension of the cam is less than ±0.2mm and the error of the phase angle of the cam is less than ±30′. In addition, production efficiency is greatly improved (the assembling time is 90‐120S/piece).Originality/valueThe paper combines feedforward‐feedback control with the quartic displacement curve acceleration/deceleration algorithm for the first time.

Absence of O antigen suppresses Shigella flexneri IcsA autochaperone region mutations

The Shigella flexneri IcsA (VirG) protein is a polarly distributed autotransporter protein. IcsA functions as a virulence factor by interacting with the host actin regulatory protein N-WASP, which in turn activates the Arp2/3 complex, initiating actin polymerization. Formation of F-actin comet tails allows bacterial cell-to-cell spreading. Although various accessory proteins such as periplasmic chaperones and the β-barrel assembly machine (BAM) complex have been shown to be involved in the export of IcsA, the IcsA translocation mechanism remains to be fully elucidated. A putative autochaperone (AC) region (amino acids 634-735) located at the C-terminal end of the IcsA passenger domain, which forms part of the self-associating autotransporter (SAAT) domain, has been suggested to be required for IcsA biogenesis, as well as for N-WASP recruitment, based on mutagenesis studies. IcsA(i) proteins with linker insertion mutations within the AC region have a significant reduction in production and are defective in N-WASP recruitment when expressed in smooth LPS (S-LPS) S. flexneri. In this study, we have found that the LPS O antigen plays a role in IcsA(i) production based on the use of an rmlD (rfbD) mutant having rough LPS (R-LPS) and a novel assay in which O antigen is depleted using tunicamycin treatment and then regenerated. In addition, we have identified a new N-WASP binding/interaction site within the IcsA AC region.

Combinatorial Biosynthesis of Cyclic Lipopeptide Antibiotics: A Model for Synthetic Biology To Accelerate the Evolution of Secondary Metabolite Biosynthetic Pathways

Nonribosomal peptide synthetases (NRPSs) are giant multi-enzymes that carry out sequencial assembly line couplings of amino acids to generate linear or cyclic peptides. NRPSs are composed of repeating enzyme domains with modular organization to activate and couple specific amino acids in a particular order. From a synthetic biology perspective, they can be considered as peptide assembly machines composed of devices to couple fatty acids to l-amino acids, l-amino acids to l-amino acids, and d-amino acids to l-amino acids. The coupling devices are composed of specific parts that contain two or more enzyme domains that can be exchanged combinatorially to generate novel peptide assembly machines to produce novel peptides. The potent lipopeptide antibiotics daptomycin and A54145E have identical cyclic depsipeptide ring structures and stereochemistry but have divergent amino acid sequences. As their biosynthetic gene clusters are derived from an ancient ancestral lipopetide pathway, these lipopeptides provided an attractive model to develop combinatorial biosynthesis to generate antibiotics superior to daptomycin. These studies on combinatorial biosynthesis have helped generate guidelines for the successful assembly of NRPS parts and devices that can be used to generate novel lipopeptide structures and have established a basis for future synthetic biology studies to further develop combinatorial biosynthesis as a robust approach to natural product drug discovery.

An economic production quantity model with a positive resetup point under random demand

In this paper, an extended economic production quantity (EPQ) model is investigated, where demand follows a random process. This study is motivated by an industrial case for precision machine assembly in the machinery industry. Both a positive resetup point s and a fixed lot size Q are implemented in this production control policy. To cope with random demand, a resetup point, i.e., the lowest inventory level to start the production, is adapted to minimize stock shortage during the replenishment cycle. The considered cost includes setup cost, inventory carrying cost, and shortage cost, where shortage may occur at the production stage and/or at the end of one replenishment cycle. Under some mild conditions, the expected cost per unit time can be shown to be convex with respect to decision parameters s and Q. Further computational study has demonstrated that the proposed model outperforms the classical EPQ when demand is random. In particular, a positive resetup point contributes to a significant portion of this cost savings when compared with that in the classical lot sizing policy.

Virtual Assembly and Kinematic Simulation of Gear Form Grinding Machine Based on Pro/E

On the basis of establishing 3D modeling of gear form grinding machine, all levels of subassemblies of the grinding machine were assembled. Then the virtual assembly of total grinding machine was completed. Based on the kinematic simulation module of Pro/EMechanism, and combined with the virtual machine assembly model, the simulation analysis on machine movement was carried out. By simulating the actual working situation of the model, it could be checked whether the location, movement and load of the product could meet actual requirements before manufacturing the physical prototype of the product. This method is helpful for improving one-time success rate of new product development and saving product development cost.

Development of the Control Section for a New Armature Components Assembly Machine and its Application Test

The armature components are the core component of the electro-hydraulic servo valve [. Its manufacturing and assembly accuracy directly affects the performance of the servo valve. The domestic existing electro-hydraulic servo valve armature assembly pressure equipment is so far behind that it is difficult to meet production requirements. For the needs of a servo valve production firm, authors department developed the armature components automatically press machine. In order to achieve automation and intelligent of press process, this article supports a electronic control system for the press machine to further improve its ability. And on the basis of certain experiments, the author proves the good performance of the pressure machine.

Design of A Center Deviation Adaptive Bearing Pressure Assembly Machine

A car transmission in order to solve the production of eight gear and nine file two models of the transmission of tapered roller bearing outer ring manual assembly accuracy, low noise, the efficiency is low, the labor intensity and difficult to realize automatic assembly line requirements so assembly problem, put forward the center deviation adaptive bearing pressure assembly machine development. Through the research, design, test and making, eventually developed used in automobile gearbox bearing pressure assembly machine. Therefore the automatic production is achieved,which improves the production efficiency, ensures the assembly quality, and brings higher profit to the enterprise. DOI: http://dx.doi.org/10.11591/telkomnika.v10i4.859

Automatic assembly sequence exploration without precedence definition

Today the assembly sequence for the products is often carried out manually and its definition, typically, is very expensive, not guaranteeing optimal solutions. Coming up with an efficient assembly sequence is the essential step to improve process productivity and reduces the time and costs related to assembly machines and equipment. The issue related to the assembly sequence of a product depends on the total number of the its components. In particular, the number of the possible sequences can be obtained through the calculus of the factorial of the number of the product components. This work presents an automatic approach intended to define assembly sequences, based on the information regard the contacts and the interferences existing among the components, which is obtained by the assembly CAD model of the product. The level of the information required by this approach allows its implementation at early stages of design, as soon as the layout of the conceptual solution of the product is defined, independently by the method used to model the CAD assembly. The procedure proposed is focused to obtain a reduced number of assembly sequences, guaranteeing that there is at least one feasible assembly sequence among them. The procedure is oriented to iteratively identify independent and important subassemblies into the CAD assembly, then merge them to specific assembling nodes and generate sequences until the whole product is analyzed. After a brief review of current methodologies developed for assembly planning, in this paper, the automated procedure for assembly sequence generation is explained and applied on an example, obtaining feasible solutions.

The Technology of Positional Detection in Automatic Wheelset Assembly Machine

This paper introduces a kind of position measurement and control systems in automatic wheelset assembly machine. This system adopts direct close-loop position control in the process of pressing and real time monitor position of wheel and axle with high accuracy. Compared with traditional wheelset assembly machine, it can improve production efficiency and ensure the quality of pressing through control the distance between backs of wheel flange and the position difference of two wheels accurately.

Tom40 is likely common to all mitochondria

Summary The evolution of the mitochondrion has involved the remodelling of the two membranes that enclose this organelle. During the transformation of the endosymbiotic bacterium into a genetically dependent organelle, the flow of proteins across the membranes reversed. This change is reflected by the distinct sets of protein transport machinery that operate in bacterial and mitochondrial membranes [1]. One of the exceptions is a β-barrel assembly machine, Sam50, a member of the Omp85 superfamily of proteins, which has been retained in the mitochondrial membranes. Other core components of mitochondrial translocases, such as Tom40 in the outer membrane and the Tim17 family of proteins in the inner membrane, cannot be directly related to any bacterial proteins. Two studies by Pusnik et al. recently showed that the mitochondrion of Trypanosoma brucei was found to be devoid of the essential Tom40 channel [2]; instead, it was found to contain an essential protein called the archaic translocase of the outer mitochondrial membrane (ATOM) that was directly linked to bacterial YtfM proteins, which are members of the Omp85 superfamily [3]. Thus, it was suggested by Pusnik et al. that ATOM and Tom40 represent mutually exclusive functional analogues of distinct origins [3]. We analysed the ATOM amino acid sequences to identify homology to known protein families and to determine the phylogenetic distribution of the closest relatives of ATOM. Surprisingly, our results clearly refute the link between ATOM and bacterial Omp85-like proteins. Moreover, we propose that ATOM is, in fact, a divergent form of the ‘classical' Tom40.

Measurement and Calibration of the Displacement and Pressure in Automatic Wheelset Assembly Machine

This paper introduces the measurement systems of the oil cylinder in automatic wheelset assembly machine, theoretically analyzes the error of the displacement measurement system by curve fitting, and gets verification the error analysis in practice. This paper also calibrates pressure sensor from zero drift, slope of the output of the pressure sensor to guarantee the system pressure, and compensated pressure sensor value consistent.