With the development of the integration of the world economy andindustry, has taken place great revolution in the environment of modern manufacturing enterprise, the Virtual Axis Machine Tools is considered the 21th Centuary’s machine tool. The study of electromechanical coupling can establish a foundation for widely application of Virtual Axis Machine Tools. The development and application of Virtual Prototyping Technology provide a technical means for the exploitation and research of NC Machine Tool. How to apply virtual and simulation technology to solve the key problem of machine tool is key in the field of machine tool. The virtual axis polishing machine tool that is exploited in Jilin university and used to polish free-form surface is applied as a study object. Use the software of ANSYS, ADAMS and MATLAB as tools to analyze the problems about virtual axis polishing machine. According to the characteristics of serial mechanism, put forward static-dynamic simulation control theory based on Virtual Prototyping Technology, study the application of virtual prototype technology in virtual axis machine tool, propose a kind of parallel controlling strategy based on CMAC and PID, and study the characteristics of transmission and electromechanical coupling. By introducing virtual technology to the study and analysis of virtual axis machine tool, provide a new technology platform for the widely using of this new type machine tool.1.On the base of analysis of machine tool structure, draw the model of series mechanism of virtual axis polishing machine tool by using CATIA, which contains dynamic platform and tool. Simply the model in order to analyze conveniently, establish and assemble the solid models of each part of mechanism. The series mechanism is as follows Fig1. Fig1.series mechanism of virtual axis polishing machine2.Constraint each component of virtual axis polishing machine tool by using SimDesigner in CATIA V5. Measures the motion path of polishing tool in the polishing machine tool and analysis the motion characteristics of series mechanism of virtual axis polishing machine tool under working of the servo-motor. The analysis results of ADAMS is as follows Fig2. Simulation analysis show that the mechanism has the properties of well acceleration performance , shorter time of adjustment, accurate and fast implementation. Fig2.The force,torque,displacement of cutterhead in working of servo-motor3.The precision of series mechanism will directly effect the precision of whole machine tool. This thesis conduct a static-dynamic analysis of series mechanism. For convenient analysis, deal with models by means of deleting some modified characteristics, such as chamfer, lug boss and keyhole that will not effect the mechanism significantly. Lead the models to Software ANSYS and come on its previous 12 order frequency and vibration mode . Fig3 is First Order Modal Logic, is clearly that the around area of polishing tool has big deformations under the effect of servo-motor. Fig3.The first order mode shape of series mechanism of virtual axis polishing machine4.Motor torque is the input of the modal and exercise volume of polishing tool is output. Draw out the kinetic curve of polishing tool based on the simulation by use of software ADAMS and MATLAB. The polishing tool can work stably in short time and the flutter of polishing tool can satisfy the processing precision’s requirement by way of analyzing the motion of series mechanism. Fig4.The cutterhead’s flutter force under effect of two driving force based on MATLAB5.Put forward a parallel control method of CMAC and PID aiming at the nonlinearity and various uncertainty existing in high precision servo systems. Study the electromechanical coupling prosperities of high-precision drive in servo systems based CMAC and PID, establish the coupling modal of servo systems and simulate the structure by use of MATLAB/Simulink. The results show that the method overcome some disadvantages that common controller can’t avoid, improve the control effect, fasten control corresponding velocity, satisfy the tracking accuracy’s requirements and fully embody cerebellum model’s characteristics, such as minor error, strong robustness. The research has considerable reference value in in improving the high precision dynamic tracking of servo systems.
Metallurgy and Metal Craft Archive
With the increase of traction load and running speed for train, the fracted failure of casting coupler yoke rise significantly, which brings severe secure incipient fault to railage, and improving coupler yoke’s property has become one urgent problem to resolve.Heat treatment technique of forgedcoupler yoke has been studied in this paper, in which the is utilized to determine the reasonable for mass production of forged coupler yoke and heat treatment parameters are optimized by using the software based on optimization design method and simulating test. Meanwhile, quenching technique of forged grade E steel coupler yoke has been studied and the with the agitated control system used in ’s quenching is designed.The research results show that the which has been determined by the is scientific and reasonable. After heat treatment on the basis of this regulation, the microstructure of is symmetrical tempering sorbite and the microstructure and properties meet the need of railway. The strength of grade E steel treated by optimized parameters has raised by 8.3% at high plasticity level. The with the agitated control system can control the cooling speed of workpieces,improve and stabilize the quenching quality of workpieces. Research on heat treatment technique of forged grade E steel coupler yoke provide new ideas and technical direction to other heat treatment technology and workpieces.
China, whose casting output occupies head of the world, is the great casting nation in the world, but compared to developed countries, our casting quality level still has a very big gap. At present, many domestic casting enterprises have been qualified for ISO 9000 quality system, butnever has been really applied into actual production. How to apply the theories and methods of quality management and control into casting production specifically and suitably, and to make the quality management land on feet , and finding out management methods suitable to national condition are urgent matters of present casting enterprises in domestic, and also have the profound significance to the development of our casting quality and the overall level of our casting industry.In this thesis, the research object is of Erzhong foundry factory. First, existing quality management of foundry factory and quality problems in have been analyzed. Then, the paper proposes applying traceability technology to the casting quality control and constructs casting quality traceability system, and also builds and implementsThe following is the main contents of the dissertation:① quality and its available quality control are introduced, and present statue of casting quality control in domestic and foreign is summarized. Then, the main contents of the dissertation and its significance are presented.②The product structure and are discussed and existing quality management of foundry factory and quality problems in casting process are analyzed. a Summary is made on frequent quality problems of casting and the reasons are analyzed.③The traceability technology is applied into casting quality control to construct a casting quality traceability system. And the implementation thought、construction and key technologies are presented.④The establishment and implementation of the casting quality traceability information system are stated, including analysis of the system functions and design of module、design of the database and the implementation of the database’s structures.Finally, a summary of the research work and the results is made, and plans for future research are presented.
The Numerical Simulation Research on Principal Axis System and Driver System of the Specialization Lathe
High-efficient centerless machine tool is one specialization lathe which is used to process steel bar, at present the centerless lathe Q3808A type that is produced by the company of heavy machine tool of Qinghai only in our country. For some question that the centerless lathe Q3808A type exists, the company cooperates with the College of Mechano-electronicof Lanzhou University of Science & Technology in optimizing design at original design foundation in order to the lathe can get superior and better machining accuracy and higher processing efficiency, and to develop the new serial lathe on this basis.In the course of overall progress of the horizontal subject, this thesis has a deep research on dynamics characteristics of the principal axis system and the drive system of the lathe. The of the principal axis system on the basis of the Riccati transfer matrix is set up, and its corresponding mathematics model is set up too. Some relevant information of its intrinsic characteristic while getting horizontal vibration of the principal axis system and of dynamic characteristic of the principal axis system influenced by those main design parameters of its are achieved through the numerical simulation of the to use , and then a detailed analysis is carried directly on them. A of the drive system on the basis of the Riccati transfer matrix is set up, and its corresponding mathematics model is set up too. Through the numerical simulation of the , some relevant information of its intrinsic characteristic on torsional vibration, and a analysis is given to them; A dangerous mode in torsional vibration is confirmed through a calculation of flexible degree of modality, then the weak links of this system are confirmed through a calculation of distributing rate of energy under this dangerous mode of the system. Finally a kind of improved project is put forward, and its dynamic behavior is predicted.
Since the discovery of the shape memory effect,NiTi shape memory alloy is considered to be the most important shape memory alloys for its salient superelasticity and shape memory effect Which are displayed in martensitic transformations,This material transforms martensitically from the parent B2 phase to a monoclinic martensitic phase at the transformation temperature of 333 K.This material has been used in the aerospace industry, for electronics and.In the last decade NiTi-based alloys have found widespread applications in medicine also.In the case of TiNi the knowledge of the nature of its biocompatibility is very important because Ti is a good implant material but Ni is well known as a hazard material. However, biocompatibility is the surface related property.The properties of materials are determined by their atomic and electronic structures, and the quantum chemistry provided a viable method in computing the behavior of electrons and atomic nuclei under arbitrary circumstances. The first principles Density Function Theory is always the most powerful tool for calculating electronic structure and characteristics in the field of Condensed State physics.The theoretical basis of CASTEP is the density functional theory (DFT) in the local density approximation (LDA) or gradient-corrected LDA version, as developed by Perdew and Wang (GGA). The DFT description of electron gas interactions is known to be sufficiently accurate in most cases, and remains the only practical way of analyzing periodic systems.In the paper, a first-principles plane-wave method, a total energy CASTEP code is utilized to systemically investigate the geometrical and electronic structure of NiTi .First we have studied the bulk properties of the NiTi alloy,such as lattice parameters, formation energy , elastic constant ,electronic structures, the results have good agreement with experimental and othercalculating results. Through computating energy at different crystal lattice distance ,Obtains when the crystal constant is 0.314nm, the energy is lowest.The alloy formation energy and cohesive energy reflect the material stability and unifies strong or weak between the alloy atom.Through the computation,the formation energy and cohesive energy of NiTi alloy is -0.335eV/atom and -5.003eV/atom respectively.The origin of unique B19′phase is a result of the coupling between C44 and C’,and C44 controls B19′transformation temperature,the harder C44, the lower the transformation temperature to is B19′.Furthermore, can be seen that the anisotropy factors A of NiTi are far smaller than those of the usual martensitic alloys,It is argued that the higher A is a sufficient condition for the B2 to B19 martensitic transformation. the paper also conforms to the above viewpoint through the elastic constant computation。Niti’Fermi levels fall on a dip of a DOS curve. As well known, a dip is generally considered to divide a DOS into a bonding state and an antibonding state,thus when a Fermi level falls on the dip, the corresponding structure may be regarded as a saveenergy system, as compared with one whose Fermi level does not fall on the dip. Thus, this kind of structure is more stable;Secondly,we have studied the geometry structures and electronic structures of NiTi (100) and(110)surface, Predicted adsorption oxygen on the NiTi alloy (100) surface. As for the surface geometry structures, there are no reconstruction in the cleaned NiTi (100)surface, but there are different relaxation in the surface layers. the interlayer distance between the surface and subsurface layers,δ12= -12.76% for Ni/NiTi andδ12= -10.31%for Ti/NiTi, whereas the second interlayer distance expanded byδ23=5.19%、δ23=5.21% in both cases.As for the cleaned NiTi(110) surface,outermost surface layer shows a large rippled relaxation in which Ni atoms contract into the bulk by 0.122? and Ti atoms expand to the vacuum region by 0.198?, the interlayer distancebetween the surface and subsurface layers,δ12=-7.35%,whereas the second interlayer distance,δ23=5.5%。the ripple,γ1=15.38%、γ2=-13.98%。The calculation of the surface electronic show that Ti-terminated surface is more reactive than Ni-terminated surface on (100) surface and the NiTi (110) surface is inert. The energy and electronic structure calculation indicated the structure with single oxygen layered at the hollow position is more stable than that at top position and at bridge position on the Ti-terminated surface.The structure with double oxygen layered at the hollow and top position is more stable than the structure with double oxygen layered at bridge position.when the position stand in the middle of bridge position and hollow position and approache (100) surface by the parallel way, O2 will decompose after adsorption,the oxygen atoms near hollow position move downwards to the subsurface,and the oxygen atoms near bridge position move to the top position, an TiO2 film could form with an Ti-O bond length and an angle of bonds which is closed to those of TiO2 .
As an effective approach to improve performances of cutting tools, the technologies of coated tools have been rapidly developed and broadly applied. The multicomponents was deposited by using physical vapor deposition (PVD) coating techonlogy of closed field unbalance magnetron sputtering ion plating. The coating characteristics, s, and of coated tools were studied.During determination of the coating characteristics, the coating surfaces and cross section were observed using scanning electron microscope (SEM) and transmission electron microscope (TEM). Results show that the multicomponent matching with high speed steel (HSS) substrate is much more ideal and the coating microstructure is uniform and compact, by X-ray Diffraction (XRD) analysis, is also found that the coating has gradient phases structure and composition along the thickness, as well as high thermal stability. By experimentations of indentation, scratch and Pin-on-Disc, the coating have many advantages including higher hardness and toughness, excellent anti-friction and wear performance and stronger bond with the substrate.A large number of turning and milling cutting tests were carried out with the multicomponent CrAlTiN coated , the cutting perfomance were analyzed. The experimental results indicated that compared with the uncoated tools, the of M2 with multicomponent is obviously improved, the cutting force is reduced, the cutting process becomes more smooth, the tools life is prolonged. With the mathematical statistics to handle the cutting force and tool life test data, the empiric formulae were built. Through analysis of tests curves and formulae, the rules are revealed which both cutting force and tool life change with cutting parameters.By observing wear regions of the tools, the worn surface morphology and the wear rule are analyzed with the multicomponent CrAlTiN coated HSS tools, results show that due to the existence of the coating, the worn surface morphology of coated tools is obviously different from the uncoated tools: The early wear stage of the coated tools is shorter, while the normal wear stage is longer; the coating is able to resist tool wear, but the effect of coating is different during each wear stage. The compositions of worn surface were analyzed by FESEM, and the of these coated tools were revealed. The analysis results show that there is some coating in the form of flakes on the abrasion area of rake face on the coated turning tools; oxidation wear of flank is severer than rake face; the oxidation wear and diffusion wear of the coated milling tool rake face is not significant, abrasive wear is the main reason; the spalling phenomenon on the coated milling tool flank is significant.The diagrams of von Mises equivalent of coated and uncoated HSS tools wasw obtained through finite elements method simulation of the cutting process, the uncoated HSS tools illustrate the maximum von Mises stress on the rake face and near the tip of cutting edge.On the other hand, the coated HSS tools develop the maximum von Mises stress at a distance from the tip of the cutting edge, still on the rake face. The experimental results exhibit that the failed zone at initial wear stage fit the zone with the maximum Von Mises equivalent stress, shows that stress is the main cause leading to early failure of coating.
Resistence spot-welding is extensively used in the fields of automobile, aviation, spaceflight manufacturing enginnering and electric appliance industry. Resistance sopt-welding process and quality control are always one of the important research subjects in welding field. With the development oftechnology, ’s a trend that technology has a wide application in the field of Resistence spot-welding.In this thesis we introduced Distribute Control System ( ) into the spot-welder control system and did research on the realization of spot welder Distribute Control System. A spot welder MCU controller was discussed in the thesis firstly. The controller is made up of three unit modules: main board control system; user-machine interface which is a independent MCU control system; control executing system. We focused on the control system of the user-machine interface, designed and relized the hardware circuit and software of the interface system. Integration of technology , we had analyzed the system of spot-welding DCS control system. The communication hardware and software were provided in the thesis. In the section of hardware circuit design, the paper carried out the alternate for signal electrifying level between and microchip controller, at the same time, lengthen the distance for transmitting data by expanging RS-232 to RS-485 system bus. Regarding to the communication software design, we had designed the software solution of validating the communication between the up computer and down computer. We used the control Active X MSComm to design the up computer programs, used C51 language and plus WAVE emulator to develop the down computer communication programs.In the last section of the thesis, we had analyzed the reliability of DCS and did some research on anti interference of RS-485 bus, ’s necessary to do these work because the it’s useful for us to improve the spot welder DCS.
Theoperation planning in the numerical control machining process is the complex and extremely important link and contact with the processing procedure establishment, the components processing quality and the benefit closely. The quality of operation planning not only can affect the engine bed efficiency the isplay, but also will directly affect the components the processing quality. Therefore, the reaserch of the NC processing craft decision-making is necessary extremely.From the view of integration of CAD/CAPP/CAM, the modeling based on machining feature is proposed. The machining feature comes from the manufacturing process considering the restriction of machining technology and machining resource. Then the framework for aided process planning is presented, where the algorithms of operation planning is studied. There are four innovations in this system:(1) The CAPP based on machining feature is proposed and establish the machining feature modeling. The machining feature comes from the manufacturing process, contact with craft information, correspond to machining method and tools and can be directly used to CAPP.(2) Make the technology as the foundation. Based on the principle of the technology, we propose the rule of machining technology to adapt to this system and make the machining process more logical.(3) The proposing algorithms of operation planning– can obtain the least number of machining steps and make the machining process more logical.(4) Sustained by Pro/ENGINEER software and SQL Server 2000 database, we create the prototype system. The established manufacture resource database、processing method database、technology parameter database and feature modeling database can directly get the manufacture feature modeling, plan the process and create the technological document finally.The practical example has been provided and results indicate that machining feature – based model can integrate with CAPP seamlessly.
Research on Safety Early-Warning Technology of Long Transport Pipeline Base on Cathodic Protection Voltage
As the exploitation of oil and gas resources and the increasing of energy market, the transport pipeline has made a rapid development in the world and become the lifeblood of the national economy. Because more than half of pipeline of the world has been in service for more than 30 years, and the long transport pipeline in China has also been run for more than 20 years. According to the pipeline operation experience of domestic and international research, lots of potential accidents may happen to the pipeline coating at present.is one of the most important methods to make long transport pipeline work safely. The cathodic protection voltage is one parameter to judge whether the pipeline is under protection, so monitoring cathodic voltage on real-time and realizing early-warning for long transport pipeline is very important.A safety early-warning technology for long transport pipeline based on cathodic protection is proposed in this paper. consists of module with high-precision, low-power consumption and GPRS communication and the monitoring center. can cathodic voltage of test pipeline and transmit data to monitoring center through GPRS. At the monitoring center it realizes piecewise data fitting of the pipeline protection voltage distribution curve. With ideal protection voltage distribution curve and single-point protection voltage trend extraction, it can achieve the and safety early-warning for protective coating of buried pipeline.Field tests show that this wireless remote measuring system is dependable and accurate; it can realize the remote real-time monitoring for cathodic protection voltage and the early-warning for the long transport pipeline. Consequently, it can enhance the management level for cathodic protection of oil and gas pipeline which are in-service, and ensure the safety of pipeline run.
Influence of Alloying Elements of Bond Coat of Thermal Barrier Coatings on Its Interface Conjunction Factors
（TBCs） are commonly used to the surface of thermo-parts. TBCs can improve the work efficency and longevity of parts by covering top coat on the surface of alloy substrate. Bond coat is a kind of coating that improved the interface conjunction between the and the top coat. Some elements of are oxidized and forms thermally grown oxide （TGO） between and ceramic top coat during the application of the thermal barrier coatings. is proved by experiments that the failure of TBCs typically occurs at the interface between the bond coat and the TGO.Based on the Empirical electron theory in solid and molecule （EET） and improved Thomas-Fermi-Dirac （TFD） theory in this thesis, the valence ofα-Al2O3 in the thermally grown oxide （TGO） are analyzed, and that is in view of the valence and interface of the crystals. The interface conjunction factor between the bonding layer and ceramic layer of the thermal barrier coatings of different content of Al、Co、Cr、Y、Hf are calculated. The results are as following. Considering the electron density parameters ofρ,△ρmin,σ,σsuper,σequal on the bond-coat/TGO interface, the following conclusion can be obtained:1. Considering the cohesion force of the interface, the most favorable aluminium content of the bond-coat is 2-wt%. The aluminium content beneath 10-wt% is favorable, and the aluminium content over 10-wt% is harmful in this case. The aluminium content of the bond-coat being not more than 8-wt% is considered to decrease the interface stress.2. When the orientation of the bonding layer is （100） or （111）, the addition of Y can improve the interface conjunction. When the orientation is （110）, the electron density parameters of△ρmin is lower than the one without Y when the Y content is more than 0.7-wt%; Furthermore,△ρmin is the lowest when the Y content is 0.7-wt%. The electron density with Y content of 0.7-wt% of its （110） crystal plane is higher than without Y, and the interface electron density slightly decreases with the increase of the yttrium content when the yttrium content is higher than 0.7-wt%. Comprehensive analysis indicates that the bond-coat yttrium content of 0.7-wt%-0.9-wt% or a little higher is also suitable for the stability of the interface cohesion of the bond coat.3. No matter what orientation of the bonding layer in, the addition of Co can be in favor of the release of interface stress and keep the continuity of the interface electron density. At the same time, the Co content of 10-wt% -14-wt% is the optimal. While the orientation of the bonding layer is （110）, the increasing of Co content can enhance the interface conjunction. However, when the orientation is （100） or （111）, the content of Co almost has no effect.4. When the orientation of the bonding layer is （100） or （111）, the addition of Cr can improve the interface conjunction of the interface. If the factors of techniques can be controlled and formed orientation of being （111）, （100） in the bonding layer, the addition of Cr can improve the interface conjunction between the bond coat and the TGO. Therefore, in the situation when the texture in the bonding layer is controlled with difficulty, considering the interface conjunction, the content of Cr of Ni-based bonding layer should be reduced as low as possible.5. The additional of Hf is beneficial for the interface conjunction. Furthermore, these tend to the better estate beneath the Hf content of 1.3-at% （3.9-wt%）. is thought that the suitability Hf content can improve the interface conjunction between the bond coat and the TGO at the condition of meeting the intensity, toughness and anti-thermo -causticity of Ni-based bond coat.