Due to the high temperature toughness and low thermal conductivity of 2.25Cr1Mo0.25V material, the rake face of the tool can easily wear out during the cutting process, which reduces the service life of the tool. In this paper, by analyzing the contact behavior, heat exchange conditions and tool wear mechanism during the cutting process, a 3 D finite element simulation model of tool wear in accordance with the actual cutting process is established. Combined with the cutting wear experiment, the validity of the model is verified. The influence of cutting speed, cutting depth, feed rate and the interaction between them on rake face wear was studied by designing a simulation scheme. The simulation results show that: With the increase of cutting speed and feed rate, the wear depth of the tool's rake face gradually increase, but for cutting depth, the depth of wear gradually decreases. The interaction of cutting speed and feed rate has a significant influence on the rake face wear, the interaction between cutting speed and feed rate, and the interaction between feed rate and cutting depth are not significant. The research results provide a theoretical basis for improving the service life of the tool and provide technical guidance for the selection of cutting parameters in the actual production.
The rapid development of architecture industry in China brings the large demand of operating skilled talents for architecture industry.The education in the major of higher vocational architecture engineering technology faces greater developing opportunities and challenges than ever.On the basis of analyzing the present condition of talents' training mode in the major of architecture engineering technology,this paper discusses talents' training mode in this major on professional talents' cultivating goal,the construction of teaching materials,the establishment of curriculum system,the construction of teaching staff,and the implementation of college-enterprise cooperation.
This paper analyzes force received by chip in process of machining the stainless steel 1Cr18Ni9Ti. The force state was analyzed respectively when cutting edge wear, groove wear, boundary wear of the minor cutting edge and the groove wear occurred. Based on analyzing the effects of cutting force changes on chip type, the effect law of tool wear upon the changes of chip type was obtained. Cutting experiments were carried out and the high-speed camera and the piezoelectric force measurement instrument were used to obtain cutting force data to verify the influences of tool wear on the changes of chip type. The research results provide the theoretical foundation for solving the key technical problems of tool breakage in the automated production.
Directed at the NC milling processing,this paper introduces the mathematic model of milling parameters optimization.The model,aimed at the greatest productivity for the object function,is subjected to the constraint conditions,such as machine,cutting tool,technics and so on.The optimization of the milling parameters by genetic algorithm,combined with the milling examples shows that the use of the optimal milling parameters takes much less processing time than that of the traditional milling parameters.
Helicopter with the advantage of light, flexible and hovering in the air, is widely used. In both military and civilian domain, it gets more and more attention. It becomes the main subject of research in the world. In the power transmission system of helicopter, the tail rotor shaft is an important part. It is one of the key technologies to predict the dynamic characteristics of the shaft accurately for improving the overall performance of the helicopter. Based on the theory of elastic mechanics, rotor dynamics and the finite element analysis, the former main drive shaft is taken as an example. The dynamic characteristics of the transmission shaft is calculated by the multi/few degrees of freedom finite element method. The validity of the finite element method with few degrees of freedom is determined. Then the structure characteristics of the helicopter tail drive shaft are analyzed, and the dynamic characteristics of the helicopter tail rotor shaft are calculated by using the finite element method with few degrees of freedom. The research results provide the basis and guidance for the design of the helicopter tail drive system.
Based on the experiments on milling the carbon structural 45 steel with the flat rake milling insert and the waved-edge milling insert with complex 3D grooves which is developed by HarBin University of Science and Technology, the paper have experiment study on the impact disrepair.Firstly, the finite element analysis and blurry synthetical judgement of the 3D stress field were carried on, and forecast that the anti-impact disrepair capability of the waved-edge milling insert is choiceness.Secondly the papaer finds out the difference of the impact disrepair invalidation types between different grooves milling inserts by the experiments.Based on the plentiful and systemic impact disrepair experiments, the impact disrepair life cumulating distribution function mathematic model is built.This paper proves that the anti-impact disrepair capability of the waved-edge milling insert is choiceness.All these studies provide the theoretic and experimental bases for solving the cutter disrepair which is the key problem in the automatization production and groove optimization.
Based on the chip space motion path, the chip dynamic simulation is carried out, which provides theoretical foundations for studying chip -forming, chip -breaking and the design of the new-style groove insert, and which can reduce the developing expenses of the new-style groove insert and shorten the developing periods.
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