Key Engineering Materials Vols. 315-316

Abstract: According to in-depth analysis of the interface between HSK shank and the spindle, the dynamic characteristic of HSK tool system in high speed machining is studied and numerical simulation is carried out with FEM. The HSK tool system deformation, contact stress and the change law of dynamic stiffness were opened out systematically. The relationship between the dynamic stiffness and loading capacity was given. The rotational speed per minute when HSK taper coordination position fails can be named limit maximum rotational speed Nmax of HSK. This provides the foundation for the design of the high speed machine tool.

Abstract: Fe-2Cu-2Ni-1Mo-0.8C (wt. pct) alloys were successfully fabricated from elemental mixed powders by high energy milling and pulse electric current sintering, and the effects of milling time and sintering parameters on the densification degree, microstructure, mechanical properties and fracture characteristic of sintered material were investigated. Results showed that with increasing milling time, pulse electric current peak and sintering time, the density and transverse rupture strength of sintered alloy were improved. However, higher pulse electric current peak and/or longer sintering time were unfavorable to the density and strength of sintered alloy, because of generating overhigh sintering temperature. The density and transverse rupture strength of sintered alloy could reach 7.74
103 kg/m3 and 2231 MPa, respectively, and the corresponding fracture morphology was characterized as intergranular fracture.

Abstract: In order to implement dynamic compensation for the wheel vibration of surface grinding machine, a micropositioning table with high stiffness and response frequency is designed. The micropositioning table is driven by three piezoelectric actuators with stiffness of 400 N/μm. Three capacitive sensors are utilized to form feedback control and flexure hinges are used to guide the moving part and preload for the piezoelectric actuators. The kinetics of the micropositioning table has been analyzed to understand the relationship of the control voltage and the posture of the moving part. Due to the coupling characteristic of the system, the decoupling control method is introduced to improve the performance of the table. Experimental tests are carried out to investigate the performance of the micropositioning table.

Abstract: The paper states the characteristic of Granite Surface Profiles. Gauss Filtering has been adopted on original granite surface profiles curver, and then researching its Roughness and Fractal. The method is an available and fast computation method for roughness and fractal to Granite surface profiles. The Relation Study of Roughness and Glossiness to Fractal have been Study by experiment.

Abstract: High-speed machining (HSM) has received great interest because it leads to an increase of productivity and a better workpiece surface quality. However, tool wear increases dramatically due to the high temperature at the tool/workpiece interface. Proper selection of cutting tool and cutting parameters is the key process in high-speed machining. In this paper, experiments have been conducted to high speed milling pearlitic cast iron with different tool materials, including polycrystalline cubic boron nitrogen, ceramics and coated cemented carbides. Wear curves and tool life curves have been achieved at various cutting speeds with different cutting tools. If efficiency is considered, Polycrystalline Cubic Boron Nitrogen cutting tool materials are preferred in finish and semi-finish machining. According to the different hardness of cast iron, the appropriate range of cutting speed is from 850 m/min to 1200m/min.

Abstract: Chemical vapor deposition (CVD) diamond is known for its superior characteristics such as hardness, toughness and wear resistance. However, due to these factors, machining CVD diamond is a difficult material removal process. A new technique to polish CVD diamond film efficiently is reported in the present paper. In the CVD deposition process, boron was doped into diamond to fabricate high-quality semi-conductive film, which make it possible to machine diamond film by electro discharged machining (EDM) method. The relationship between EDM parameter and removal processing was investigated in details. The machined surface of boron doped (B-doped) diamond films was studied by Scanning Electron Microscope (SEM) and Raman Scattering Spectroscopy (Raman). The experimental results show that EDM polishing is a highspeed material removal and low cost method for CVD diamond polishing. When the discharge current and pulse-on time increase in a certain range, the cutting-off speed and roughness will increase correspondingly. The roughness of EDM polished CVD diamond film surface is Ra<0.5μm when the discharge current is at 4A and pulse-on time is at 200μs.

Abstract: This paper introduces a kind of new homemade and low cost multi-channel nucleic acid pyrosequence detector for at least ninety-six channels and presents the detail of related software and hardware development. We construct a kind of automatic instrument to fulfill the pyrosequencing processes. First we select the X-86 personal computer as host computer, the AT89C51 micro-controller as slave computer, the PMT (photoelectric multiply tube) as photoelectric transformation equipment, and the HY-6022 as data sampling device; Second we use the Visual C++ 6.0 as coding tools to design the measure and control system based on Windows 2000 operating system; Third we sample the fluorescent signal in all of the cuvettes during the reaction between nucleic acid and reagent; Last we analyze these data to realize the function of the multi-channel nucleic acid detection. In this paper the whole instrument design and key parts design are both introduced such as the liquid injection process and related structure design, the communication module between the host personal computer and the MCS51, the high sensitivity multi-channel detector (at least 96 channels, the sensitivity is 2.45×10-9w) etc. The result of the instrument for two channels data processing is also reported in this paper.

Abstract: End mills with small diameter have found their wide application with the development of high-speed cutting. It becomes more and more important to develop effective methods to monitor and control the milling process with small end mills. In this paper, a measuring system of projection image for small end mills is introduced, and the application of the projection image to monitor the behavior of the end mill is discussed. It is found that for static state of the end mill, the measurement accuracy can be easily controlled within 1 μm. When the end mill rotates, it is not so difficult to control the accuracy within 3 μm. By using of the change in image width, the radial wear of end mill can be predicted. On the other hand, if the centre shift of the image is pre-measured, the deflection of the end mill during cutting can be predicted.

Abstract: The mechanism of vaccination was analyzed in the immune system and the improved immune algorithm for the job-shop scheduling problem was presented. The proposed method can reserve the advantage of vaccination and it is independent of the initial antibodies. Especially, the adaptive process of vaccination with the automatic pattern recognition can not only quicken the convergence of the algorithm but also overcome some deficiencies in distilling manually the transcendent knowledge of the problem. Simulation results show that it is an effective approach.

Abstract: An ultra-precision machine is developed to machine components made of KDP crystal with single point diamond fly cutting technique. This paper presents a compensating control algorithm of error disturbance feed-forward which enhances the stability of ultra-low speed motion of the semi-closed loop feed control servo system of the machine. The simulation results indicate that the values of the steady-state tracking error decreases to 1/10 after using the compensating control algorithm. The fluctuation ratio is less than 4% when machining KDP crystal with the feed rate of 60μm/s.