Abstract: Stepping tapping is a new tapping mode for Nickel-based superalloy GH4169. Longer
life of tap and higher machining efficiency can be obtained. But chipping of tap is very prevalent. In
this paper, the mechanism of chipping in step tapping is investigated. Based on the wavelet analysis
of the signals of tapping torque, the load applied to the tap in every stage of the period of motion is
studied. It is found that chipping is prone to occur at the moment when the rotating direction of tap
shifts from forward to backward, which is caused by the too large and rapidly changed tensile stress
on cutting edge. The excessive wear of cutting edge results in the too large tensile stress. To reduce
the wear, the backward rotating angle of tap should be selected to be smaller than 100°.
Abstract: In this paper, the wear behavior of the ID (inner diameter) saw blade in the cutting
process of silicon ingot was observed with SEM. Its wear mechanism was discussed and the relation
between the blade wear and vibration, deflection was analyzed. The results show that the blade
worn manners include flatted diamond, micro-fractured diamond, macro-fractured diamond,
pulled-out hole, tortoise-fractured bond, and polished bond. In the abnormal working stage of a
blade, however, the working surface of the blade is displayed mainly with pulled out diamond,
flatted diamond, macro-fractured diamond grains. Abnormal initial tension condition will induce
severe vibration and deflection, and so then lots of diamond grits fractured or pulled out too early.
Abstract: As a “bottom-up” approach to nanostructures for nanofabrication, self-assembled block
copolymer thin films have received much attention not only thanks to the scale of the microdomains
but also due to the convenient shape tunability. In order to realize applications of self-assembled
block copolymer thin films in nanotechnologies, control over microdomain spatial and orientational
order is paramount. In this paper, using atomic force microscopy (AFM), we studied systemically
nanostructure transitions induced by post-solvent annealing in self-assembled block copolymer thin
films. Furthermore, a variety of thin films with well-ordered nanostructures, which can be employed
as templates for nanotechnologies, have been realized simply and at low cost.
Abstract: The influence of the ultrasonic vibrated diamond tool on the transition of ductile cutting
to brittle cutting of the glasses is investigated by facing turning. It is understood that the critical
depth of cut for the ductile cutting of the brittle materials is increased obviously by the ultrasonic
vibrated diamond tool. The optical quality surface of the glasses is obtained, the surface roughness
of which is less than0.03m. Finally, the relation between the roughness of machined surface and
the cutting distance is studied experimentally.
Abstract: Electrode materials are important factors affecting machining performances (MP) of
electrical discharge machining (EDM). Experiments using different electrode materials were carried
out in compressed air aim to realize MP of electrical discharge machining in gas (dry EDM).
Experimental results show that a minimum pulse interval exists for given parameters and tool
material. Calorific performances of tool materials are main influencing factors of MP on the
condition of thorough deionization. Copper achieves the best MP in the experimental tool materials.
Experimental results of different workpiece materials depict that material remove rate (MRR) and
surface roughness (SR) value increase with increases of discharge energy. SKD61 steel achieves the
highest MRR and SR value in the experimental materials. Material holding better performance of
heat resistant, such as titanium alloy (TC4), achieves the lowest MRR.
Abstract: As environmental problems have become more serious, a sustainable society is necessary.
To realize the inverse manufacturing system the prime problem is how to improve the rate of reusing
the product modules. Therefore analyzing the life-time of the disassembled modules is very important
before reassembling process. In this paper, a cumulative damage model is proposed to discuss the
quality of the product that is assembled by reuse modules. It is supposed that modules suffer damages
due to shocks and fails when the cumulative damage level exceeds the failure level. Then
maintenance cost will be analyzed in order to minimize the expected maintenance cost-rate by
optimal maintenance time T and optimal number of damages N in this cumulative damage model. The
probable safe life-time of module reuse will be explored. Finally numerical examples are given to
confirm the validity of the proposed model.
Abstract: Micro-Electromechanical Systems (MEMS) has been regarded as one of the most
promising technologies for the 21st Century. Recently, some highlight areas attract great attention
including Inertial MEMS, Optic MEMS, RF MEMS, BioMEMS, Power MEMS, and NEMS. The
state of arts on MEMS research in China is briefly introduced and research activities in
Northwestern Polytechnical University such as MEMS CAD tool, inertial MEMS devices, flexible
substrate for MEMS integration, micro mirror, micro battery and three dimension measurement are
Abstract: This contribution aims at the mechanism of electrochemical mechanical finishing (ECMF).
The change in surface micro-profile of workpiece and its influence on anodic electrochemical
dissolution (ECD) as well as the action of the mechanical role were investigated. The results show
that the peak-like micro-profile of surface is in favor of improving the ability of ECD. The mechanical
role not only scratches the passive film resulted from ECD, but also changes the surface micro-profile
of the workpiece. The action of the mechanical role influences the final finished surface quality of the
Abstract: An arc envelope grinding method for non-axisymmetric aspheric surface was proposed in
order to achieve the mould core used for the precision injection molding of optic reflector. In
grinding, the arc-shaped diamond grinding wheel trued on CNC grinder was used to envelope
workpiece and generate curve surface, and the spacing distance between tool paths is controlled by the
equal-envelope height between wheel and workpiece. In this paper, arc envelope grinding principle
was investigated in connection with wheel coordinate calculation and tool path number. The
theoretical analysis and grinding experiment showed that arc envelope grinding may improve form
grinding efficiency especially for large curvature and smoothness of ground surface and a smooth
curve surface can be produced when the equal-envelope height is less than a certain value.