Abstract: Utilizing gas as the dielectric instead of dielectric liquid has enabled the development of
dry wire electrical discharge machining (WEDM) technology for finishing cut. This paper studies
on the surface quality of tool steel with WEDM method, which is conducted in gas to improve the
accuracy of finishing cut, and compares the surface quality in atmosphere and in water. Experiment
results showed that Low-Speed WEDM in atmosphere offers advantages such as better straightness,
lower surface roughness and shorter gap length, but WEDM in atmosphere has poorer material
removal rate than conventional WEDM in water. It was also found the removal rate in atmosphere
can be improved by increasing the wire winding speed.
Abstract: Based on the 3D FE model of conventional spinning, the influence of curvature radius
of roller-trace on the conventional spinning process has been studied. It is found that when the
curvature radius of roller-trace is smaller, the maximum of thinning rate and hoop compressive
stress increases dramatically with the increasing of the radius, and curvature radius does little
effect on the forming process when it is up to a critical value. To obtain a more reasonable
selection criterion of curvature radius of roller-trace, a new index named flange width has been
put forward， which represents the comprehensive effect of workpiece diameter and mandrel
diameter in the forming process of conventional spinning. Further research has been done and the
selection criterion of curvature radius is obtained: the smaller the flange width is or the larger the
workpiece thickness or the entry tangential angle is, the larger the range of reasonable curvature
Abstract: The composite materials, 3Y-TZP added with TiN or/and Al2O3 particles, were fabricated
by hot-pressing techniques. The effect of TiN and Al2O3 on the low temperature degradation of
3Y-TZP was investigated. It is shown that both TiN and Al2O3 can inhibit t-m transformation of
3Y-TZP and prevent the transformation from propagating into the specimen interiors when aged at a
low temperature. The inhibition to the low temperature degradation of 3Y-TZP by Al2O3 is more
sensitive to the aged temperature than by TiN. Compared with Al2O3, TiN is more available to
inhibit t-m transformation on aged surfaces. The degradation resistance of 3Y-TZP codoped by TiN
and Al2O3 is stronger than that of 3Y-TZP dispersed only by TiN or Al2O3.
Abstract: The present study was undertaken to examine the effects of metal coatings on the surfaces
of diamond crystals embedded in two kinds of bond matrix. Diamonds with or without coatings were
incorporated into two matrices for hot-pressing, thereby forming four kinds of diamond composites.
The transverse rupture strength (TRS) of the composites was measured to assess the bending strength
of the composites. SEM and EDS were used to analyze the fractured surfaces of the composites. It was
found that the TRS of the composites containing coated diamonds increased in both bond matrices.
But the coatings in the bond matrix without rare earth increased TRS a little more than the case with
rare earth due to a different failure mechanism of metal coatings.
Abstract: Ceramic coating materials own some advantages, for example high-rigidity, good
abradability and good performance under high temperature. At the same time, ceramic coating
materials are also difficult-to-machine materials. High machining precision and efficiency can be
obtained in grinding WC-Co coating by cup wheel. The affection of grinding temperature is very
important for grinding processing. But there is no research on grinding temperature of WC-Co
coating by cup wheel. So in this paper, grinding temperature by cup wheel is researched on theory,
the new concept, which is effectiveness width of arc moving heat source, is presented, and
theoretical formula of grinding temperature is also built. Then experimental research on grinding
temperature of WC-Co coating by cup wheel is done by use of thermocouple temperature
measurement technology. The experimental results show the validity and effectivity of the
theoretical formula. The affection of grinding parameters to grinding temperature is researched also.
Abstract: According to the principle producing the cutting track of cutter, to study the influence of
the cutting track of cutter on the process of high speed ball-end milling, the single-factor models for
evaluating the cutting track of cutter are established. Adopting four kinds of the typical cutting track
of cutter, the experiment of high speed ball-end milling is processed. The model of multi-ply fuzzy
comprehensive evaluation for the cutting track of cutter is established, fuzzy comprehensive
evaluation for the cutting track of high speed ball-end milling cutter is accomplished by the
application of fuzzy mathematics theory. Results show that the cutting contact curve of cutter
affects directly the process of high speed ball-end milling, fuzzy and uncertain properties exist in
the evaluation for the cutting track of cutter. The optimum cutting track can be selected by multi-ply
fuzzy comprehensive evaluation for the cutting track of high speed ball-end milling cutter.
Abstract: The experimental results for silicon carbide (SiC) wheel with fine grit size grinding of
silicon carbide (Si3N4) revealed that the grinding parameters affect not only the ground silicon
nitride surface roughness, but also the degree of surface damage. There exists complex non-linear
relationship between the grinding parameters and surface quality. Better surface roughness doesn’t
surely mean less surface damage. A method of prediction of grinding quality based on support
vector regression is then presented according to the condition of small samples. The result shows
the prediction accuracy based on this method is obviously higher than neural network, which
provides an effective way for optimizing the grinding parameters to ensure the grinding quality as
well as grinding efficiency while grinding of silicon carbide using conventional abrasive.
Abstract: In Polishing Process based on Vibration of Liquid (PVL), abrasive particles driven by
polishing liquid will brush and etch workpiece to achieve material removal. Because the liquid is
vibrated in ultrasonic frequency, polishing process will be greatly affected by cavitation phenomenon.
The critical thermal conditions and high-speed liquid jet produced by bubble dynamics may damage
workpiece. A refined Dissipative Particle Dynamics method is applied to study the effect of acoustic
cavitation on PVL. Validity of the numerical simulation is tested according to experimental results.
Abstract: A new deposition method is described using EDM to deposit tool electrode material on
workpiece in air. Then by exchanging the polarities the deposited material can be removed
selectively, thus micro structure can be fabricated. First, the EDD realized conditions are predicted.
Then with ordinary brass, steel and tungsten electrodes and high-speed steel workpiece, EDD
experiments are carried out to obtain micro structure in air. With continuous deposition strategy of
single cylinder, a HIT character type array made up of 15 micro cylinders is deposited. And micro
three-dimensional spiral structure can be obtained with brass electrode using feed of only z axis.
The 19-circle micro spiral structure is 0.19mm in external diameter, 0.1mm in wire diameter and
3.39mm in height. Measurements show that deposited material has obvious delaminating structure
and is corrosion resistant, whose components depend on those of the tool electrode material.
Abstract: Present modeling algorithm for large-sized revolving parts’ camber can not ensure the
smoothness, so a new modeling algorithm based on NURBS Curve was proposed in this study. In
detail, the new modeling algorithm is as following: Firstly transfer these discrete points, which are
measured along the part’s axial lead by equal distant, into a weighting unity sequence. Secondly filter
this sequence by wavelet de-noising algorithm. Thirdly replace the discrete points’ amplitudes by the
corresponding weights of filtered sequence, thus yield a group of new discrete points. Lastly calculate
the control vertexes and weighting factors by local rational interpolation algorithm, and construct a
spatial NURBS Curve through the new discrete points to obtain the model of large-sized revolving
parts’ camber. It was experimentally confirmed that this model can represent drilling stem’s camber
smoothly and improve its pressure straightening precision.