Abstract: The fabrication of a large Al-4.5wt%Cu-0.5wt%Mn wheel with 670mm diameter by
indirect squeeze casting process was studied. The casting system including modified hydraulic press
and die structure was introduced, and the casting procedures was designed and described. The
filling behavior of the casting process was simulated with software Flow3D. It was found that while
flowing from spoke to rim, turbulence flow of liquid melt in the vicinity of free surface was found,
and that at the end of the filling, the unwanted solidification might occur. To reduce the turbulent
flow and the unwanted solidification, a modified injection condition was proposed. The simulation
results with the modified injection indicated that the turbulence was prevented and the unwanted
solidification during the filling was reduced as well. The squeeze wheel castings were fabricated
with the modified injection condition. Cross sections of the castings were checked. A number of
specimens were obtained from different parts of the castings to evaluate microstructure of the wheel,
and both high density and fine grain microstructures were found in the specimens. Mechanical
properties of the tensile samples from the wheels with T5 heat treatment were measured. The
average tensile strength and elongation were 390 MPa and 10%, respectively.
Abstract: To investigate the effect of tool geometry on single-crystal silicon nano-cutting, parallel
molecular dynamics (MD) simulations are carried out with different tool rake angles. In this study,
a parallel arithmetic based on mechanism of spatial decomposition together with MD is applied to
simulate nano-cutting processes of single-crystal silicon (100) plane by using a single-crystal
diamond tool. The simulation results show that tool rake angle has great effects on cutting forces
and subsurface stress, and the effect of tool rake angle variation on work-piece potential energy is
not evident while cutting single-crystal Silicon (100) plane. Moreover, the analysis of cutting forces
and potential energy show that there is not evident dislocation in the nano-cutting.
Abstract: Rotary ultrasonic machining (RUM) is one of the cost-effective machining methods for
advanced ceramics, which is a hybrid machining process that combines the material removal
mechanisms of diamond grinding and ultrasonic machining (USM). This paper presents an
overview of the investigations on RUM of advanced ceramics. The issues about the material
removal mechanisms, process modeling, material removal rate, and tool wear in RUM are
reviewed. Directions of future research on RUM are also presented.
Abstract: Chatter during boring process is one of the main adverse factors influenced on the
machining accuracy of precision hole, surface quality and working efficiency. In order to suppress
chatter, an innovative controlling means of MR-intelligent-boring-bar with self-chatter-suppression is
proposed, which is composed of MR fluid, shell structure, excitation coil and boring bar. The MR
fluid’s mechanical characteristic can be adjusted by changing the intensity of magnetic field, thus the
system stiffness and damping will be modified, and then the boring chatter can be suppressed.
Otherwise, the dynamic model of MR-intelligent-boring-bar with self-chatter-suppression is built.
Lastly, the experimental system of MR-intelligent-boring-bar is established, and the experiments of
chatter suppression during boring process are performed. The results of experiments show that the
new means of chatter suppression is effective.
Abstract: Air cooling is a near dry machining method, which cools cutting area and evacuates chip
using low temperature wind instead of cutting liquid. It can decrease tool wear, improve tool life,
reduce cost and produce no chemical pollution. In this paper, air cooling system is established, in
which vortex tube is used for cooling. Air cooling test was carried on, in which high hardness bear
steel GCr15 is machined by PCBN tool. Experiment results indicated that cold air from vortex tube
has a significant effect on cutting force, cutting temperature and chip formation process. Cutting
force and cutting temperature were simulated using Marc. Change rules that analysis results
indicated are in accordance with experiment results. This paper’s conclusions have a great reference
value for the practical application of air cooling technology.
Abstract: Although the porous metal bonded diamond grinding wheel, which has recently been
developed, had an excellent grinding performance for hard-brittle materials, its applications were only
in precision grinding in past study. A new method for fabricating the new porous metal bonded
diamond grinding wheel by Ni-Cr alloy as bond and vacuum loose powder sintering was proposed in
this paper. The morphology of cross section of the segments and microstructure of interface between
diamond grits and bond were analyzed. The wetting mechanism between Ni-Cr alloy bond and
diamond is reacting wetting. Machining performance experiments about grinding ratio and surface
roughness have been carried out. The testing results show that the porous Ni-Cr alloy bonded
diamond grinding wheel has certainly fine machining performance in high grinding force occasion,
and the maximal grinding ratio and best surface roughness were 6660 and 1.08 m, respectively.
Abstract: An experimental study on induction brazing diamond grinding wheel with Ni-Cr filler
alloy was carried out. Brazing trial was conducted at the temperature range of 1020-1080 oC and the
brazing time were 10, 20, 30 and 40 seconds in a flowing argon environment with a flow rate of
5000cm3/min. The scanning electron microscopic (SEM) results indicate that good wetting existed
between the brazing alloy and diamond. The element distribution of C, Cr, Si and Ni were examined
by energy dispersive spectrometer (EDS), the results demonstrated an intermediate layer rich in the
chromium formed between the filler metal and diamond. Kinds of compounds formed in the interface
were detected by means of x-ray diffraction (XRD), and the graphitization of the brazed diamond grits
was determined by Raman spectroscopy. The monolayer induction brazing diamond grinding wheels
were used in grinding of nature granite, experimental results show that induction brazing wheels
performed better than vacuum brazing diamond wheels, and no pullout of diamond grits or peeling of
the filler metal layer took place.
Abstract: A kind of brazed monolayer diamond grinding wheel was developed with a relatively
regular distribution of grains on the wheel surface. Grinding performances of this kind of brazed
wheel in the surface grinding of cemented carbide were studied. The experiment results show that the
grinding forces ratio becomes higher with the increasing of the maximum undeformed chip thickness
and the specific energy falls with the material removal rate during grinding cemented carbide process.
Under certain grinding conditions, the material was removed almost through plastic deformation and
good surface quality is gained. Furthermore, the grits of the brazed diamond grinding wheel fail
mainly in attritious wear modes other than pull-out ones in conventional electroplated and sintered
diamond tools, which indicates that the strong retention of brazing alloy to the diamond grits and
longer service life of this kind of wheel.
Abstract: An investigation is reported of the effects of three different coatings onto diamonds in the
composites for the beads of wire saws. The matrix of the composites contained 80% (w/w) cobalt.
Ti, W, and W-Co were coated onto diamond surfaces respectively and then incorporated into the
matrix. The mixed powders were hot-pressed to form the specimens for bending tests. Coupled with
the results of bending tests and the strength of coated diamonds, the coatings of W were found to be
best among the three coatings. Further experiments indicated that the thickness of W-coatings onto
the diamonds should be controlled around 10(m in order to obtain an excellent retention of
Abstract: The measuring temperature and force experiments of cutting heat-resistance steel
(3Cr-1Mo-1/4V alloy and 1Cr18Ni9 alloy) by plane milling insert and milling insert with complex
groove that invented by ourselves has been done, meanwhile, the falling process of
sticking-welding chip when milling insert cut-in and cut-out has been observed by high-speed
photograph. Mechanical-thermal coupled field has been analyzed using ANSYS, and equivalent
complex stress of the coupled field is larger than the stress of single field distinctly, it shows that
they have a relation of direct proportion. The results of test and analysis show that the main reasons
of adhesion failure are heat that produced in cutting process and the change of temperature grads
during cut-in or cut-out and alternate tension stress and stress impact during cut-in or cut-out.,
which provides technical support and experimental data for the groove's optimization and
reconstruction of milling insert with 3D complex groove.