Engineering, 2010, 2, 184-189
doi:10.4236/eng.2010.23026 lished Online March 2010 (http://www.SciRP.org/journal/eng/)
Pub
Applications of High-Efficiency Abrasive Process with
CBN Grinding Wheel
Yali Hou1, Changhe Li1, Yan Zhou2
1College of Mechanical Engineering, Qingdao Technological University, Qingdao, China
2Department of Mechanical Engineering, Qingdao Feiyang Vocational&Technical College, Qingdao, China
Received October 8, 2009; revised November 20, 2009; accepted November 26, 2009
Abstract
High-efficiency abrasive process with CBN grinding wheel is one of the important techniques of advanced
manufacture. Combined with raw and finishing machining, it can attain high material removal rate like turn-
ing, milling and planning. The difficult-to-grinding materials can also be ground by means of this method
with high performance. In the present paper, development status and latest progresses on high-efficiency
abrasive machining technologies with CBN grinding wheel relate to high speed and super-high speed grind-
ing, quick point-grinding, high efficiency deep-cut grinding, creep feed deep grinding, heavy-duty snagging
and abrasive belt grinding were summarized. The efficiency and parameters range of these abrasive machin-
ing processes were compared. The key technologies of high efficiency abrasive machining, including grind-
ing wheel, spindle and bearing, grinder, coolant supplying, installation and orientation of wheel and work-
piece and safety defended, as well as intelligent monitor and NC grinding were investigated. It is concluded
that high efficiency abrasive machining is a promising technology in the future.
Keywords: CBN Grinding, Super-High Speed Grinding, High Efficiency Deep-Cut Grinding, Quick-Point
Grinding
1. Introduction
With the increasing requirements of modern industrial
technology and high-performance technological products
in respect of part precision, surface integrity, machining
efficiency and batch-quality stability, grinding has play-
ed a more and more important role. It becomes an im-
portant part of advanced machining technology and
equipment, and is a research frontier in manufacturing
science.
Generally, the wheel velocity between 30 and 35 m/s
is defined as conventional grinding; The wheel speed
exceeding 45 to 50 m/s is defined as high speed grinding;
The wheel speed between 150 and 180 m/s or higher is
defined as Super-high Speed Grinding.
The specific material removal rate in conventional
grinding is less than 10 mm3/mm.s. It has long been a pu-
rsuit in academe and engineering field to improve grind-
ing efficiency. There are three approaches: 1) adopting
high-speed, super-high speed or wide-wheel grinding to
increase the amount of active abrasive per unit time; 2)
increasing cutting depth so as to increase the length of
grinding debris; 3) adopting powerful grinding to in-
crease the mean cross-sectional area of grinding debris.
Any grinding techniques adopting single or multiple met-
hods mentioned above to improve specific material re-
moval rate in comparison with conventional grinding can
be called as high-efficiency grinding techniques. Among
them, the development of high-speed/super-high speed
grinding, creep-feed deep-cutting grinding, high-efficie-
ncy deep-cutting grinding, belt grinding and heavy-duty
snagging has drawn most of the attentions.
When the material removal rate is fixed, the increase
in grinding wheel’s rotation speed causes the active abra-
sive amount per unit time to increase greatly, and the
cutting thickness of each abrasive grain is thinned if the
feed rate is fixed. Besides, material removal in super-
high speed grinding is also accompanied by a process of
heat-insulating shock-induced chip formation with ex-
tremely high strain rate [1-3]. Therefore, high-speed/su-
per-high speed grinding has the following characteristics:
1) High production efficiency. The material removal rate
is multiplied and can reach as much as 2000 mm3 /(mms)
[4-10]; 2) It improves the dynamic wearability of grains

Y. L. Hou ET AL. 185
and increases the service life of abrasive wheel, being
favorable to grinding automation. The service life of
grinding wheel at the speed of 200 m/s is twice that at
80m/s when the abrasive force is fixed; the service life of
abrasive wheel at 200 m/s is 7.8 times of that at 80 m/s
when the grinding efficiency is fixed [11-15]; 3) The
grain cutting thickness decreases, the height of surface
plastic-upheaval decreases, and the value of surface
roughness decreases. The cutting debris is formed under
extremely high strain rate and insulated cutting state, and
the material removing mechanism changes. Thus, it can
achieve high-performance machining on brittle materials
and materials difficult to machine; 4) Low abrasive force
and high machining precision. At the same cutting depth,
the abrasive force at the grinding speed of 250 m/s is
reduced by nearly one half in comparison with that at
180 m/s; 5) The amount of grinding heat transferred into
workpieces is reduced, which causes the grinding tem-
perature at the workpiece surface to decrease [16]. The
layer under denatured force and high temperature is
thinned, and the surface integrity improves. With CBN
abrasive wheel to grind steel parts at 200 m/s, the layer
with surface residual stress has the depth less than 10μm
[17]; 6) The excellent properties of superhard abrasive,
such as high hardness and high wearability, can be fully
exhibited, and high-temperature brazing-metal bonded
wheel is presently a novel abrasive wheel for super-high
speed grinding; 7) It is a latest grinding technique capa-
ble of achieving high efficiency and high precision si-
multaneously as well as performing machining on vari-
ous materials and shapes.
2. Industrial Applications
A) High efficiency deep grinding (HEDG)
HEDG is a high-speed, high-efficiency grinding tech-
nique integrating super-high wheel rotation speed, fast
feed and large cut depth. It was primarily developed in
Germany in 1980s, and deep-cutting grinders with the
super-high speed of 200 to 300 m/s were developed on
the basis of CBN abrasive wheel. In high-efficiency
deep-cutting grinding, the cutting depth is 0.1 to 30 mm,
the workpiece velocity is 0.5 to 10 m/min, and the wheel
velocity is 80 to 200 m/s [18,19]. High metal removal
rate and high surface quality can be obtained with it. The
surface roughness of workpieces approaches that in con-
ventional grinding, and the metal removal rate is 100 to
1000 times higher than that in conventional grinding.
German FD613 grinder can reach the feed rate of 3000
mm/min when grinding with CBN, a 10 mm-wide and 30
mm-deep rotor slot at 150 m/s wheel velocity [20]. In
U.S., the dominant development type is multi-axis CNC
high-efficiency deep-grinding machine, and the surface
quality of the hardened steel obtained through
high-efficiency deep grinding using CBN formed abra-
sive wheel can match that of conventional grinders.
B) Super-high speed cylindrical grinding
In CNC super-high speed cylindrical grinding, CBN
wheel is used to perform super-high speed, high-effi-
ciency, high-precision grinding on the cylindrical rotary
surfaces of parts such as stepped shafts and crankshafts,
with the wheel cylindrical velocity of 150 to 200 m/s.
Such a technique has been successfully applied in auto-
mobile industry. For example, a ductile-iron camshaft
with the grinding depth of 5 mm from a CNC super-high
speed cylindrical grinder (GCH63B, Toyota Industrial
Machinery OMIC) produced in Japan achieves the spe-
cial removal rate ZW as much as 174 mm3/mm·s, the
wheel grinding ratio (G ration) can reach 33500, and a
roughcast can be ground into a finished product directly.
Employing CBN abrasive wheel, a RB625 super-high
speed cylindrical grinder from Guhring Automation in
German can grind roughcast into a spindle in one time,
and can grind off 2kg of metal each minute [16].
C) Quick-point grinding
Quick-point Grinding developed in Germany in 1994
is a new application form of super-high speed grinding.
Integrating three advanced technologies: NC flexible
machining, CBN superhard abrasive and super-high
speed grinding, it is mainly used to machine parts such as
shafts and disks. Its wheel axis forms a certain angle
against the workpiece axis in horizontal and vertical di-
rections, shown as in Figure 1, so the wheel and work-
piece form small-area point contact. Combined with con-
tinuous-path NC technology, it achieves both high flexi-
bility in NC turning as well as higher efficiency and pre-
cision; moreover, the service life of abrasive wheel is
extended.
The technique has been applied in industries of auto-
mobile and machine tools and has extensive application
prospect. Automobile manufacturing enterprises in China
also introduced this technique and related equipment in
large scale, which were used to machine camshafts and
gear shafts, etc., and to achieve significant economic
benefits [12].
Contact point Grinding wheel
Feeding directionContact
zone
Workpiece
Figure 1. Contact diagram of wheel and part in quick-point
grinding.
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Y. L. Hou ET AL. 186
Volkswagen Group China applied the technique to
grind engine camshafts. The wheel rotation-velocity is
4300 r/min, and 3000 workpieces can be ground each
wheel dressing. NC quick-point grinding is also the de-
velopment trend of applying semi-permanent tools to NC
turning.
D) Super-high speed grinding of hard and brittle ma-
terials
With the development of modern hi-tech and industri-
alization, hard and brittle materials, such as engineering
ceramics, functional ceramics, single-crystal silicon,
ruby and sapphire, and optical glass, has found increas-
ingly wide applications. Grinding hard and brittle mate-
rials with superhard abrasive under high speed/su-
per-high speed has becomes almost the only machining
method. The abrasive can penetrate deeper into work-
pieces under conventional grinding conditions, and
grinding debris is mainly generated in the form of brittle
fracture. In super-high speed grinding, the cutting thick-
ness of single abrasive is extremely thin, so it is easier to
achieve ductile grinding for hard and brittle materials.
When materials difficult to grind, such as Ni-based
heat-resistant alloy and Ti-alloy, are ground at high
speed, the deformation rate of grinding debris ap-
proaches the propagation speed of static plastic deforma-
tion stress waves. The plastic deformation lags and re-
duces the hardening tendency, so brittle machining on
ductile materials can be realized. In pure-aluminum
grinding at 200 m/s (approximately the propagation speed
of static stress waves of pure aluminum), the workpiece
surface hardness is 50HV, and the surface roughness Ra is
2.2 μm; when the grinding speed is at 280 m/s, the work-
piece surface hardness is 45HV, and Ra is 1.8 μm [16].
E) Powerful grinding
Powerful grinding using radial feed or normal grinding
force tens to hundreds times of those in conventional
grinding to increase the average cross-sectional area of
grinding debris and improve machining efficiency.
Through power grinding, desired shapes and sizes can
be obtained upon the roughcast surface directly. This
method is especially suitable for grinding various shap-
ing surfaces and grooves, and generally involves
high-speed powerful cylindrical grinding, creep-feed
grinding and high-speed heavy-duty snagging.
High-speed powerful cylindrical grinding combining
cylindrical high-speed grinding and powerful grinding,
which adopts up-grinding to make grinding speed equal
to the sum of wheel speed and workpiece speed. Its spe-
cial removal rate can reach 8 to 40 mm3/mm·s.
The process of high-speed cylindrical powerful grind-
ing is generally divided into two stages: firstly, most
margins are cut off with high efficiency through large
radial feed; then, the radial feed is reduced to perform
conventional high-speed grinding on workpieces and
carry out finish machining.
Creep feed grinding technique adopting large cutting
depth (1 to 30 mm) and low workpiece feed rate (3 to
300 mm/min). It achieves high material removal rate by
increasing the length of grinding debris, and is mainly
used to grind grooves and shaping surfaces in surface
grinding.
F) Belt grinding
Belt grinding belongs to elastic grinding and has the
multi-functions of grinding, milling and polishing, etc. It
is characterized by good workpiece-shape adaptability,
low vibration of grinding system, low roughness of ma-
chining surface, maintenance of residual compressive
stresses, low grinding temperature and resistance to
workpiece burning; it also has the feature of cool grind-
ing. Belt grinding has the advantages of flexible process,
wide machining range, wide application fields, high ma-
terial cutting rate, high power utilization, high belt
grinding ratio, low cost for comprehensive machining,
low investment and fast effect. The precision of hard-
brittle material machined using ultramicro-abrasive belt
with electrophoresis absorption can reach tens of nano-
meters, and ductile grinding can be realized. Therefore,
belt grinding has been developed into an effective
method for high-efficiency precision machining.
Presently, about one third of abrasive-wheel grinding
has been replaced by belt grinding. The quantity of belt
grinders has approached that of abrasive-wheel grinders.
Their yield ratio is 49:51 in U.S., 45:55 in Germany, and
25:75 in Japan. Currently nearly 400,000 belt grinders
and 950,000,000 m2 of belts are produced each year
around the world.
Belt grinder is developing rapidly in directions of
small size as well as high strength, high efficiency,
automation, large power and wide belt. The maximum
width of belt grinder has reached 4.9 m, the maximum
power has exceeded 200 kW, and belt grinders with the
high speed of 100 m/min are in pilot production.
Advanced technologies, such as ultrasonic belt grind-
ing, electroplated belt grinding, electrolytic belt grinding
and powerful belt grinding, have emerged and been ap-
plied successively. Novel belt manufacturing technolo-
gies, such as hollow ball compounded abrasive, cork belt
abrasive, multilayer coating abrasive and vitrified co-
rundum abrasive, have been developed rapidly.
In recently years, belt grinding has been applied to
precision machining and ultra-precision machining in
other countries. The precision has reached micron level,
and the surface roughness Ra has reached 0.01 to 0.25
μm.
3. Automation Intelligence and Virtualization
CNC grinding has developed rapidly in recent years, and
grinding centers capable of online measurement, auto-
matic wheel replacement and automatic workpiece as-

Y. L. Hou ET AL. 187
sembly and disassembly have emerged, so have grinding
robots. For aspherical grinding, lapping and polishing,
Computer Controlled Optical Surfacing (CCOS) is ap-
plied to control grinding-disk pressure and the relative
velocity at grinding points according to required material
removal quantity at a certain point on the machined sur-
face.
With continuous track NC grinding, point grinding for
cam profile, crankshaft and complex surfaces can be re-
alized.
Intelligent grinding is currently an important research
direction. Intelligent grinding system processes process
information based on multi-sensor information fusion, so
the information can be provided for decision making and
control planning, and act on the machining process
through NC controller to achieve optimal grinding con-
trol. Besides, it is also capable of self learning and main-
tenance. An acoustic emission sensor can monitor grind-
ing process, finishing process, wheel abrasion and disre-
pair, and workpiece surface integrity effectively. Another
new development in grinding sensors is the application
of multi-frequency multi-sensors’ grinding burning, sur-
face hardening and hardened-layer depth in online in-
spection system. In Hanoverian University, a new optical
measuring method combining 32 mW continuous laser
tube, position photosensitive detector and lens was
adopted to evaluate the impact of wheel shape on the
stability of grinding process and to carry out online deci-
sion on the micro-characteristic information and status of
abrasive wheel.
Due to the complexity of grinding process, in-depth
research is still required on problems concerning the
monitoring system in grinding process in respect of the-
ory and practice. S. Malkin in U.S. also developed an
intelligent abrasive wheel which collects and monitors
acoustic emission signals through the sensors properly
distributed and mounted on abrasive wheel and a collec-
tion and storage chip based on digital signal processor. It
can perform real-time signal collection and data proc-
essing on rotating wheel and carry out computer system
control and online monitoring of the grinding process
and finishing process, etc. of ceramic grinding.
Simulation and prediction of grinding process and re-
sults through computer provides a new approach to
grinding mechanism research. Developed in U.S., a grin-
ding software package (GRINDSIM) has the functions of
simulation, calibration and optimization, etc. In Germany,
kinematics simulation was used to analyze and predict
three grinding process. Three-dimensional mathe matical
models describing the macro and micro morphology of
abrasive wheel were built based on abrasive and wheel
examination, including abrasive shape, size and distribu-
tion, and bond uplifts, etc. Multi-abrasive accumulated
cutting was adopted to simulate grinding process [15].
In grinding simulating technique, vivid virtual grind-
ing environment is established based on modeling and
simulation to evaluate and predict grinding process. The
built wheel morphology model is applied in the dynamic
simulation of the process grinding-debris formation, en-
ergy conversion, grinding force variation, grinding-area
temperature, grinding precision and ground-surface qual-
ity, and to reproduce the grinding process with the im-
pact of grinding and geometrical parameters, grinding
force and heat, grinding vibration and deformation, etc.
taken into account, by which the grinding performance
and effects under different conditions can be analyzed
and predicted.
Molecular dynamics analysis plus grinding mechanism
simulation is a new method in grinding mechanism re-
search. Molecular dynamics is a micro method to analyze
the characteristics of atomic and molecular solid models
from the atomic angle. It can provide considerable in-
formation that cannot be obtained through existing ex-
perimental methods, and is a powerful tool in the re-
search of micro-machining mechanism. In Japan in 1990,
an atomic-scale cutting model was built for the mi-
cro-machining process of single-crystal copper and dia-
mond; in 1994, simulation of machined-surface structure
was performed based on molecular dynamics. The results
show that accurate blade with the blunt radius of 1/10 to
1/20 can achieve micro-cutting, and the workpiece atoms
disturbed by the ploughing cutting blade are rearranged
perfectly after the cutting blade passes.
4. Research Direction
1) Research of basic theories and key technologies for
high-speed/super-high speed grinding (super-high speed
grinding, high-efficiency deep-cutting grinding and qui-
ck-point grinding): including understanding and discus-
sions of high-speed/super-high speed grinding mecha-
nism, surface generation and integrity control, core and
key technologies and theoretical research of high-effi-
ciency deep grinding and quick-point grinding;
2) Research of basic theories and key technologies for
high-efficiency grinding: including key technologies and
basic theories for powerful high-efficiency grinding pro-
cess and equipment, and research of high-efficiency low-
pollution stone grinding technology and theory;
3) Research of basic theories and key technologies for
hard-brittle material grinding: including theories for brit-
tle/plastic transformation under complex grinding stress,
grinding damage mechanism of hard and brittle materials,
damage evaluation and control, and mechanism research
and implementation of deep-cutting, creep-feed and high-
speed/super-high speed grinding with hard and brittle
materials;
4) Research of basic theories and key technologies for
intelligent examination and control of the grinding proc-
ess: including research on the parameter information
sensing in grinding process and multi-sensor signal fu-
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Y. L. Hou ET AL. 188
sion, and methods, theories and implementation of intel-
ligent control in grinding process;
5) Research of basic theories and key technologies for
complex surface automation and high-efficiency grinding:
including research and technical implementation of com-
plex-surface robot grinding and NC grinding, and that for
complex-surface automatic high-efficiency grinding pro-
cesses;
6) Research of basic theories and key technologies in
fabrication and application of novel abrasive tools: inclu-
ding technologies for developing and combining novel
abrasives and bond systems, structures and preparation
technology innovation of novel abrasive wheel for high-
speed/super-high speed and high-efficiency grinding,
quantitive evaluation technology and system for the finis-
hing and machining performance of superhard abrasives;
7) New principles, methods and process exploration
for non-pollution and low-pollution grinding.
5. Conclusions
The basic mechanisms and the applications for the tech-
nology of high-efficiency grinding with CBN grinding
wheels are presented. In addition to developments in pro-
cess technology associated with high-speed and super-hi-
gh grinding, quick point-grinding, high efficiency deep-
cut grinding, creep feed deep grinding, heavy-duty snag-
ging and abrasive belt grinding are also analyzed. The
paper concludes with a presentation of current research
and future developments in the area of high-efficiency
grinding. The need for high accuracy finishing and for
high efficiency machining of difficult-to-machine mate-
rials is making the application of abrasive technologies
increasingly important. It is concluded that high effi-
ciency abrasive machining is a promising technology in
the future.
6. Acknowledgment
This research was financially supported by the National
Natural Science Foundation of China (50875138); the
National Basic Research Program of China (2009CB
724401); the China Postdoctoral Science Foundation
(20080431234); the Shandong Provincial Natural Sci-
ence Foundation of China (Z2008F11); the State Key
Laboratory for Manufacturing Systems Engineering’s
Specialized Fund; and the Specialized Construct Fund
for Taishan Scholars.
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