Okayama university Manufacturing engineering laboratory
Development of advanced and optimized technology in cutting, grinding, and abrasive machining
High efficiency cleaning of wheel surface

Abrasive jet micromachining

The high efficiently cleaning technology using dry ice blasting is developed forrecovering grinding performance after loading by dry grinding of carbon parts.

The abrasive jet machining technology for micro profiles with high efficiency and highaccuracy is developed. Specifically, advanced micro-abrasive machining such ascontrolled three-dimensional precision patterning is developed.
Machining width

Distribution ofstock remocal

工作物

Patterning mask

Before dry ice blasting(loading surface)

Bｌasting
conditions

Nozzle feed speed f
speed fAfter dry ice blasting(l =0.167g/s, v =0.02m/s, s =1mm)

Distribution of stock removal

Patterning using abrasive jet machining

SEM
image

Cleaning effect by dry ice blasting

Output example of decision treee ≧55

YES2-w

0w
Axial location x mm

φ6①e ≧26

YES④ e ≧47
YES

AnalysisprocessNO③S µm

Experimental
profileTarget profile
Simulated profile

05

X110CR17GC 1000
P = 0.5 MPa
y = 5 mm

1 mm

Sectional profile of herringbone grooves

Support systemNO② HV≧2050

・「どんな連携を希望するか」・「どんな連携を希望するか」
Cutting conditions
・Cutting speed ・Feed rate
・Depth of cut・MRRφ3

The machining of micro-profiles with high efficiency
by controlling machining conditions such as thenozzle feed speed according to the target profile.

Herringbone grooves by abrasive jet
micromachining(Shaft diameter: f 4mm）

Decision support system for skillful engineer

PCHV≧572

NOYES⑤ φ≧0.75YES8NOYESNOe <36s <2300HV<495

YESNO

Target dataNOYES⑥ s <32240

YES

Data-mining process

YESNO

HV<374e ≧51

YESNO

YESNO

32A 32A WA97A

WA② Attribute extraction

Support system

NO

HV≧950

HV<135

YESNO

YESNO

WRA 8BPWARA

PA

HV≧300

8BP GCYES

NO

Grinding wheel databaseNOθ=30degree, z=2, Price=5970yen

9A

WA

WA

RA

Visualizedprocess① Clustering

PChhmax

Stock removal

Control of nozzle feed speed
for target profiles

Loading that occurs during dry grinding of carbon, etc. can be efficiently removed by dry ice blasting. As a result, thetotal wheel life is extended, and it is possible to stably obtain a high-quality ground surface with high efficiency.

?

aSimulation of machining profiles

Cleaning mechanism by dry ice

Skillful engineer

hmin

Calculation of nozzle feed speed

Profileimage

Unknown
recommended
cutting conditionsa aahMachining
profilep=250kPa

Dry iceaRotatingspeed ofworkpiece

p=400kPa

Cleaning system of wheel surface

Nozzle feed
speed

Nozzle feed speed f mm/sProblems in conventional dressing

2-dimensional visualization
Grain typeGrain size

Bonding strength

HV②2050③ Cutting condition estimationsHV950

8BPWAWAWA374s

2300

9A WRA57232A

WA 300GCWARAPA

13532Aφ⑤ 0.75RAe51⑥ 322495

97A③ 26 36 ④ 47

Intelligent grinding system to estimate net stock removal
Tangential grinding
force F 2.015.0mm N
側板熱変形量dqp

・「どんな連携を希望するか」To improve the dimensional accuracy, the intelligent grinding system is developed. This system can reduce
the effect of the thermal deformation of the workpiece by considering the analyzed thermal deformation.
Workpiece

Sizing gauge

Wheel01020x1 x10

Sizing gauge Workpiece

Net grinding stock
Before grinding cycle

Wheel retraction

Grindingstock SR

During the grinding cycle, the grinding heat is conducted into theworkpiece. The thermal deformation of the workpiece causes
the dimension error.

Workpice

InfeedSparkoutWheel
retraction

Tangentialforce F

Tangential grinding force F N

Decrease in radius of workpiece R mm

Decrease in radiusof workpiece Rdqw

Thermaldeformation dqw

Themal shurinkag of workpiece after grinding cycle

In the left figure, the workpiece shrinks 1.5μm in radius after the wheel retraction.
This shrinkage causes the dimension error. To reduce the effect of the thermal
deformation of the workpiece, the developed system can estimate the net
grinding stick during the grinding process.
Net grinding stock : The grinding stock (Decrease in diameter of the workpiece)
after the thermal deformation of the workpiece is converged.
The net stock removal is calculated by adding the measured grinding stock andthe simulated thermal deformation of the workpiece. The thermal deformation isanalyzed based on the tangential grinding force measured by the strain gauges.

Grinding time t sWorkpiece

VpWheelStraingaugeVw

VsCenterPCResult of grinding experiment with developed system （Grinding allowance in diameter :125μm）
Grinding stock
SR，SRn mm

Wheel

Sizinggauge

After thermal shrinkage

Wheel

Contact prove

Simulated thermal deformation 3.7 mm
工作物熱変形量dqw
1.1 mmof workpiece dqw
寸法生成量 SR50.0 mm
Measured stock removalSR 45.0 mm
正味の寸法生成量 SRn53.7 mm
Net stock removalSRn46.1 mm
砥石後退 2
Simulated thermal
パラメータ of workpiece 1deformation
100 mm
所要の取代
Grinding allowance01020 s1.84
熱変形量比 150(dqw/dμmqp)

Net grindingstock SRn

Grinding stock in diameter SR，SRn，Wheel travel distance d mm

Sparks emitted at grinding point

SR

Simulation analysis of thermal deformationmmIntelligent grinding system
improving dimentional accuracy

e

① 55

150

128

Extended figure of grinding stock
Wheel retraction at SRn=125.6mm

126124SRnSR

122

The simulated thermal deformation agreed well withthe experimental one as shown in the left figure. Thegrinding stock after the shrinkage of the workpiece
was converged within 0.6 μm of grinding allowance.

Grinding allowance: 125mm
Grinding stock after shurikage
of workpiece SR=125.4mm

10Infeed

Spark-out

Measured grinding stock SR8120
Net grinding stock SRn

90

Wheel travel distance d60

WA80H8VSK-1
VP 1 = 5.0 mm/s
VP 2 = 2.5 mm/s
VS =28.3 m/s
VW =0.273 m/s

64Measured thermal deformation of workpiece dqw

230
Simulated thermal deformation dqw

0-30

Wheel
retraction

03060900120

Thermal deformation dqw mm

Catalog database

8BPHV

Other research subjects involved in grinding・ Fabrication of tapered profile in internalgrinding
・ Improvement of form accuracy in
cylindrical traverse grinding
The accuracy and the efficiency are improvedby adjusting the grinding conditions that wasdetermined based on the results of monitoring
the grinding phenomenon.

Duration after wheel retraction t s

Researches shown above are expected to use：High-precision high-efficiency machining for automobile and aviationindustries, In-process evaluation technology of machining accuracy, Optimization system of machining conditions
Research collaboration ： Research Training and information provision about sustainable manufacturing technologies forthe next generation，Researches under academic-industrial partnerships，Recurrent education in doctoral program

CONTACT: Prof. K. Ohashi, Faculty of natural science and technology：E-mail k-ohashi＠okayama-u.ac.jp