Diamond milling servo based mechanical machining

State Key Laboratory in Ultra-precision Machining Technology

超精密加工技術國家重點實驗室

Diamond milling servo based mechanical machining system for micro/nanomanufacturing Zhiwei Zhu Supervisor: Dr. Sandy To, State Key Laboratory of Ultra-precision Machining Technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China. E-mail: [email protected] 1/50



Outline  Background  Literature review  Main research work

 Part I: Diamond milling servo based machining system • Application for the generation of Microlens Array • Bi-axial DMS for active control of surface nanotextures • Intersecting DMS for hierarchical micro/nanostructures • A combination of the intersecting and bi-axial DMS 

Part II: Rotary vibration assisted diamond milling servo • Mechatronic design of the rotary vibration system • RV-DMS for the generation of micro/nanostructures • RV-DMS for micro/nanomachining of brittle materials

 Overall contribution and future work 2/50



Background a

c

d

Microlens array Backlight diffraction based 3-D glass-free display After: D Fattal et al. Nature 495, 348-351 (2013)

After: Li and Yi, Appl Optic, 51: 1843-52 (2012) Yi et al. Optic Express, 21: 22232-45, (2013) Song, et al. Nature 497(7447), 95-99 (2013)

3/50



Background

Characteristics of the shark skin After: L Wen et al. J. Experimental Biology 217(10): 1656-66 (2014).

Artificial and natural nanostructural colour After: F. Cheng et al. Scientific reports 5 (2015) http://www.nanotypos.com/portal/portfolio/structural-color-generation/

4/50



Background Attacus atlas moth eye

Typical fabrication methods:  Bottom-up methods:  Self-assembly  Two-photon polymerization  Top-down methods:

 Lithographic techniques  Chemical based processing

• material limitation; low efficiency; • flat surface; low structure accuracy. D. Ko, et al. Soft Matter 7, 6404-6407 (2011)

 Mechanical machining  Diamond micro/nanomachining 5/50



Literature review  Motion based direct cutting Fast-/slow-tool-servo (F-/STS)

Nano-FTS

After: Li and Yi, Optics letters 30: 1707-1709 (2005) Scheiding, Yi et al. Optics Express 19: 23938-51 (2011) F Fang, et al. Optics Express, 16(10), 7323-7329 (2008). After: E. Brinksmeier et al. CIRP Annals, 59(1), 535-538 (2010).

6/50



Literature review  Motion based direct cutting

Ultrasonic elliptical vibration based micor/nanosculpturing After: Suzuki et al. Precis Eng, 35 (1): 44-50 (2011).

Elliptical vibration based Ultramill After: T. A. Dow et al. In: ASPE Spring Topic, (2007).

7/50



Literature review  Micro/nanopatterned tool printing

Tool Tip Diamond Tool

Micro-patterned cutter by grinding in milling After: J. Xie et al. CIRP Annals, 64(1), 101-4 (2015).

Nanopatterned diamond tool by FIB in turning After: X. Luo et al. J Micromech Microeng, 22, 115014 (2012).

8/50



Literature review  Tertiary motion modulation

Ultrasonic elliptical vibration Texturing After: P. Guo et al. CIRP Annals, 63(1), 553–556 (2014). Guo and Ehmann, Int J mach Tool Manuf, 64: 85-95 (2013)

Rotary ultrasonic Texturing After: Shao, Int J mach Tool Manuf, 86: 12-17 (2014)

9/50



Objectives The overall objective is to develop an innovative diamond cutting based micro/nanomanufacturing system for flexible generation of the microstructured and hierarchically micro/nanostructured surfaces, accordingly extending the applications of the structures in a variety of related fields.  To propose and comprehensively investigate a micro/nanomanufacturing system, namely the Diamond Milling Servo (DMS), based on optimal combination of the concepts of diamond raster milling and fast- or slowtool-servo diamond turning;  To develop Computer-Aided-Manufacturing (CAM) system for the DMS based mechanical machining as well as the practical mechatronic system for the implementation of the DMS.

10/50



Part I: Diamond milling servo based machining system Basic principle of the DMS system Basic Features:

Y X

Operating in the Cartesian coordinate system with constant rotation distance of the diamond tool, accordingly the constant cutting velocity; Constant angle sampling strategy also results in constant arc length in the machined surface;

Y X

Interrupted nature of the cutting process enables sufficient cooling of the diamond tool, being beneficial for extending tool life.

Configuration of the DMS System, (a) hardware configuration, (b) the horizontal cutting and (c) the vertical cutting.

11/50



Part I: Diamond milling servo based machining system (a) Application for the generation of Microlens Array Main Challenges in F-/STS turning of MLA:  Azimuth sampling conflicts. Numerous sampling points are required to reduce the position dependent interpolation error; Too many controlling points in one revolution will significantly reduce the spindle speed; The volume of required toolpath data is often too large to be easily operated by the control system.  Tracking bandwidth limitation. Cutting operation cannot always keep working in its optimal dynamic status during cutting; Phase-lag effects of the servo system dependent on the working frequency lead to poor form accuracy of each lenslet as well as distortions of the whole array.

Typical microlens array After: Hung et al. Optical Eng, 46(4), 043402. (2007).

Summary: Inconsistence! 12/50



Part I: Diamond milling servo based machining system (a) Application for the generation of Microlens Array Uniqueness and solutions to the challenges The constant cutting velocity, consistent arc length sampling, and consistent tracking bandwidth in any cutting revolution can be achieved deriving from the intrinsic constant rotational distance, thereby, leading to the homogeneous quality of the machined MLA. For the planar MLA, it can be subdivided into several basic lens array cells due to its rigid periodicity. By repeating cutting of a basic cell, the computational costs as well as the volume of data file of the toolpath can be significantly reduced. Accordingly, the whole MLA with arbitrary size can be uniformly achieved. 13/50



Part I: Diamond milling servo based machining system (a) Application for the generation of Microlens Array Cutting parameters Materials Rotation radius Rd Inclination angle α Spindle speed S Feedrate fx Sampling number Ns Tool nose radius Rt Tool rake angle γ0 Workpiece dimension Basic cell dimension

Brass C2600 2.3448mm 3.891o 13 rpm 2.5μm/rev 1800 0.104mm 0o 5010mm2 2.52.5mm2

The aspheric lenslet z ( x, y) 

sCRo 2

-

sC  2 ( x, y)

4  4 1  (1  k )C 2 Ro 2 4  4 1  (1  k )C 2  2 ( x, y)

With Curvature C Micro-asphere radius R0 Conic constant k Shape parameter s Height of each leaslet h Distance between successive lenslets

0.8 mm-1 0.1 mm -0.6 1 4 μm 0.25 mm

14/50



Part I: Diamond milling servo based machining system (a) Application for the generation of Microlens Array (a)

μm

(a)

2.0

1.5

1.0 0.5

0

0

0

(b)

1

(c) (c)

15

10

5. 18

.1 8

19

-0.5

0

Y:

1200 1500 1800 2100 2400 2700 3000 3300 3600 μm

900

10

600

0

μm

-1.0

95

300

15

0

X: 1

0

μm

50

-2

-3

50

μm

0 -1

-1.5

μm 0 0

20

30

0

.9 4 94

0

0

4.039μm

μm

0 -1 -2 100

150

200

250 μm

300

350

400

450

500

2

(c)

2 1

1

-1 -100

Des. Exp. Error

4

0

0

-3 50

z / μm

50

45

(d)

125.316μm

5

z / μm

20

0

10

40

0

0

:4

15

35

0

0

μm

30

0

0

25

μm

0

25

4 .9 94

125.316 μm

(b)

3

3

X

4 Y:

4

1

0

Des. Exp. Error

35

0

0

15

40

0

0

45

10

0

50

5

-50

0 x / μm

50

100

-1 -100

-50

0 y / μm

50

100

4.039 μm

15/50



Part I: Diamond milling servo based machining system (b) Bi-axial DMS for active control of surface nanotextures

Periodic tool mark enhanced scattering After: Dumas, et al. SPIE (2005)

Hybrid microoptics for multifunction integration After: Malinauskas, et al. J Optic, 12(12), 124010 (2010)

16/50




(b)

-3

z / mm

1

x 10

Surface profile Tool edge data3

0.5

5 0

Side feeding

x 10

Bi-axial strategy for tool mark control

-4

-0.02

fi+1 fi fi-1 Tool loci

0

0.02

Spindle side-feeding

Rd y v

0 -0.03

-0.02

-0.01

0 0.01 y / mm

0.02

hp =Rt  Rt  0.25 f

Orbital transfer zone Cutting zone

2

Otherwise  hp = 

   Rt 

2

2

x

0.03

if    2

o

2

f f     Rt 2      2 2

 Actively control of the residual tool marks to be functional secondary nanostructures by changing the side-feeding motions;

 The feeding changing operation in the OTZ had no impacts on surface generation. 17/50



Part I: Diamond milling servo based machining system (b) Bi-axial DMS for active control of surface nanotextures Primary surface

F-theta freeform surface

Sinusoid grid micro-structures

Surface features Rotation radius Spindle speed Feedrate*

z(x,y)=ax2+by2+cy4 a=-110-3, b=-110-4, c=3.6810-6. 22.3108 mm 40 rpm random

Tool nose radius Tool rake angle

104 μm 0o

z(x,y)=Axsin(2πfx)+Aycos(2πfy) Ax=Ay=0.5μm, fx=fy=13.33/mm. 1.1648 mm 13 rpm fs=1 μm/rev fg=2.8 μm/rev 5 μm 0o

18/50



Part I: Diamond milling servo based machining system (b) Bi-axial DMS for active control of surface nanotextures F-theta freeform surface (a)

(b)

nm 25

nm 77

1014

20 60

40

nm3

10 5

105

0

102

-5 -10

0

-20

X:

. 91

.19

110

123

25

Y:

Y:

X:

-15

-25

2

. 89 50

μm

30 1015 -60

1012

z / nm

z / nm

100

-10

(d)

nm3

(c)

0

50

50

100

x / m

150

200

250

60

90

120 150 180 210 Spatial frequency 1/mm

240

(b)

270

300

330

Window: Hann

9

106 103 100

0

10-3

-20 -30 0

10

nm

nm

10

X: Linear Y: Log 10

-40

-35

20

f=200/mm

10-1

-20

μm

μm

-30

Window: Hann

108

20 0

μm . 89

(a)

1011

15

-50 0

50

100

x / m

150

Characteristics of surface micro-topography

200

250

X: Linear Y: Log 10 30

60

90

120 150 180 210 Spatial frequency 1/mm

240

270

300

330

Power spectral density of cross-sectional profiles

19/50




Characteristics of the tool loci for generating the hybrid structure

Characteristics of the sinusoid grid micro-structure with imposition of secondary unidirectional phase gratings

20/50



Part I: Diamond milling servo based machining system (c) Intersecting DMS for generating hierarchical micro/nanostructures

v

Transfer motion of the spindle axis

PA

HCM

yS

Spindle feed motion in HCM

Rd

Tool loci

v oS

PB

v PC

ys

VCM

Spindle feed motion in VCM

os

oW

h/2 yW

xs

ym w/2

PD v

xW

Rd

xS

Side-feeding Tool loci Workpiece

The induced cutting modes in DMS

om

xm

Cutting kinematics for the multitier micronanostructure generation 21/50



Part I: Diamond milling servo based machining system (c) Intersecting DMS for generating hierarchical micro/nanostructures Tool pose compensation

VCM HCM

Tool geometry compensation Optimal toolpath for a F-theta substrate

 Conditions:

PDS: z(x,y)=ax2+by2+cy4 Feedrate: fx=fy=20μm/rev

Schematic of toolpath determination

Diamond tool: Rt=0.1 mm Inclination angle: α=0.5 degree. 22/50




 Conditions: PDS: z(x,y)=ax2+by2+cy4 Feedrate: fx=fy=20μm/rev Diamond tool: Rt=100μm

 Features:  Accurate PDS  Homogeneous secondary nanostructures (nanopyramids) Characteristics of the hybrid surface obtained by numerical simulation 23/50




 Cutting system:

 Moore Nanotech 350FG  Single crystal diamond tool with Rt=0.104mm  Brass C2600 for the workpiece

 Primary aspheric array  Pitch=250 μm  Apurture=200 μm  Height=1 μm 24/50



Part I: Diamond milling servo based machining system (c) Intersecting DMS for generating hierarchical micro/nanostructures Primary F-theta surface

(a)

Improved secondorder robust Gaussian regression filter

Nanostructured F-theta freeform surface

Nanopyramids 25/50




Characteristics of the obtained secondary nano-pyramids 26/50


Part I: Diamond milling servo based machining system (d) A combination of the intersecting and bi-axial DMS

0.115 0.11

(a) 0.105

zCLP / mm

-0.4

Toolpath

-0.2

-0.5

0.11

x

0.105 0.1 -0.3

fs

0 yCLP / mm 0.2

0.1 0.115 -0.3 -0.4

CLP

-0.6

-0.5

-0.6

(b)

-0.2 0 yCLP / mm 0.2

Side -feeding fg

-0.4

-0.8-0.4 0.4

-0.7

/ mm

xCLP / mm

zCLP / mm

zCLP / mm


-0.7

-0.8 0.4

Tool loci in VCM Tool loci in HCM

0.11 0.105 0.1 -0.5

-1

0 yCLP / mm

-0.5 xCLP / mm 0.5 0

Characteristics of the micro-pyramid array with phase gratings on each side face 27/50



Part I: Diamond milling servo based machining system A brief summary

 Combining the concepts of fast- or slow-tool-servo (FTS/STS) and end-face raster milling, the mechanical machining system named Diamond Milling Servo (DMS) was proposed and investigated;  The DMS based machining system is more suitable for large-scale generation of the microstructures due to the intrinsic constant cutting velocity;  The DMS based machining system is promising for the generation of the hierarchical micro/nanostructures by actively controlling features of the residual tool marks.

28/50



Part II: Rotary vibration assisted diamond milling servo Basic principle of the RV-DMS system (a)

Cutting kinematics th

ith

(i+1)

(i-1)th

Motion characteristics  Spindle rotation (c-axis) and side-feeding along the x- and y-axis direction of the machine tool;

Forward feeding Side-feeding

S

x

o

Workpiece

y

 Servo motion along the z-axis (from STS) for the generation of freeform primary surfaces;  The rotary spatial vibrations for the assistance of the structure generation

Tool loci

(b)

Motion Features Workpiece S

Side-feeding

xt Diamond

Rd

tool

zt

x

xs

ot

zs S

os o

yt

ys

r

p

y

d pin

z

rv Se

xis le a

on oti m o

 NX   30x,i P  a sin     R  i x,i  d    n ( k ,l ) i 1   P    x(Mk ,l )    r( k ,l ) N Y    M    30y,i P   P 0   y ( k ,l )      R z ( k ,l )    bi sin   n ( k ,l )   y,i  i  1     P P  M   f (r , ) ( k , l ) ( k , l ) z    NZ   ( k ,l )  30z,i P  Primary Surface   ci sin   ( k ,l )   z,i   n    i 1  Rotary Vibration

29/50



Part II: Rotary vibration assisted diamond milling servo (a) Mechatronic design of the rotary vibration system Rotary vibration system

Design Criteria  Compact and rotationally symmetric structure

 Piezo-actuated three-DoF compliant vibrator

 High working bandwidth

 Four sets of L-FHs to achieve three-DoF motion guidance of the end-effector

 Decoupled output motions of the end-effector  High output stiffness for machining stability

 Orthogonally arranged three piezoelectric actuators to achieve 3-DoF vibrations 30/50



Part II: Rotary vibration assisted diamond milling servo (a) Mechatronic design of the rotary vibration system (b)

(a)

(c)

Elastic deformation behavior of the CSV with actuation along each direction FEA and analytical result comparisons FEA Analytical Deviation

C1,1out (μm/N)

out C2,2 (μm/N)

out C3,3 (μm/N)

0.118 0.107 9.32%

0.121 0.107 11.6%

0.047 0.034 27.66%

FEA Analytical Deviation

f1/Hz

f2/Hz

f3/Hz

2613.2 2664.1 1.95%

2625.9 2664.1 1.45%

4005.9 4340.8 8.36%

Equivalent stress

31/50



Part II: Rotary vibration assisted diamond milling servo (a) Mechatronic design of the rotary vibration system

Configuration of the off-line testing system 32/50



Part II: Rotary vibration assisted diamond milling servo (a) Mechatronic design of the rotary vibration system

0 -5 -10 0

1

2

3

4

Time / s

1

2

-0.1 3

4

3

4

10

-5 -10 0

-0.1 1

2

2

3

4

3

4

Time / s

5

(b)

0.2

0

-0.2 0

5

1

(b)

0.1

(a)

0

5

x z

x y

0.1

1.5%

0 -0.1 -0.2 0

5

Time / s

Time / s

12.254 μm

z

5

0.2

0

2

-4

Time / s

Displacement / m

Displacement / m

0.1

(a)

0

-8 0

5

y z

1

y 4

(b)

0.2

-0.2 0

10.100 μm

8

Displacement / m

(a)

Displacement / m

Displacement / m

x 5

Displacement / m

11.067 μm

10

1

2

3

4

5

Time / s

2 1.5 1

3 2

1000 y z

1 0 0

2000 3000 Frequency / Hz

4000

5000

(b)

f x, f y

Displacement / m

0.5 0

fz

f x, f y 1000


4000

5000

y 3

(a)

fy fz

2 1 0 0

1000


4000

5000

(b)

2 1.5

x z

f x, f y

fz

1 0.5 0 0

1000


Displacement / m

fx

4

Displacement / m

(a)

fz

x

Displacement / m

3 2.5

Displacement / m

Displacement / m

Static performance tests

4000

5000

fM,x=f M,y=2.8 kHz Dynamic performance tests

6

(a)

fz

z 4 2 0 0 3 2

1000 y x

4000

5000

(b) fz

f x, f y

1 0 0


1000


4000

5000

f M,z=4.3 kHz 33/50



Part II: Rotary vibration assisted diamond milling servo (b) RV-DMS for the generation of micro/nanostructures

(b) Workpiece S

Side-feeding

xt Diamond

Rd

tool

zt

x

xs

ot

zs S

os o

yt

ys

r

dle pin

s axi

z

rv Se

on oti m o

p

y

34/50



Part II: Rotary vibration assisted diamond milling servo (b) RV-DMS for the generation of micro/nanostructures Numerical simulation

I

Primary surface

z( x, y )  Ax cos(2 f x x)  Ay sin(2 f y y ) with Ax=Ay=1.25 μm, and fx=fy=5 mm-1

Machining parameters

n=7 rpm

f=15 μm/rev

Vibration parameters

II

Frequency: 200 Hz Amplitude:  b=0.50 μm, c=0.25 μm (I)  a=2.50 μm, b=0.50 μm (II) 35/50




Detailed parameters employed in machining Diamond tool Radius Rt Rake face angle

Machine tool

104 μm 0o

Feedrate f Spindle speed Rotational distance Rd

Workpiece 15 μm/r 8 rpm 2.25 mm

Material

Brass C2600

Detailed parameters employed for the RV system f1=40 Hz * a1 / μm b1 / μm c1 / nm E1 E2 E3 E4 E5

0 0 0 1.5 0

0 0 0 0 0

0 0 75 0 0

f2=200 Hz a2 / μm b2 / μm c2 / nm 0 2.5 0 2 0

0.5 0.5 0.5 0.5 0.5

125 0 75 0 125

Primary surface Planar Planar Planar Planar Sinusoid grid **

36/50



Part II: Rotary vibration assisted diamond milling servo (b) RV-DMS for the generation of micro/nanostructures Nano-dimple array generated in E1

Nano-ridge array generated in E2

37/50




Hierarchical nano-dimple array generated in E3

Tadpole-looking nanostructures generated in E4

38/50




Characteristics of the fabricated hierarchical micro/nanostructures 39/50

T



Part II: Rotary vibration assisted diamond milling servo (c) RV-DMS for micro/nanomachining of brittle materials ST

 xv  S’ a sin(2 f vt  x )  Rd   )  yv   k b sin(2z 'f vt   y(k+1) p Cutting   zv  c sin(2 f vt  z ) duration   y y'

(a)

(b)

th

th

yv

s R

L

yt

xv

xt ot

d

t

o'

ST

hc,max v (t )  Maximum depth-of-cut: d

ov

C

Spindle

Diamond tool

ST

(b) z'

kth

(k+1)



yt

Cutting duration

y'

o'

Diamond tool

hc,max

to

d

M

tm vM 

HSR 

d

vC (t )

 n Rd 30





arcsin   1   2  arcsin 0.5 2

 Horizontal speed ratio:

te 0.5 pL

tm

DC  (te  to ) f v 

th

pL

xv

hc,max ≅ c   2 v2n30 R 1   2      to

 Duty cycle:

Tool Position

S’

te 0.5 pL

with: and:



 n Rd



30 f v pL

a b

 2



 n Rd



30 f v a  b , b   nt  Turning    cos Milling   a 2  b2 ,  30  . 2

2

2

2

cd d  1 c c. 40/50



Part II: Rotary vibration assisted diamond milling servo (c) RV-DMS for micro/nanomachining of brittle materials 3

(a)

Displacement / μm

2

z y x

1 0 -1 -2 -3 2

2.5

3

3.5 Time / s

1.5

4

4.5

5 -3

x 10

(b)

1

z / μm

0.5 0

fv=2 kHz

-0.5 -1 -1.5

2.4 μm

2 1

4.8 μm 0

-1 0 0.2 -0.2 x / μm

μm

-2

0.5

1. the spindle, 2. the fixture, 3 the slip ring, 4. the CSV, 5. the dynamometer, 6. the workpiece, 7. the tool holder and the diamond tool, 8. the piezo-actuators, and 9. the endeffector

Practical tool motion

y / μm

41/50



Part II: Rotary vibration assisted diamond milling servo (c) RV-DMS for micro/nanomachining of brittle materials

Sa = 4.3 nm

Sa = 66.2 nm

Critical-depth-of-cut=58 nm Machined surface without vibration assistance

Critical-depth-of-cut=744 nm Machined surface with rotary vibration assistance

Characteristics of micro-topography of the micro-groove generated on single crystal silicon 42/50



Part II: Rotary vibration assisted diamond milling servo A brief summary

 Design, modeling, analysis and experimental tests of the piezo-actuated rotary compliant vibration mechatronic system are comprehensively conducted;

 Theoretical and experimental investigation on the rotary vibration assisted diamond milling servo (RV-DMS) system for generating hierarchical micro/nano-structures as well as enhancing machinability of brittle materials are systematically conducted;  The RV-DMS system is more promising for the generation of the hierarchical micro/nanostructures due to the inherent hierarchical cutting architecture and consistent cutting operation of the RV-DMS system.

43/50



Overall contribution and future work Contribution  Provide an efficient and powerful DMS based micro/nanomanufacturing system for large-scale generation of the micro-structured functional surfaces as well as the bio-inspired hierarchical micro/nanostructures;  Provide the thorough and systematic guidance for advanced design and implementation of the compliant mechanism based mechatronic system with multiple degree-of-freedoms for micro/nanomanufacturing;  Provide solid theoretical basis for optimal toolpath determination and structured surface estimation for the DMS based micro/nanomanufacturing system.

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Overall contribution and future work Future work

 To improve the surface estimation model with consideration of system dynamics and cutting force variations.  To develop self-sensing based feedback control strategy for nanopositioning of the diamond tool in the rotary vibration system.  To synthesize motions of the rotary vibration system and the machine tool to have a coordinate operation for ultra-precision generation of the intricately shaped surfaces.

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Acknowledgements • Committee members for valuable guidance, discussions and insights. • My chief supervisor, Dr. Sandy To, for her continuous support and encouragements on my Ph.D. study and research. • Prof. Ehmann from Northwestern University for beneficial comments and guidance.

•All past and current members of the State Key Laboratory in Ultra-precision Machining Technology for their help on the experiments and enlightening discussions. •Specific acknowledgement is given to the research committee of the Hong Kong Polytechnic University for their generous support of this work with grant number of RTJZ.

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Publication Lists

1. Zhiwei Zhu, Suet To, and Shaojian Zhang, (2015). "Theoretical and experimental investigation on the novel end-fly-cutting-servo diamond machining of hierarchical micro--nanostructures" International Journal of Machine Tools and Manufacture, 94: 15-25. 2. Zhiwei Zhu, Suet To, and Shaojian Zhang, (2015) "Large-scale fabrication of micro-lens array by novel end-fly-cutting-servo diamond machining," Optics Express 23 (16), 20593-20604. 3. Zhiwei Zhu and Suet To, (2015) "Adaptive tool servo diamond turning for enhancing machining efficiency and surface quality of freeform optics", Optics Express, 23 (16), 20234-20248. 4. Zhiwei Zhu, Suet To, Xiaoqin Zhou, et al. (2016). "Characterization of spatial parasitic motions of compliant mechanisms induced by manufacturing errors", Journal of Mechanisms and Robotics- Transactions of the ASME, 8 (1), 011018. 5. Zhiwei Zhu, Suet To, and Shaojian Zhang, (2015). "Active control of residual tool marks for freeform optics functionalization by novel biaxial-servo assisted fly-cutting", Applied Optics, 54 (25), 7656-7662.

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Publication Lists

6. Suet To, Zhiwei Zhu*, and Peng Wang, (2015). Evolutionary diamond turning of optics for error correction covering a wide spatial spectrum. Optical Engineering, 54(1), 015103-015103. (*Corresponding author) 7. Zhiwei Zhu, Suet To, and Shaojian Zhang, (2015) "High throughput generation of hierarchical micro-/nanostructures by novel spatial vibration assisted diamond cutting." Advanced Materials Interfaces, doi: 10.1002/admi.201500477. 8. Zhiwei Zhu, Suet To, Gaobo Xiao, Kornel F. Ehmann, and Guoqing Zhang, (2015) "Rotary spatial vibration-assisted diamond cutting of brittle materials." Precision Engineering, doi: 10.1016/j.precisioneng.2015.12.007. 9. Zhiwei Zhu, Suet To, Kornel F. Ehmann, Gaobo Xiao and Wule Zhu, (2015) "A novel diamond micro-/nano-machining process for the generation of hierarchical micro-/nano-structures." Journal of Micromechanics and Microengineering, accepted.

10. Zhiwei Zhu, Suet To, Kornel F. Ehmann, Xiaoqin Zhou and Wule Zhu, " Design, analysis, and realization of a novel piezoelectrically actuated rotary spatial vibration system for micro-/nanomachining." IEEE/ASME Transactions on Mechatronics, under review.

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Conference attendance

1. Zhiwei Zhu and Suet To, "Nonlinear vibrations of a typical fast tool servo induced by the contacts between the piezo-actuator and the flexure mechanism", In: Proceedings of the 4th International Conference on Nanomanufacturing, 8-10 July, 2014, Bremen, Germany. 2. Zhiwei Zhu and Suet To, "Adaptive diamond turning for micro-structured surfaces." In: Asia Pacific Conference on Optics Manufacture 2014 (APCOM 2014), 9-11 November, 2014, Guangzhou, China. 3. Zhiwei Zhu and Suet To, "Spatial nano-vibrator assisted fly-cutting-servo diamond machining of micro-/nanostructured surfaces." In: CIRP 2015 SURFACES Scientific Technical Committee meeting, 22-28 August, 2015, Cape Town, South Africa.

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Q&A

Thanks for your attention!

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