Parameters Analysis for Low Power Q-Switched Laser Cutting in Parameters Analysis for Low Power Q-Switched Laser Cutting in Singulation Process of HDD ManufacturingSingulation Process of HDD Manufacturing

Parameters Analysis for Low Power Q-Switched Laser Cutting in Parameters Analysis for Low Power Q-Switched Laser Cutting in Singulation Process of HDD ManufacturingSingulation Process of HDD Manufacturing

The 4th AIT Masters Theses Competition

Present By

Sujin Wanchat

Industrial Systems EngineeringAsian Institute of Technology

May 18, 2009

The 4th AIT Masters Theses Competition

Present By

Sujin Wanchat

Industrial Systems EngineeringAsian Institute of Technology

May 18, 2009

- Introduction- Statements of Problem- Objective- Methodology- Results- Conclusions

- Introduction- Statements of Problem- Objective- Methodology- Results- Conclusions

OUTLINEOUTLINE

INTRODUCTIONINTRODUCTION

Hard Disk Drive (HDD) = A main digital data-storage in a computer.

A HDD suspension = A part of HDD that carries the read-write head flies over the disk media.

INTRODUCTIONINTRODUCTION

Manufacturing process of HDD suspensionManufacturing process of HDD suspension

Etching stainless steel

Component forming

Assembly all components

Functional forming

Cutting (singulation)

INTRODUCTIONINTRODUCTION

The suspension bridge and the cutting lineThe suspension bridge and the cutting line

INTRODUCTIONINTRODUCTION

Laser cutting Laser cutting Die cutting Die cutting

INTRODUCTIONINTRODUCTION

Laser cutting has more advantage in reducing clinging

particles on cut-finished surface.

Laser cutting has more advantage in reducing clinging

particles on cut-finished surface.

Laser cutting can not avoid the thermal effect which may cause malfunction of HDD suspension. Thus, the surface roughness (Ra) and heat affected zone (HAZ)

must be reduced as much as possible.

STATEMENTS OF PROBLEMSTATEMENTS OF PROBLEM

- According to die cutting process, the number of waste products still appears.

- The tool wearing can be found in die cutting, but does not exist in laser.

- The laser cutting shows the evidence of better cut- finished surface than conventional die cutting technique.

- According to die cutting process, the number of waste products still appears.

- The tool wearing can be found in die cutting, but does not exist in laser.

- The laser cutting shows the evidence of better cut- finished surface than conventional die cutting technique.

Quality LaserPunch (die)

Plasma NibblingAbrasive fluid jet

Wire electric discharge machining

(EDM)

Numerical control milling

Sawing UltrasonicOxy

flame

Rate Edge quality Kerf width Scrap and swarf Distortion

Noise Metal + non-metal Complex shapes Part nesting Multiple layers

Equipment cost Operating cost High volume Flexibility Tool wear

Automation Heat affected zone Clamping Blind cuts Weldable edge Tool changes

= Advantage = Disadvantage

STATEMENTS OF PROBLEMSTATEMENTS OF PROBLEM

OBJECTIVEOBJECTIVE

To investigate the influent parameters which affect the surface roughness of cutting plane and the HAZ

length based on Nd:YAG pulsed laser

To investigate the influent parameters which affect the surface roughness of cutting plane and the HAZ

length based on Nd:YAG pulsed laser

Nd:YAG Metal

Wavelength = 1.06 m

CO2 Non-metalWavelength = 10.6

m

Laser Types

CW - Cannot modify “power profile”

Pulsed - Reduce interacting time

- Raise peak power

Laser Modes

METHODOLOGYMETHODOLOGY

METHODOLOGYMETHODOLOGY

DOE is analyzed based on the experimental data using “24 factorial designs with addition of center points” technique.

Controllable factorsLow level

(-)Medium level

(0)High level

(+)

Beam focal spot size, (m) 46.279 50.545 61.327

Pulse frequency, f (Hz) 50103 72.5103 95103

Cutting speed, v (m/s) 1,000 1,150 1,300

Laser power, P (Amp) 16 17.5 19

Controlled factors:1. The same work piece’s model2. Pulse width, Td = 2 s3. Room temperature = 28 C4. Each specimen has thickness of 25 m, and the bridge’s width of 2 mm.

METHODOLOGYMETHODOLOGY

Conduct the real experimental data from the total 20 cases.Conduct the real experimental data from the total 20 cases.

METHODOLOGYMETHODOLOGY

11

22

33

1. Workpiece after cutting 2. Surface Profile 3. Ra value reported

1. Workpiece after cutting 2. Surface Profile 3. Ra value reported

1st2nd

3rd

A = Beam focal spot size (m) B = Pulse frequency (Hz) C = Cutting speed (m/s) D = Laser power (Amp)

RESULTSRESULTS

RaRa

1st

2nd

3rd4th

5th

RESULTSRESULTS

HAZHAZ

A = Beam focal spot size (m) B = Pulse frequency (Hz) C = Cutting speed (m/s) D = Laser power (Amp)

ABD(+) Low A, B, and D consequently Low Ra

CD(+) Low C and D consequently Low HAZ

Significant Factor for RaSignificant Factor for Ra

Significant Factor for HAZSignificant Factor for HAZ

CONCLUSIONSCONCLUSIONS

A = Beam focal spot size (m) B = Pulse frequency (Hz) C = Cutting speed (m/s) D = Laser power (Amp)

CONCLUSIONSCONCLUSIONS

Ideal pulsed laser for cutting process must have: short wave length, very short Td, very high f, high Pp, small and fast cutting speed.

Ideal pulsed laser for cutting process must have: short wave length, very short Td, very high f, high Pp, small and fast cutting speed.