Parameters Analysis for Low Power Q-Switched Laser Cutting in Singulation Process of HDD Manufacturing The 4th AIT Masters Theses Competition Present By SujinWanchat Industrial Systems Engineering Asian Institute of Technology May 18, 2009
OUTLINE - Introduction - Statements of Problem - Objective - Methodology - Results - Conclusions
INTRODUCTION 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.
INTRODUCTION Manufacturing process of HDD suspension Etching stainless steel Component forming Assembly all components Functional forming Cutting (singulation)
INTRODUCTION The suspension bridge and the cutting line
INTRODUCTION Laser cutting Die cutting
INTRODUCTION 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 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.
STATEMENTS OF PROBLEM = Advantage = Disadvantage
OBJECTIVE To investigate the influent parameters which affect the surface roughness of cutting plane and the HAZ length based on Nd:YAG pulsed laser
METHODOLOGY Laser Types • CO2 • Non-metal • Wavelength = 10.6 m • Nd:YAG • Metal • Wavelength = 1.06 m Laser Modes CW - Cannotmodify “power profile” Pulsed - Reduce interacting time - Raise peak power
METHODOLOGY • DOE is analyzed based on the experimental data using “24 factorial designs with addition of center points” technique. Controlled factors: 1. The same work piece’s model 2. Pulse width, Td = 2 s 3. Room temperature = 28 C 4. Each specimen has thickness of 25 m, and the bridge’s width of 2 mm.
METHODOLOGY Conduct the real experimental data from the total 20 cases.
METHODOLOGY 2 1 3 1. Workpiece after cutting 2. Surface Profile 3. Ra value reported
RESULTS Ra 3rd 2nd 1st A = Beam focal spot size (m) B = Pulse frequency (Hz) C = Cutting speed (m/s) D = Laser power (Amp)
RESULTS HAZ 5th 3rd 4th 1st 2nd A = Beam focal spot size (m) B = Pulse frequency (Hz) C = Cutting speed (m/s) D = Laser power (Amp)
CONCLUSIONS ABD (+) Low A, B, and D consequently Low Ra A = Beam focal spot size (m) B = Pulse frequency (Hz) C = Cutting speed (m/s) D = Laser power (Amp) Significant Factor for Ra Low C and Dconsequently Low HAZ CD (+) Significant Factor for HAZ
CONCLUSIONS Ideal pulsed laser for cutting process must have: short wave length, very short Td, very high f, high Pp, small and fast cutting speed.