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Overview of Tape Research at CMRR
Jason WangCenter for Magnetic Recording Research
University of California, San Diego La Jolla CA 92093-0401
Phone:+1-858-534-7578, Fax:+1-858-534-2720E-mail: [email protected]
Presented at the THIC Meeting at the Hilton San Diego/Del MarDel Mar CA 92014-1901
on January 22, 2002
STUDY OF TAPE EDGE WEAR
Graduate Student: Jason Wang
Advisor: Prof. Frank Talke
Center for Magnetic Recording Research, UCSD
Outline
• Background• Experimental Setup and Procedures• Previous Results• Results since Last Meeting
Edge wear vs. tape speedEdge wear vs. different guide pad materialsEdge wear vs. different substrate materials
• Summary• Future Work
Background• To increase storage density in tapes, track density
must be increased
• Increasing track density requires better tape guiding
• Tape guiding is done by using pressure pads
• Pressure pads cause wear which degrades performance
• SEM investigation observed tape edge wear
• AFM obtained a quantitative measurement to study tape edge wear as a function of guide force
Experimental Setup and Procedures
• Measurement Method
• Creation of Indentation
• Guide Force Calibration
• Test Drive Setup
• AFM Measurement
• Data Processing
Measurement Method* WEAR (∆d) = INITIAL DEPTH - REMAINING DEPTH
10 um
1 um, INITIAL
REFERENCE PLANE
REMAINING DEPTH
TAPEEDGE
Measurement Method* WEAR (∆d) = INITIAL DEPTH - REMAINING DEPTH
SLIDER/GUIDE PAD
TAPEEDGE
REFERENCE PLANE
REMAINING DEPTH
1.6 mm
10 um
1 um, INITIAL
10 um
1 um, INITIAL
Creation of Indentations
Reference Surface
Knife
Picture fromMicroscopeSliding Table
Dial Indicator
Indentations under Microscope
AfterIndentation After Re-pack
A
B
2k Passes
B
A
4k Passes
B
A
Tape with 45-mN Guide Force
Test Drive Setup
Removed Original Guide PadsBottom View
Slider
Tape
Suspension
Rollers withoutFlange
Section view of edge wear at 30-mN guide force
2,000 passes,
d=616 nm,delta d=65 nm
Initial,
d=681 nm,delta d=0 nm
Specific Wear Rate (WS) Calculation
NPdWS×∆
=
WS= Specific Wear Rate
∆d = Removed Depth (Wear)
P = Guide Force
N = Number of Passes
Results Since Last Meeting
• Wear vs. tape speed
• Wear vs. different guide pad materials
• Wear vs. different substrate materials (preliminary)
• Wear vs. different guide pad materials
TAPE EDGE
REFERENCE INDENTATION10 um
SLIDER1.6 mm
CERAMIC or COPPER
PAD
4.85 mm
Test Drive Setup for Ceramic and Copper Pad
Ceramic Pad Copper Pad
Rollers withoutFlange
Tape elongation was observed
6k-pass4k-pass
2k-passInitial
Indentations under Microscope(Sample-H w/ ceramic pad)
Initial 2k-pass
4k-pass 6k-pass
Indentations under Microscope(Sample-I w/ copper pad)
Difficulties in this study• Packing (staggering) problem was found by using DLT tape on LTO drive• Tape edge’s surface variation is too large to measure from AFM
Aramid tape under microscope
Summary• Tape edge wear as a function of tape speed and different guide pad materials was evaluated.
• Tape edge wear increases with increasing tape speed.
• Regarding to the effect of guide pad materials on tape edge wear, the ceramic pad caused more edge wear than the copper pad.
• Edge wear was negligible between 2,000 to 6,000 passes when the copper pad was used.
Summary• Tape elongation was observed between 2,000 to 6,000 passes
• The specific wear rate decreases with increasing number of passes. This happened in all three experiments (wear vs. guide force, tape speed and guide pad materials).
Future Work• Continue tape edge wear with respect to different substrate materials (PET, PEN and Aramid)
• Study edge wear as a function of tape tension and guide surface roughness
• Determine the effect of thermal conductivity and hardness on tape edge wear
• Evaluate the tape edge wear as a function of tape path misalignment
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