Overview of Tape Research at CMRR

Transcription

1 Overview of Tape Research at CMRR Jason Wang Center for Magnetic Recording Research University of California, San Diego La Jolla CA Phone: , Fax: Presented at the THIC Meeting at the Hilton San Diego/Del Mar Del Mar CA on January 22, 2002

2 STUDY OF TAPE EDGE WEAR Graduate Student: Jason Wang Advisor: Prof. Frank Talke Center for Magnetic Recording Research, UCSD

3 Outline Background Experimental Setup and Procedures Previous Results Results since Last Meeting Edge wear vs. tape speed Edge wear vs. different guide pad materials Edge wear vs. different substrate materials Summary Future Work

4 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

5 Experimental Setup and Procedures Measurement Method Creation of Indentation Guide Force Calibration Test Drive Setup AFM Measurement Data Processing

6 Measurement Method * WEAR ( d) = INITIAL DEPTH - REMAINING DEPTH TAPE EDGE 1 um, INITIAL 10 um REMAINING DEPTH REFERENCE PLANE

7 Measurement Method * WEAR ( d) = INITIAL DEPTH - REMAINING DEPTH 1.6 mm SLIDER/ GUIDE PAD TAPE EDGE 1 um, INITIAL 10 um REMAINING DEPTH REFERENCE PLANE

8 Creation of Indentations Sliding Table Picture from Microscope Dial Indicator Knife Reference Surface

9 Indentations under Microscope A B After Indentation After Re-pack B A B A 2k Passes Tape with 45-mN Guide Force 4k Passes

10 Test Drive Setup Rollers without Flange Tape Slider Suspension Bottom View Removed Original Guide Pads

11 AFM Measurement Scanning Tip Reel of Tape Camera

12 View from AFM Monitor Cantilever Bar Indentation Scanning Tip

13 Data Processing 3-D image of edge wear at 30-mN guide force Initial 6,000 Passes

14 Section view of edge wear at 30-mN guide force Initial, d=681 nm, delta d=0 nm 2,000 passes, d=616 nm, delta d=65 nm

15 Previous Results 60-mN 45-mN 30-mN

16 6k-pass 4k-pass 2k-pass

17 Specific Wear Rate (W S ) Calculation WS = d P N W S = Specific Wear Rate d = Removed Depth (Wear) P = Guide Force N = Number of Passes

18 60-mN 45-mN 30-mN

19

20 Results Since Last Meeting Wear vs. tape speed Wear vs. different guide pad materials Wear vs. different substrate materials (preliminary)

21 4 m/s 2.5 m/s 1 m/s

22 6k-pass 4k-pass 2k-pass

23 4 m/s 2.5 m/s 1 m/s

24 Particles inside indentation at 1 m/s (Sample-E) Initial 2K

25 Particles inside indentation at 1 m/s (Sample-G) Initial 4K 2K 6K

26 Particles inside indentation at 1 m/s (Sample-G) Initial 4K 2K 6K

27 Wear vs. different guide pad materials 4.85 mm CERAMIC or COPPER PAD 1.6 mm SLIDER TAPE EDGE 10 um REFERENCE INDENTATION

28 Original Slider Pad Ceramic Pad Copper Alloy Pad

29 Copper Pad Surface Roughness: Ra = 13.62

30 Ceramic Pad Surface Roughness: Ra = 13.33

31 Test Drive Setup for Ceramic and Copper Pad Rollers without Flange Ceramic Pad Copper Pad

32 Ceramic Copper

33 Ceramic Copper

34 Tape elongation was observed Initial 2k-pass 4k-pass Indentations under Microscope (Sample-H w/ ceramic pad) 6k-pass

35 Initial 2k-pass 4k-pass Indentations under Microscope (Sample-I w/ copper pad) 6k-pass

36 Wear Mark on Copper Pad after 6,000 Passes

37 Wear mark measured by WYKO 3 um 40 um

38 Wear vs. different substrate materials (preliminary)

39 Data Sheet for Tape Samples

40 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

41 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.

42 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).

43 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