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Agenda

Agenda.

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Agenda

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  1. Agenda • Preliminary Agenda:1. Overview - schedule and plan (chris)2. Tradiational thin section preparation (skok and jim)3. Epoxy, self-supported thinsection, and support concepts (cbd)4. Sectioning stage with diamond wire (steele)5. Profilometer results (chris)6. Thin section grinder (kris zacny)7. Requirements discussion (chris and all)

  2. Traditional Sectioning Methods • Jim, talk about slicing with Skok • Drawback being it takes a lot of power, large amount of dust generated, and it would take a 12” diameter blade to cut a 5” rock • …. Which leads us to diamond wire

  3. Diamond Wire Tech A summary of what we have learned from our visit. Special thanks to Cynthia Christianson for all the help and expertise.

  4. Wire characteristics • Small size (.006”-.012” diameter) • Expect low energy requirements • Little material loss (kerf = wire diameter + .001”) • Small amount of debris generated from cut • Excellent flatness capabilities A Microphotograph of Diamond Wire Cross-Section of Diamond Wire http://www.diamondwiretech.com/diamond_wire/diamond_wire.html

  5. Tangential Cutting • Reduced cut time • Must determine if cut time reduction is worth the energy requirement • Allows for a higher quality cut (less drift) • Patented by DWT

  6. Process Quality http://www.diamondwiretech.com/process/process.html

  7. Capstan Wire Guide • Capstan holds short wire lengths (100’ held on ~3” OD x 5” length shown above • Maintains wire integrity better than reel to reel system • Larger package than reel to reel • Reverses cutting direction every 5 sec • Fairly simple to rethread wire in case of a break

  8. Reel to Reel Wire Management • Holds long wire lengths (2 km) that runs between two reels • Wire wears faster because it lays over itself • More compact package overall • Cutting direction reverses less often (~30 sec – 90 sec?) • Slightly more complicated to re-thread wire in case of a break

  9. DWT Cutting Control • Wire tension is maintained with air pressure (set to ~15 psi) • The wire is programmed to cut at a set rate OR at a set rate with bow no greater than θ˚ (Typically 3˚) • Downward cutting force is less than 1 lb which allows us to use a light holding force on the rock • Low cutting forces cause rock to resemble ground rock face finishes

  10. Wear Items • Pulleys will need to be replaced after ~250 hours of use (AL hub stays, neoprene V guide slides over hub) • Wire tends to break from bending stresses, not wear of diamond.

  11. Preliminary Concepts • Insert various solidworks sketches

  12. Questions • Do you have a preferred delivery method for receiving the cubic? In a container, a “vise” on a stage, with robotic manipulator? • How do you plan to hold this for grinding? • Are there temporary epoxies, tapes that could be used or reused? I believe C Dreyer mentioned something about this. • If we are to do this without a slide, doesn’t that limit you to boring into our cubic to create the thin section? • What materials are you looking at to do the grinding? • If we wanted to collect dust from cutting to analyze there would be very little from the diamond wire. Would we be able to rely on the rover to pull a dust sample from the ground?

  13. System Requirements • Minimal consumables (epoxy, wire, guides, etc.) • Low Power Usage per function (quantify?) • Least Mass Possible to do the job • Fewer moving parts means fewer broken pieces • Robust enough to last for X-months or X-many sections? • No fluids, all electromechanical • Must be able to function at ~40 Kelvin? Would we be able to simulate anything near that?

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