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 * Activity report for week of 12/12
  * Mark, Fabian and Enzo continued BS Test Hang work:
   * We shipped BS mirror box parts to Shoda-san and components for a new LVDT cable to Hirata-san.
   * We posed for pictures of the BS by a team from National Geographic.
   * We installed the BF fishing rod stepper motor adaptor cable.
   * We tried to install the BF LVDT cable but first we encountered trouble routing it, and then several wires broke at the D-Sub end.
   * We laid 6 in-air cables from the tank to the PR2 rank for BF and SF picos, steppers and LVDTs.
   * We lifted the BF/IRM/IM/RM/BS section to weigh it and check its balance.
    * It was 195.6 kg, which is 18 kg(!) less than the capacity of the SF.
    * There was a major imbalance in roll: with all four built-in trim masses moved up the +Y end, it still needed 270 g of extra trim mass to be level. This can probably be made up easily by designing the 18 kg of extra mass appropriately.
   * Unfortunately when we put the payload, the IM was slightly yawed and ended up on the horizontal EQ stop screws. This let the IM-BF maraging rod go slack, which disturbed the leveling of the IM (because every time it is picked up the maraging rod settles in a different place, giving a different suspension point).
   * We removed the end panels of the IRM to get access to the IM and rearranged the trim mass on the the IM to get it balance to bubble-level precision. (We still need to do fine pitch adjustment with the OL so that the BS is at the right angle, secure the trim mass properly and replace the IRM panels and OSEMs.)
  * Miyakawa-san and Yamamoto-san redid the cabling from the computer room to the PR2 rack and expected to finish by lunchtime on Friday.
  * Hirata-san
   * Did parts and fastener lists for the SR payload.
   * Did a 3D model with the SR suspension on the BS assembly frame (to help Mark make adjustments to the frame design).
   * Did 2D drawings of Fabian's concept for BS EQ stop parts.
   * Did a 3D model of a wire clamp with replaceable jaw parts (to avoid having to reuse parts with scars from pressure).
   * Did 2D drawings of a new wire clamps for on top of the BS and SR RMs.
 * BF issue
  * The BF has four issues that may or may not be related:
   * The keystone is sitting at an angle, so the bottom of the keystone just barely clears the magnet yoke without rubbing.
   * The suspension point for the IM rod is offset. Thus:
    * The BF does not hang level when the IM is suspended from it, even with all built-in trim masses moved to their limits (an additional 270 g stacked on the +Y side of the cap is required).
    * The offset of the rod also causes an offset of the IRM and IM, which uses up all the adjustment range of the IRM OSEMs and means the EQ stops screws between the IRM and IM cannot be inserted without rubbing.
   * The load capacity is slightly less than measured by Hirata-san during tuning at the ATC.
   * The frequency is rather higher than measured by Hirata-san.
  * Also, the BF/IRM/IM/RM/BS system is 18.1 kg light (195.6 kg) compared to the load capacity of the SF (213.7 kg).
  * Diagnosis:
   * The direction of the tilt lines up exactly with one of the blades (the one in the +X,+Y direction on the assembly frame).
   * The blade bases are adjusted symmetrically relative to the outer edge of the BF.
   * Therefore the +X,+Y blade is probably either stronger or weaker than the other two.
   * However even if this was true at the ATC, something has changed during transit.
   * Designing asymmetric trim mass would fix the imbalance problem but not the offset problem (IRM and IM would still be displaced; EQ stop screws could still not be used).
  * Quick summary: this is a major nuisance and is repeatedly costing us time, but we could probably make it work if we absolutely had to.
  * Options:
   * Bring the BF back to ATC for a tuneup before proceeding with the test hang.
    * Could almost certainly fix the frequency problem.
    * ''Might'' be able to fix the offset and/or tilt problems by swapping in the spare blade.
    * ''Might'' be able to fix the offset problem by adjusting the blade bases to different distances from the edge.
    * If successful, makes some subsequent steps simpler and/or safer (less asymmetrical trim mass; IRM/IM stops can be used).
    * Reduces the chance of discovering a show-stopping problem with the BF later.
    * Might delay design of 18 kg of trim mass (unless it's very adjustable).
    * Delays finding any problems in other areas (SF, PI etc).
    * Would distract Hirata-san from SRx procurement at a crucial time.
   * Allot time for a tuneup between the test hang and the real hang.
    * Same chance of success at fixing the immediate problem as above.
    * Possible worse delay design of 18 kg of trim mass (unless it's very adjustable).
    * Test hang work is harder and slower.
    * Greater chance of running into a show-stopping problem related to the BF and having to back up in the test hang.
    * Advances finding any problems in other areas (SF, PI etc).
    * Could allow more spare blades to be ordered - better chance of getting a well-matched set.
    * Probably better for Hirata-san.
   *		 === Type B (Mark) ===
==== Past week report ====
At Kamioka (Enzo):
 * Enzo (with help from Miyo-kun) fixed the broken actuation coil on PI LVDT #0.
 * Enzo worked on the final cabling plan for BS and SRx.
 * Enzo replaced the LVDT driver again to have one with no dead channels (and free up the partly non-working cards for servicing).

At Mitaka and Kashiwa (Mark, Hirata-san, Fabian, Enzo):
 * We glued magnets into their holders.
 * We did a walk-through of the gluing procedure at Mitaka and discovered that the secondary prisms were missing.
 * We took the mirror box and gluing tools to Kashiwa to do as much of the gluing as possible.
 * Hirose-san applied First Contact to the BS and he and Kieran moved it into the mirror box.
 * We practiced putting sapphire prisms on the BS but didn't apply glue.
 * We tried the magnet gluing jigs designed by Aso-san and found two major issues: the overall length was about 25 mm too long, and there was no adjustment to allow for the wedge.
 * We designed a simple modification to the jigs that hopefully would be trivial for the ATC to do: the jigs will be cut in half and the bottom section will be mounted with adhesive on an 11 mm rod that slides in the central hole of the top section. Thus the top half can be screwed into the existing recess, and the bottom half with the magnets and glue can be allowed to drop about 3 mm onto the face of the optic. Hirata-san worked with ATC to get this done and it should be ready today (Friday 7/7).
 * Hirata-san also got ATC to make some jigs to hold the old 5-mm prisms so that they can be ground down to 3 mm to replace the missing ones. Hirata-san will do the grinding himself today (Friday 7/7/).
 * We decided to continue the gluing work at Kamioka, so we brought the BS back to Mitaka and will ship it on to Kamioka next Tuesday.
 * Hirata-san did a version of the 3D CAD with the as-built BS Test Hang configuration.

==== Plan for weeks of 7/10, 7/17 ====
Mark, Enzo mostly at Kamioka.
 * More TFs.
 * Receive BS at Kamioka, do gluing if possible.
 * Document LVDT driver rebuild and other changes.
 * Learn how Miyo-kun's pico driver software works and make fixes/improvements.
 * Design/install matrices, blend filters and damping filters.
 * Finish tidying rack and labeling cables.
 * Add temporary ballast to LBB and find total required.
 * Try rearranging arc weights to make room for magic wand.
 * Start on creating SR3 rack.
 * Preparation for BF rebuild.
 
Fabian, Hirata-san at Mitaka.
 * Clean BS secondary prisms and modified gluing jigs (Hirata-san).
 * Ship gluing tools and BS to Kamioka.
 * Do new 3D CAD for final BS install (Hirata-san):
  * On-assembly-frame version.
  * In-tank version.
 * Design SR assembly frame (Fabian).
 * Do 2D Drawings and procurement of final IM/BF/SF ballast masses (Hirata-san).
 * Other purchasing and preparation (spare BS clamps, suspension wire, 8-mm rod receptacles)
 * Do mass budget for LBB - design ballast masses (Fabian)

Vacation Info:
Hirata-san: Thu 7/20 through Mon 7/24
Enzo: Sat 7/22 through Sun 8/6
Fabian: Fri 8/4 through Mon 8/21
Mark: TBD Mid-Oct

Scraps of text for incorporation in the VIS Meeting Minutes

KAGRA/Subgroups/VIS/MeetingNAOJ

Type B (Mark)

Past week report

At Kamioka (Enzo):

  • Enzo (with help from Miyo-kun) fixed the broken actuation coil on PI LVDT #0.
  • Enzo worked on the final cabling plan for BS and SRx.
  • Enzo replaced the LVDT driver again to have one with no dead channels (and free up the partly non-working cards for servicing).

At Mitaka and Kashiwa (Mark, Hirata-san, Fabian, Enzo):

  • We glued magnets into their holders.
  • We did a walk-through of the gluing procedure at Mitaka and discovered that the secondary prisms were missing.
  • We took the mirror box and gluing tools to Kashiwa to do as much of the gluing as possible.
  • Hirose-san applied First Contact to the BS and he and Kieran moved it into the mirror box.
  • We practiced putting sapphire prisms on the BS but didn't apply glue.
  • We tried the magnet gluing jigs designed by Aso-san and found two major issues: the overall length was about 25 mm too long, and there was no adjustment to allow for the wedge.
  • We designed a simple modification to the jigs that hopefully would be trivial for the ATC to do: the jigs will be cut in half and the bottom section will be mounted with adhesive on an 11 mm rod that slides in the central hole of the top section. Thus the top half can be screwed into the existing recess, and the bottom half with the magnets and glue can be allowed to drop about 3 mm onto the face of the optic. Hirata-san worked with ATC to get this done and it should be ready today (Friday 7/7).
  • Hirata-san also got ATC to make some jigs to hold the old 5-mm prisms so that they can be ground down to 3 mm to replace the missing ones. Hirata-san will do the grinding himself today (Friday 7/7/).
  • We decided to continue the gluing work at Kamioka, so we brought the BS back to Mitaka and will ship it on to Kamioka next Tuesday.
  • Hirata-san did a version of the 3D CAD with the as-built BS Test Hang configuration.

Plan for weeks of 7/10, 7/17

Mark, Enzo mostly at Kamioka.

  • More TFs.
  • Receive BS at Kamioka, do gluing if possible.
  • Document LVDT driver rebuild and other changes.
  • Learn how Miyo-kun's pico driver software works and make fixes/improvements.
  • Design/install matrices, blend filters and damping filters.
  • Finish tidying rack and labeling cables.
  • Add temporary ballast to LBB and find total required.
  • Try rearranging arc weights to make room for magic wand.
  • Start on creating SR3 rack.
  • Preparation for BF rebuild.

Fabian, Hirata-san at Mitaka.

  • Clean BS secondary prisms and modified gluing jigs (Hirata-san).
  • Ship gluing tools and BS to Kamioka.
  • Do new 3D CAD for final BS install (Hirata-san):
    • On-assembly-frame version.
    • In-tank version.
  • Design SR assembly frame (Fabian).
  • Do 2D Drawings and procurement of final IM/BF/SF ballast masses (Hirata-san).
  • Other purchasing and preparation (spare BS clamps, suspension wire, 8-mm rod receptacles)
  • Do mass budget for LBB - design ballast masses (Fabian)

Vacation Info: Hirata-san: Thu 7/20 through Mon 7/24 Enzo: Sat 7/22 through Sun 8/6 Fabian: Fri 8/4 through Mon 8/21 Mark: TBD Mid-Oct

KAGRA/Subgroups/VIS/TypeB/Minutes (last edited 2022-10-28 10:02:46 by fabian.arellano)