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Entry  Thu Jun 28 23:19:49 2018, johannes, Disha, Notes, Cavity, Gaussian beam mode for the new cavities New_Cavities.pdf
    Reply  Sun Jul 1 23:19:25 2018, johannes, Notes, Cavity, Gaussian beam mode for the new cavities 6x
       Reply  Tue Jul 3 11:58:25 2018, johannes, Notes, Cavity, Gaussian beam mode for the new cavities cavity_support_ring_gen2_15deg.PDFcavity_support_shelf.PDFshelf__contacts.pngcyl__contacts.png
          Reply  Wed Jul 11 22:38:54 2018, johannes, Notes, Cavity, Some assembly required 20180706_212353.jpg20180706_202052.jpg
             Reply  Wed Jul 11 23:27:38 2018, johannes, Notes, Cavity, new breadboard assembly 20180710_143617.jpg20180710_143629.jpg20180710_145112.jpg20180710_163221.jpg20180710_163803.jpg
                Reply  Wed Jul 11 23:51:18 2018, johannes, Notes, Cavity, first light 
                   Reply  Thu Jul 19 23:19:01 2018, johannes, Summary, Cavity, cryostat closed and pumping 20180719_114735.jpg20180717_164839.jpg
                      Reply  Sun Jul 22 00:52:10 2018, johannes, Summary, Cavity, transmission paths set up, mode-matching improved, post-baking ringdowns 6x
Message ID: 2101     Entry time: Wed Jul 11 22:38:54 2018     In reply to: 2099     Reply to this: 2102
Author: johannes 
Type: Notes 
Category: Cavity 
Subject: Some assembly required 

I had placed the expedited order for the modified cavity mounts on Tuesday last week and received them on Friday afternoon, as expected. The tapped holes on the barrel were not going to be machined by them, which was pointed out beforehand and known to me. I flattened the outsides opposing the 2-56 tapped holes for mounting the cylindrical PEEK pieces which hold the cavity for this purpose in the solidworks file, so I would be able to drill and tap the holes with reasonable precision after receiving the part. I also had to tap the 8-32 holes for the set screws which make the parts lock on to the guide rods. Basically none of the hole features in radial direction were machined due to the CNC-only machining.

After tapping a few holes successfully the tap broke off and got stuck in the part. I tried to drill it out and did free its side but is was too fused with the part for me to eject it, so I had to cut it out from the side. The result is quite a bit of cosmetic damage and that one of the PEEK mounts is only attached with one screw. There is still plenty of connecting material left to complete the ring, and due to the geometry I don't think that this compromises the mechanical stability of the part. I went ahead with the assembly, we can order a replacement part later. All other holes were tapped with no problems (I had spare taps, and half the holes were already tapped at this point, although I proceeded being extra careful).

I tested the whole assembly to see if any other modifications were needed. I was particularly worried that the holes for the guide rods were not going to line up well enough between the four parts to be joined. It turns out that they line up quite well though. After finishing the machining I cleaned the parts first with soap, then sonicated them in 60C DI water with 3% detergent (the standard stuff) for 20 minutes, followed by two 2-minute rinsing cycles in lukewarm pure de-ionized water. I included the existing parts of the mounting jig in this cleaning run, since they came in contact with the residually-oily parts during test-fitting. After drying them off I cleaned the parts with Isopropanol and placed them in the QIL baking tank. The parts were baked at 120C for >48 hours over the weekend.

The new optical breadboard was air-baked at 190 C for ~5 days total on a hot plate. The breadboard was flipped at half-time.

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