BW May 2018

5/1: Jim explained that he ground the metal pieces for the ferrules so they will direct light more directly toward the fuse site. We may need a collimator to block some of the light if it is heating too far from the fuse site.

Jim wants to have a machinist make some high quality, professional grade pieces that would be the best ones we have. Then we would have two sets and while we are cleaning one we can be installing new ferrules with the other.

Because of the high pressure and heat that we use to fuse the fibers, the melted material is almost as hard to contain as water. In our current setup we can't avoid wings without risking a weak set of fibers.

However, there are things we can do to reduce the potential for wings. One is to put an additional lamp behind the fibers to be fused. The current lamp is in front, and it needs to heat a lot to reach the back as well as the front. With a rear lamp we would not have to heat as much or we wouldn't have to push as hard to fuse the fibers.

The problem with a rear lamp is that we could not put it on a line perpendicular to the fibers and intersecting the fuse site unless the lamp is much smaller than the front lamp. We would have to angle a larger lamp and use collimators to direct the light correctly.

Instead of a lamp, we might use another kind of heater, but we would need to ensure that it would heat the fibers, not just the outside of the quartz ferrules.

5/2: Today I wanted to cut two more bundles of sci-fis, one to replace the "To be milled" fibers that we will not use and the other as an extra bundle. But when I was about to start cutting, I found that we are out of snack bags to put the fibers in.

I looked around for somewhere to put the fibers temporarily. There was an empty bag from Thor Labs for 5 micron grit. I will use that one for one of the sci-fi bundles. In the storage closet in lab 405 I found a Thor Labs lab snacks box. Inside there were some shiny foil strips. Some of the strips were in a snack bag and some were loose in the box. There was also an empty snack bag in that box. Since it was empty, I will use it for the other sci-fi bundle to be cut today. It can be a permanent bag since we can always get another snack bag for the foil strips from the lab snacks box if we ever need one. I will label the empty bag and use it to store a bundle of sci-fis.

I put one bundle of sci-fis in the empty snack bag and labeled it as bundle 8. Bundle 9 goes in the Thor Labs 5 micron bag.

5/3: I made a histogram of the fiber color codes, and orange is our most used elastic color with a count of 221. I would think if we order 350 orange elastics that should be enough. We just need to cover 7 regular bundles and however many spares we will finally need. Assuming 6 colors in a package and equal numbers of each color, we will have to order 2,100 elastics.

Jim on Color Codes and Fusing

Jim said the elastics can't go too far from the end because there is some kind of material that would not allow it. Nor should they be too close to the end since we have to put the fibers through the chimneys. Putting the closest one six inches from the end might be all right. I would rather have them farther from the end in case they need to be bundled again, though. We need to figure out where to put those elastics.

We should wrap the elastic three times around the syringe so it will be at the right tightness on the fiber. Twice would be too loose, and 4 times around the syringe might break the elastic. We may have to move the elastic a little once it is on the fiber, but we should avoid that if possible.

It is important to keep the ferrules clean during fusing because dust between them can keep them ever so slightly apart, which is enough for liquid fiber material to leak between them and form a wing. Maybe if there were no dust on the ferrules they would meet perfectly and prevent wings.

A lint-free cloth does clean the fibers, but it can move some dirt down to the end where it should not be. It would be good if we could use compressed air to clean the fiber cladding and ends before fusing as well as using a lint-free cloth. Even compressed air might mess with the cladding, though, so we should be careful with it.

Jim and I talked while he was working on getting the ferrules back in the splicing unit.

I said I thought if I fused rough cut fibers strong enough, I would definitely fuse polished fibers strong enough since the polished fibers have much better contact than rough cut ones. But Jim said the rough cut ones with their rough surface might absorb more light and heat up more than polished fibers. The light might be more likely to shine through polished fibers and not heat them as much. We don't know for sure, so it is best to polish the scrap fibers before fusing and weight testing them. We only need to polish as far as 5 micron grit, though.

Jim also explained that the ferrules crack if they are slammed together during fusing. When we fuse we need to hold the top ferrule down against the bottom one before pressing the start button that would slam them together.

He explained how he glues the ferrules onto the appropriate parts of the splicing unit. He wraps string around them and includes the most turns at the ends of the ferrules. There is also a higher number of turns in the middle of the ferrules, but not as many as at the ends. He puts heat shrink over the coils at the ends and cuts it away after both ferrules are glued on.

The top ferrule needs to be glued when the part is out of the splicing unit because if it were left in the glue would drip down and cement the ferrules together. Even when applying the glue for the bottom ferrule, you need to be careful not to allow it to creep up and attach the two ferrules to each other.

5/4: I cut 9 full-length spare light guides and finished off the spool. There is one shorter fiber that came off the end. I put a white strap around them and put them in the storage box.

I cut some scrap fibers to get them ready for weight testing during fusing. I started polishing a bundle of scraps and finished one end with 400 grit.

I remember I also need to polish some short scrap fibers to substitute for sci-fis in weight testing. I will have to cut those to 0.907" so that polishing will get them to the right length.

5/7: I think sci-fi bundle 6 can come out of the collar so we can try putting short light guides in for polishing.

We need to polish the spare light guides. There are 10 that are already polished downstream as far as 5 micron grit, but Micah said they may need to be repolished because the bundle was not properly aligned.

The 10 spares in bundle 408 seem to have been polished partially with 400 grit upstream. The downstream ends do not appear very good to me. It might be best to repolish those.

I polished the 10 color coded spares upstream, starting with 400 grit and ending with 5 micron and copier paper.

5/8: Next I want to highly polish the downstream ends of all the spares. When we are done with that, we can label the new ones with color codes on the downstream ends. We also need to work on labeling all the fibers at the downstream ends.

We need to start color coding the fibers, and it seems good to start with the bundle we will be fusing. I started fusing bundle 403, so I should start color coding that bundle. I will probably choose one fiber as an example of where to put the color codes and try to get them in the same position at the downstream end as they are now at the upstream end.

Today I moved all the color codes on the fibers in bundle 403 from the upstream end to the downstream end.

I also bundled the spare bundle and I am about to polish it. However, I have some misgivings now about whether I correctly identified the spare bundle (bundle 408). It is supposed to have a cyan strap, but it does not. I put a white strap around it for now. I do see one or two cyan straps in the storage box. I wonder if one of those is marking the spare bundle. I should check the color codes.

5/9: I looked for canned air on amazon.com.

12-Pack

5/10: I found yesterday that the collar around the short scrap bundle was cracked because I tightened it too much. This morning I found that the collars around sci-fi bundles 3 and 9 are cracked also. The cracked ones are no good anymore.

5/11: Jim suggested increasing the pressure in the splicing unit to avoid wings. I tried that today and it doesn't reliably work by itself.

One possibility is that I am pressing too hard on the fibers. I should try reducing the force I put on them.

5/14: Jim adjusted the splicing unit so that we could push the top ferrule down without the strong force resisting its motion. I started to adjust the minimum pressure for the compressor. I unplugged the compressor and turned the setting screw. I did that twice because the pressure still seemed inadequate after my first try.

Later I started to try fusing, but instead of lowering easily as I expected, the top ferrule seemed harder to push down than before Jim worked on it.