betsy.weaver@LIGO.ORG - posted 12:24, Friday 26 January 2018 - last comment - 16:01, Wednesday 07 February 2018(40291)
ETMY PenRe reworked
In order to compensate for the missing mass of the new holey AERM optic being installed in the ETMY suspension, I had to rework the PenRe mass to be heavier. SYS had designed a heavier new set of parts to swap, and I'll report that the rebuild went smoothly - the weigh compensation was pretty spot on and the install of the parts which we have had fit troubles with in the past, went in easy (thanks to Eddie's tweak on the design based on my feedback).
For the record, the weights of these masses are as follows. Note, the idea is to make the old PenRe mass plus the old ERM mass weight equal the total of the new sets, such that the suspension hangs in the same vertical position as before.
| OLD ETM01 mass | 25,993g | NEW AERM07 | 14,873g |
| OLD PenRe mass | 53,236g | NEW PenRe mass | 64,356g |
| Total | 79,229g | 79,229g |
Assembly weighs of the new PenRe:
| OLD PenRe | New PenRe | |
| Keeping Same Main Body | 29,857g | 29,857g |
| Keeping Same batch of small parts | 3,002g | 3,002g |
| Keeping Same wire clamp assys | 168g | 168g |
| Cans and Plates (new and old species) | 19,087g | 30,284g |
| Addable mass assys, to make total weight | 1,122g | 1,045g |
| Total from above | 53,236g | 64,356g |
Doh - Typo, the ETMY AERM is AERM06, not 07.
The difference in weight between these 2 is a negligable 8g however.