[Halld-cal] Temporary suspension of gluing light guides

[Elton Smith]

Dear collaborators,

We have temporarily suspended gluing light guides. We are using Norland 
NOA 87 UV-curing glue. A new batch of the glue was opened on Monday and 
some areas do not cure completely clear. Our lead tech, Tina Mann, 
summarized various tests comparing the new and old batches in the e-mail 
below. All indications are that problems in the gluing can be attributed 
to differences in the glue batches. Norland is preparing a new batch, 
which should ship in the next couple of days. They do not know of any 
changes in the preparation between the two batches.

Cheers, Elton.
**


-------- Original Message --------
Subject: 	UV Glue
Date: 	Wed, 20 Feb 2013 07:25:05 -0500 (EST)
From: 	Tina Mann <mannt at jlab.org>
To: 	Elton Smith <elton at jlab.org>
CC: 	Tom Carstens <carstens at jlab.org>, Scot Spiegel <spiegel at jlab.org>, 
David Butler <debutler at jlab.org>, Timothy Whitlatch <whitey at jlab.org>



Hi All,

  Monday I opened a new bottle of UV Glue and noticed some difference in the thickness but it wasn't until the curing process that we noticed two other issues that made the glue unusable, Many bubbles occurred during the cure process and a tackiness texture after cure. I tried several different methods to verify and pin point that the glue was the issue. Here are the things I tried


Modular #37

1. One row of lights guides with the new UV Glue-Failed
2. One row of lights guides with the previous UV Glue-Passed

Different Modular to rule out Modular face ON Modular #37

Modular #30

1. Two rows of lights guides with the new UV Glue-Failed
2. One row of lights guides with the previous UV Glue-Passed

Also tried this application

Modular #30

New Lot of UV Glue

1. Light coat of the new lot of UV Glue-Failed
2. Med coat of the new lot of UV Glue-Failed
3. Heavy coat of the new lot of UV Glue-Failed


Modular #30

Previous Lot of UV Glue

1. Glued one row of light guides-passed

I have noticed that over time (two weeks) that the glue gets thicker and works better with our application, maybe...aging and being exposed to off and on ambient light from opening and closing the bottle makes it thicker and becomes more pliable for our application, just a thought but maybe over time this BATCH of UV glue would individually be OK to use.


I contacted Norland yesterday and talked to Tim Norland, he said the batches are made to order so it would be 2-3 business days before he could get new product to us. I'm expecting Friday at the earliest and Monday or Tuesday at the latest. He did mention that he talked to the manufacturer and the glue specs have not changed and there were no issues on their side and I let him know there we know changes on ours.

I am keeping three small bottles of this particular batch behind because I want to see what happens over a period of time. This info may be helpful later on.

As far as how this will affect production will solely count on the new batch of glue we will be receiving on Monday or Tuesday. If the glue comes in workable we will be back on line and will catch up to our 4 per week. This is another reason why I would like to keep three small bottles of this batch behind because if it is the aging (thickness)we need for our application then we will have some to work with until the new ages :)

I will be back and forth between Blue Crab and the ESB. Here's my cell if you need to contact me or have any questions 757-272-8202

Thanks Have a great day!

Tina






   




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