Made clarifications in the section on Vac-Seal v18 26 Aug 2011 See DCC record Added general stipulations in section 12.2 such as for design applications where dimensional control is extremely important or tolerances are exceedingly tight, it is the responsibility of the design engineer to (a) establish a basis for baking parts at temperatures lower than the default temperatures recommended herein, and (b) get a waiver for a lower temperature bake from the LIGO Vacuum Review Board. Corrected indium entry Combined copper and copper alloys (such as aluminum bronze, phosphor bronze and beryllium copper) into a single section v19 24 Sep 2011 See DCC record section regarding Class B cleaning and baking of Viton v20 19 Oct 2011 See DCC record Changed section 12.27.8 to show updated cleaning procedure for viewports V21 See DCC record Changed Section 12.27.8 (again) to show updated viewport cleaning procedures Clarified and updated section regarding electrical feedthroughs V22 26 March 2012 See DCC record Clarified responsibilities of cognizant engineer and VRB Added section about DI water and inspection of DI water systems that supply Clean and Bake facilities Augmented fluoroelastomers section with reminder to maximize surface exposure and minimize surface contact during baking and made it explicit that CIT is the default site for baking Viton, etc. Clarified OSEM cables and sensor sections Removed note about not using water on electro-polished parts Clarified labeling section to mention ICS generated labels explicit note about oven ramp up and cool down times for feed-throughs Updated optics cleaning and baking section to indicate VRB acceptance of “no bake” proposal Added section about Clean and Bake requests including link to CNB Ticketing System Clarified cleaning process for Macor process for cleaning Optics Lens Caps Added link to CNB of Siskiyou Mirror Mounts Added Zerodur and Invar clean and bake instructions
Stuff that still needs to be done: clean and bake of anodized Al, clarification of CNB of taps, CNB of PEEK cable clamps, etc. v23 13 April 2012 see DCC record Viewports section updated to reflect the following: -Commercial viewports being solvent cleaned (isopropanol followed by methanol if required) rather than Liquinox-ed and -Custom viewport glass being cleaned according to Freon Wipe Procedure (), states that no FTIR is required. Link to (LIGO Lab Disposal of Solvent Contaminated Materials) added to Solvent Cleaning section v24 27 Jun 2012 see DCC record Clarified rules regarding mixed material bake loads (section 13.2) TABLE OF CONTENTS
3: Suggested Gross Cleaning Steps – (Try Processes A, B, C, or D as needed followed by tap water rinse and drying.) Material Surface Condition A. Aggressive Mechanical Clean (detergents + steel wool, brushes) B. **Solvent degrease Meth/Acet PPE Required* C. Acidic Cleaning (acidic solution + ultrasonic cleaning) PPE Required* D. Cleaning E. Detergent Pre-Cleaning (Liquinox + ultra sonic cleaning) Tap Water Rinse Drying Aluminum Machined X X Citrojet (Alconox), Citronox Protex (Thermodyne Arcair p/n 57014000) X X X Rolled X X Citrojet, Citronox Protex X X X Weld Scale, Corrosion, or Oxidation X X X Citrojet, Citronox Protex X X X Brass Copper Phosphor- Bronze Machined X X X X X Corrosion or Oxidation X X Citrojet, Citronox X X X Stainless Steel Machined X X X X X Weld Scale, Corrosion, or Oxidation X X X Citrojet, Citronox Gosh X X X X X X X X Polished
2. Maintain 182 C (360ºF) +/- 1 C (2ºF) and a vacuum pressure not to exceed 10-6 torr for 48 hours. 3. Cool down in vacuum at rate not to exceed 3 C/min (5ºF/min). Handling of parts out of the vacuum oven is particularly critical. It should be performed with clean tools and/or gloved hands (Latex gloves only). Gloves must be changed for new ones, should operators touch anything other than the parts or the packaging material. 4. After cool down, perform an RGA measurement (per LIGO-E960022). RGA test results shall indicate an out-gassing rate (for AMU components 41, 43, 53, 55 and 57) of 2 x 10-12 torr-liters/cm2/s requirement. If necessary based on RGA test results, re-bake for an additional 24 hours and repeat the RGA analysis. Repeat the last step until satisfactory RGA results are achieved O-rings (ie. in EQ stop applications) Bake in vacuum for 48 hours at 120 C. (To Class B – ultrasonic clean in DI water for 10 minutes, air bake at 120 Cfor 48 hours.) VE Seals and O-rings: (less than 8” diameter with cross section ≤ .275” nominal) Bake in vacuum for 48 hours at 120 degrees C. Wipe with isopropanol thoroughly immediately before each use. VE Larger diameter O-rings (ie. for VE chamber doors) Process per LIGO document: E960159-01-V Vacuum bake at 150 C for 48 hours. Storage of Fluoroelastomers the above fluorine extraction and baking steps have been performed, either: seal the items in Class B paint cans backfilled with dry N2, or seal the items double bagged with a desiccant between bags. Masterbond EP30-2 (Vacseal replacement) Assemblies glued with EP30 should be cured and vacuum baked as per E1000386. Note some assemblies can be found in the Assemblies section below – instructions there take precedence over these basic instructions for EP30.