Working with CF Vacuum Flanges | Thorlabs Insights

A vacuum coupling that supports operation at ultra-high-vacuum levels (greater than 10E-8 Torr; greater than 1.33 x 10E-8 mbar, greater than 1.33 x 10E-8 hPa) can be achieved when a metal gasket is compressed between two CF or ConFlat® flanges. An approach for making this coupling is demonstrated using a CF-flanged fiber optic feedthrough and a port on a CF-flanged tee. Since the quality of the vacuum seal and the time required to pump the vacuum system down to operating pressure depend on more than just ensuring the bolts are tightened correctly, this demonstration also highlights several practices for working with vacuum components and systems that can help achieve good results. Damage to the knife edge, an aggressive approach to tightening the bolts, and reusing gaskets can all result in leaky CF vacuum couplings. The techniques demonstrated in this video reduce the risk presented by these factors, which are all related to the limited malleability of the metal gasket. It is important that the knife edges are in pristine condition, since the gasket is not soft enough to fill narrow or abrupt features, such as a nick in a knife edge. An approach of gradually and iteratively tightening the bolts is effective in maintaining a uniform thickness of the gasket around its circumference, while tightening each bolt all at once can result in thickness variations in the gasket that are difficult or impossible to flatten. This is a consequence of the metal gasket’s limited ability to flow and can result in gaps between the gasket and knife edges. Using a new gasket is always recommended. Even a gasket that was only partially compressed during a previous use may not be malleable enough, when reused, to conform to the contours of the knife edges. This is because compression has the effect of strain (work) hardening the metal. While a leaky vacuum connection can result in time lost to leak checking and re-opening the vacuum system to locate and fix the problem, productive work can also be delayed as a result of broken or malfunctioning components in or attached to the chamber. Due to this, an overview of special considerations for handling and using fiber feedthroughs is also included in this video. ConFlat® is a registered trademark of Agilent Technologies, Inc. 00:00 Introduction 01:03 Sleeve and Glove Partnership 02:55 CF Flange Coupling Overview 06:00 Flange Decoupling Demonstration 09:41 Safely Remove a Stuck Gasket 10:38 Feedthrough Handling, Cleaning 12:09 Copper Gasket Use 13:01 Fiber End Face: Inspect, Clean 13:58 Flange on Port: Inspect, Wipe 14:51 Couple the Two Flanges 19:43 Glove and Sleeve Removal Key Components used in this Demonstration Include: Ultra-High-Vacuum Fiber Feedthrough Flanges: https://www.thorlabs.com/newgrouppage... Ultra-High-Vacuum Fiber Optic Patch Cables: https://www.thorlabs.com/newgrouppage... VGC10 1/4-Hard Copper Gaskets: https://www.thorlabs.com/newgrouppage... FS201 Fiber Inspection Scope: https://www.thorlabs.com/newgrouppage... FCC-7020 Fiber Connector Cleaner: https://www.thorlabs.com/newgrouppage... BD8 Solvent Dispenser: https://www.thorlabs.com/newgrouppage... Nitrile Gloves: https://www.thorlabs.com/newgrouppage... KW32 Wipes: https://www.thorlabs.com/newgrouppage... For more photonics how-to videos, visit https://www.thorlabs.com/newgrouppage...