Mounting Adapter for CF Vacuum Flanges

Overview
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Item #	Qty	Description
VFA275	1	Mounting Adapter for Ø2.75" CF Vacuum Flange, 1/4"-20 Taps
LCPM	1	Horizontal Platform: 30mm & 60mm Cage System
PM4	1	Large Adjustable Clamping Arm, 6-32 Threaded Post
ER3	2	Cage Assembly Rod, 3" Long, Ø6 mm
MRAK25-M01	1	Knife-Edge Right-Angle Prism Prot. Gold Mirror, 800 nm-20 µm
LMR1	2	Lens Mount with Retaining Ring for Ø1" Optics, 8-32 Tap
TR2	2	Ø1/2" Optical Post, SS, 8-32 Setscrew, 1/4"-20 Tap, L = 2"
TR3	2	Ø1/2" Optical Post, SS, 8-32 Setscrew, 1/4"-20 Tap, L = 3"
RA90	2	Right-Angle Clamp for Ø1/2" Posts, 3/16" Hex

View Metric Product List

Item #	Qty	Description
VFA275/M	1	Mounting Adapter for Ø2.75" CF Vacuum Flange, M6 Taps
LCPM/M	1	Horizontal Platform: 30mm & 60mm Cage System, Metric
PM4/M	1	Large Adjustable Clamping Arm, M4 Threaded Post
ER3	2	Cage Assembly Rod, 3" Long, Ø6 mm
MRAK25-M01	1	Knife-Edge Right-Angle Prism Prot. Gold Mirror, 800 nm-20 µm
LMR1/M	2	Lens Mount with Retaining Ring for Ø1" Optics, M4 Tap
TR50/M	2	Ø12.7 mm Optical Post, SS, M4 Setscrew, M6 Tap, L = 50 mm
TR75/M	2	Ø12.7 mm Optical Post, SS, M4 Setscrew, M6 Tap, L = 75 mm
RA90/M	2	Right-Angle Clamp for Ø1/2" Posts, 5 mm Hex

The VFA275 mounting adapter supports a knife edge prism used to split a beam coming from inside the vacuum chamber or combine two beams going into the chamber.

Thorlabs' Mounting Adapter for Ø2.75" CF Vacuum Flanges offers six relief cuts and a clearance channel for versatile mounting.

Mounting Adapter Specifications
Item #	VFA133	VFA133/M	VFA275	VFA275/M
Flange Compatibility	Ø1.33" (CF 16)		Ø2.75" (CF 35)^a
Face Mounting Taps	12 x 8-32	12 x M4	13 x 1/4"-20	13 x M6
Edge Mounting Taps	3 x 1/4"-20	3 x M6	3 x 1/4"-20	3 x M6
Outer Diameter	2.44"	61.0 mm	4.00"	101.6 mm
Cage System Compatibility	30 mm		60 mm
Cage Rod Locking Hex	5/64" (2.0 mm)		0.05"	1.3 mm

The outer diameter of this flange can vary from 2.72" to 2.75", depending on the manufacturer. The VFA275(/M) has been designed to accommodate all flanges within this size range.

Features

Mount Optomechanical Components to a Ø1.33" or Ø2.75" CF Vacuum Flange
Four Smooth Bores for 30 mm or 60 mm Cage System Rods
Array of 8-32 (M4) or 1/4"-20 (M6) Tapped Holes on the Adapter Face
Three 1/4"-20 (M6) Tapped Holes on the Edge
Allows 360° of Continuous Rotational Adjustment

These Mounting Adapters provide a way to mount optomechanical components to a standard Ø1.33" or Ø2.75" vacuum flange. Four smooth bores for Ø6.0 mm cage rods provide compatibility with Thorlabs' 30 mm or 60 mm cage systems. In addition, both mounting adapters have three 1/4"-20 (M6) tapped holes on their perimeters at 90° increments. The VFA133(/M) includes an array of twelve 8-32 (M4) tapped holes on its face, and the VFA275(/M) has thirteen 1/4"-20 (M6) tapped holes. The taps on each adapter are separated by 15° or 30°. Both adapters are secured to a CF flange by means of a flexure lock mechanism that is actuated with a 3/16" (5 mm) balldriver. The VFA275(/M) is compatible with our Ø2.75" CF flange viewports.

The animation above demonstrates how to install the VFA275(/M) adapter. The adapter features six relief cuts around the inner diameter which, when aligned with the bolts on a Ø2.75” CF flange, allow the adapter to slide past the flange hardware and mount onto the vacuum system. If the system uses a zero-length reducer flange or is otherwise space-constrained, the VFA275(/M) also features a clearance channel which fits around the washers allowing the adapter to rotate without clearing the flange hardware. The adapter can be installed or removed while the vacuum system is in use without disturbing the flange. This is ideal for vacuum systems that require a bake-out process, as the adapter can be removed before heating and easily replaced once the system has returned to ambient temperature.

Due to the smaller diameter of the VFA133(/M), this adapter cannot slide over a Ø1.33” flange that uses standard-sized washers. These washers must be replaced with custom-sized Ø0.260” washers; ten are included with the VFA133(/M). The vacuum flange will have to be disassembled to replace the washers. After the washers are replaced, the adapter can be installed on the vacuum flange in the same way as the VFA275(/M) and can be subsequently installed and removed without disturbing the vacuum.

Posted Comments:

John Sinko (posted 2019-09-05 16:30:41.383)

Would it be possible to modify a version of this component for 8", 6", or 4.5" conflat viewports? Thank you and kind regards, John E. Sinko Associate Professor Department of Physics & Astronomy St. Cloud State University

llamb (posted 2019-09-09 10:05:57.0)

Hello John, thank you for contacting Thorlabs. For future custom quote requests, you may email techsupport@thorlabs.com directly. I have reached out to you directly to discuss the possibility of a larger custom conflat viewport.

user (posted 2019-03-14 13:32:14.833)

Dear Sir/Madam, I plan to use several VFA275 as mechanical support of a vacuum chamber with several 2.75" flanges. The vacuum chamber will be baked at 300°C. Does the VFA275 support this high temperature ? Best regards

llamb (posted 2019-03-14 04:50:24.0)

Thank you for your feedback. The VFA275 is designed to be mounted around vacuum flanges for a way to mount optomechanical components to the vacuum flange. The VFA275 itself is not vacuum compatible. The anodization layer on the aluminum will outgas in a vacuum environment and will typically crack and craze at temperatures beyond 100°C. I saw that you have submitted this anonymously, so please email techsupport@thorlabs.com if you have any additional questions.

graham.stutter (posted 2017-12-07 19:21:48.38)

Do you have any plans to expand this range to other CF flange/cage mount sizes? eg CF16 and 30mm?

nbayconich (posted 2017-12-15 09:34:13.0)

Thank you for contacting Thorlabs. We are currently in the process of designing new conflat flange adapters and expect to release them in 2018.

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Mounting Adapter for CF Vacuum Flanges

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