What are CF Fittings & Flanges?

ConFlat (CF) fittings are flanges that use metal seals to achieve vacuum conditions. The combination of a copper gasket (OFHC) and a stainless steel knife-edge flange makes for an almost impenetrable vacuum barrier.

The integrity of the knife edge on the stainless steel flange is critical for the seal. The hardness of the stainless steel coupled with the softer copper gasket means that there are few alternative configurations offering equally airtight capabilities.

As the stronger, sturdier metal, the stainless steel knife-edge cuts an indentation into the softer copper gasket.

The CF knife edge system, guarantees the best performing vacuum seal, allowing vacuum levels in the excess of 10-12mbar. Unlike other vacuum seals that use elastomers and clamps, CF flanges use a series of bolts. This guarantees a strong and uniform seal across the copper gaskets. CF fittings can be supplied with both threaded and through-bolt holes, depending on the application.

The Appearance of CF Fittings

The majority of CF fittings are manufactured from high tensile metals such as stainless steel while the material for the gaskets are made from soft materials. The most common material used for the gaskets is OFHC copper, when pure copper cannot be used silver plated copper of aluminium gaskets provide a viable alternative. The main benefits of utilizing such robust materials are two-fold; increased durability and an elevated propensity for withstanding  high temperatures. The seals can be baked to temperatures as high as 400°C which, in turn, allows for more efficient pumping of your system.

Due to the varied environment where CF fittings are used a certain level of flexibility is required. There is a variety of standard products, with fixed and rotatable flanges. Rotatable flanges are necessary for bolt holes to align and allow components to interface with each other. CF fittings are used for UHV application, but not exclusively, another common application is for high temperature processes. The all metal seal will withstand temperatures up to 400° making it a popular choice for coating systems and furnaces to name but a few.

When to use CF Fittings

Allectra’s team of specialists will recommend using CF fittings when the vacuum level requires it or in a high temperatures process. The naturally low outgassing of metals, durability at high temperature and the superior metal sealing technology, makes it the obvious choice for processes in demanding environments.

CF Fittings from Allectra

Our experienced manufacturing team can customize CF flanges to fit any customer request, we can produce the optimum equipment for your vacuum processing operations.

Contact us or visit our website to find out the multitude of benefits our CF fittings and flanges can provide for you and your team.