Custom CF Flanges Components Manufacturers

Why are ConFlat flanges the standard choice for UHV applications?

ConFlat (CF) flanges have become the universal standard for ultra‑high vacuum (UHV) applications due to their ability to achieve and maintain pressures below 10⁻⁹ mbar through bakeout cycles up to 450 °C. The all‑metal sealing system, using copper or aluminum gaskets deformed by a knife‑edge sealing surface, provides leak‑tight performance that elastomer‑sealed systems cannot match. SUNFUN Group has been manufacturing CF flanges since 1986, applying precision machining to produce components that meet the exacting requirements of UHV systems in semiconductor research, particle accelerators, and surface science instrumentation.

Product Category 1: CF Flange Bodies and Knife‑Edge Sealing Surfaces

Definition and Positioning

CF flange bodies are manufactured from stainless steel with precision‑machined knife‑edge sealing surfaces that deform metal gaskets during assembly. The flange design includes the knife‑edge profile, the flange face geometry, and the bolt hole pattern specified by the CF standard. SUNFUN Group manufactures CF flange bodies from 304L, 316L, and 316LN stainless steel grades selected for their thermal stability and corrosion resistance, positioning them as the fundamental component of UHV connection systems. As ConFlat flanges components, these flanges provide the mechanical interface for all‑metal sealed UHV connections.

Core Functions and Technical Features

The CF flange sealing mechanism operates through a mechanical principle that differs fundamentally from elastomer‑sealed systems. The knife‑edge sealing surface is machined to a specific profile with controlled sharpness and surface finish. When the flange is assembled with a metal gasket and bolted, the knife‑edge penetrates the gasket material, forming a leak‑tight seal that can be baked at temperatures up to 450 °C. The knife‑edge geometry must maintain its profile through repeated assembly cycles, requiring precise machining and appropriate material selection.

Surface finish and dimensional accuracy are critical for reliable CF flange sealing. SUNFUN Group's CF flanges are manufactured with knife‑edge surface finishes below 0.8 µm Ra, providing the surface quality required for consistent metal gasket sealing. Our 0.001‑mm precision machining ensures that the knife‑edge profile meets the dimensional requirements for reliable seal formation. The flange body is manufactured with bolt holes positioned to provide even compression distribution around the gasket. These UHV flanges components are designed for the demanding conditions of ultra‑high vacuum systems.

Typical Application Scenarios

CF flanges are specified in all UHV applications where pressures below 10⁻⁹ mbar are required. Semiconductor research equipment—including molecular beam epitaxy (MBE) systems, atomic layer deposition (ALD) tools, and electron beam lithography systems—uses CF flanges for all vacuum connections. Surface science instruments including scanning tunneling microscopes, X‑ray photoelectron spectrometers, and low‑energy electron diffraction systems require CF flanges for UHV compatibility. Particle accelerator vacuum systems use CF flanges throughout beamline sections that must maintain UHV conditions.

Differentiation from Other Flange Systems

CF flanges are distinguished from elastomer‑sealed systems by their all‑metal sealing mechanism and bakeout capability. Unlike KF and ISO flanges that use elastomer O‑rings limited to approximately 200 °C, CF flanges with metal gaskets can be baked to 450 °C. This bakeout capability is essential for achieving and maintaining UHV conditions. The all‑metal seal also eliminates the outgassing sources that limit the ultimate pressure of elastomer‑sealed systems.

SUNFUN Group's Manufacturing Capabilities

SUNFUN Group's CF flange production applies precision machining and quality control appropriate for UHV applications. Our fully intelligent process management maintains energy consumption within 0.1 % across manufacturing operations. Through our open innovation ecosystem, established in partnership with governments, enterprises, universities, and institutions, we maintain knowledge of UHV connection requirements. Our accredited technology enterprise status—demonstrated through national‑level R&D tasks and projects commissioned by the NDRC, MOST, and MIIT—supports quality systems for CF flanges components.

CF Flange Specifications

• Materials: 304L, 316L, 316LN stainless steel
• Size range: DN 16 to DN 400
• Sealing method: Metal gasket (copper, aluminum, silver)
• Bakeout temperature: Up to 450 °C
• Surface finish: Ra ≤ 0.8 µm sealing surface
• Standards: ISO 3669, ANSI, JIS

Product Category 2: Metal Gaskets for CF Flange Sealing

Definition and Positioning

Metal gaskets are the sealing elements used with CF flanges, manufactured from deformable metals that conform to the knife‑edge profile during assembly. SUNFUN Group supplies metal gaskets in copper, aluminum, and silver materials, each selected for specific temperature and compatibility requirements. These gaskets are designed for single‑use application—they are replaced each time the flange connection is opened. As ConFlat flanges components, metal gaskets complete the UHV sealing system.

Core Functions and Technical Features

Metal gaskets function by deforming under the pressure of the knife‑edge sealing surfaces, creating a leak‑tight seal that withstands thermal cycling. The gasket material must be sufficiently soft to deform under the clamping force applied by the flange bolts while providing enough resistance to maintain the seal through bakeout cycles. Copper gaskets are the most common choice for general UHV applications, offering a good balance of deformability and temperature resistance. Aluminum gaskets provide lower outgassing for the most demanding applications. Silver gaskets are used for specific compatibility requirements.

The design of metal gaskets includes specific dimensions and tolerances that ensure proper engagement with the knife‑edge sealing surfaces. SUNFUN Group's metal gaskets are manufactured with controlled thickness and hardness, ensuring consistent deformation and sealing performance. Gaskets are typically supplied with a captive alignment feature that simplifies assembly and ensures correct positioning. These UHV flanges components are critical to the sealing performance of CF systems.

Typical Application Scenarios

Metal gaskets are used in every CF flange connection, regardless of application. The gasket material selection depends on the specific temperature requirements, chemical compatibility, and vacuum performance specifications of the system.

Differentiation from Elastomer Seals

Metal gaskets differ from elastomer seals in their material properties, sealing mechanism, and service characteristics. Metal gaskets are single‑use components that are replaced after each opening, while elastomer O‑rings can be reused multiple times. Metal gaskets maintain sealing integrity through high‑temperature bakeout, while elastomer seals degrade at elevated temperatures. These differences make metal gaskets essential for UHV applications.

SUNFUN Group's Gasket Supply

SUNFUN Group supplies metal gaskets in multiple materials and sizes to support our CF flange product line. Our quality systems ensure consistent gasket dimensions and material properties. Our in‑house institute provides guidance on gasket selection for specific application requirements.

Gasket Material Options

• Copper: Standard choice, bakeout to 450 °C
• Aluminum: Lower outgassing, bakeout to 450 °C
• Silver: Specific compatibility requirements
• Gold‑plated: Enhanced corrosion resistance
• Size range: DN 16 to DN 400
• Single‑use: Replace after each opening

Product Category 3: CF Flange Installation and Bakeout Hardware

Definition and Positioning

CF flange installation and bakeout hardware includes bolts, nuts, washers, and bakeout accessories that enable proper assembly and thermal cycling of CF connections. SUNFUN Group supplies CF installation hardware selected for compatibility with the flange material and the bakeout temperature requirements of the application. These components complete the CF flange system, enabling the reliable assembly and operation of UHV connections.

Core Functions and Technical Features

Installation hardware for CF flanges includes bolts and nuts manufactured from materials that maintain strength at bakeout temperatures. The bolts are typically manufactured from stainless steel grades with high‑temperature strength, with threads designed for consistent torque application. Washers are used to distribute load and prevent galling. Bakeout accessories—including heating blankets and temperature monitoring components—may be required for applications requiring controlled bakeout cycles.

Bolt tightening is critical for CF flange sealing performance. SUNFUN Group provides guidance on bolt torque values and tightening sequences to achieve consistent gasket deformation. Our in‑house institute supports customers in developing assembly procedures for reliable CF flange sealing. These CF flanges components ensure proper system assembly.

Typical Application Scenarios

Installation hardware is used in every CF flange assembly. The hardware selection and tightening procedures are critical for achieving the consistent gasket deformation required for UHV sealing.

Differentiation from Standard Hardware

CF installation hardware differs from standard hardware in its compatibility with UHV requirements and bakeout temperatures. Hardware materials are selected for low outgassing and high‑temperature strength. Bolts are manufactured to tighter tolerances to ensure consistent compression.

SUNFUN Group's Installation Support

SUNFUN Group provides hardware and technical support for CF flange installation. Our quality systems ensure consistent hardware quality. Through our open innovation ecosystem, we maintain knowledge of UHV assembly best practices for UHV flanges components.

Key Specifications Comparison

ConFlat flanges are the standard choice for UHV applications because their all‑metal sealing system provides the bakeout capability, low outgassing, and leak‑tight performance that elastomer‑sealed systems cannot achieve. SUNFUN Group manufactures complete CF flange solutions, including flange bodies, metal gaskets, and installation hardware, applying precision machining and quality control developed over four decades of experience. Our 0.001‑mm precision machining ensures that CF flange components meet the dimensional requirements for reliable UHV sealing. Through our in‑house institute, talent academy, and open innovation ecosystem—established in partnership with governments, enterprises, universities, and institutions—SUNFUN Group maintains the technical expertise required for ConFlat flanges components in the most demanding UHV applications.

Frequently Asked Questions

Q1: Why are metal gaskets required for CF flange sealing?

Metal gaskets are required because they can withstand bakeout temperatures up to 450 °C without degradation. Elastomer seals would fail at these temperatures, preventing the outgassing required to achieve UHV conditions. CF flanges components rely on metal gaskets for their high‑temperature performance.

Q2: How many times can a CF flange be assembled and disassembled?

CF flanges can be assembled and disassembled many times—the flange body and knife‑edge sealing surface are designed for repeated use. However, the metal gasket is single‑use and must be replaced each time the connection is opened. ConFlat flanges components are designed for long service life with proper maintenance.

Q3: What bakeout temperature is required for UHV applications?

Bakeout temperatures typically range from 150 °C to 450 °C, depending on the application. Higher temperatures provide faster desorption of water vapor and other contaminants. UHV flanges components in the CF style are designed to withstand these bakeout cycles without degradation.

Q4: What quality controls apply to SUNFUN Group's CF flange manufacturing?

SUNFUN Group applies material certification, dimensional verification, surface finish measurement, and visual inspection to all CF flange production. Our accredited technology enterprise status supports comprehensive quality systems for CF flanges components, ensuring consistent component quality and reliable UHV performance.