Custom ISO-KF Vacuum Fittings Manufacturers

What is the easiest way to assemble and disassemble KF vacuum fittings without tools?

The KF (Klein Flange) vacuum fitting system is designed for tool‑free assembly and disassembly, enabling rapid connection changes in research, semiconductor support, and industrial vacuum applications. The easiest method involves using the standard wing nut and clamp design—no wrenches, torque tools, or specialised equipment are required. SUNFUN Group has been manufacturing KF components since 1986, applying precision machining to produce fittings that ensure consistent seal compression and reliable vacuum performance with hand‑tight assembly.

Product Category 1: KF Flanges and Centering Rings

Definition and Positioning

KF flanges are quick‑release vacuum connection components that use a wing nut clamp to secure two flange faces with an O‑ring seal between them. The centering ring positions the O‑ring at the correct location for consistent seal compression. SUNFUN Group manufactures KF flanges from stainless steel with precision‑machined sealing surfaces, producing ISO‑KF fittings that maintain vacuum integrity while supporting rapid assembly and disassembly without tools.

Core Functions and Technical Features

The KF connection system functions through a simple mechanical principle: the wing nut clamp applies uniform circumferential compression to the flanges, compressing the O‑ring against the sealing surfaces. The centering ring positions the O‑ring at the correct location for consistent seal compression. No tools are required—the wing nut is tightened by hand to the specified finger‑tight compression. The clamp mechanism includes a captive nut that remains attached to the clamp, preventing loss of components during assembly or disassembly.

Surface finish is important for reliable sealing in KF connections. SUNFUN Group's KF flanges are manufactured with sealing face roughness values below 1.6 µm Ra, providing the surface quality required for effective O‑ring sealing. Our 0.001‑mm precision machining ensures that flange faces meet dimensional requirements for consistent seal compression. The centering ring is manufactured with tolerances that position the O‑ring correctly without binding or misalignment. These quick release flanges enable repeated assembly and disassembly cycles without performance degradation.

Typical Application Scenarios

KF flanges are used in applications where frequent connection changes are required. Research laboratories use KF connections for experimental setups that are reconfigured regularly. Semiconductor support equipment—including load locks, transfer systems, and roughing lines—uses KF flanges for connections that must be opened for maintenance. Industrial vacuum systems employ KF connections for ease of assembly and service access.

Differentiation from Other Connection Types

KF flanges are distinguished from other vacuum connections by their tool‑free assembly. Unlike bolted flanges that require torque wrenches and specific tightening sequences, KF connections are assembled by hand. This ease of use makes KF vacuum fittings the preferred choice for applications requiring frequent connection changes.

SUNFUN Group's KF Manufacturing

SUNFUN Group's KF flange production applies precision machining and quality control appropriate for vacuum applications. Our 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 vacuum 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 NW vacuum fittings.

KF Flange Specifications

• Standards: ISO 2861, DIN 28403, KF/ISO‑KF
• Size range: KF 10, KF 16, KF 25, KF 40, KF 50
• Sealing method: O‑ring with centering ring
• Surface finish: Ra ≤ 1.6 µm sealing face
• Materials: 304/316L stainless steel standard
• Assembly: Wing nut clamp, hand‑tight only

Product Category 2: KF Clamps and Wing Nuts

Definition and Positioning

KF clamps and wing nuts are the mechanical components that secure KF connections, providing the compression force required for seal integrity. SUNFUN Group's KF clamps are manufactured from stainless steel or zinc‑plated steel with precision‑formed engagement surfaces that distribute clamping force evenly around the flange circumference. These components enable quick release flanges that can be assembled and disassembled without tools, supporting efficient system maintenance and reconfiguration.

Core Functions and Technical Features

KF clamps function by capturing the flange lips and applying compression through the tightening of the wing nut. The clamp design includes engagement features that fit the flange geometry, with a hinged or split construction that enables placement around assembled flanges. The wing nut provides mechanical advantage for hand tightening, enabling the application of sufficient compression for vacuum sealing without tools.

The clamp design must accommodate flange thickness variations while maintaining correct seal compression. SUNFUN Group's clamps are manufactured with engagement surfaces that provide even load distribution, preventing flange deformation that could affect seal integrity. The wing nut threads are manufactured to specifications that ensure smooth operation and consistent tightening. These ISO‑KF fittings support repeated assembly cycles without loss of function.

Typical Application Scenarios

KF clamps are used wherever KF flanges are specified—research laboratories, semiconductor support equipment, and industrial vacuum systems. The tool‑free assembly feature makes KF clamps particularly suitable for applications requiring frequent connection changes, such as experimental setups and systems requiring regular maintenance access.

Differentiation from Standard Clamps

KF clamps differ from standard vacuum clamps in their design for tool‑free operation. The wing nut provides hand‑tight compression without requiring wrenches or torque tools. The clamp geometry is specifically designed to engage KF flange lips correctly.

SUNFUN Group's Clamp Manufacturing

SUNFUN Group manufactures KF clamps with attention to dimensional accuracy and engagement surface quality. Our in‑house institute provides engineering support for clamp design and application. Through our accredited technology enterprise status, we maintain quality systems for KF vacuum fittings.

Clamp Specifications

• Materials: Stainless steel or zinc‑plated steel
• Size range: KF 10 to KF 50
• Finish: Passivated or electroplated
• Operation: Hand‑tight wing nut
• Features: Captive nut, hinged or split design

Product Category 3: KF Adaptors and Adapters

Definition and Positioning

KF adaptors enable the connection of KF fittings to other vacuum connection standards, including ISO, CF, and JIS flanges, as well as tubing and pipe connections. SUNFUN Group manufactures KF adaptors that support interconnection of systems with different connection standards, applying precision machining to ensure dimensional accuracy on both sides of the adaptor.

Core Functions and Technical Features

KF adaptors are manufactured with a KF flange face on one side and a different connection standard on the other. The KF flange face is manufactured to KF specifications, with appropriate sealing surface finish and dimensions. The other flange face is manufactured to the applicable standard, with dimensions and surface finish appropriate for that connection type. The adaptor body provides the transition between the two standards.

The adaptor design must maintain concentricity between the two flange faces while providing sufficient material thickness for structural integrity. SUNFUN Group's adaptors are manufactured with dimensional accuracy that ensures proper sealing on both connections. These NW vacuum fittings enable system integration across different connection standards.

Typical Application Scenarios

KF adaptors are used when connecting KF flanged components to equipment with other connection standards. Research laboratories frequently use KF‑to‑ISO adaptors to connect equipment from different manufacturers. Industrial vacuum systems may require KF‑to‑CF adaptors for connections between general vacuum sections and UHV systems. Semiconductor support equipment may require KF‑to‑JIS adaptors for compatibility with Japanese standard equipment.

Differentiation from Standard Fittings

KF adaptors differ from standard fittings in their dual‑standard design. Standard KF fittings have KF flanges on both ends, while adaptors provide a transition between different connection standards.

SUNFUN Group's Adaptor Manufacturing

SUNFUN Group manufactures KF adaptors for multiple standard combinations. Our precision machining capabilities ensure dimensional accuracy for both flange faces. Our in‑house institute provides engineering support for custom adaptor configurations. Through our open innovation ecosystem, we maintain knowledge of vacuum system interconnection requirements for quick release flanges.

Key Specifications Comparison

The easiest way to assemble and disassemble KF vacuum fittings is to use the standard wing nut clamp system—no tools are required beyond hand tightening. SUNFUN Group manufactures complete KF connection solutions, including flanges, clamps, centering rings, and adaptors, applying precision machining and quality control developed over four decades of experience. Our 0.001‑mm precision machining ensures that KF components meet dimensional requirements for consistent seal compression and reliable vacuum performance. 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 ISO‑KF fittings that support tool‑free assembly in research, semiconductor support, and industrial vacuum applications.

Frequently Asked Questions

Q1: What is the correct way to tighten a KF clamp?

KF clamps should be tightened by hand using the wing nut until the clamp engages the flange lips with even compression. The correct tightness is achieved when the wing nut can no longer be turned by hand with moderate effort. Quick release flanges in the KF style do not require tools or specific torque values—consistent seal compression is achieved through the clamp design.

Q2: Can KF fittings be reused after disassembly?

Yes, KF fittings are designed for repeated assembly and disassembly cycles. The O‑ring seal and centering ring should be inspected and replaced as needed, but the flanges and clamps are reusable. ISO‑KF fittings maintain sealing performance through multiple assembly cycles with proper seal maintenance.

Q3: What is the maximum pressure for KF connections?

KF connections are suitable for vacuum applications from atmospheric pressure down to approximately 10⁻⁶ mbar. The sealing performance depends on O‑ring material, surface finish, and seal compression. KF vacuum fittings are not designed for positive pressure applications above atmospheric pressure.

Q4: What quality controls apply to SUNFUN Group's KF component manufacturing?

SUNFUN Group applies material certification, dimensional verification, surface finish measurement, and visual inspection to all KF components. Our accredited technology enterprise status supports comprehensive quality systems for NW vacuum fittings, ensuring consistent component quality and reliable vacuum performance.