Why Choose OMSS VCR Fitting
- 15+ years of VCR fittings manufacturing experience
- Each VCR fitting is produced through strict process, dimension, and surface inspections
- All VCR fittings obtained ISO, CE, and 3A international certifications
- Advanced CNC machining technique ensures consistent sealing performance
- All stainless steel materials are traceable
OMSS—Your Reliable VCR Fitting Manufacturer
OMSS has over 15 years of experience in manufacturing high-purity stainless steel VCR fittings, and we provide reliable VCR fitting solutions trusted by more than 300 customers worldwide.
Our VCR fittings are specially designed for ultra-high purity and vacuum environments, featuring helium leak rates ≤1×10⁻⁹ atm·cc/sec and internal surface finishes as smooth as Ra ≤0.25 μm.
From precision machining and surface finishing to strict quality inspection and clean packaging, we deliver a complete one-stop solution for VCR fittings used in semiconductor, vacuum, and UHP gas applications. If you want to purchase high-quality VCR fittings, never hesitate to contact us.
VCR Fittings Series
Made from 304 or 316 stainless steel (designator “SS”) with a standard industrial finish.
Made from 316L VAR (Vacuum Arc Remelt) stainless steel and undergoes electropolishing (EP) to meet SEMI standards for semiconductor use.
Designed for higher flow rates, often providing the capacity of a 3/8″ system within a 1/4″ VCR footprint.
Features of VCR Fittings
A thin metal gasket is compressed between two precision-machined “beads” of the fitting to form a gas-tight, metal-on-metal seal.
Allow for inline removal. You can slide a component out of a manifold without moving the rest of the piping
Smooth internal geometry to prevent gas entrapment and ensure easy purging. Electropolished face achieves a surface finish of 10 µin. Ra or better.
Internal threads of the female nuts are silver-plated, preventing cold welding of the stainless steel threads during high-torque tightening.
During tightening, the glands do not rotate against each other, preventing the transmission of torque to the tubing and ensuring the polished sealing beads are not scratched.
Apply a precision-drilled fixed orifice, which allows the fitting to act as a permanent flow limiter, eliminating the need for an external flow control valve.
Specific “High Flow” versions, equipped with a larger internal diameter (ID) to reduce pressure drop while maintaining the same external envelope.
Most of our UHP VCR fittings are stamped with a material heat code, allowing for full metallurgical traceability.
Precision-Machined 316L VAR for UHP Applications
OMSS VCR fittings achieve Precision-Machined 316L VAR status through a combination of advanced metallurgy and stringent finishing processes. We apply Vacuum Arc Remelted (VAR) stainless steel to minimize non-metallic inclusions and sulfur content, creating a dense, uniform molecular structure that supports a superior electropolished surface finish. Combined with the high chemical stability of the 316L material, this effectively prevents particle accumulation, gas escape, and “virtual leakage” phenomena.
Ra ≤ 0.25μm Electropolished Surface Finish
To achieve a Ra ≤ 0.25μm (10 μin.) surface finish, we immerse the stainless steel components in an electrolyte tank, and a controllable current is applied. In this way, small or burrs from the metal surface are removed, effectively smoothing the tiny topographical structures to a mirror-like smoothness. This treatment not only eliminates the mechanical scratches but also forms a chromium-rich passivation layer, ensuring that the joints meet the strict ultra-high purity (UHP) standards.
Metal Gasket Face Seal Technology
Our VCR fittings employ a precision-engineered crush-seal mechanism. In this mechanism, a sacrificial metal gasket is pressed between two polished and arc-shaped sealing “bulges”. When the male and female nuts are tightened, the axial force causes the softer gasket to undergo controlled plastic deformation, allowing it to perfectly fit the minute contours of the hardened joint surface. This design provides a robust, non-rotating interface that can maintain seal integrity under extreme pressure, high temperature, and ultra-high vacuum conditions.
Applications of VCR Fittings
VCR fittings are widely used in semiconductor manufacturing. In gas delivery systems, VCR fittings are applied in processing tools for transporting inert (Nitrogen, Argon) and highly reactive or toxic specialty gases (Silane, Ammonia). In cleanroom integration, using OMSS VCR fittings can help maintain a sterile, outgas-free environment.
In aerospace and defense, a mistake can be fatal, so VCR fittings are used for their high reliability. They can be applied in propulsion and fuel systems to handle volatile fuels. NASA and other agencies also use them for cryogenic fluid management. They are also important for spacecraft life support, as minute leaks could endanger the crew.
Our VCR fittings meet stringent regulatory standards (FDA, cGMP) by providing a crevice-free flow path that prevents microbial growth. They can be used in bioreactors and drug synthesis for Active Pharmaceutical Ingredients (APIs) and purified water systems. Their metal-to-metal seals withstand the aggressive chemicals and high-temperature steam used during frequent sterilization cycles.
VCR fittings are essential for research facilities and industrial vacuum production lines to maintain a high vacuum environment. Many analytical tools, such as mass spectrometers, gas chromatographs (GC/HPLC), and electron microscopes, use VCR fittings to prevent atmospheric gases from interfering with sensitive measurement results.
OMSS VCR fittings can be employed in some specialized energy systems. For example, they can be used in fuel cell research and hydrogen delivery because they minimize the risk of leakage with this highly diffusive and flammable gas. VCR fittings are also employed in coolant loops and monitoring systems due to their resistance to radiation and high-temperature durability.
In chemical processing, VCR fittings with stainless steel gaskets or Hastelloy gaskets are ideal for handling highly corrosive acids or alkalis, which would otherwise degrade standard elastomeric O-rings, due to their high resistance to corrosion and erosion by strong acids, strong alkalis and solvents.
- Certificate of Compliance
Customer Reviews
We purchased sanitary tri clamp fittings and stainless steel ferrules from OMSS for our beverage processing system. The dimensions were accurate, the polishing was clean, and the fittings connected smoothly with our existing pipes without additional adjustment. The consistent quality helped us improve installation efficiency.
EmilyOMSS supported our custom stainless steel fitting project from drawing confirmation to final production. Their engineers provided useful suggestions on material selection and processing details. The finished components matched our requirements well and performed reliably in our food equipment applications.
JohnWe have strict requirements for surface finish and hygiene standards in pharmaceutical equipment. OMSS stainless steel fittings showed excellent workmanship, with smooth surfaces and precise machining. Their products helped us meet our equipment assembly requirements and maintain reliable production performance.
Michael
Usually, the main body and the nut of the VCR fittings can be reused, but the metal gasket is usually disposable. Reusing a deformed gasket that has already been compressed may lead to sealing failure or leakage.
One of the greatest advantages of OMSS VCR fitting is its zero clearance disassembly capability, which means that during disassembly or maintenance, there is no need to move adjacent pipes or components in the system in order to remove a particular part.
Our VCR fitting employs a compression sealing mechanism. On the surface of the connecting piece, there is a pair of precisely machined protrusions, with a thin metal gasket sandwiched between them. When the nut is tightened, the gasket will slightly deform to fill in the tiny gaps, thereby achieving a sealing effect.
The pressure rating depends on the size and material of your VCR fittings, and usually ranges from 2800 psig (192 bar) to 8000 psig (551 bar).
We provide various materials options for you.
For bodies and gaskets, we have 304, 304L, or 316L stainless VAR (Vacuum Arc Remelt) stainless steel for maximum purity.
If there is a leak of your VCR fitting, the reasons may be the use of old or damaged gaskets, scratches on the sealing surfaces (beads), insufficient tightening torque, or the introduction of foreign particles during installation.
Yes. The tubes are welded to the gland, and the gasket is also a metal-to-metal connection. This assembly structure is much more resistant to loosening caused by vibration than the traditional tube fittings.
Yes. OMSS VCR fittings are manufactured according to strict quality control standards and are designed to be compatible with mainstream VCR systems used in semiconductor and high-purity gas installations worldwide.
What is a VCR Fitting?
A VCR face seal fitting is a high-performance metal-to-metal face seal connection. It is designed for ultra-high purity (UHP) and high-vacuum applications to prevent leaks and control contamination.
It achieves a gas-tight seal by compressing a sacrificial metal gasket between two precisely machined and polished “bead-like” components on the joint surface, forming a robust helium leak protection barrier that outperforms standard elastomer O-rings.
Why Do You Need a VCR Fitting?
Inevitable Leak
If you use an ordinary compression or O-ring sealing instead of metal gasketed face sealing, you cannot eliminate micro-leakage, and the vacuum stability will be affected. For semiconductor or UHP gas systems, the leakage always means a decrease in yield.
Compromised Gas Purity
Different from our high-quality VCR fittings, ordinary seals, such as the O-ring, will slowly release gas, adsorbing impurities before releasing. This will affect the purity of high-purity gases, leading to the increasing of impurity concentration.
Particle Risk
Without a controlled surface finish of the VCR fittings, the particle risk increases. Dead corners accumulate contaminants, making the cleaning difficult. If the Ra value does not meet the standard, the UHP system cannot pass the inspection, and GMP or Fab audits will fail.
Risky Replacement
OMSS VCR fittings are compatible with the mainstream VCR standard. Without this advantage, it becomes difficult for you to find a replacement for your existing system, and the engineering renovation cost is also higher.
Unpredictable Large Projects
The lack of professional VCR fittings can cause unstable size and torque control. This may lead to uneven sealing force during installation and leakage at some interfaces, so the construction efficiency will be significantly decreased, and your project may be delayed.
How to Choose Suitable VCR Fittings?
When choosing VCR fittings, there are several factors you need to consider.
First, you need to match the material compatibility of the main body and the gasket with the specific pressure and temperature requirements of your system. If you need corrosion resistance, we can provide high-quality 304, 304L, or 316L stainless steel options for you.
Second, you must determine the correct nominal size and series to ensure the flow capacity.
Third, choose an appropriate type of sealing element. Make sure to select the appropriate type. We have the butt welding of permanent high-purity pipelines, or dedicated adapters for existing configurations.
Finally, it is essential to ensure that the connectors meet the necessary surface finish and cleanliness standards to prevent contamination and to meet the zero-leakage maintenance requirements specific to your semiconductor, laboratory, or industrial environment.
If you are not sure which type of VCR fittings to choose, contact us to get professional advice.
Correct VCR Fitting Installation Steps
The installation process of VCR fittings can be divided into three parts:
- Ensure that the type of gasket (such as stainless steel, nickel, copper, etc.) matches the application.
- Connect the male nut or valve body to the female nut and continue to tighten until it cannot be tightened by hand.
- For stainless steel and nickel gaskets, typically an additional 1/8 turn is required to achieve the rated pressure seal. This needs a wrench.
VCO vs VCR Fitting
| Comparison Item | VCR Fitting | VCO (Vacuum Coupling O-Ring) Fitting |
| Sealing Method | Metal gasket face seal | O-ring elastomer seal |
| Seal Material | 304, 304L, or 316L stainless | Fluorocarbon (FKM), Buna, etc. |
| Leak Rate | ≤ 1×10⁻⁹ atm·cc/sec (helium tested) | Higher than the metal seal type |
| Vacuum Performance | Excellent for high & ultra-high vacuum | Limited by O-ring permeability |
| Reusability | The gasket must be replaced each time | The O-ring may be reusable |
| Particle Generation | Extremely low (metal-to-metal seal) | Possible elastomer degradation |
| Outgassing Risk | Very low | Higher due to the elastomer |
| Typical Applications | Semiconductor, UHP gas, high vacuum systems | General gas, hydraulic, pneumatic systems |
| Cost | Higher initial cost | Lower initial cost |
If your system requires an extremely low leakage rate, high vacuum stability, and zero pollution risk, then for semiconductor and high-purity gas applications, VCR connectors are the best solution.
