Seals in semiconductor thermal processes and vacuum chambers have to handle heat, process chemicals and long pump-down hours at the same time. The Lixing M-FFKM-02 perfluoroelastomer O-ring is rated to 320°C, offers chemical resistance close to PTFE, and shows a 20% compression set after 70 hours at 300°C, so it keeps recovery to press against the sealing face after thermal cycles. Match three inputs first, temperature, media and groove squeeze, then use a vacuum leak approximation for an order-of-magnitude estimate and confirm with samples in your own chamber.

Long service in 320°C thermal process chambers

In thermal process and high-temperature vacuum equipment, the seal sits against hot chamber walls and doors for the whole process cycle. According to the M-FFKM-02 perfluoroelastomer O-ring product page, this seal operates reliably in temperatures up to 320°C and suits high-heat vacuum processes. Check the usable range against your equipment's peak temperature and dwell time.

Process chemicals and cleaning agents stay off the sealing face

Perfluoroelastomer combines the chemical inertness of PTFE with the flexibility of an elastomer, and the product page lists resistance to acids and bases, organic solvents and strong oxidizers. Chemical supply lines, wet process tools and chemical process equipment can use one seal material for both heat and media, instead of stocking a different compound for each fluid.

Recovery remains after 300°C thermal cycles

An O-ring seals by being squeezed against the flange. If it takes a large permanent set at temperature, it loses recovery after reassembly or thermal cycling and the contact band narrows. In ASTM D395 testing, M-FFKM-02 shows a compression set of 13% after 70 hours at 200°C and 20% after 70 hours at 300°C. For heat aging and contact design in more depth, see our FFKM O-ring high-temperature sealing article.

75 Shore A and 17.77 MPa give assembly talks real numbers

Hardness is 75 Shore A (ASTM D2240), tensile strength is 17.77 MPa (ASTM D412) and elongation at break is 135.3%. During maintenance the ring is stretched slightly to fit the groove, so these values give the equipment team and the material supplier a shared basis for discussing installation stretch. Confirm the stretch against the groove design.

Where it fits in semiconductor and chemical processing

The product page lists semiconductor, chemical processing and high-temperature vacuum equipment as applications. Chamber doors, vacuum flanges and valve bodies in these tools often rely on static O-ring seals, and the same location sees heat, vacuum and process media at once. Temperature rating alone, or chemical rating alone, does not settle the choice.

Two field details help during maintenance. When helium leak checking, holding helium on an O-ring for a while produces a signal that rises slowly and falls only after the helium moves away. That is permeation through the rubber, while a real leak usually gives a sudden increase (Normandale vacuum and thin film technology notes). The same source advises against cleaning O-rings with solvents, since absorbed solvent causes swelling that greatly increases permeation; wiping with lint-free tissue is enough.

Estimate the order of magnitude with a vacuum leak approximation

NASA preferred reliability practice PD-ED-1223 gives an approximation for the leak rate of an O-ring seal (NASA PD-ED-1223 Vacuum Seals Design Criteria):

L = 0.7 × F × D × P × Q × (1 − S)^2

• L: approximate leak rate of the seal, std. cc/sec
• F: permeability of the gas through the elastomer at the operating temperature, std. cc·cm/(cm²·sec·bar)
• D: inside diameter of the O-ring, inches
• P: pressure differential across the seal, lb/in²
• Q: factor set by percent compression and whether the O-ring is lubricated or dry (Figure 3 of the source)
• S: compression of the O-ring cross section as a decimal (20% = 0.20)

Leakage scales with permeability F, inside diameter D and pressure differential P, and higher squeeze S makes (1 − S)^2 smaller. With everything else unchanged, raising squeeze from 15% to 25% moves that term from 0.72 to 0.56. A material with low compression set is better placed to hold its designed contact and recovery after thermal cycles.

Conditions and limits: the source calls this a rough order-of-magnitude approximation for static, clamped, temperature-stabilized circular O-rings, and it requires the permeability of the specific gas through the specific material at the operating temperature. It assumes a rectangular compressed section with unchanged area and permeation proportional to pressure differential, and it expects plus or minus 50% variation from predicted values. It does not cover scratches, groove defects or installation leaks, and it is not a measured leak rate for this product. Confirm FFKM permeability for each process gas from material data.

What to send with a quote request

• Peak process temperature and dwell time, plus the number of heating and cooling cycles
• Chemicals and cleaning agents in contact, plus the process gases
• O-ring inside diameter and cross section, plus groove dimensions and design squeeze
• Chamber vacuum level and pressure differential across the seal
• Whether the seal sees plasma, or has outgassing or metal ion limits. The product page does not list these data, so verify with samples in your own equipment

Request samples or a specification review

Send these conditions and your equipment drawing to yw@zh-lx.com, or contact us from the perfluoroelastomer O-ring product page to request samples. Lixing Composite Materials Co., Ltd. can review specifications and samples against your groove and process conditions.

Product data: Perfluoroelastomer O-Ring, M-FFKM-02 series, material FFKM. Values are taken from the official Lixing product page, verified on 2026-10-27. This article is an AI draft pending human review.

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