FKM and FFKM O-Rings

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FKM and FFKM sit at the top of the seal material range and are frequently confused with each other. FKM is a high grade fluoroelastomer with strong resistance across chemicals and temperatures, covering petroleum products, hydraulic fluids and acidic compounds. FFKM goes further, withstanding even aggressive chemicals, and belongs in semiconductor manufacturing and chemical processing. We supply both and will tell you which one your application actually needs.

Key Benefits

• FKM resistance across petroleum products hydraulic fluids and acidic compounds
• FFKM for near universal chemical resistance where FKM reaches its limit
• Both grades available from one supplier so the comparison is honest
• Standard AS568 sizes from existing moulds and custom cross sections tooled here
• Small quantities of high specification compound accepted rather than refused

Problems It Solves

• Seals degrading in fluids that general purpose elastomers cannot handle
• Paying FFKM prices for an application FKM would cover
• Under specifying and paying for it in unplanned downtime
• Suppliers who will not quote small quantities of a specialised compound

Who It Is For

• Process engineers specifying seals against a defined chemical list
• Semiconductor and electronics plant maintenance teams
• Buyers who have been quoted FFKM and want to know whether FKM would do
• Distributors carrying a high specification seal range

Application Scenarios

• Chemical processing seals for reactors mixers and transfer systems
• Semiconductor manufacturing equipment
• Petroleum and hydraulic systems
• High temperature engine and fuel system components
• Equipment handling acidic compounds

What You Are Actually Buying

Only values our own records support appear here. Anything we cannot evidence is left out rather than estimated.

Materials	FKM fluoroelastomer and FFKM perfluoroelastomer
FKM Suited To	Petroleum products, hydraulic fluids, acidic compounds
FFKM Suited To	Aggressive chemicals and solvents, semiconductor and chemical processing
Standard Sizes	AS568 series from moulds held in house
Custom Sizes	Tooled to drawing
Country of Manufacture	China

Materials

• FKM
• FFKM

Manufacturing Process

• Compound selection
• Mould selection or tooling
• Moulding
• Post cure
• Inspection
• Packing

Technical Features

• FKM fluoroelastomer for wide chemical and temperature resistance
• FFKM perfluoroelastomer for the most aggressive chemistries
• Precision moulded cross sections for consistent sealing
• Available across the AS568 size series and to custom drawing

Quality Control

• Compound chosen against the stated chemistry by our formula engineers
• First article approved before series production
• Dimensional check against the approved sample
• Repeat orders run from the same formulation and tool

Customisation Options

• FKM or FFKM in any AS568 dash number
• Custom cross sections tooled in our own workshop
• Small pilot quantities for qualification before volume
• Supplied within a mixed compound schedule

Where This Is the Right Choice and Where It Is Not

Compared With FFKM alone

For most demanding industrial fluids FKM is adequate. Specifying FFKM by reflex spends money on chemical margin the application never uses.

Compared With NBR

Nitrile covers oil and fuel at moderate temperature and nothing like this chemical range.

Compared With EPDM

EPDM is for water, steam and weather. It has no place in petroleum or aggressive chemical service.

How to Specify and Order This Part

• List every fluid including cleaning agents and occasional exposure

List every fluid including cleaning agents and occasional exposure

• Give continuous and peak temperature separately

Give continuous and peak temperature separately

• Ask for samples of both grades where the choice is genuinely marginal

Ask for samples of both grades where the choice is genuinely marginal

• Use an AS568 dash number where the groove allows it

Use an AS568 dash number where the groove allows it

• Record the service life achieved so the next specification is data driven

Record the service life achieved so the next specification is data driven

Related Products

FFKM O-Rings

FFKM O-rings exist for the applications where every other elastomer has already been ruled out.

FFKM Material Seals

Not every FFKM application is an O-ring.

FKM Rubber Parts

This is FKM outside the sealing catalogue: custom moulded fluoroelastomer parts made to a customer drawing.

O-Rings

An O-ring is the cheapest part in most assemblies and the most common cause of a warranty return.

Related Guides and Industries

FFKM or FKM Which One Your Application Actually Needs

FFKM is not simply a better FKM. It is a different commercial decision, and specifying it by reflex wastes money as reliably as under specifying wastes uptime.

How to Choose a Rubber Seal Material in Six Questions

Six questions decide almost every seal material choice. Answer them before you ask for a price, and the quotation you get back will be worth comparing.

FKM and FFKM O-Rings Questions

FKM is a fluoroelastomer with strong resistance across a wide chemical and temperature range. FFKM is a perfluoroelastomer whose resistance is close to universal, at higher cost.

Tell us the chemistry and the temperature, and what a failed seal costs you. We will recommend the lower grade where it is genuinely safe.

Yes. Small quantities of high specification compounds are normal in semiconductor and laboratory work.

Yes, from the complete mould set we hold.

Yes. Our own mould workshop designs and builds the tool.

One working day once we have the chemistry, the size and the quantity.

Quote FKM and FFKM O-Rings

Send the size or drawing, the working conditions and the quantity. One working day for a considered reply.