There are a few materials, though, that actually do the job that no other material can do. PTFE is no exception, and indeed, it has been there for decades. PTFE is a common specification used by semiconductor fabs, chemical processing plants, food production lines, medical device manufacturers, and aerospace wiring engineers in industries that rely on precision-manufactured components where material failure is not an option.
When you need something that will resist essentially any chemical known to industry, run without lubrication, insulate electricity at extreme levels, and stand up to temperature ranges that destroy most other polymers, it is PTFE that keeps coming up.
PTFE comes with its own flip side, however. Mechanically, it’s soft. It is load-dependent and crawls under load. It machines awkwardly. It can’t be processed the way most thermoplastics are made. If you don’t know these trade-offs, you will end up with components that will perform poorly in ways not mentioned in the datasheet.
Here are both sides of the material to help you decide whether to use PTFE in your application.
What Is PTFE?
PTFE is the acronym for Polytetrafluoroethylene. It’s more commonly known by its brand name, Teflon, which DuPont registered in 1945, to the point that it’s now a generic term for the material in industry.
PTFE is a member of the family of fluoropolymers. It contains only carbon-fluorine bonds, which are some of the strongest bonds in organic chemistry. This molecular stability is the primary source of the most important properties, including chemical inertness, thermal resistance, non-stick surface behavior, and outstanding electrical insulation.
Key Properties of PTFE Engineering Plastic
PTFE numbers are important—but how they translate in a real production environment is even more so.
Chemical resistance
Chemical resistance is one of the most nearly absolute of any engineering material. PTFE is highly resistant to all industrial acids, bases, solvents, and chemicals over the entire pH range (0 to 14). Outside the realm of research, molten alkali metals, elemental fluorine, and a few compounds of high reactivity are virtually never seen. PTFE is non-reactive to chemicals for practical manufacturing use.
Temperature range
The temperature range of use is from -200°C to +260°C. It’s a 460° operating window, larger than that of nearly any other engineering polymer. It remains flexible at cryogenic temperatures, at which other materials become brittle, and maintains its properties at continuously elevated temperatures significantly higher than those of nylon, acetal, and standard grades of PEEK.
Coefficient of Friction
Against most surfaces, the coefficient of friction is between 0.04 and 0.10, one of the lowest of any solid substance on record. It has a very high anti-adhesion performance and will not adhere even if not lubricated, and almost nothing will adhere to it unless treated specially. It is not an effect on the surface, but rather a property of the bulk material of the component itself.
Excellent Electrical Insulation
Excellent electrical insulation over a broad frequency range. The material has a high dielectric strength of 60-173 kV/mm and high volume resistivity of more than 10¹⁸ ohm·cm. These are constant over a wide range of temperatures and frequencies, which are tested and exceed the performance of other insulating polymers, making PTFE the material of choice for high-frequency electronic and aerospace wiring.
PTFE Grades and Filled Compounds
Not all PTFE is created equal; there are grades of PTFE, fillers to alter the grade, and things it can change.
Virgin PTFE provides the complete chemical and thermal characteristics. Mechanical properties are substantially improved, but at the expense of some loss of purity in the filled grades. It’s important to make the right selection between them, as this can make the difference between a component that works and one that does not when placed under load.
Glass fiber filled PTFE (15-25% glass) is used to significantly increase compressive strength and creep resistance. When mechanical load is to be carried, this is the common requirement for PTFE parts such as valve seats, bearing pads, structural gaskets, and seal faces subject to bolt loading.
Carbon filled PTFE makes it more wear-resistant, also gives it some electrical conductivity, and enhances the compressive strength. In bearing and seal applications that require dry running, along with load-carrying capacity.
Graphite-filled PTFE offers an even greater degree of lubricity. It enhances its thermal conductivity, which is beneficial in dynamic seal applications where friction creates heat and requires it to be dissipated, not concentrated in the contact area.
Bronze-filled PTFE
The highest compressive strength and best creep resistance are obtained with the bronze-filled grades. The compensation for this is a compromise in chemical resistance in some harsh environments, which is not an issue in others.
Where PTFE Is Used in Modern Manufacturing
PTFE doesn’t get used everywhere. It is specifically used where the combination of its properties solves a problem that nothing cheaper can deal with as well.
Chemical Processing
Chemical processing is the largest use category. Rubber, silicone, and most other sealing materials are vulnerable to attack by process chemicals, which is why they need to be replaced by PTFE in seals, gaskets, lined pipe, pump components, and valve seats in chemical plants. PTFE is often the sole sealing material in a plant that deals with sulfuric acid, hydrofluoric acid, or an aggressive solvent.
Electrical and Electronics Manufacturing
PTFE’s use in electrical and electronics manufacturing ranges from wire and cable jacketing to the high-frequency circuit board substrates (PTFE-based PCB laminates are the foundation for most microwave and RF electronics) for insulating components in high-frequency equipment, where temperature and frequency dielectric stability is a requirement.
Bearings and Bushings
In environments where lubrication is not possible, operationally unacceptable, or contaminated, bearings and bushings, especially carbon or graphite-filled, run dry. PTFE bearings are particularly used in food processing conveyors, pharmaceutical mixing equipment, and textile machinery because there is no need to put any oil or grease close to the food product. Producing these components to tight dimensional tolerances requires experienced CNC machining—especially given PTFE’s tendency to deflect under cutting loads.”
Semiconductor Fabrication
Materials used in semiconductor fabrication require to be compatible with the high concentration of wet process chemicals used without releasing contaminants into the highly purified process environment. For this reason, PTFE tubing and fittings, wafer carriers, and chemical bath components are typical components of semiconductor fabrication equipment.
Medical Devices
PTFE is employed in the coating of surgical instruments, implantable devices, and the interior of catheters, where all three characteristics, which are biocompatibility, chemical resistance, and non-stick properties, are required in the same application.
Machining PTFE: Where It Gets Tricky
The material is soft and sticky to the cutter. Instead of cutting straight through, it tends to bounce off the cutting edge and return, resulting in dimensional inaccuracy that will be apparent in inspection once the part is removed from the machine. It also frequently adheres to and drags on cutting tools by virtue of the soft material clinging to the tool geometry, not by chemical adhesion but by the pickup of the soft material.
The basic rule for machining PTFE:
- Sharp tooling is a must. Soft PTFE is deflected by dull tools, rather than cut. Clean cuts and dimensional results are obtained by using carbide or HSS tools with positive rake angles.
- Operate at high surface speeds. PTFE machines work better at higher cutting speeds—the material is easier to cut, and tool sticking is less of a problem. Bad surface finish and dimensional issues occur at low speeds all the time.
- Maintain a uniform and even cut. Deflection occurs due to the heavy depth of cut. The controlled passes provide more accurate, quality dimensions.
- Cool with coolants and compressed air. Unlike metals, PTFE does not heat up; cooling can aid in flushing away the chips and keep the workpiece cool, reducing its tendency to deform during cutting.
- Fix for support, but not compression. Under clamping pressure, PTFE material is compressed. Over-clamp it, machine it, and remove the clamp, and it springs back out of tolerance. Hold it up, but do not press it.
- Permit dimensional stabilization before inspection. Dimensional relaxation may occur after machining PTFE parts, especially thin-section features. Add stabilization time to the final measurement.
These behaviours are commonplace in precision CNC machining in engineering plastics. If the shop is new to PTFE, the learning curve is a reality and may manifest itself in the form of surface finish or dimensional rejects until the process is dialed in.
Working with a precision CNC machining partner experienced in engineering plastics is critical. FST Metals offers CNC Machining and CNC Turning services suited for demanding materials like PTFE
PTFE vs. PEEK: Choosing the Right High-Performance Plastic
Both are often used to compare with each other because they are at the top end of the engineering plastics range. They are so distinct that it is generally easy to decide once the application requirements are fully specified.
| Property | PTFE | PEEK |
| Max continuous service temp | 260°C | 250°C |
| Tensile strength | 20–35 MPa | ~100 MPa |
| Compressive strength | Low | High |
| Creep resistance | Poor | Good |
| Chemical resistance | Near-total | Very broad (fewer exceptions) |
| Coefficient of friction | 0.04–0.10 | 0.35–0.45 (unfilled) |
| Machinability | Moderate (sticky) | Good (heat-sensitive) |
| Cost | Moderate | High |
| Biocompatibility | Limited grades | Medical-grade available |
The choice usually boils down to this: PTFE if the main goals of the application are low friction, sealing, or chemical containment. PEEK should be used if structural load-bearing, dimensional accuracy under load, or mechanical strength at high temperatures are required.
Using PTFE where PEEK is needed results in components that creep out of position under load. Specifying PEEK where PTFE is needed adds unnecessary cost and may not match PTFE’s chemical resistance in the most aggressive environments. If you’re unsure which material suits your application, FST Metals can help evaluate your requirements and get a custom quote here.
Conclusions
PTFE is well deserved of its reputation. The chemical resistance, temperature range, coefficient of friction, and electrical-insulating properties it provides are truly hard to compare with any other product at the same price level. When used properly, it is the most obvious specification on the list!
PTFE users who always deliver the best results do so by treating it as a precision material choice, matching grade to application demand, designing around its creep and thermal expansion characteristics, and finding a cutting partner who understands the material in the cutting tool.
Make the right decision, and PTFE can address problems in a way that nothing else can, easily and economically.
FAQ
Polytetrafluoroethylene is classified as a polymer, and what type of polymer is it?
PTFE is a semi-crystalline thermoplastic that is composed of extremely stable carbon-fluorine bonds and is therefore a fluoropolymer. It is a high performance engineering plastic. It cannot be injection molded, unlike most thermoplastics; it is produced by powder sintering, a process distinct from conventional plastics manufacturing.
What are the key disadvantages of PTFE that the engineer must overcome?
Low mechanical strengths, poor creep resistance under sustained load, high thermal expansion, and failure to bond with conventional adhesive without surface treatment. These are not faults; they are inherent properties of materials. If they are designed properly, they cease to be a problem.
What are the performances of PTFE when compared to other engineering plastics in high-temperature and chemically aggressive conditions?
It is superior to almost any other chemical resistance, and it can resist almost all industrial acids, bases, and solvents across the entire pH spectrum. From a temperature perspective, it operates constantly up to 260°C. Its drawbacks include lower mechanical strength under such conditions; for load bearing at high temperatures, PEEK is the better option.
