If you’ve ever specified a bushing, bearing, seal, or sliding component, you’ve probably run into the same question: what’s actually the best plastic for low friction parts? The honest answer is that it depends on what else the part needs to do, because friction is rarely the only requirement. Temperature, load, chemical exposure, and lubrication availability all factor into the decision, and the “best” material changes depending on which of those variables matters most.
At Reading Advanced Machining, we machine low-friction engineering plastics every day for customers in aerospace, medical, semiconductor, and industrial applications where a part that binds, wears prematurely, or seizes isn’t an option. Here’s how the most common low-friction plastics compare, and how to think through which one fits your project.
Before comparing specific materials, it helps to understand what “low friction” actually means in a machined part. A material’s coefficient of friction describes how easily two surfaces slide against each other, but a good low-friction plastic also needs to resist wear over repeated cycles, hold up under load without deforming, and often perform without any added lubrication, since many applications — vacuum environments, cleanrooms, food processing — can’t tolerate grease or oil.
That combination of low friction, wear resistance, and load tolerance is why certain plastics show up again and again in bearings, bushings, seals, gears, and wear strips, while others that seem similar on paper fall short in practice.
When people ask about the best plastic for low friction parts, PTFE (commonly known as Teflon) is usually the first material that comes up, and for good reason — it has one of the lowest coefficients of friction of any solid material available. It also resists sticking, doesn’t absorb water, and holds up across an unusually wide temperature range, from cryogenic conditions to several hundred degrees Fahrenheit.
The tradeoff is that PTFE is relatively soft and can deform slightly under constant load, a behavior known as cold flow. For parts that need to hold precise dimensions under sustained pressure, PTFE alone may not be the right call — though PTFE-filled blends of other plastics can help offset this weakness, which we’ll get to below.
Delrin, DuPont’s trademarked acetal homopolymer, offers a different kind of low-friction performance. It’s not as slick as PTFE, but it combines low friction with considerably more strength, stiffness, and dimensional stability, making it a popular choice for gears, bushings, and bearings that need to handle mechanical load in addition to sliding smoothly.
Delrin is also significantly easier and more cost-effective to machine than most other high-performance plastics, which is part of why it remains one of the most common materials specified for precision mechanical components. Some Delrin grades are even reinforced with PTFE fibers specifically to combine Delrin’s strength with PTFE’s slipperiness — a practical middle ground when a part needs both properties at once.
For applications where PTFE or Delrin can’t handle the heat, load, or environment, Vespel and Torlon are the materials engineers typically turn to next. Vespel, a polyimide, combines low friction and excellent wear resistance with the ability to perform reliably at continuous temperatures far beyond what PTFE or Delrin can tolerate, which is why it’s a go-to material for bushings and seals in aerospace, semiconductor, and vacuum applications. We’ve covered Vespel and Torlon machining in more depth if you want a closer look at how these materials compare to each other.
Torlon, a polyamide-imide, trades a bit of PTFE’s slipperiness for significantly higher compressive strength and stiffness, making it the preferred choice for heavily loaded bearings, bushings, and valve seats that need to resist wear under real mechanical stress rather than just sliding freely. If your application combines high heat with heavy mechanical loads, our guide to Torlon machining covers what makes this material particularly well suited to that combination.
Ultem, by comparison, isn’t typically the first choice when friction is the primary concern. It’s an excellent material for heat resistance, strength, and electrical insulation, but it doesn’t offer the same inherent low-friction properties as PTFE, Delrin, Vespel, or Torlon. If your application needs both electrical insulation and some degree of wear resistance, it’s worth discussing with your machining partner whether Ultem or one of these other materials is the better fit — sometimes the “best” plastic for a project is really about balancing multiple requirements rather than optimizing for friction alone.
As this overview of wear-resistant plastics points out, the right material genuinely depends on the type of contact occurring, the environmental conditions, and the load the part will see in service. A seal in a dry, room-temperature environment has very different requirements than a bushing in a high-heat vacuum chamber, even though both are technically “low-friction” applications.
That’s why material selection is rarely a simple lookup — it’s a conversation about tradeoffs. A more slippery material might not hold up under load. A stronger material might not be as forgiving under constant sliding contact. Getting this decision right the first time avoids costly redesigns and premature part failures down the line.
Choosing the best plastic for low friction parts isn’t just about picking the material with the lowest published coefficient of friction — it’s about understanding how that material will actually perform in your specific application, and how well it can be machined to the tolerances your part requires. At Reading Advanced Machining, we work with PTFE, Delrin, Vespel, Torlon, and other advanced engineering plastics daily, and we’re glad to help you weigh the tradeoffs before you commit to a design. Request a quote and let’s talk through what your application actually needs.
