PTFE is the most chemically inert common plastic and the most difficult to hold a tolerance on. It is soft (about 25 MPa tensile), extremely slippery, and creeps under load — the workpiece deflects away from the cutter rather than being cut. Everything about machining it comes down to support and sharpness.
| Tensile strength | 25 MPa |
|---|---|
| Yield strength | 23 MPa |
| Hardness | Shore D50 |
| Density | 2.20 g/cm³ |
| Elongation | 300% |
| Thermal conductivity | 0.25 W/m·K |
| Series | Fluoropolymer |
Typical values for the standard condition (PTFE (Polytetrafluoroethylene / Teflon)). Heat treatment, temper and product form move these numbers — confirm against the mill certificate for your order.
Exceptional chemical inertness — resists almost all acids, bases and solvents
Very low friction coefficient, the lowest of common engineering plastics
Wide service temperature range (roughly −200°C to +260°C)
Excellent electrical insulation and low dielectric constant
Starting parameters for carbide tooling. These are the shop's working numbers, not brochure values — adjust for machine rigidity, tool geometry and workholding.
| Surface speed | 300–600 m/min |
|---|---|
| Feed per tooth | 0.10–0.30 mm/tooth |
| Tooling | Very sharp carbide, high rake, polished flutes |
| Coolant | Air blast or mist; flood is fine |
Soft and slippery — it deflects away from the tool rather than cutting. Use sharp tools, light passes and rigid support, and expect to hold tolerances no better than ±0.05mm on thin sections. Clamping pressure alone can deform the part.
Material costs three to five times aluminum by weight, but the bigger issue is yield: PTFE is easy to scrap through clamping deformation or tolerance shortfalls. Budget for conservative tolerances rather than paying for precision it cannot hold.
For the full cost structure — material, programming, setup, cycle time, finishing and inspection — see CNC machining cost per hour, and for how price changes with quantity see machining by production volume.
On rigid sections, roughly ±0.05mm is realistic. Thin walls and large flat parts are much worse — PTFE creeps and deflects, so a tolerance that looks reasonable on the drawing may be unachievable in practice. Design for the material: avoid thin sections, and specify tolerances only where function requires them.
It is soft and creeps under sustained load, so clamping pressure alone can distort the part before the cutter touches it. The practical responses are low clamping force with broad contact area, vacuum fixturing where possible, and light finishing passes.
Food-grade PTFE is widely used in food processing equipment. Whether a specific grade is acceptable depends on the applicable regulation and certification, so confirm with the material supplier for your application rather than assuming from the polymer type.
Only with difficulty. Its very low surface energy makes adhesion poor, and bonding requires surface treatment (such as sodium etching or plasma treatment) before any adhesive will hold. If the design needs a bonded joint, plan the surface treatment into the process.
Tell us the grade and temper, the quantity and what the part has to do. You get a line-item quote within 24 hours, with DFM feedback on anything that is raising the cost.