We mill and turn filled and unfilled PTFE to ±0.005 mm, holding flatness on seals, insulators and valve parts that move with temperature. Send a drawing and get a DFM review in 12 hours.
PTFE has a linear thermal expansion around 12 × 10⁻⁵ /°C, roughly ten times that of steel. A 100 mm bushing machined at 22 °C and measured in a 30 °C inspection room can read 0.10 mm larger. If the drawing carries no reference temperature, the gauge and the customer argue about the same part.
The material conducts heat poorly, so the cutting edge keeps the heat instead of the chip. A dull tool rubs, the surface turns waxy, and the sealing lip picks up a burr that will leak. This is a tooling problem, not a feed-rate tweak.
PTFE creeps under sustained load. A press-fit pin or a bolt torqued to a metal standard keeps squeezing the wall, and a Ø6 mm bore can lose several hundredths over weeks. The joint design has to allow for cold flow.
Three-jaw pressure deforms a 2 mm wall before the tool touches it. The cut looks fine on the machine and springs back on the bench. Vacuum fixturing or a soft collet solves it, but the setup has to be planned before the first chip.
Three decisions set the outcome: tool sharpness, how the part is held, and where the heat goes.
PTFE has a coefficient of friction around 0.04, among the lowest of any solid. A tool with a honed edge rubs instead of shearing, and the rubbed material smears across the face. We run polished high-speed steel or uncoated carbide with a positive rake and a generous clearance angle, so the edge slices the polymer rather than pushing it.
Spindle speed is where the heat balance is set. We run small-diameter end mills in the 15,000–25,000 rpm range, take light radial passes, and keep the chip load high enough that the tool cuts instead of polishing. Flood coolant is normally left off because the material does not carry heat away and wet chips cling to the flutes. Compressed air clears the pocket and cools the edge.
PTFE is soft and elastic. A vise or three-jaw chuck point-loads the wall, the material deflects under the clamp, and the finished bore is out of round once the pressure comes off. We plan the workholding around the part: soft jaws bored to the actual diameter, vacuum plates for thin washers, and sacrificial backing for long slender seals.
Inspection follows the same logic. We check at a controlled temperature and record it, because a PTFE part has no meaningful size without a reference condition. Where the drawing calls for a tight bore, we cut to the middle of the tolerance band and let the material settle before final measurement. CMM reports and dimensional records are available on request for medical, aerospace and semiconductor parts.
Unfilled PTFE is the default for chemical and electrical duty. Fillers trade some of that away for dimensional stability.
| Grade | Best for | Trade-off to know |
|---|---|---|
| Unfilled PTFE | Seals, gaskets, insulators, liners | Highest creep and thermal expansion |
| 25% glass-filled | Bearing pads, wear rings | Lower creep, more abrasive to tooling |
| Carbon / graphite filled | Compressor rings, bushings under load | Better stiffness and thermal conductivity |
| Bronze filled | High-load wear parts | Not for strong acids or oxidizers |
| PFA / FEP | Melt-processable liners | Softer, lower continuous service temperature |
Pockets, slots, manifolds and seal faces on 3-axis and 4-axis mills, with air blast and light radial engagement to keep edges clean.
Bushings, washers, valve seats and liners on mill-turn centers, up to Ø400 mm on the rotary table. Soft jaws protect thin walls.
Angled ports and contoured sealing surfaces cut in one setup, so a critical face and its bore share a datum.
One-off seal samples or test insulators in a few days, before a mold or a production run is committed.
From a single prototype to 10,000+ part runs, with the same setup sheet carried through the batch.
Deburring, tumbling and polishing where the drawing calls for a specific Ra. Laser marking available with a 1.5 mm minimum character height.
Figures apply to polymer work unless the drawing states otherwise.
| Capability | Range | Notes |
|---|---|---|
| Achievable tolerance | ±0.005 mm | On stable, supported features |
| Surface finish | Ra 0.2–0.8 μm fine | Ra 1.6–3.2 μm as-machined typical |
| Maximum part size | 4,000 mm | Long liners and profiles |
| Rotary table | Ø400 mm | Turning and 4-axis work |
| Spindle speed | 15,000–25,000 rpm | Small-diameter cutters |
| Inspection | 100% before shipment | Material, in-process, final |
Three wholly-owned plants in Dongguan and a Singapore facility, 7,600 m² of production space and 150 technicians.
16 simultaneous 5-axis centers, 16 mill-turn centers and 12 four-axis mills. PTFE jobs run on machines set up for light-touch cutting.
Held on supported polymer features at a recorded temperature. Imperial equivalent is ±0.0002 in.
Raw material check, in-process monitoring and final inspection on every order.
We review the drawing, flag creep and expansion risk, and return a quotation with the free DFM analysis.
One prototype or a 10,000+ part run. Uploads stay confidential and an NDA is available on request.
High-purity PTFE manifolds and valve bodies with no metallic contamination at the wetted face.
Machined insulators and seal rings where dimensional records matter as much as the part.
Low-friction seal rings and bushings that tolerate temperature swings without losing preload.
The polymer chain is rigid and the melt viscosity is extremely high, so injection molding and extrusion need special equipment and still struggle with tight features. CNC machining cuts the finished geometry directly from rod, tube or plate. That suits low and medium volumes, prototypes, and parts where the sealing face has to be held to a close tolerance.
We quote ±0.005 mm on supported features measured at a recorded temperature. Thin walls, long unsupported lengths and parts that will see a wide temperature swing are harder, and we will say so in the DFM notes. For those features a realistic band is often two to three times wider.
Normally no. PTFE does not conduct heat away, and wet chips tend to cling to the flutes and pack the pocket. We use compressed air to clear chips and cool the cutting edge, take light radial passes, and run spindle speeds in the 15,000–25,000 rpm range with small cutters.
It depends on the section and the temperature change. With a linear expansion around 12 × 10⁻⁵ /°C, a 100 mm PTFE feature grows roughly 0.12 mm over a 10 °C rise. If the drawing has no reference temperature, agree on one with your inspector before the run. For critical bores we cut to the middle of the band and let the part settle.
They can, but the joint has to allow for cold flow. Sustained bolt load keeps compressing the polymer, so preload drops over time. Use a metal backing washer, a controlled compression stop, or a design that limits strain. Tell us the mating hardware and we will flag the risk in the DFM review.
Yes. Glass-filled grades lower creep but wear tooling faster, so we shorten the tool-change interval. Carbon and graphite filled grades cut more cleanly and resist load better. Bronze-filled material is fine for wear parts, but we would not put it in an oxidizing chemical service.
We also machine PEEK, POM, PA, PC, ABS, PMMA, PP and HDPE, as well as carbon fiber composite. If stiffness, temperature range or wear resistance is the driving requirement rather than chemical inertness, PEEK is often the better starting point. Send the duty cycle and we will compare both.
Quotation and free DFM analysis come back within 12 hours, and production can start within 24 hours of release. Standard parts ship in 3–5 days. There is no minimum order quantity, so a single prototype and a 10,000+ part run follow the same route.
Upload the model and we will check expansion, wall thickness and workholding, then quote within 12 hours. Every part is inspected before it ships.
12-hour quote100% inspectionNo minimum order quantityNDA on request
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Upload your 3D model or 2D drawing and get a quotation with a free DFM analysis. Maximum processing size 4,000 mm.
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