How to Strip PTFE (Teflon) and Coaxial Cable: Thermal Stripper Selection & Blade Guide

1. First, "Teflon" is really four different materials

"Teflon" is the everyday name for fluoropolymers, but in purchasing documents and drawings you will usually find four distinct types: PTFE, PFA, FEP and ETFE. Their temperature resistance and processing behaviour differ enough that stripping parameters cannot be carried over from one to another — and that is the root cause of the classic field complaint: "the same machine strips one supplier's wire fine and fails on the next batch."

Note: the values above are common industry figures. Always confirm against the wire supplier's datasheet — formulations (fillers, foaming, thin-wall processes) vary between manufacturers.

Safety note: PTFE-type materials begin to decompose and release hazardous fumes well above their service temperature (generally above 400°C). Carry out thermal stripping in a ventilated area and avoid running the blade at high power in a small enclosed space for long periods. Normal thermal stripping happens far below the decomposition temperature and is a safe operating range.

2. Why PTFE and coaxial cable need a thermal stripper, not a mechanical one

The properties of fluoropolymers create three dead ends for mechanical stripping:

• Hard and slippery — the blade tends to "climb" and slip on the insulation instead of cutting through, and the extra force bruises the conductor;
• High elongation and spring-back — even when cut, the insulation tears rather than separating, leaving frayed edges and whiskers;
• Strong adhesion — the insulation grips the conductor tightly, so pulling it off shears the conductor and easily breaks strands in fine multi-strand wire.

A thermal stripper works by "soften first, then separate": the blade softens the insulation locally to a plastic state at a precise temperature, and a mechanical action pushes the softened layer off the conductor. The conductor experiences almost no cutting force, so the cut is clean, the conductor is untouched and no micro-cracks remain. That matters most for aerospace, defence and precision harnesses that must survive vibration, thermal cycling and salt spray.

Coaxial cable is a special case: the problem is not "it won't strip" but "it strips badly very easily."

3. Coaxial construction defines the stripping challenge

A typical coaxial cable, from outside in, is: outer jacket → shield braid (or foil + braid) → dielectric (foamed PE / PTFE, etc.) → centre conductor. Stripping is usually done in stages: first the jacket to expose the braid, then the dielectric to expose the centre conductor.

Conclusion: for coaxial and fluoropolymer wire, choose thermal stripping first; only consider laser stripping for very high volume lines that require a non-contact process (see our article "Thermal wire stripper vs laser stripping machine").

4. Blade setup: aperture matching comes first

The number-one variable in stripping quality is not temperature — it is hole size. Too small scores the conductor and breaks strands; too large leaves a thin film and a frayed edge. The ZIRONX T-2 handpiece / K-700 blade range offers four aperture types (A / B / C / D):

Three-step selection method:

1. Measure the actual outer diameter of the layer you are stripping (for the jacket use the jacket OD, for the dielectric use the dielectric OD — do not go by the overall cable OD alone);
2. Within the appropriate blade type, pick the closest aperture that is not smaller than that OD; when clamped, the wire should be held, not crushed;
3. Trial-strip 3–5 samples from the same batch to confirm, then freeze the setting into the work instruction.

If no Type A or B aperture fits, go to a Type C flat blade or a custom Type D — do not "make do" with an undersized hole. That is the number-one cause of damaged conductors.

5. Temperature settings: start low and step up

For the same gauge, the insulation formulation and thickness can differ between batches and suppliers, so there is no universal temperature — trial-strip every time. The table below gives general starting references (based on the ZIRONX X700 / B700 digital models, adjustable 0–700°C):

Tuning rule of thumb: start low and step up one setting at a time. Will not release → go one step hotter. Frayed cut or a shiny/blackened conductor → go one step cooler or shorten the dwell. The figures are only starting points; follow your own trial-strip results.

Practical tip: write "temperature setting + blade type/aperture + strip length + wire type/batch" into a station SOP. When the wire batch changes, change only one item and keep a reference sample — that gives the best consistency and traceability. ZIRONX digital models (X700 / B700) show real-time blade temperature on the display, which makes recording and reproducing settings easy.

6. FAQ

Q1: The conductor is blackened or shiny after stripping PTFE? The temperature is too high or the dwell is too long, oxidising the conductor (especially tin-plated strands). Drop one temperature step and shorten the dwell.

Q2: The cut is frayed with whiskers? Usually not enough heat, so the insulation is torn rather than softened and separated — or the aperture is too large and leaves a thin film. Step the temperature up first; if that fails, go one aperture size smaller.

Q3: The braid is cut when stripping a coaxial jacket? Blade depth / aperture mismatch. Use an aperture matched to the jacket OD and reduce the temperature slightly, so the layer softens and separates in one pass instead of being cut.

Q4: The foamed dielectric got shorter after stripping? Too much heat shrank it, which changes the electrical length. Use a low temperature setting, work quickly and avoid prolonged contact with the heat.

Q5: Fine wire keeps breaking strands? Check the aperture first (most likely too small) → then the temperature (too low causes tearing) → finally clamp force and dwell. If all three check out, switch to a Type C flat blade or a custom Type D.

Q6: Why is digital closed-loop control essential? Fluoropolymers are very temperature-sensitive: a few tens of degrees change the outcome on the same wire. Digital control lets different operators and shifts produce identical results — the prerequisite for stable volume quality and for reproducible changeover settings.

7. Matching models

Warranty: 12 months on the machine (main unit/power supply), 6 months on consumables (handpiece/blades).