How to Strip Polyimide (PI) Wire Without Damaging the Conductor

1. Why polyimide wire is hard to strip

Polyimide (PI, widely known as Kapton) insulation has high tensile strength and strong adhesion — and its heat resistance is exactly why it is hard to strip. A conventional mechanical stripper assumes it is cutting soft plastic; on PI it usually nicks the conductor or leaves a ragged cut.

In other words, the blade must be significantly hotter than the insulation's continuous service temperature before the layer softens enough to peel cleanly. That is why PI wire is stripped thermally — and why a heater with a high ceiling (e.g. up to 700°C, with the working setpoint far below it) is recommended. Typical applications: aerospace & aviation harnesses, defence electronics, precision electronic wire processing. Two more characteristics matter:

• Fine gauges — commonly 0.15–1.22 mm, leaving very little margin for a mechanical blade;
• Fragile conductors — stranded or silver-plated copper nicks, breaks strands and leaves micro-cracks that fail later under vibration.

2. Mechanical vs laser vs thermal stripping

Bottom line: for polyimide and PTFE wire, choose a thermal stripper; consider laser only for very high volume.

3. Six selection criteria

1. Temperature range — a ceiling of ≥700°C gives headroom; closed-loop control with a digital readout keeps results repeatable.
2. Blade material & hole sizes — alloy + ceramic composite blades resist wear, do not conduct and are ESD-safe; match the blade hole (A/B/C/D) to the wire gauge so the cut is clean and the conductor untouched.
3. Strip length — commonly 2–40 mm adjustable; solder-cup and crimp work needs consistent lengths.
4. Wire gauge range — e.g. 0.15–1.22 mm covers precision work; special gauges can be customised.
5. Form factor — benchtop for fixed production stations, portable/battery for field, cabinet and shipboard work, automatic for high-volume consistency.
6. Throughput — a few seconds per wire (e.g. ~3 s/wire on the automatic model); consistency matters more than shaving a second.

4. Trial-strip tuning (the key to a clean result)

PI layer thickness varies between batches and suppliers, so always trial-strip a sample from the same batch and freeze the settings:

• Start cool and step the temperature up until the insulation peels cleanly with no discolouration or nicks on the conductor;
• If it will not release, go one step hotter; frayed cuts or a shiny/discoloured conductor mean too hot or held too long;
• On shielded and multi-strand wire, cut only the jacket — protect the shield and braid;
• Inspect after stripping: no scores or broken strands, and a clean insulation edge.

Practical tip: put the temperature setting, blade hole size and strip length into a work instruction at the station. When the wire batch changes, only one parameter moves — best consistency and traceability.

5. FAQ

Q: The insulation shrinks back after stripping? Slight shrinkage is normal; excessive shrinkage means the temperature was too high or the dwell was too long.

Q: Scored or broken strands? Usually a blade hole that is too small or too little heat causing a tearing action — change to the matching blade and go one step hotter.

Q: A thin film of insulation remains? Not enough heat or too short a dwell; PI conducts heat slowly, so lengthen the dwell or strip in two passes.

Q: Do I really need digital closed-loop control? Yes, recommended — PI is temperature-sensitive, and control is what makes different operators and shifts produce identical results.

6. Matching ZIRONX models

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