01 Tensile strength in a thin wall
PI has a tensile strength around 120–200 MPa and keeps its shape even at a 0.02 mm wall. That means a thinner wall and a larger lumen within the same OD. What to check: the required wall and the break strength needed at that wall.
02 Thermal stability
With a continuous service temperature of 250–300 °C, the inner layer does not melt or deform when the outer layer is reflowed or thermally bonded. What to check: the peak temperature and exposure time of downstream processes.
03 Chemical resistance
It resists most organic solvents and disinfectants. It is weak against strong alkalis, however, so check the pH of cleaners and coating pre-treatment chemicals.
04 Dimensional tolerance
Because it is built up by repeated coating and curing, the wall is uniform, and we produce IDs of 0.10–5.00 mm within ±0.01 mm. What to check: whether the tolerance is on ID or OD, and how it is measured.
05 Biocompatibility
Medical PI tubing has long been used in devices such as catheters that contact blood vessels for short periods. ISO 10993 evaluation of the finished device is still done separately. What to check: the contact type and duration.
06 Predictable bending behavior
PI is stiff, so it transmits push well even through a thin wall. Conversely, a sharp bend can kink it, so sections with tight bends are reinforced with braid or coil. What to check: the minimum bend radius and the stiffness needed in each section.
07 Process compatibility
PI tubing works well with downstream processes such as braid reinforcement, a PTFE composite inner surface, laser-drilled holes, hydrophilic coating and printing. Keeping those steps with the tube maker makes dimensional control easier. What to check: the list and order of downstream processes you need.
Spec request checklist
- 01ID, wall, length and tolerances
- 02Whether a PTFE composite inner surface is needed
- 03Whether braid or coil reinforcement is needed, and where
- 04Downstream processes — holes, coating, printing, tip forming
- 05Expected volume and sample schedule
Octudex supplies single-layer PI tubing and PI braided tubing. Send whichever of the items above you have settled, and we will tell you first whether it can be made.