PPA Rod — Diameters, Lengths & Tolerances
PPA rod is a round extruded stock form produced from Polyphthalamide (PPA), a high-performance semi-aromatic nylon. PPA delivers superior strength, stiffness, and temperature resistance compared to standard nylons such as PA6 and PA66, making it the preferred choice when components must maintain mechanical integrity in hot, chemically aggressive, or highly loaded operating environments. PPA rod is selected for precision structural components, high-temperature bushings, and demanding industrial parts where standard engineering thermoplastics are no longer adequate.
At a glance:
- Diameter range: 0.25" to 4.0" (common stocked sizes)
- Standard lengths: 4 ft
- OD tolerance: +0.000" / −0.015" (typical)
- Material: Polyphthalamide (PPA) — extruded
- Color: Natural (off-white/light tan)
Standard Diameter Table
PPA rod is stocked in precision machining sizes suited to its high-performance applications:
| Diameter | Standard Lengths | Notes |
|---|---|---|
| 0.25" | 4 ft | Precision pins, small structural fasteners |
| 0.50" | 4 ft | High-temp bushings, small shafts |
| 0.75" | 4 ft | Bearings and spacers |
| 1.00" | 4 ft | General high-performance machining stock |
| 1.50" | 4 ft | Structural and thermal-barrier components |
| 2.00" | 4 ft | Larger precision components |
| 3.00" | 4 ft | Heavy structural PPA parts |
| 4.00" | 4 ft | Maximum standard diameter |
Contact Ready Plastics for custom diameters and non-standard lengths.
Mechanical & Thermal Properties
PPA's defining advantage over standard nylons is its combination of high mechanical strength and elevated temperature resistance:
| Property | Notes |
|---|---|
| Tensile strength | Superior to PA6 and PA66 — high stiffness supports precision structural roles |
| Stiffness | High tensile modulus — resists deflection under load better than standard nylons |
| Heat resistance | Significantly higher continuous service temperature vs. PA6/PA66 |
| Dimensional stability | Excellent — low moisture absorption relative to standard nylons |
| Chemical resistance | Good resistance to oils, fuels, and industrial fluids |
| Flammability (UL 94) | HB |
Numeric property values are available in the PPA material datasheet. Engineering specifications should reference current datasheet values.
Compared to PA66 rod, PPA rod provides a step-change improvement in thermal and mechanical performance. For the highest performance in this nylon family, PPA is the premium grade available from Ready Plastics.
Typical Applications
PPA rod is specified for the most demanding thermal and mechanical applications within the nylon family:
- High-temperature structural components — operates reliably in environments where PA6 and PA66 would soften or deform
- Precision bushings near heat sources — under-hood automotive and industrial equipment adjacent to hot surfaces
- Fluid handling components — chemical resistance and thermal stability support pump and valve components
- Electrical connector bodies — dimensional stability and dielectric properties support precision electrical assemblies
- Automation components in high-temperature zones — stiffness and temperature resistance support reliable operation in heated processing equipment
Machining PPA Rod
PPA machines well with sharp carbide tooling. Its higher stiffness and hardness compared to standard nylons require slightly lower feed rates for fine finishes. PPA produces consistent chips and holds close tolerances well. Low moisture absorption means minimal dimensional conditioning is required — parts can be machined and assembled with minimal allowance for moisture-induced growth. Coolant or compressed air is recommended to manage heat during extended operations.
Related
- PPA Material Line Card
- PPA Sheet — flat plate for high-temperature structural panels
- PPA Tube — hollow stock for high-performance sleeve applications