Custom PAI (Torlon®) CNC Machining Services in China
Machining the Pinnacle of High-Performance Polymers for Extreme Strength and Temperature Applications.
- ISO 9001 & AS9001 Compliant
- Highest Strength & Stiffness of any Thermoplastic
- Expert Machining of Torlon®
Your Expert Partner for PAI (Torlon®) Machining
Celerity Precision is an elite-level manufacturer in China with specialized expertise in the CNC machining of PAI (Polyamide-imide), most commonly known by the trade name Torlon®. PAI is arguably the highest-performance melt-processable thermoplastic, offering the highest strength and stiffness of any plastic up to 275°C (525°F). Its unparalleled combination of extreme temperature resistance, dimensional stability, and exceptional wear properties makes it the ultimate material for replacing metal in the most severe service environments. From jet engine components and semiconductor test sockets to racing engine parts, machining PAI is a highly demanding process. Celerity Precision has the advanced capabilities and rigorous process controls required to machine this ultra-performance material to the most demanding specifications.
Why Choose PAI (Torlon®) for Your Machined Parts?
PAI is the solution when all other plastics, including PEEK and PEI, fail to meet the required strength, stiffness, or temperature demands. It has a very low coefficient of thermal expansion and superior creep resistance, meaning it holds its shape and tolerances under extreme loads and temperatures without deforming. While it is one of the most challenging polymers to machine and requires a multi-stage curing process, its performance is unmatched. At Celerity Precision, we utilize specialized diamond-coated tooling, rigid CNC machines, and a deep understanding of the material’s curing cycles to produce PAI components with the highest possible level of precision and stability.
Highest Strength of any Unreinforced Thermoplastic
Possesses incredible strength and stiffness, outperforming even filled grades of other high-performance polymers.
Extreme High-Temperature Performance
Retains its strength and dimensional stability at continuous service temperatures up to 275°C (525°F).
Outstanding Wear & Friction Properties
Bearing-grade PAI offers exceptional performance in high-load, high-temperature wear applications.
Superior Dimensional Stability
Very low coefficient of thermal expansion (similar to aluminum) and high creep resistance.
Excellent Chemical Resistance
Resistant to a broad range of industrial chemicals, hydrocarbons, and aviation fluids.
High Impact Strength
A tough and durable material that resists chipping and cracking.
PAI 4203 (Unfilled Electrical Grade)
This is the standard, unfilled grade of Torlon®. It offers the highest toughness and impact strength, and is an excellent electrical insulator.
| Tensile Strength, Yield (MPa) | 152 MPa |
| Elongation at Break (%) | 10% |
| Deflection Temp. @ 1.8 MPa | 280°C (536°F) |
| Density (g/cm³) | 1.41 |
PAI 4301 (Bearing Grade)
This grade is modified with graphite and PTFE. It offers an extremely low coefficient of friction and superior wear resistance for high-temperature bearing and bushing applications.
| Tensile Strength, Yield (MPa) | 111 MPa |
| Elongation at Break (%) | 5% |
| Deflection Temp. @ 1.8 MPa | 280°C (536°F) |
| Density (g/cm³) | 1.45 |
PAI 5530 (30% Glass-Filled Grade)
The addition of glass fibers provides the highest level of stiffness, rigidity, and the best dimensional stability (lowest thermal expansion) of all PAI grades.
| Tensile Strength, Yield (MPa) | 221 MPa |
| Elongation at Break (%) | 3% |
| Deflection Temp. @ 1.8 MPa | 282°C (536°F) |
| Density (g/cm³) | 1.60 |
Surface Finishing Options for PAI
PAI is an extreme-performance functional material and is never used with a secondary finish.
As Machined
This is the only finish available. PAI machines to a very clean, smooth, hard surface. The color is typically an opaque dark amber/brown for unfilled grades, and dark grey or black for filled grades.
Pros and Cons of PAI CNC Machining
Pros
- Ultimate Mechanical Performance: The strongest, stiffest, and most dimensionally stable thermoplastic available.
- Performs in Extreme Heat: Retains usable strength at temperatures that would destroy almost any other polymer.
- Superior Bearing Performance (4301 Grade): Can replace metal bearings in high-load, high-temperature, non-lubricated applications.
- True Metal Replacement: Directly competes with and can replace aluminum, titanium, and bronze in many demanding applications.
Cons
- Extremely High Cost: PAI is one of the most expensive polymers on the market, reserved for only the most critical applications.
- Very Difficult to Machine: It is highly abrasive and requires specialized (often diamond) tooling, rigid machines, and a multi-day post-curing process, all of which contribute to the high cost.
- Hygroscopic (Absorbs Moisture): Must be carefully dried before machining and can be dimensionally affected by moisture before the final cure.
- Poor Chemical Resistance to Steam & Strong Bases: While generally excellent, it can be attacked by steam and certain strong chemicals.
Applications of CNC Machined PAI Parts
Aerospace
Jet engine components, compressor parts, seals, and structural insulators.
Semiconductor
Test sockets for IC chips (which get very hot during testing), wafer handling components, and CMP rings.
Automotive
Racing engine components, transmission thrust washers, and high-load bearing components.
Oil & Gas
Non-lubricated bearings, seals, and backup rings for downhole equipment.
Industrial
High-temperature pump components, valve seats, and wear-resistant pads in manufacturing equipment.
Electronics
High-temperature electrical connectors and insulators.
PAI Machining FAQ
What is the main difference between PAI (Torlon®) and PEEK?
PAI is generally stronger, stiffer, and has better wear resistance and dimensional stability at high temperatures than PEEK. PEEK, however, has superior chemical resistance, especially to steam and hydrolysis, and does not require the lengthy post-curing process.
Why is the post-curing step so important for PAI?
In its “as-machined” state, a PAI part has not achieved its full properties. The multi-day curing cycle completes the polymerization process, which is essential to maximize the mat
Why is PAI so difficult and expensive to machine?
Its high strength and abrasive nature (especially filled grades) require very rigid machines and expensive diamond-coated tools to cut effectively. The process is slow, and the mandatory, energy-intensive post-curing cycle adds significant time and cost.
Can I use PAI in a hot, wet, or steam environment?
While PAI has low moisture absorption, it is susceptible to degradation from prolonged exposure to high-pressure steam. For these applications, PEEK is often a better choice.
What color is PAI?
The standard unfilled electrical grade (4203) is a distinctive dark amber or brownish-yellow. The bearing grade (4301) and filled grades are typically dark grey or black.
Can PAI be glued or bonded?
It is extremely difficult to bond. It requires specialized surface preparation and high-performance industrial adhesives like epoxies.
Is PAI a good bearing material?
The bearing grade (Torlon® 4301) is one of the best high-performance bearing materials available. It can operate at high loads and temperatures without any external lubrication.
Do you manage the entire curing process?
Yes, absolutely. We have the calibrated ovens and expertise to perform the critical, multi-day post-machining curing cycle in-house. We do not ship any PAI parts until they are fully cured and dimensionally stable.