Introduction

Analytical instruments and testing equipment have come a long way. With the advent of higher precision CNC machining techniques, better process engineering, and higher purity materials, there has always been an increasing demand for testing equipment that could match the precision of the products themselves.

To achieve this precision, equipment and instruments are being constantly upgraded. While traditionally, metals were the default choice for components used in such equipment, the shift to non-metallic high-performance materials have been necessitated by the fact these materials are more resistant to chemicals, less likely to interfere with the sensors, and have mechanical strengths more than sufficient to meet the end application. Coupled with the fact that such equipment is usually high-end this means that any cost differentials between metals and other materials ceases to be a major concern, provided the efficiency is boosted.

The shift toward high-performance polymers has accelerated in recent years. Materials such as PEEK, PTFE, Polyimide, PPS, PEI, PAI, and engineered Nylon offer a unique combination of chemical resistance, dimensional stability, and low friction—while also eliminating issues like corrosion, ion leaching, and excessive weight.

Why Precision Matters in Analytical Equipment

Analytical systems—such as gas chromatographs, mass spectrometers, spectrophotometers, and particle analyzers—depend on tight tolerances and consistent material behaviour. Even minor deviations in component geometry or material properties can lead to:

• Measurement inaccuracies 
• Sample contamination 
• System drift or calibration loss 
• Increased maintenance cycles 

Precision polymer parts are typically used in:

• Fluid handling systems (valves, manifolds, fittings) 
• Sample pathways and seals 
• Electrical insulation components 
• Structural supports and housings 

Key Material Requirements

For analytical and testing environments, polymers must meet stringent criteria:

1. PEEK (Polyether Ether Ketone)

PEEK is widely regarded as the gold standard for high-performance polymer components in analytical instruments.

Key Advantages:

• Continuous use temperature up to ~250°C 
• Excellent chemical resistance (including organic solvents) 
• High mechanical strength and stiffness 
• Low outgassing and high purity grades available 

Typical Applications:

• Chromatography fittings and ferrules 
• Valve components in fluid handling systems 
• Pump housings and manifolds 
• Semiconductor testing fixtures 

PEEK’s ability to combine strength with chemical inertness makes it ideal for critical flow path components, where both mechanical integrity and purity are essential.

2. PTFE (Polytetrafluoroethylene)

PTFE remains unmatched in terms of chemical resistance and non-stick properties.

Key Advantages:

• Virtually universal chemical resistance 
• Extremely low coefficient of friction 
• Excellent dielectric properties 
• Wide temperature range (-200°C to +260°C) 

Typical Applications:

• Seals and gaskets in analytical systems 
• Tubing for aggressive chemical transfer 
• Linings for sample pathways 
• Insulating components 

PTFE is especially valuable in applications where zero reactivity and minimal sample interaction are critical.

3. Polyimide (PI)

Polyimide is known for its exceptional thermal stability and mechanical performance at elevated temperatures.

Key Advantages:

• Continuous use above 300°C (depending on grade) 
• Excellent dimensional stability 
• High dielectric strength 
• Low creep under load 

Typical Applications:

• High-temperature electrical insulation 
• Components in vacuum environments 
• Precision spacers and structural elements 

Polyimide is often used in extreme environments, such as aerospace-grade analytical systems or high-temperature testing setups.

4. PPS (Polyphenylene Sulfide)

PPS offers an excellent balance of cost and performance, particularly in chemically aggressive environments.

Key Advantages:

• Strong chemical resistance (especially to acids and bases) 
• Good dimensional stability 
• Naturally flame retardant 
• Low moisture absorption 

Typical Applications:

• Pump components 
• Valve bodies 
• Structural parts in wet chemical systems 

PPS is commonly used where cost-effective durability is required without compromising on performance.

5. PEI (Polyetherimide)

PEI (commonly known as Ultem) is widely used in applications requiring electrical insulation and dimensional stability.

Key Advantages:

• High dielectric strength 
• Good mechanical properties 
• Continuous use up to ~170°C 
• Excellent dimensional stability 

Typical Applications:

• Electrical connectors and housings 
• Insulators in testing equipment 
• Transparent components for optical systems 

PEI is often selected for precision electronic interfaces within analytical instruments.

6. PAI (Polyamide-Imide)

PAI is one of the highest-performing thermoplastics in terms of mechanical strength and wear resistance.

Key Advantages:

• Exceptional wear and creep resistance 
• High compressive strength 
• Continuous use up to ~260°C 
• Excellent dimensional stability 

Typical Applications:

• Bearings and bushings in moving assemblies 
• High-load structural components 
• Precision wear parts 

PAI is ideal for dynamic components where mechanical loads are significant.

7. Nylon (Engineering Grades – PA6, PA66, PA12)

While not as high-performing as the materials above, engineered Nylon grades still play an important role in cost-sensitive applications.

Key Advantages:

• Good mechanical strength 
• Cost-effective 
• Easy machinability 
• Good wear resistance 

Typical Applications:

• Non-critical structural components 
• Housings and covers 
• Cable management systems 

Nylon is typically used in secondary or support components where extreme conditions are not present.

Machining vs Injection Moulding: Choosing the Right Process

For analytical equipment, the choice of manufacturing process is just as important as the material. For the most part, volumes and part geometries make injection moulding less viable than machining. In some cases – such as enclosures or simple spacers – injection moulding is employed. However, machining offers the flexibility for small changes in design and for parts with extremely close tolerances that cannot be maintained by injection moulding.

CNC Machining:

• Ideal for low to medium volumes 
• Enables tight tolerances (±10–20 microns) 
• Suitable for complex geometries 
• Preferred for PEEK, PTFE, PAI, and Polyimide components 

Injection Moulding:

• Cost-effective for high volumes 
• Consistent repeatability 
• Suitable for PPS, PEI, Nylon, and some PEEK applications 
• Requires careful design to avoid warpage and internal stresses 

In many cases, critical flow path or sealing components are machined, while structural or high-volume parts are moulded.

Replacing Metals: A Strategic Shift

The move from metals to polymers in analytical instruments is driven by several factors:

This shift is particularly evident in semiconductor and life sciences industries, where contamination control is paramount.

Key Considerations in Material Selection

Selecting the right polymer involves balancing multiple factors:

• Chemical exposure (solvents, acids, gases) 
• Operating temperature 
• Mechanical loads 
• Tolerance requirements 
• Regulatory compliance (FDA, USP Class VI, etc.) 

No single material fits all applications—hence, multi-material systems are often used within a single instrument.

Conclusion

Precision polymer components have become indispensable in modern analytical instruments and testing equipment. Materials such as PEEK, PTFE, Polyimide, PPS, PEI, PAI, and Nylon each offer distinct advantages, enabling engineers to optimize performance across a wide range of applications.

For OEMs and system designers, the focus is no longer just on material selection—but on integrating the right polymer, manufacturing process, and precision engineering capabilities to achieve consistent, high-performance outcomes.

As analytical technologies continue to evolve—particularly in semiconductor, life sciences, and environmental monitoring—the role of high-performance polymers will only become more central to innovation and reliability.

Read More

1. PTFE Tubes in Railways: High-Performance Solutions for Safety, Reliability, and Electrification

2. PEEK Machined Components – Why OEMs Choose PEEK for Critical Applications

3. Polyphenylene Sulfide (PPS) in Vacuum Systems: A High-Performance Alternative to Metals