High-performance plastics in mechanical engineering: advantages, materials and applications
High-performance plastics in mechanical engineering: more about PEEK, PPS and PAI, typical applications, advantages and choosing the right material.
In mechanical and plant engineering, components frequently have to withstand high temperatures, mechanical loads, aggressive media or continuous wear. At the same time, requirements for low weight, high precision and long service lives are increasing. This is exactly where high-performance plastics come into play.
Materials such as PEEK, PPS or PAI can represent an alternative to metals and classic engineering plastics in demanding applications. Depending on the material, they combine high temperature and chemical resistance with good mechanical properties, low weight and advantages in friction and wear.
Which high-performance plastics are available and which material is suitable for a specific application, however, always depends on the actual operating conditions.
Why are high-performance plastics used in mechanical engineering?
In mechanical and plant engineering, materials are not selected on the basis of their strength alone. Temperature, pressure, friction, chemical media, moisture, component geometry and the desired service life must all be considered together.
High-performance plastics offer several technical advantages here.
Low weight
Plastics have a significantly lower density than many metallic materials. Particularly in moving components, a reduction in weight can help to reduce mass inertia and the load on adjacent components.
This is of interest, for example, in guides, moving machine elements or components in automated systems.
Corrosion resistance
Plastics do not rust. Depending on the material, high-performance plastics also offer high resistance to numerous chemicals, oils, fuels or cleaning media.
As a result, they are suitable among other things for pump components, valve parts, seals or machine parts that regularly come into contact with aggressive media.
High temperature resistance
When conventional engineering plastics reach their limits at permanently elevated temperatures, special high-temperature plastics can be used.
These materials include, for example, PEEK, PPS and PAI. The actual service limit, however, always depends on the material grade, load, component geometry and ambient conditions.
Good sliding and wear properties
For bearings, guides and other moving components, friction and wear are important selection criteria. Suitable high-performance plastics can offer good tribological properties and thereby reduce the need for lubrication in certain applications.
Special modifications allow these properties to be further adapted to the respective application.
High dimensional accuracy
In precision components, materials must reliably maintain their dimensions even under changing loads.
Materials with low moisture absorption, high stiffness and good dimensional stability are therefore particularly suitable for guides, holders, valve components, bearing parts or other precise machine elements.
Which high-performance plastics are suitable for mechanical engineering?
Not every high-performance plastic is equally suitable for every mechanical engineering application. The materials differ among other things in terms of temperature resistance, mechanical strength, chemical resistance, friction behaviour and dimensional stability.
| Material | Typical properties | Examples of applications in mechanical engineering |
|---|---|---|
| PEEK | high temperature resistance, high mechanical load capacity, good chemical and wear resistance | bearing parts, gears, guides, valve components, precision parts |
| PPS | high chemical resistance, low moisture absorption, good dimensional stability | pump parts, housings, electrical components, precision components |
| PAI | very high strength and stiffness, good wear resistance and temperature resistance | bearings, seals and highly loaded precision components |
This overview serves as initial guidance. For the specific material selection, the operating conditions of the component must be taken into account.
When can high-performance plastics replace metal?
Replacing a metal component with plastic is particularly interesting when not only high strength but also other requirements have to be met.
These include, for example:
- low component weight
- corrosion resistance
- electrical insulation
- low friction
- wear resistance
- chemical resistance
- low moisture absorption
- good dimensional accuracy
- reduced noise development in moving components
A direct material swap based on the principle of "replacing a metal part with a plastic part" is not always sensible, however. Plastics have a different mechanical and thermal behaviour from metals.
Component geometry, wall thicknesses, tolerances, load direction and fastening should therefore be matched to the selected plastic at the design stage.
Typical applications in mechanical and plant engineering
High-performance plastics are used both for moving components and for structural and media-carrying components.
| Application area | Typical components | Important requirements |
|---|---|---|
| Drive technology | gears, coupling elements, bearing parts | wear resistance, strength, low weight |
| Guide and bearing technology | plain bearings, guide rails, sliding elements | low friction, wear resistance, dimensional accuracy |
| Fluid technology | valve seats, pump components, seals | media resistance, temperature resistance |
| Automation | guides, holders, sensor components | low weight, precision, electrical properties |
| Plant engineering | housings, insulating parts, connecting elements | chemical resistance, freedom from corrosion |
| Food machinery | guides, transport elements, structural components | cleanability and suitable material approval |
The actual material selection always depends on the specific operating conditions.
How do you select the right high-performance plastic?
Material selection should not be based on a single characteristic value such as the maximum temperature alone.
In particular, check the following factors:
1. Temperature
Which temperatures occur continuously? Are there short-term temperature peaks? Is the material simultaneously in contact with mechanical loads or chemicals?
2. Mechanical load
Is the component subjected to tension, compression or bending? Do dynamic loads occur? Must the material remain dimensionally stable over a long period?
3. Chemical load
Which oils, cleaning agents, acids, alkalis or other media does the component come into contact with? Concentration, temperature and contact duration can significantly influence resistance.
4. Friction and wear
In plain bearings or guides, the sliding partner, speed, surface pressure and lubrication must also be taken into account.
5. Dimensional accuracy
With tight tolerances, thermal expansion, moisture absorption and creep behaviour play an important role.
6. Approvals and special requirements
Depending on the industry, requirements relating to food contact, electrical properties, purity or sterilizability may also apply.
You can also find a systematic approach in our guide to material selection for high-performance plastics.
Machining high-performance plastics and manufacturing precision parts
Many high-performance plastics can be machined. This allows individual mechanical engineering components to be produced from semi-finished products according to drawings or CAD data.
Depending on the material and geometry, milling, turning, drilling or other methods of plastic machining are used, for example.
Particularly with tight tolerances, machining must be matched to the respective material. Heat generation, stresses in the semi-finished product, tool selection and clamping can influence the quality and dimensional accuracy of the finished component.
When is the use of high-performance plastics worthwhile?
High-performance plastics are particularly interesting when classic engineering plastics no longer permanently meet the requirements of an application or metallic materials cause functional disadvantages.
Typical reasons for a change are:
- high or changing service temperatures
- contact with aggressive media
- corrosion problems with metallic components
- high wear on bearings or guides
- requirements for low weight
- electrical insulation
- high requirements for precision and dimensional accuracy
- maintenance effort due to lubrication or corrosion
The technically best solution is not automatically the material with the highest characteristic values. What makes sense is the plastic whose property profile matches the actual load on the component as closely as possible.
High-performance plastics as materials for demanding mechanical engineering components
High-performance plastics open up design possibilities in mechanical engineering that cannot always be implemented economically or technically sensibly with standard plastics or metals.
PEEK, PPS, PAI and other high-performance polymers can be used, for example, at high temperatures, with aggressive media, wear or special requirements for weight and dimensional accuracy.
Martan Plastics supports you from the selection of the suitable material through to the individually manufactured component. An overview of the available materials can be found under high-performance plastics for demanding applications.
Frequently asked questions about high-performance plastics in mechanical engineering
What are high-performance plastics?
High-performance plastics are engineering plastics for particularly demanding operating conditions. Depending on the material, they offer high temperature, chemical and wear resistance as well as high mechanical load capacity and dimensional stability.
Which high-performance plastics are used in mechanical engineering?
The materials frequently used include PEEK, PPS and PAI. Which plastic is suitable depends on temperature, mechanical load, chemical media, friction, tolerances and other operating conditions.
Can high-performance plastics replace metal?
With suitable design, high-performance plastics can replace metallic components in certain applications. Advantages can include lower weight, corrosion resistance, electrical insulation and good sliding and wear properties.
Which high-performance plastic is particularly temperature-resistant?
For applications with high temperatures, PEEK, PPS and PAI are among the options. The permissible service temperature, however, depends on the material grade, load duration, mechanical stress and ambient conditions.
Which components are manufactured from high-performance plastics?
Typical components are plain bearings, guides, gears, seals, valve seats, pump components, holders and other precision parts for machines and systems.
