Engineering Plastics: How to Choose the Right Material for Your Application
Engineering Plastics: How to Choose the Right Material for Your Application
Blog Article
Choosing the right material for an industrial component is about more than simply finding something that is strong or durable. Different applications require different combinations of strength, temperature resistance, chemical resistance, dimensional stability, weight and machinability.
This is where engineering plastic can offer a practical alternative to traditional materials such as metal.
Engineering plastics are used across a wide range of industries for components that need to withstand demanding operating conditions while remaining lightweight, durable and suitable for precise manufacturing. However, with materials such as nylon, acetal, PTFE, polyethylene, PEEK, polycarbonate and PVC available, selecting the right option requires an understanding of the application.
What are engineering plastics?
Engineering plastics are high-performance plastic materials designed for applications where standard plastics may not provide the required mechanical, thermal or chemical properties.
Unlike commodity plastics, engineering plastics are generally selected for their ability to perform under specific operating conditions. Depending on the material, they can offer properties such as:
* High strength and durability
* Low friction and wear resistance
* Chemical resistance
* Temperature resistance
* Dimensional stability
* Low moisture absorption
* Impact resistance
* Electrical insulation
* Lightweight construction
These properties make engineering plastics suitable for applications ranging from machine components and guides to protective covers, bearings, seals and other industrial parts.
Why are engineering plastics used in industrial applications?
One of the main advantages of engineering plastics is their ability to combine performance with relatively low weight.
In some applications, replacing a metal component with an appropriate engineering plastic can help reduce weight, minimise friction or corrosion and simplify machining or maintenance.
The benefits depend on the material selected and the specific application. For example, PTFE is known for its low-friction and non-stick properties, while polycarbonate offers high impact resistance and is commonly used where transparency and durability are required.
This means there is no single engineering plastic that is suitable for every application. The material needs to be selected according to the conditions the component will experience.
Common types of engineering plastics
Polyethylene
Polyethylene is widely used because of its combination of durability, chemical resistance and low moisture absorption.
Depending on the grade, polyethylene can be suitable for applications where toughness, low friction or resistance to chemicals is important.
Nylon
Nylon is valued for its strength, toughness and wear resistance. It is commonly considered for mechanical components where durability and resistance to repeated movement are required.
Its properties can vary depending on the grade and operating environment, so factors such as moisture exposure and temperature should be considered during material selection.
Acetal
Acetal, also known as POM, is commonly used for precision engineering components because of its strength, dimensional stability and relatively low friction.
It can be suitable for applications involving moving parts, gears, bushes and other components where accurate dimensions and smooth movement are important.
PTFE
PTFE is well known for its extremely low coefficient of friction and excellent chemical resistance. It also has a wide operating temperature range compared with many other plastics.
These characteristics make PTFE useful for applications where friction, chemical exposure or non-stick properties are important.
PEEK
PEEK is a high-performance engineering thermoplastic used in demanding applications where a combination of mechanical, thermal and chemical performance is required.
Because of its performance characteristics and cost, PEEK is generally selected for applications where standard engineering plastics may not provide the required performance.
Polycarbonate
Polycarbonate is known for its high impact resistance and dimensional stability. Its transparency can also make it useful for applications such as machine guards and covers where visibility is required.
PVC
PVC is used across a wide range of industrial applications and can offer useful chemical resistance, durability and versatility.
The appropriate grade will depend on the intended application and environmental conditions.
What should you consider when choosing an engineering plastic?
Selecting an engineering plastic should start with the application rather than the material name.
Before choosing a material, consider the following factors.
1. Operating temperature
Temperature can significantly affect the performance of a plastic component. Consider both the normal operating temperature and any potential temperature peaks the component may experience.
A material that performs well at room temperature may not be appropriate for a high-temperature application.
2. Chemical exposure
If the component will come into contact with oils, solvents, acids, cleaning chemicals or other substances, chemical compatibility needs to be considered.
The correct choice will depend on both the chemical and the concentration, temperature and duration of exposure.
3. Mechanical load
Consider how much force the component will need to withstand and whether that load is continuous, intermittent or impact-related.
Tensile strength, compressive strength, impact resistance and wear resistance may all be relevant depending on the application.
4. Friction and wear
Components that move against another surface may require a material with good wear resistance and low friction.
This is particularly important for items such as bushes, guides, rollers and other moving components.
5. Dimensional stability
Some applications require components to maintain accurate dimensions under changing temperatures, loads or moisture conditions.
Dimensional stability should therefore be considered when precision is important.
6. Moisture and environmental conditions
Moisture absorption can affect the performance and dimensions of certain plastics.
The environment should also be considered more broadly. Outdoor exposure, UV radiation, dust, chemicals and other environmental factors can influence material performance.
7. Machining and manufacturing requirements
The way a component will be manufactured can also influence material selection.
Some engineering plastics can be machined using conventional tooling, while others may be better suited to moulding or other manufacturing processes.
Engineering plastics vs metal
Engineering plastics are not necessarily intended to replace metal in every application. Instead, they can provide an alternative where their specific properties offer an advantage.
Compared with metal, engineering plastics can provide benefits such as lower weight, corrosion resistance, electrical insulation and reduced friction.
However, metals may remain more appropriate for applications involving certain loads, temperatures or operating conditions.
The right choice ultimately depends on the requirements of the component rather than simply choosing between "plastic" and "metal".
Why material selection matters
Choosing the wrong material can result in premature wear, deformation, cracking, dimensional changes or component failure.
For this reason, engineering plastic selection should take into account the complete operating environment rather than one isolated property.
For example, a material may have excellent wear resistance but be unsuitable for the temperature or chemical conditions in which the component operates.
Working with an experienced engineering supplier can help businesses identify the properties that matter most and select a material appropriate for the intended application.
Engineering plastics for industrial applications
At DEMS, the engineering plastics range includes materials such as polyethylene, nylon, acetal, PET, PVC, PTFE, polypropylene, PEEK, polycarbonate, cast acrylic and a range of laminate materials.
With more than 60 years of experience in engineering solutions, DEMS supplies engineering plastics, laminates and composites to customers across South Africa. The company has facilities in Durban, Johannesburg and Cape Town, supporting a national customer base.
The DEMS team can also provide technical guidance to help customers identify suitable products for their specific requirements.
Frequently Asked Questions
What are engineering plastics used for?
Engineering plastics are used to manufacture industrial components that require properties such as strength, wear resistance, chemical resistance, low friction, dimensional stability or temperature resistance. Applications vary depending on the material and operating environment.
What is the strongest engineering plastic?
There is no single engineering plastic that is universally the strongest. Different materials offer different combinations of tensile strength, impact resistance, wear resistance, temperature performance and other properties. The most suitable material depends on the application.
What is the difference between engineering plastics and standard plastics?
Engineering plastics are generally developed and selected for applications that require higher or more specific performance characteristics than standard commodity plastics. They may offer improved mechanical, thermal, chemical or dimensional properties.
Is PTFE an engineering plastic?
Yes. PTFE is a high-performance fluoropolymer used in engineering applications where properties such as low friction, chemical resistance and non-stick performance are important.
How do I choose the right engineering plastic?
Start by assessing the component's operating temperature, mechanical loads, chemical exposure, friction and wear requirements, moisture exposure, pvc dimensional tolerances and manufacturing process. A technical plastics supplier can then help identify suitable materials for the application.
Choosing the right material for your application
The right engineering plastic can make a significant difference to the performance, durability and reliability of an industrial component.
Rather than selecting a material based on one property alone, consider the complete operating environment and the demands placed on the component.
For expert advice on engineering plastics, laminates and industrial materials, speak to the DEMS team about your application and requirements.
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