Plastics processing remains the most important aspect of the plastics industry. Various methods are used to design and manufacture plastic products from different plastic materials that meet end-user specifications.
However, some plastics classified as engineering plastics have plastic types that differ from traditional plastic materials. Therefore, this guide discusses the types, properties and applications of engineering plastics. Let's get started right away.
What are engineering plastics?
Engineering plastics, also called thermoplastic polymers, are a group of synthetic resins that offer high performance capabilities and improved plastic properties compared to other standard plastics.
More specifically, engineering plastics have a wide range of properties (particularly mechanical and/or thermal), allowing them to perform much better in structural applications than traditional commercial plastics. Furthermore, they are stable over a wide temperature range and withstand significant mechanical stresses as well as chemical or physical changes in the environment.
Technical plastics are also specifically made available to part manufacturers in raw form in order to transform them into the desired end products through plastic processing.
Engineering Plastics Versus Mass-Produced Plastics: What's the Difference?
Basic plastics include types of plastic used in mass applications where technical performance is not essential – for example, common household items. Bulk plastics include polypropylene, polyethylene, polyvinyl chloride, polyurethane, polystyrene, etc. Although bulk plastics are not as sophisticated as engineering plastics, they are still widely available and widely used. They are used for packaging, containers, clothing, disposable items, etc.
Technological advancement and continuous research to improve plastic materials have led to engineering plastics such as polycarbonate, polyamide, polyphenylene oxide, etc. In many cases, these plastic materials are increasingly replacing traditional engineering materials such as metals and ceramics for certain purposes due to their high performance. and combined strength. Additionally, typical engineering plastics offer the following advantages compared to standard plastics:
- Heat resistant up to temperatures between 120 and 150°C.
- Excellent machinability and formability into various shapes.
- Light weight, greater strength and minimum friction.
- Good chemical resistance, elasticity, rigidity, durability and electrical properties.
For these reasons, engineering plastics are mainly used in the production of mechanical parts in various industries such as automotive, medical, electrical and electronics, aerospace, construction, consumer goods, etc. more expensive, which justifies their use for smaller products or low-volume applications.
Properties of technical plastics
For a long time, many types of plastic have been used in various industries. Today there are more than 50 different categories of plastic materials, and each plastic material is often limited to specific purposes due to its inherent properties and certain design considerations. Consequently, not all types of plastic are suitable for technical applications. Some general properties of engineering plastics are listed below:
- Good mechanical properties (abrasion resistance, impact resistance)
- Optical properties (translucent and transparent)
- Chemical resistance
- Dimensional stability
- Low flammability
- Thermal resistance (minimum and maximum operating temperature)
- Water repellent
- Sliding properties
- Electrical properties
A brief overview of plastics technology
Plastics technology is a field that deals with the production of plastic parts from suitable plastic materials. This includes several procedures such as:
- Acquisition of suitable plastic materials for projects
- Specification-Based Plastic Product Design
- Manufacturing of plastic parts
- Plastic Product Performance Testing
Above all, plastics engineers must consider and quantify the critical properties of plastic raw materials to meet specific application requirements while keeping operating costs to a minimum. The inherent properties of plastic materials therefore pose certain challenges to plastics engineers during manufacturing processes.
CNC plastic machining services offer real solutions for machining precise and functional plastic components from engineering plastics. This automated technology is used in the production of engineering plastic products because it is more precise, efficient and compatible with a wide range of engineering plastic materials.
Common Types of Engineering Plastics
Technical plastics come in many different versions. Therefore, it is sometimes difficult to choose the right material for your machining project. Furthermore, the properties of different types of engineering plastics determine their respective use in specific machining processes and applications. However, you can use plastic prototype options to make more optimized decisions. Here are some of the most common types of engineering plastics.
1. Polycarbonates (PC)
PC plastics contain carbonate groups in their chemical composition. This type of engineering plastic is made from thermoplastic polymers that combine toughness, rigidity, durability and impact resistance. They can be easily edited or molded into the desired shape. Furthermore, unlike standard plastics, polycarbonates offer good thermal, electrical and weather-resistant properties. Some types of PC plastic are also optically clear. This combined property makes them suitable for the production of motorcycle helmets, bumpers and optical discs.
2. Acrylonitrile Butadiene Styrene (ABS)
As the name suggests, ABS is a copolymer created by the polymerization of acrylonitrile and styrene in the presence of the additive polybutadiene. ABS offers high performance due to its properties such as heat resistance, flame retardancy, chemical resistance, electrical insulation, easy coloring, waterproof surface, impact resistance, etc. Additionally, the relative content of the monomers that make up ABS can be altered to further improve insulation and heat resistance properties. These features, as well as low production costs, make it suitable for CNC machining and 3D printing. Experts often use ABS to finish car dashboards, hubcaps and bumpers.
3. Polymethyl methacrylate (PMMA)
PMMA plastics, affectionately known as acrylic, are another common engineering plastic used to improve performance, particularly in the construction industry. It has high surface strength, temperature resistance, chemical resistance, optical transparency and attractive appearance.
Furthermore, PMMA has excellent wear resistance and is lightweight compared to aluminum. Furthermore, it can be transformed into specific plastic parts, such as taillights and protective shields, through molding or machining.
4. Polyphenylene oxide (PPO)
The list of common types of engineering plastics is incomplete without PPO. This crystalline thermoplastic grade offers high rigidity and hardness, impact resistance, wear resistance, good dimensional stability and electrical properties. Furthermore, modified PPO also offers exceptional heat resistance over 100°C to 195°C. Therefore, most manufacturers use this engineering plastic material for automotive parts, electrical components and instruments that require high heat resistance and stability.
5. Polyoxymethylene (POM)
This technical thermoplastic offers high wear resistance, rigidity and hardness. POM plastic can also be easily processed into various high-performance parts. Therefore, POM is mainly used for gears, fasteners, automotive parts, ball bearings and products with skeletal functions.
Applications of technical plastic products
From a technical point of view, engineering plastic products or parts are classified into different categories depending on the specifications and requirements for their application. Here are some of the applications of engineering plastic products:
1. Plastic mechanical units
Examples include cams, clutches and gears. High impact and tensile strength as well as good long-term stability at high temperatures are important properties of these plastic parts.
2. Chemical and heat resistant plastic components
Examples include valve covers and seats, fuel rails, water pump casings, etc. These engineering plastic products must have exceptional resistance to corrosion and high temperatures.
3. Plastic electrical parts
These parts must have excellent electrical resistance, tensile strength and stability. Examples of this are connectors and relays.
4. Low friction components
The most important requirement for the use of these parts is a low coefficient of friction. Examples of this include wear-resistant surfaces, bearings, guides and slides.
Concluding
Engineering plastics are high-performance plastics used to produce plastic parts that require much more technical or advanced features. Furthermore, these plastics have become the preferred material to replace traditional engineering materials such as metals and ceramics. And this is due, among other things, to its excellent mechanical and chemical properties, its resistance, stability, as well as its electrical and optical properties. Therefore, they remain interesting for many industries and diverse applications.
Common questions
What is the difference between engineering plastics and specialty plastics?
Engineering plastics are suitable for demanding applications. They are mainly used for parts that require high performance and performance. Special plastics, on the other hand, are suitable for certain purposes.
Is polyurethane an engineering plastic?
In short, polyurethanes are not engineering plastics. This is because polyurethanes do not have the necessary properties to function in harsh or technical conditions.
Which is better, LDPE or HDPE?
This mainly depends on the usage. Low-density polyethylene is soft, flexible and lightweight, but is suitable for applications where rigidity, heat resistance and impact resistance are not required. Therefore, LDPE is still widely used in plastic bags, bottles and tubes.
On the other hand, high-density polyethylene is stronger, harder and offers greater impact resistance as well as good resistance to heat, chemicals and moisture. Therefore, HDPE is classified as an engineering plastic and is used in the production of automotive parts and piping systems.
