Injection moulding is a typical method of thermoplastic production. While there are several common plastics that can be used for injection moulding, material selection is tricky. Thermoplastic is a term used to describe a substance that is usually made of plastic polymers. This means that it can be remelted, reshaped, and refrozen after it has melted.
Plastic injection moulding materials come in a variety of shapes and sizes, each having a different purpose.
Choosing the Right Material for Injection Moulding Acrylonitrile Butadiene Styrene (ABS):
Acrylonitrile butadiene styrene is an abbreviation for ABS. This is a common thermoplastic injection moulding material that can be found in pipes, automobile body pieces, and keyboards.
ABS has several advantages in addition to its good qualities. For example, the material’s great impact resistance makes it difficult to break because it is both sturdy and lightweight. It can also resist high temperatures and withstand heat.
However, one disadvantage is that it is readily damaged, making it very sensitive when utilised. Furthermore, because it is made of oil and produces hot plastic fumes during production, it can be extremely harmful to the environment.
Nylon:
Because of its diverse nature, nylon, also known as polymer fabric, is one of the most adaptable injection moulding materials. It’s utilised in a variety of clothing, as well as vehicle tyres, fishnet, and electrical applications such as insulators.
As an injection moulding material, Nylon has numerous advantages. One is that it has a high abrasion resistance, making it durable and stretchy. On the other side, the material has the disadvantage of melting easily. This makes it difficult to utilise the material in its liquid condition. It can also absorb water directly from the air or from moisture in the air.
High-Density Polyethylene (HDPE):
Plastic bottles, shampoo bottles, toys, recycling bins, and flower pots are all made of high-density polyethylene, which is an injection moulding material that is a robust, solid plastic thermoplastic. The key benefit of adopting HDPE is that it is inexpensive while also providing stiff, high-strength material.
The disadvantages of HDPE are that it is very flammable and non-biodegradable, making it difficult to dispose of. Furthermore, high-density polyethylene is difficult to construct and weathers poorly.
Low-Density Polyethylene (LDPE):
Low-density polyethylene is a much softer and more flexible polymer than HDPE. Bottles, plastic bags, and plastic wraps, as well as playground slides, are made from low-density polyethylene injection moulding materials. Moisture and chemical resistance are two advantages of using this material. It’s also inexpensive and food-grade, so it’s safe to use in food.
Furthermore, low density has the disadvantage of being combustible and having a low temperature capacity, making it unsafe near a fire. Furthermore, it can be difficult to join and has low weathering resilience.
Polycarbonate (PC):
Polycarbonate is a clear, robust, rigid injection moulding material used in engineering. Compact discs, safety hamlets, bulletproof glass, and other electrical and telecommunication hardware all contain PC.
It has the advantage of being nearly unpleasant because of its bullet resistance and great quality. It also protects against discoloration, but it can turn yellow if exposed to UV rays for an extended period of time. Scratching might also cause it to become irritated.
Polyoxymethylene (POM):
POM stands for plastic injection moulding materials, often known as acetal. It is a robust, hard material. Acetal is a material that can be used to make automotive parts. Zippers, fan wheels, door knobs or lock systems, as well as insulin pens, are all made of acetal. It has a high gloss finish and is resistant to organic solvents and chemicals, with the exception of phenols.
The downsides are that it is difficult to bind, has low acid resistance, and is UV sensitive.
Acrylic Poly (Methyl Methacrylate) (PMMA):
Acrylic, one of the above-mentioned injection moulding materials, comes in a lightweight sheet and is commonly used as a substitute for glass. PMMA is used in a wide range of items, including windows, eyeglass lenses, and vehicle back lights, to name a few. Acrylic has the advantages of being resistant to weathering, having a high gloss, and being abrasion resistant. However, it has drawbacks such as weak heat resistance and the ability to break under pressure.
Thermoplastic Polyurethane (TPU):
Elasticity, transparency, and resistance are just a few of the features of TPU. Its soft and hard portions are its distinguishing features. Cases for mobile phones, as well as keyboard protectors and footwear, are the most common uses for this sort of plastic.
Polyurethane has the advantage of being extremely robust and flexible, as well as being resistant to impacts such as tearing and grease and oil. Due to its limited responses to tears over time, it has good dimensional stability. However, it has the disadvantage of not being cost-effective in compared to other options. It has a short shelf life as well.
Thermoplastic Rubber (TPR) :
Another injection moulding material is thermoplastic rubber, sometimes known as elastomer. It is made up of a combination of plastic and rubber elements. Used in vehicle parts such as wires and cable insulation, as well as other home appliance uses. The capacity to stretch and return to its original shape is one of the benefits.
It is also environmentally beneficial because it does not contain non-toxic recyclable plastics, which helps to reduce the environmental impact. Furthermore, one of the downsides is that obtaining this material might be rather pricey. Even if the material can withstand high temperatures, it will lose its stretchy properties.
Polypropylene (PP):
Finally, Polypropylene, also known as polypropene, is one of the last injection moulding materials we’ll look at. Polypropene is a thermoplastic polymer that is utilised in a wide range of applications and will account for 34.2 percent of total sales in 2020. Because it does not combine chemicals with food, it is most commonly used in the food storage and packing business. Other advantages of this material are its great impact strength and resistance to dampness.
The downsides are that it can be affected by UV, losing 70% of its strength when exposed to the sun. Furthermore, due to the chemical content, it may be combustible.
