Introduction

Injection molding is a process that turns liquid plastic into a solid object or part. It’s one of the most popular ways to make stuff. There are a lot of different plastics you can use for injection molding, but they’re not all the same. Each material has its own unique features and is good for making different types of things.

Things can get tricky if you don’t know the process and choose the wrong material to make your part. This article will help you learn more about the common injection molding plastic types to help you decide which one is best for your needs!

What is the Meaning of Plastic Injection Molding？

Plastic injection molding is a manufacturing process used to produce a variety of plastic parts and products. The process involves melting plastic resin pellets and injecting them under high pressure into a prefabricated mold. Once the plastic cools and solidifies, the mold opens and the finished part is ejected.

Acrylonitrile Butadiene Styrene (ABS)

ABS is a plastic that engineers like because it melts at a low temperature and is easy to shape. It’s also an opaque polymer, which means it’s easy to add color to it. You can also make it feel different ways and make the surface look different ways.

ABS has a lot of good things going for it. It’s tough, durable, and strong, which makes it useful in a lot of different industries. It’s got a high tensile strength and can take a hit without breaking. Plus, it’s lightweight, which makes it perfect for making cars and other vehicles.

Another thing that makes ABS injection molding very popular is its ductility, which can be easily molded into various shapes. ABS’s ability to stick to other plastics makes it good for coating metals and other materials.

ABS is known for its durability and impact resistance. However, it doesn’t do well in sunlight, water, and weather. Injection molded ABS is not suitable for outdoor applications compared to acrylic.

ABS plastic is high quality and is suitable for the production of computer parts, medical devices, toys, automobiles, electronics, music, and sports equipment.

ABS is used to make electronic components and keyboard keys, protective headgear, plastic sidings for electrical outlets, and car parts like dashboards, wheel covers, and car bodies. It’s also used for consumer goods, sports equipment, and industrial accessories.

ABS can also be combined with glass fillers for added strength or with polycarbonate for improved low-temperature impact resistance. Some suppliers make filled and unfilled ABS plastics. Also, injection molded ABS plastic is used to make keyboards, helmets, sidings for electrical outlets, dashboards, wheel covers, and other vehicle parts.

Low-Density Polyethylene (LDPE)

LDPE, or low-density polyethylene, is a lightweight, soft plastic. It’s flexible, tough, and can handle low temperatures.

It’s not good for things that need to be stiff, or that need to be able to handle high temperatures, or that need to be strong. It’s often used in orthopedics and prosthetics. LDPE is good at resisting chemicals and impacts, and it’s easy to make and shape.

LDPE is used to make a bunch of different containers, like dispensing and squeeze bottles, tubes, plastic parts for computer components, molded lab equipment, and all kinds of lids.

This plastic resin is great at resisting moisture and chemicals. It’s got good impact strength and is really flexible. It’s also cheaper than most plastic resins, so it’s a good deal. You can use LDPE in lots of plastic products, like computer parts, toys, compost bins, produce, and household items. Some medical product parts also have this plastic resin.

One limitation of this plastic resin is that it can handle low temperatures perfectly, but it can’t handle high temperatures.

High-Density Polyethylene (HDPE)

HDPE is a petroleum-based thermoplastic polymer. It’s the perfect plastic pellet for injection molding and is great for injection molding applications that need high impact, high stress fracture resistance, and extreme strength.

When it comes to food packaging, HDPE is the king of plastics. It can take a beating, it can handle moisture, and it can handle heat. It’s strong, so it doesn’t break or crack.

When you need strength, heat resistance, and stiffness, HDPE is the plastic resin you want. It’s great for kitchenware, water bottles, plastic bags, and more because it can handle the heat. HDPE is perfect for laundry detergent, shampoo, conditioner, mops, motor oil, antifreeze, and recycling bins because it can handle the chemicals.

Nylon (Polyamide, PA)

Nylon is a synthetic polyamide that has high toughness and heat resistance, as well as strong wear resistance, fatigue resistance, and noise reduction.

This is one of the most stable plastic resins. It is resistant to electricity, abrasion, and chemicals. Its wear and tear resistance makes it ideal for use in the manufacture of products that involve chemical contact, abrasion, and high impact.

Nylon is not as resistant to strong acids and bases as other polymers. It is not as strong or impact resistant as polypropylene and polycarbonate.

It has a wide range of applications, including the automotive industry, sports equipment, and medical parts.

Also, nylon is often used in strong mechanical parts like bearings, bushings, gears, and slide grooves. It’s also good for dynamic components, thread beads, boots, quick connector covers, and clamps.

Polypropylene (PP)

Polypropylene is the second most common plastic in the world. It has a high melting point and high chemical resistance. It keeps its shape after you twist or bend it and doesn’t break down when it gets wet. PP, also known as injection molding polypropylene, is a recycled material.and good chemical resistance .

There are many advantages to producing with this plastic resin, ranging from chemical and electrical resistance to high elasticity. It also has a high melting point, making it very effective in producing high heat exposed plastic parts.

PP has high stress resistance and high tensile strength. It is a strong plastic commonly used for insulation, but most manufacturers add fillers to this resin to increase strength.

Polypropylene is a great material, but it has some drawbacks. It’s flammable and sensitive to UV rays. When it gets hot, it breaks down into dangerous chemicals. It’s hard to paint or glue.

It has a wide range of applications in different fields like the automotive industry, construction, and electronics. Polypropylene is safe to use in the production of food containers and has applications in packaging for the food and beverage industry. Since this plastic resin reduces friction between objects, it also has applications in the production of contact point plastics.

Polycarbonate (PC)

PC is a lightweight, strong, and naturally transparent material. The physical properties of PC remain consistent over a wider temperature range.

Polycarbonate is a lightweight, strong, and naturally transparent material. It has consistent physical properties over a wide temperature range.

This material keeps its color and strength when dyed, but it also has some amazing optical properties that help light pass through it.

Polycarbonate is one of the toughest plastic resins. It’s also highly resistant to impacts. Polycarbonate is highly resistant to fire and heat, so it’s great for use in places where temperatures get really high.

This resin is also transparent, so it can be used in places where you need clear plastic. That includes cars (bulletproof glass), phones (phone screens), and medical stuff (eyeglasses).

Also, polycarbonate plastic is used to make machine protection panels, clear and tinted windows, diffusers, and light guides for LEDs and clear tubes. It can also be used to make transparent molds for silicone and polyurethane molding processes.

Acrylic (PMMA)

PMMA (polymethyl methacrylate), also known as acrylic, is one of the most popular resins in the world. Just like PC resin, acrylic is transparent.

Acrylic is a type of plastic that is stronger, clearer, and less likely to break than glass. It is also very clear, so it lets a lot of light through. Unlike some plastics, acrylic doesn’t get ruined by water.

This injection molding materials can also hold tight tolerances. PMMA doesn’t like chemicals or odors. Grease and oil also mark it easily. Although acrylic has excellent tensile strength, it cracks under stress when you put a lot of weight on it.

Because it’s transparent, many manufacturers use this resin to make transparent products. They use this acrylic resin to make picture frames, eyeglass lenses, car screens, and even paint. Another thing about acrylic is that it’s hard and can take a hit.

Plus, it’s easy to get and cheap to use in plastic production. Also, acrylic is used in windows, greenhouses, solar panels, shower enclosures, and other transparent things for outdoor, architectural, and lighting purposes.

Polyetheretherketone (PEEK)

PEEK plastic is a highly sought-after engineering material because it’s super tough, super durable, and super workable. It’s high heat resistance , wear, chemicals, fatigue, and creep. It’s got a high strength-to-weight ratio that competes with metals like aluminum and it doesn’t break down in chemically or physically demanding environments like metals do.

It is known for its extreme resistance to any chemical attack, which makes it widely accepted. Another benefit of this PEEK is that it resists water and thermal degradation.

Also, PEEK has some unique features like 100% biocompatibility, UV resistance, pure light transmission, gamma radiation resistance, and low or no toxicity in various forms.

PEEK resin is one of the strongest resins and has applications in the automotive industry to make compressor plates, piston components, and pumps. Because it is resistant to chemicals, it is used in the production of chemical processing industries and is used in liquid chromatography columns.

Polyoxymethylene (POM)

Acetal, also known as polyoxymethylene, is a type of engineering plastic. It has a low friction coefficient and is very hard and thermally stable. POM plastic is naturally white and opaque. Acetal resins are divided into homopolymers and POM copolymers, which have better hardness and tensile strength.

POM has good color, good heat distortion, and low moisture absorption, and can be used in any field where you need it to stay the same size. It’s used in cars, making plastic gears, and in food and drinks.

It’s got low friction, high hardness, chemical resistance, and wear resistance. It’s good for making pumps and valve parts because it’s slippery. It’s good for making guitar picks, clamps, and buckles because it’s hard.

Thermoplastic Polyurethane (TPU)

TPU is a type of TPE, often referred to separately because it’s so popular. It’s like rubber, but harder, so it can be used instead of hard rubber.

TPU is more resistant to harsh temperatures and chemicals than TPE. However, TPU may be too hard for some injection molded items.

TPU is the plastic resin you want when you need something to be stretchy. It’s like rubber. It’s a soft plastic that you can make into different things using plastic injection molding.

This resin can handle high temperatures and has high tensile strength. That’s why it’s used in cable insulation, sports gear, and power tools.

TPU is used in footwear, mats, cart wheels, and sporting goods. Covers or housings for electronic and medical devices are other examples of applications. TPU is sometimes used in medical applications to replace PVC, a material that can irritate the skin.

Thermoplastic Rubber (TPR)

TPR is a type of plastic that is made by mixing plastic and rubber together.

TPR has the properties of both rubber and plastic. It is also a type of plastic that can be melted and re-melted. TPR is strong, can be used with chemicals, can be hit without breaking, and can be recycled.

TPR compounds are used in footwear, gaskets, cable jacketing, toys, automotive applications, soft touch molds, and general cast items.

High Impact Polystyrene (HIPS)

HIPS, or high impact polystyrene, is a low-temperature amorphous thermoplastic polymer. It’s a flexible, low-cost polymer made from tough polystyrene plastic.

It’s often used in low-strength structural applications that need impact resistance, processability, and low cost. It has great dimensional stability and is easy to make.

HIPS is used a lot in point-of-purchase displays and indoor signage where you need to keep things simple. It’s also used to make yogurt containers, plastic cutlery, salad bowls, refrigerator liners, medical industry trays, and insulation.

Thermoplastic Elastomer (TPE)

TPE is a blend of rubber and plastic. TPE (thermoplastic rubber) can be stretched to moderate elongation and then return to its original position when the force is removed.

TPEs are cheaper to mold than liquid silicone rubber and easier to process. TPEs creep, which means they permanently deform under continuous load.

TPEs are poured into molds to make footwear, medical devices, automotive parts, and pet products. In automotive, they’re used for dust boots and weatherproof seals. Medical devices include ventilation masks, catheters, valves, and breathing tubes.

TPE is different from other injection molding materials because it is a plastic-rubber hybrid. It combines a thermoplastic material and an elastomeric (rubber) material. The resulting material acts like a thermoplastic while also having rubber-like properties. So, TPE is used in applications that need great flexibility. This material is also called thermoplastic rubber (TPR) and can be recycled over and over.

It combines the advantages of both materials. It is flexible, can be stretched to great lengths, is strong, and is recyclable. Moreover, its main advantage is that it is cheap compared to most rubber alternatives. However, it is not suitable for use at high temperatures because it loses some of its material properties. Moreover, it should not be stretched too much for too long because it tends to creep.

TPE is flexible because it has rubber in it. It goes back to its original shape after you stretch it. It’s also easy to work with when you’re making stuff with it. Besides being flexible, TPE is also really strong when you hit it, it doesn’t get messed up by chemicals, and it doesn’t get messed up by the weather.

However, this type of plastic is more expensive than other plastic injection molding material. So, designers must carefully consider whether TPE alternatives will produce the same results.

Thermoplastic elastomers are used in a bunch of different stuff, like: shoes, medical stuff, electronics, things you buy, sports stuff, things that keep stuff from leaking, hoses, shoe parts, things that keep stuff from shaking, things that keep stuff from bumping, etc.

Polystyrene (PS)

Styrofoam is cheap, light, and doesn’t get wet or grow germs. The two main kinds are regular Styrofoam and the kind that doesn’t break.

Also, these common polymers are resistant to gamma radiation and have high chemical resistance to dilute acids and bases, both of which are used in the sterilization of medical devices.

Polyethylene (PE)

Polyethylene is the most used plastic in the world and is a commercial polymer that can be chosen based on density. High-density polyethylene and low-density polyethylene are both resistant to chemicals, but they differ in rigidity, flexibility, melting points, and optical clarity.

These plastic materials may not be suitable for various processing applications because they can’t take the heat. Injection molded polyethylene is commonly used in household appliances, toys, food containers, and automotive parts.

Polystyrene is used in medical, optical, electrical, and electronic applications. HIPS is used in machinery and equipment because it is stronger. Injection molded GPPS is used to make plastic pallets, boxes, and toys. But both compounds are flammable and can be easily degraded by sunlight.

Conclusion

This article talks about a bunch of different plastics that are used for injection molding and what they’re good for. According to the article, the best plastic for injection molding depends on what you’re making and where you’re using it. Basically, you need to think about how the plastic looks and feels, how long it lasts, and how much it costs to make sure it’s right for what you’re doing and what people want to buy.