Introduction: Plastic parts are everywhere. They’re in every gadget, appliance, and device we use. They protect us from the electrical guts inside, hold electrical components in place, and make things work.

Some plastics are even tools we use every day. Injection molding is the fastest way to make plastic parts. So, it’s no surprise that it’s the most popular way to make plastic consumer products. This article is about injection molding advantages.

What is Plastic Injection Molding?

Thermoplastic injection molding is a standard process that uses a mold filled with polymer melt. The injection molding machine allows injection pressure and speed, quality control and small errors, so the product is usually ready to ship immediately after production.

Plastic pellets are loaded into a barrel, where they are melted, squeezed and shot into the mold cavity. The hot material cools and solidifies in the mold, creating a molded part.

Injection molding technology means that the ejector finally pushes the part out of the mold and the part drops into a bin. Once the run is complete, the parts (or master run) are boxed up and shipped out.

What is the Process Flow of Injection Molding?

Raw Material Preparation

Pick plastic particles that are good for injection molding. They need to be the same size and not have any junk in them.

Adding Materials

Put plastic pellets into the hopper of the injection molding machine. The hopper has a heater to keep the plastic pellets melted .

Melting Plasticization

The plastic particles are heated by the heater under the hopper to melt them into a uniform molten state.

Pressure Establishment

After the molten plastic is squeezed by the screw, it is injected into the mold. At this time, it is necessary to apply pressure to the mold through the injection column to make the molten plastic fill the mold cavity.

Cooling and Solidification

The melted plastic is cooled in the mold for a certain period of time and gradually solidifies and forms. This process needs to be controlled according to the cooling time of the plastic and the temperature of the mold.

Mold Opening

When the molten plastic cools down and hardens, the injection column slowly reduces the pressure, and the mold starts to open, usually driven by hydraulic or pneumatic pressure.

Take out the molded product: After the mold opens, take out the molded product and do the subsequent trimming, deburring and other processes.

Cycle

Once the trimmed molded product is removed, you just refill the hopper with new plastic pellets and do it all over again for the next round of injection molding.

What are the Commonly Used Materials for Injection Molding?

Polypropylene (PP)

PP, or polypropylene, is a versatile thermoplastic that has a lot of uses in injection molding. It’s lightweight, can handle chemicals well, and is really tough, so it’s great for making things like packaging, containers, and car parts.

ABS

ABS is a strong, impact-resistant plastic that stays the same size. It’s easy to shape and color, so people use it to make things like toys, car parts and computer cases.

Polyethylene (PE)

Polyethylene (PE) is a lightweight plastic that’s known for being flexible and cheap. It has different types like HDPE and LDPE and can be used in a bunch of different industries from packaging and containers to agricultural products and toys.

Polystyrene (PS)

Polystyrene (PS) is clear, hard and cheap. PS is often used in throwaway stuff like packaging, food containers and throwaway tableware, and is liked for its easy molding and cheapness.

Nylon (PA 6)

Nylon, specifically nylon 6 or PA 6, is known for being strong, tough, and resistant to wear. It’s great for making mechanical parts and is used a lot in things like gears, bearings, and other parts that need to be made in large quantities, last a long time, and be made very precisely.

Polycarbonate (PC)

PC, or polycarbonate, is known for being see-through, tough, and able to handle high heat. That’s why it’s used to make things like eyeglass lenses, computer parts, and clear stuff that doesn’t break.

What are the Advantages of Injection Molding?

Provides Complex Part Designs

Injection molding is great for making complex parts, it’s consistent, and you can make millions of parts that are almost exactly the same. To get the most out of high-volume injection molding and make sure your parts are as precise and high-quality as possible, you need to think about a few things when you’re designing them.

Designing parts to maximize the inherent efficiencies of high-volume molding is key. With the right design, you can make parts that are high quality without sacrificing complexity.

Increases Production Efficiency and Speed

There are a lot of good reasons why this is the most common and effective form of molding. First, the injection molding process is faster than other methods, and the high production output makes it more effective.

The speed depends on the complexity and size of the mold, but there are only about 15-120 seconds between each molding cycle. With shorter cycles between cycles, you can produce more injection molded parts in a given production time.

Greater Strength

Plastics have gotten a lot stronger and tougher over the years. Modern lightweight thermoplastics can take a beating in harsh environments just as well as metal parts, and in some cases, even better than metal.

Plus, there are over 25,000 engineering materials available for complex injection molding applications. You can also make high-performance plastic blends and hybrids to meet specific part requirements and properties, like high tensile strength.

More Flexibility in Color and Materials

Plastic injection molding is a flexible process. It’s flexible in terms of the plastics you can use and the colors you can choose. That’s a big deal for OEMs. It’s a big deal because it gives you a lot of design freedom. You can do a lot more with plastic than you can with metal. You can use a lot more materials.

The molding process can make transparent parts or a variety of colors by adjusting the plastic, additives, and biocompatibility to get the color you want. But when you need a product with multiple colors, you can do that with overmolding.

Reduced Waste

The plastic injection molding process produces very little post-production waste compared to traditional manufacturing processes. Any waste plastic usually comes from the gates and runners. However, any unused or waste plastic can be reground and recycled for future use.

Being able to reduce the amount of waste and harmful substances that are released into the environment and affect our health is a win for everyone. The whole process is highly repeatable, which means less waste is created. The waste that is created is then recycled and used in other production. So, less waste.

Injection molding is a cheap process that uses recyclable materials and produces less waste. Plastics are cheaper than other materials like metals and rubber. That’s why plastic molding is often a popular choice. Recycling leftover plastic materials for another production process can also reduce waste.

Plastic injection molding is different from CNC machining because it doesn’t cut plastic from large blocks or sheets. With CNC machining, you might start with a 100-gram piece of plastic, but at the end of the manufacturing process, you may be left with a final product weighing only a few grams.

Plastic injection molding is more efficient. On average, only 20 grams of virgin plastic material becomes waste. This results in less waste.

Injection molded parts usually don’t need much post-processing because they usually come out of the mold with smooth surfaces and precise dimensions and not much scrap.

Offers a Variety of Surfaces

Most injection molded parts have a smooth surface finish that is close to the desired final appearance.

However, a smooth appearance is not suitable for all applications. Depending on the physical and chemical properties of the plastic material used, the plastic injection molding manufacturing process creates a surface finish that does not require secondary operations. The process offers the flexibility of surface treatments, from matte surfaces and unique textures to engraving.

Low Labor Costs

The cost of labor for injection molding operations is relatively low compared to other types of molding processes. The ability to produce high-quality parts at high production rates helps to reduce manufacturing costs through its efficiency and effectiveness.

Molding equipment often comes with automatic pouring, automated process tools to keep operations streamlined and large-scale production is carried out with minimal supervision.

Injection molding is highly automated, which increases production efficiency and reduces labor costs. Automated injection molding machines can run continuously with minimal human intervention, ensuring consistent part quality and high productivity.

This automation also enables fast production cycles, allowing manufacturers to meet tight deadlines and scale up production as needed.

Use Multiple Types of Plastics

Complex part designs often require components made from different materials. While this may seem simple, safely combining plastics can be very complex. In any case, the plastics expertise of mold project engineers reduces defects, risk of injury, and warranty claims by ensuring compatibility.

Injection molding is great because it can handle all sorts of materials. You can use it with thermoplastics, thermosets, elastomers, and composites. This means you can pick the best material for your project, whether you need it to be strong, resistant to chemicals, or just look good.

Have Consistency

To make a lot of complicated plastic parts, you need a process that can make the same part over and over again, and make it the same every time. That’s what injection molding does. It uses the same mold to make the same part over and over again.

And the people who do it are always trying to get better at it. They’re always trying to use the latest technology to make the best parts they can.

Plastic injection molding is a super repeatable process. With an injection molding machine, you can make thousands of plastic parts in a day and they will all be pretty much the same. Before you get your mold design, material selection, and product design right, injection molding can have a scrap rate of less than 1%.

If consistency is important to your brand or project, plastic injection molding is a great way to make your stuff.

Create Precision Products

Modern, high-speed injection mold equipment that is properly maintained allows for the mass production of precision molded plastic parts. This molding process is the best choice for the production of plastic parts such as connectors and gears that require high-precision production, with tolerances up to +/-0.0002 inches.

Also, manufacturers often equip molding machines with advanced control systems. These automated systems monitor and adjust process parameters in real time. As a result, plastic parts are molded to precise specifications.

Injection molding is a process that can make parts with really tight tolerances and consistent dimensions. It lets manufacturers make parts with complex shapes and intricate details really accurately, so each part is exactly what it’s supposed to be. That’s how you make precision products.

Shortened Product Development Time

injection molds engineers with different skill sets can help OEMs achieve shorter product development times. This ensures faster production cycles and brings defect-free parts to market faster, which is a decisive competitive advantage for manufacturers.

What are the Applications of Injection Molding?

Household Daily Necessities

Injection molding technology can make a lot of household daily necessities, such as plastic straws, water cups, tableware, baby bottles, plastic toys, etc. These products are light, cheap, beautiful and practical, and people like them.

Automotive Parts

Injection molding technology can make car parts like dashboards, door panels, roofs, etc. These parts are strong and light, and are used a lot in the car industry. Injection molding parts are cheap and fast to make, which is good for the car industry.

Medical Equipment

Injection molding technology is used to make a lot of medical devices, like syringes, infusion sets, nebulizers, and so on.

These things need really good materials, so they have to be made from materials that are really good, that don’t have any bad stuff in them, that don’t smell bad, and so on. Injection molding technology can make really good medical stuff, so that the things that get made are what the medical people need.

Electronic Products

Injection molding technology can make a lot of electronic products, like phone cases, computer cases, keyboards, mice, and so on. These products look good, are light, and don’t cost much. Injection molding technology can make electronic products that look good and are good quality, so they can meet customers’ needs for how they look and how good they are.

Conclusion

In short, plastic injection molding is great for a lot of things. It’s fast, it’s accurate, and it’s flexible. You can use it to make everything from toys to car parts to medical devices to electronics. It’s not just fast and accurate, though. It’s also good for the environment because it lets you use less material.

So, if you need to make a lot of parts that all have to be the same and work really well, plastic injection molding is a good way to go. It’s also a good way to save time and money when you’re making new products.