What Is Plastic Injection Molding, and What Are Its Benefits?

Aug 20, 2024, 14:11 PM by The Stoner Molding Solutions Team
Do you own a plastic molding company? Are you looking to enter or take on the production of plastic parts? You might hear plastic injection molding mentioned quite often, as this method of plastic production is one of the most common and valuable methods today. So, if you’ve asked, “What is plastic injection molding?” we have the answer!

A close view of a plastic injection molding machine, with bright yellow, white, and cyan parts of the frame visible

With just a little knowledge and high-powered equipment, this production format can help you create high-quality molded parts at an unmatched rate! Here at Stoner Molding, we have been assisting thermoplastic molding companies to produce higher-quality goods faster than ever, and we are always excited to help both new and old companies dive deeper into the incredible field of plastics.

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What Is Plastic Injection Molding?

Plastic injection molding uses heat to melt plastic material and hydraulic or electronic plungers to apply high amounts of pressure to it. This mechanism forces the material into a mold, filling it and creating a plastic product. This reasonably simple process requires robust machinery and initial investment to get production off the ground.

A polished and well-cleaned injection mold for a plastic part.

The Mold

Because of this molding process's high heat and pressure, the mold must be highly durable. These are often custom-made via CAD or 3D printing prototypes and machining steel or aluminum for the final mold. Taking the time to prototype a mold is essential and will help you create a mold optimized for production concerns, including wall thickness and geometric complexity that might impact injection.

The Plastic

Many types of plastic are used in plastic injection molding, and the most common will be explained in-depth below. Most manufacturers use plastic pellets fed into the plastic molding machinery. The barrel of the machine will heat the plastic to the melting point until it is liquid. This temperature may have to be very high, depending on the material used.

The Injection

Once the material has melted, the injection molding machine will draw the material in like a syringe, and the mold opens and closes for the halves to be pressed and held together. Then, injection pressure is applied to the material, forcing it into the mold at a consistent rate that will carefully fill it without wasting material.

Holding and Cooling

What is plastic injection molding’s most important step? The cooling step. Depending on the product, the cooling process may take just a few seconds or minutes. Cushing the cooling process and producing poorly formed parts isn't uncommon.

Ejection and Finishing

After cooling times have passed and the part is formed, the piece is ejected from the machine. These typically eject into a conveyor belt where any finishing touches are applied: Removal of excess material, polishing, dying, or any other step your parts require.

These steps are the complete plastic injection molding process. Depending on the exact details of your products or materials, you may have slight differences or adjustments to each step. This general process is tried-and-true for cost-effectiveness and high-quality production.

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What Plastics Are Used for Injection Molding?

a closeup of dark and light blue plastic granules used in injection molding

The plastic injection molding process is flexible and can use many kinds of thermoplastics. Thermoplastics melt when heated but do not chemically change during the process. You can reheat and recycle thermoplastics fairly easily. This class of plastic Includes ABS, nylon, polypropylene (PP), and polycarbonate (PC), among other less common materials.

ABS Plastics

These plastics provide injection molding products with a smooth finish, high tensile strength, and stability. This material is common in medical applications and toys and is common throughout industrial and recreational products. ABS is one of the most common plastics today. Its features include:

  • Recyclable
  • Machinable
  • Flammable
  • Body-Safe

Nylon

This plastic can come in a range of formulations that have a variety of applications. Temperature and chemical resistance are highlights of this material. Nylon is the most common material in automotive parts that benefit from heat resistance due to its desirable characteristics:

  • Recyclable
  • Heat Resistance
  • Chemical Resistance

Polycarbonate

Polycarbonate plastic is very lightweight and has high impact strength and long-term stability. This type is one of the most common plastics throughout electronics, construction, 3D printing, and even DVDs and Blu-ray discs, thanks to its clarity. Safety goggles and windows are standard products made with PCs because of its:

  • Clarity/See-through
  • High Strength
  • Body-Safe

Polypropylene

Polypropylene (PP) has a low density for light and is a flexible plastic. This material is exceptionally resistant to chemical degradation. However, UV radiation can be damaging to PP products, which include piping, medical and laboratory items, and food containers. It’s known to be:

  • Recyclable
  • Flammable
  • Body-safe

There are many thermoplastic materials used in injection molded plastics today, and new types of plastic are invented every day. When you use thermoplastic injection molding, you open your production up to the use of recyclable and more eco-friendly materials. When using these materials, you can make the most of them with high-quality molding products like ours!

 

The Benefits of Plastic Injection Molding

Plastic injection molding has some of the highest production rates, lowest costs, and most flexible design processes available in the plastic molding industry. These benefits are not unique to injection molding, but this method of plastic molding might fit your needs perfectly!

Fast Production Time

Injection molding is capable of producing high volumes of plastic parts. Because of the high heat and pressure within the cartridge, molten plastic flows quickly into the mold. Depending on the size and shape of your product, cooling can take as little as a few seconds for unmatched production volume. This process is easy to automate and speed up for a more efficient than ever production!

Cost-Effective Production

Because of the nature of manufacturing, you need to have minimal production costs and maximum production volume. Producing plastic parts is often cost-effective thanks to the low cost of this miracle material. Most plastics are recyclable or extremely cheap to make, keeping costs low.

Unique Design Opportunities

Shaping molten plastic is not simple, but it can be one of the most valuable and impressive avenues of design. Between the range of materials and unique mold shapes, the design flexibility provided by the injection molding production process can give you the opportunity to stand out in your field with exceptional products.

 

Enjoy High-Quality Plastic Production Thanks to Stoner Molding!

Now you know the answer to the question, “What is plastic injection molding?” Plastic molding production is a rich and varied industry, but entering it cannot be easy. If you aren’t familiar with the industry, just hearing the terminology can be confusing and unhelpful. However, once you have a firm grasp of the plastic industry, the many production processes are beneficial for endless use.

The mechanical properties of plastic make it one of the most highly desired materials throughout the world.

Are you ready to experience the incredible benefits of a plastic injection molding process? Once you’ve started, use our products, which will ensure you have a fast release, clean mold, and fail-proof production! Call us today and experience the difference we can make.

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Resources:

https://www.iqsdirectory.com/injection-molded-plastics/

 

 

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