Different Types of Injection Molding Technology

Injection molding is a modern and more advanced casting process. It is one of the manufacturing methods that has been evolving over the years to speed up and improve the production efficiency of different products. From complex automotive parts to daily consumer products, injection molding plays a vital role in shaping the modern world.

If you want to make injection molds or mass production, choosing the right technology is crucial to achieve the best quality and save costs. This article will introduce the different types of injection molding technology and their working principles and uses.

What Is Injection Molding Technology?

Injection molding technology is one of the most widely used plastic processing methods in modern manufacturing. Its core is to inject molten plastic into the mold cavity and cool and solidify it to obtain the desired shape of the product. Although this process can be used for one-time production, it is usually used to produce the same parts in batches. The most commonly used materials in injection molding are plastics or elastomers.

Main Types of Injection Molding Technology

Each of these molding types has its own vibe, and it's worth knowing what makes them different.

1. Traditional Injection Molding

Let's start with the classic. This is the process that springs to mind when someone mentions “injection molding.”

How it works:

The plastic is heated, then forced into the mold cavity, where it cools off and is released as a solid piece. Simple, right?

Where it shines:

Ideal for turning out large numbers of common objects such as bottle caps, kitchen utensils, storage containers and even medical devices.

Why it's awesome:

• Super consistent part quality

• Great for high volumes

• Works with a wide range of materials

What to watch out for:

• Upfront tooling cost can be high

• Not ideal for low-volume jobs unless the part is used long-term

It's the standard choice when you need to produce lots of identical parts that must withstand wear and tear.

2. Overmolding

Now we're getting fancy. Overmolding involves building up a part by adding a second material over or around an existing one.

How it works:

The first step is to mold the basic part of the object. Next, the part is placed in a new mold and a different material is injected on top or all around it.

Common uses:

• Toothbrushes with rubber grips

• Power tools with soft handles

• Electronics with multiple textures

Perks of overmolding:

• Better grip, comfort, and look

• Reduces the need for extra assembly

• Combines different materials in one go

Heads-up:

• Needs special mold design

• May increase cycle time slightly

Overmolding allows manufacturers to produce parts with various levels of toughness and feel. It's ideal for items that require toughness as well as easy-to-handle finishes.

3. Insert Molding

Not to be confused with overmolding, though they're cousins.

How it works:

Instead of molding over plastic, insert molding involves molding plastic around a solid insert—usually metal.

Great for:

• Electrical parts

• Threaded components

• Tools and automotive parts

What makes it useful:

• Combines strength and flexibility

• Cuts down on separate parts

• Strong bond between insert and plastic

The flip side:

• Placement of inserts must be super precise

• Cycle time can be longer due to handling

Insert molding helps build tough parts with embedded functionality, like threading or conductivity.

4. Gas-Assisted Injection Molding

Sounds high-tech? It kind of is—but the concept is clever and simple.

How it works:

Once the plastic is injected into the mold, a burst of nitrogen gas follows. This pushes the plastic into corners while hollowing out thicker sections.

Why it rocks:

• Reduces weight of the part

• Less warping in thick parts

• Saves on material

Where it's used:

• Furniture (like plastic chairs)

• TV frames and handles

• Large parts with thick walls

Caution:

• Needs gas equipment setup

• Not suited for very thin-walled parts

Gas-assisted molding is ideal when weight and strength both matter—like in car interiors or big appliances.

5. Liquid Silicone Rubber (LSR) Molding

When you need flexibility and strength, LSR molding steps in.

How it works:

Liquid silicone rubber is mixed and injected into a heated mold where it cures into shape.

Best for:

• Medical devices

• Baby products

• Seals and gaskets

Why people choose it:

• Non-toxic and heat resistant

• Great for soft, flexible parts

• Ideal for cleanroom production

Watch out:

• Not your typical injection setup

• Higher mold cost for custom shapes

LSR is the go-to when flexibility, biocompatibility, or heat resistance are a must.

6. Micro Injection Molding

Tiny parts? No problem. Precision is the main factor in micro molding.

How it works:

The principle is the same as traditional molding, only the parts made are much smaller (with dimensions in millimeters or microns). 

Used in:

• Medical implants

• Micro-electronics

• Mini gears and switches

Pros:

• High accuracy

• Minimal waste

• Great for small-batch production

Cons:

• Needs advanced machines and tools

• Mold alignment must be perfect

Micro molding is essential since a tiny mistake can result in a major trouble in the tech and medical sectors.

7. Reaction Injection Molding (RIM)

Here's something new—plastic pollution has become much more than just melted plastic.

How it works:

Two different liquids are combined and injected into the mold which causes them to react and harden into plastic.

Common for:

• Car bumpers

• Enclosures

• Foam-like parts

Good stuff:

• Can make thick, lightweight parts

• Low pressure means cheaper molds

• Great surface finish

Keep in mind:

• Longer cure time

• Only works with certain resins

RIM is the best option for thick parts that are not too heavy, mainly in auto and industrial design.

8. Structural Foam Molding

Let's focus on toning muscles while keeping the extra weight off.

How it works:

A foaming agent is mixed into the resin before creating the mold. While forming the part, a thick outside surface covers a hollow and light center.

Ideal for:

• Industrial panels

• Storage bins

• Machinery parts

Upsides:

• Strong yet lightweight

• Low stress and warping

• Handles thick parts easily

Downsides:

• Surface finish isn't always smooth

• Not for fine-detail parts

This method is all about function over form. Perfect when you need parts that can take a beating.

9. Cube Molding (Stack Molding)

Need speed and volume? Cube molding has your back.

How it works:

Uses rotating cube-shaped molds with multiple faces. While one side is molding, the others are cooling or ejecting.

Used in:

• Packaging

• Medical syringes

• Personal care items

Why it's a beast:

• Crazy fast cycle times

• Multiple parts per shot

• Better use of machine time

Drawback:

• Very complex mold design

• Higher equipment cost

Cube molding is great when time is money and you need to produce at scale.

What to Think About Before Choosing a Method

Choosing the right injection molding type isn't just about the tech—it's about what your product needs. Here are a few things to ask yourself before locking it in:

• What kind of material are you using? Some methods only work with certain plastics or rubbery materials.

• How complex is the part? Multi-material or insert-heavy designs may need specialized molding.

• What's your volume goal? For large-scale runs, traditional or cube molding might make sense.

• Is weight or strength a concern? Structural foam or gas-assisted methods could help.

• Do you need tight tolerances? Micro molding is the go-to for high precision.

Always talk to your mold maker about your design goals. A quick chat upfront can save weeks (and a lot of money) down the road.

GV MOLD: Your trusted injection molding expert

Once you decide which injection molding technology is right for your requirements, there are three criteria to achieve the best results: the capabilities of the equipment, the experience of working on similar projects and the expertise of the human resources involved in the production.

With more than three decades of experience in the mold making industry, GV MOLD offers comprehensive mold customization design services and injection molding services for a variety of applications. We undertake general plastic injection molding, insert molding, overmolding and 2K molding, as well as various other technologies.

If you have your drawings ready, our engineers can help you from the beginning, from design optimization, mold making to surface treatment. In addition, the automated injection molding equipment in our factory runs 24/7 to ensure fast delivery of parts or products with high consistency and stable quality.

For additional questions or to get a quote for your design, please submit your files and questions to our online portal.

Conclusion

Injection molding is actually a group of processes that excel at different things. Each type of molding has its own areas of strength. If you're producing millions of bottle caps or only a handful of flexible gaskets, there’s a molding process designed with your needs in mind.

Choosing the right molding technology can save you from costly mistakes and delays in the future. If you're unsure which molding method is right for your project, contact us and we will help you choose the one that suits your needs.