2k Injection Molding

For your 2k Injection Molding, you can rely on Inox Casting. We have accumulated 20 years of experience and development in this manufacturing processes. Contact us immediately!

  • 20+ years of history and experience
  • Sophisticated and advanced manufacturing machine
  • Excellent R&D capabilities
  • Provide turnkey solutions

Why Inox 2k Injection Molding is Your Best Choice

Here in  Inox Cast, world-class products and reliable services await you. We are equipped with high-technology machines and in-house facilities, expert technicians, and engineers. Based on your detailed specifications and requirements, Inox Casting is willing  to be your reliable manufacturer and supplier! Settle with us now!


Multi-Cavity 2k Injection Molding
Multi-Cavity 2k Injection Molding

Multi-Cavity 2k Injection Molding is manufactured using high-quality thermosetting plastic. It is performed with multi-cavity molding.

2k Injection Molding Polishing

2k Injection Molding Polishing is structured with the superior quality type of plastic ABS. It has beautiful and great polishing surface treatment.

3 2K Mold Plastic Bike Handle
2K Mold Plastic Bike Handle

This 2K Mold Plastic Bike Handle is mould with 1*1, 1*2, 1*4, 1*8 cavities, or as per your requests. It can be treated with mirror polishing, textured, or EDM surface finishing.

4 Customized 2K Double Shot Plastic Injection Molding Parts
Customized 2K Double Shot Plastic Injection Molding Parts

Customized 2K Double Shot Plastic Injection Molding Parts is manufactured using a single process combination mode type. You can choose the color, shape and design of your product.

High Precise 2K Injection Molding

Inox can manufacture High Precise 2K Injection Molding to meet your requirements. Get in touch with our experienced sales staff and service team.

Medical Equipment 2K Injection Molding

For your Medical Equipment 2K Injection Molding, you can trust InoxCast. We are experts in accurately manufactured the specific standards and requirements of medical equipment.

Compact Structured 2K Injection Molding

All products produced from 2K Injection Molding are compact structured, durable, and cost-effective. Even for your large volume production needs, we can support you.

8 Multi-component 2k Injection Molding
Multi-component 2k Injection Molding

Our Multi-component 2k Injection Molding products are widely used in many applications such as in computers, machinery, power tools, lighting technology, and so on.

9 2k Injection Mold
2k Injection Mold

Inox Casting offers custom 2k injection mold to high-valued customers. All 2k injection mold we produced has a precise structure and high standard.

2k Injection Molding

Inox 2k Injection Molding

Whenever you require 2k injection mold for your precision mold needs, Inox Cast is willing to support you with that. We highly offer a complete 2k injection molding solution and services that can complete your current or upcoming projects.

Inox 2k injection molding is a process that is beneficial because to its economically more practical. This also allows for manufacturing products in any shape and design you demand.

Inox Cast provides a highly precise 2k injection molding solution to a wide range of applications including beverage & food, data/telecommunication, electronics, irrigation, commercial building products, aerospace, and medical applications. All the products we offer are completely ROHS certificated.

2k Injection Molding by Inox Cast sometimes referred to as 2 shot molding or double injection, is an invented production process used to make complex molded components from two different materials into the multi-compartment mold.

During the 2K injection molding process, we also used high-tech and advanced production machines to ensure stable quality finished products. This can create products that owned several features and amazing advantages.

Here are some of 2K Injection Molding Advantages:

  • Low handling,
  • Fast cycle times,
  • No secondary assembly steps,
  • Superior adhesion to the plastic component,
  • High degree of automation,
  • Reasonable Cost,
  • Multi-material efficiency,
  • Improved part integrity,
  • Enhanced cosmetic & tactile product features, and
  • Firm production process

The technology 2K injection molding by Inox Cast makes it easier to create an absolute product so that this won`t require more assembly steps and secondary processing. Through a highly automated and specialized process, we attentively control the injection of various materials.

Whether you are a company, supplier, or factory, Inox Cast is your ultimate source of 2k injection molding.

Choose now the Inox Cast and see how we can help you!

2K Injection Molding: The Ultimate FAQ Guide

In this guide, you will find all information about 2k injection molding.

From benefits, characteristics, material to working principle; everything you are looking for is right here.

Keep reading to learn more.

1. How Does 2K Injection Molding Process Work?

2K or double injection molding is also known as two-shot or two-color injection molding process.

It involves blending two different plastic materials or two different colors into one end product through single injection molding process.

A 2K injection molding machine is multi-chambered and is designed to perform two injections in one cycle.

2K injection moulding

2K injection mouliding

First, the necessary raw materials are loaded into a two injection molding machine canisters.

These raw materials are the subjected to relevant temperatures and pressure in order for them to maintain a molten state.

Next, the first nozzle then opens and injects the molten plastic material into a mold.

The mold is quickly cooled to a certain temperature and then automatically rotated at 180 degrees using robotic hands.

A different plastic material injection is then shot into the mold from the second nozzle.

The two different materials are then subjected to the right temperature and pressure to avoid having a deformed end product.

Double injection molding machine has separate temperature cavities for the different materials to avoid material damage.

For instance, rubber temperature cavity is set at 160 degrees Celsius while thermoplastic temperature cavity between 80-100 degrees Celsius.

2. What Are The Available Types Of 2K Injection Molding?

  • Multi-color molding

2 Multi color molding

multi color molding

  • Dual-shot molding

dual shot molding

dual shot molding

  • Core pull 2K injection molding

core pull 2K injection molding

Core pull 2K injection moling

3. When Should You Use 2K Injection Molding Manufacturing Process?

Double injection molding process can be used during large scale production, that is quantities from 300,000pieces onwards.

This is because 2K injection molding will save you on production cost thus is economical and efficient.

When you have opposite polymers that can blend perfectly under certain conditions and within one injection to form a product.

Materials with such properties are suitable for use in 2K injection molding manufacturing process.

Another instance when you can use 2K injection mold is when you have a complex product design.

In such cases 2K injection mold will be better than single injection mold which is slow and costly.

4. What Products Are Manufactured Through 2K Injection Molding?

2K injection molding process is applicable in various industries such as automotive, medical, electronic, commercial and domestic appliances, etc.

Some of the products manufactured through this innovative technology include;

  • Lid seals
  • Bicycle handlebar grip
  • Anti-slip applicators
  • Toothbrushes
  • Electronic components such as earphones, phones, cameras, etc.
  • Household appliances; refrigerators, washing machines, cooker, etc.
  • Vehicle starring wheels and dashboard

5. What Are The Characteristics Of 2K Injection Molding Process?

2K injection molding process identifies with the following characteristics:

I. In most cases, the hard material is injected first followed by the soft material. This is because the soft material easily deforms when injected first.

II. The two front mold kernel have different shapes while rear mold kernels have similar shapes.

III. When the rear mold part is rotate at 180 degrees from the center and front mold part remains unmoved they become identical.

IV. The guide sleeves of the mold must be symmetrical up and down, similar to front and rear molds.

V. The product size of the first mold is slightly larger to allow tight sealing with the second mold.

6. Why Should You Choose 2K Injection Molding Over Traditional Injection Molding Types?

2K injection molding manufacturing process has several advantages over single injection molding process.

  • Economical

Double injection molding is completed within a single cycle thus eliminating costs that come with several injection stages.

Secondly, it makes production process much faster with the single cycles, hence ideal for large scale production.

Additionally, this technology is easily automated minimizing handling in the process thus cutting on labor cost.

  • Customizable

A client can determine the colors or materials to be blended in the mold to suit to their product needs. Effects such as waterproof, anti-skid, moisture-proof and shock absorption can be achieved in your product.

  • High quality products

2K injection molding manufacturing process works with materials that are highly compatible.

This material precision ensures that the molds completely blend thus producing a high quality product.

Besides, it also assures of product durability.

  • Aesthetic purposes

This manufacturing process is capable of combining different colors into one end product thus enhancing product appearance.

  • Complex production possible

2K injection molding process involve two different materials or colors which chemically combine to produce a single product.

traditional injection molding

Traditional injection molding

For instance, hard plastic material can be blended with soft plastic material to produce a bicycle handle.

This rather complex product is easily produced by 2K injection molding technology.

7. What Is The Comparison Between 2K Injection Molding And Plastic Over Molding?

  • 2k injection molding is a manufacturing technique that combines two different colors or materials into one product through a single shot.
  • Over molding is a process whereby two separate substrates are combined to make a single mold separately.

This is the traditional method of plastic injection molding.

  • In 2K injection molding the materials and colors used blend chemically whereas in over molding, materials combine mechanically.
  • 2K injection molding machine is very expensive to buy, while over molding machine is cheap. This is because the latter can use any type of single injection machine in its production.
  • 2K injection molding is faster due to single shot cycle thus suitable for large scale production. Over molding involves more than one cycle hence it is a bit slow and can only be used in low scale production.

plastic over molding

plastic over molding

  • While 2K injection molding cost less per unit due to automation, over molding involves several steps which attract higher production cost.
  • Over mold process has a limit choice of plastic materials to use compared to 2K injection molding.
  • Since over molding has more than one cycle, there is an increase in product waste compared to 2K injection molding.

8. What Materials Are Used In 2K Injection Molding?

Double injection molding process is an advanced manufacturing process which involves co-polymerization of different materials to produce a single product.

It therefore utilizes materials with certain characteristics that make this process possible.

The materials are:


Are eco-friendly plastic materials which are commonly used in 2K injection molding process.

They are mostly fine cut and can be re-used so many times without losing their properties.

Examples of thermoplastics are; PE-Polyethylene, PS-Polystyrene and ABS-Acrylonitrile butadiene styrene.

These materials are cheap, easily available and have a low melting point.


This material is available in so many forms such as synthetic rubber which is mostly used.

Rubber can be easily molten thus is used in various design applications.


This is one of the most popular material that is used in 2K injection molding manufacturing.

It is easily available and used in manufacture of mechanical parts for automotive and aerospace industries.


Glass material is rarely used due to its delicate nature. It is mostly used when molding products needed in medical industry.


Several metal types are used in 2K injection molding process such as steel, aluminum and brass.

These metals are easily available, are affordable and are easy to molding.

Additionally, products manufactured from these metal types are durable hence are always on high demand.


Thermosets are almost similar to thermoplastics only that they are not recyclable. They are used in making various domestic and commercial tools.

Due to their non-reuse nature, they are rarely used in order to protect the environment from plastic pollution.

9. How Do You Differentiate Primary And Secondary 2K Injection Material?

Primary or base material is the material that goes into the mold first during the first shot.

Secondary material is injected as the second shot and also referred as covering material.

Primary material should have the right wall thickness to prevent secondary material from overflowing.

10. What Properties Should You Consider When Selecting Materials For 2K Injection Molding Process?

  • Chemical bonding

The materials used in 2K injection molding process possess opposite properties which allow them to blend chemically.

It is therefore important to understand what bonds different materials form when they are chemically bound. This compatibility is what makes chemical bonding possible.

  • Melting temperature

Molding temperature affects the way materials or colors will mix to produce the final product. If the right temperature is not used, then deformities or rough edges are likely to occur in the product.

For instance, thermoplastics melt at a lower temperature than rubber material, therefore thermoplastics should be injected first to avoid rubber deformation.

Additionally, you should introduce the right raw material into their respective temperature cavity.

  • The coefficient of thermal expansion of primary (base) and secondary (covering) material should be similar as possible.
  • The shrinkage rate of primary and secondary material should be similar as possible.

11. How Long Does 2K Injection Molding Process Take?

2K injection molding lead time is between 25-60 days from the date of order confirmation. This period is dependent on product volume, design and material/color properties.

12. What Are The Temperature Requirements For 2K Injection Molding?

Temperature requirement for 2K injection molding materials is not constant.

This is because, different materials utilize different temperature requirements in order for them to melt.

Rubber requires hot temperatures of about 160 degrees Celsius while thermoplastics need low temperature between 20-100 degrees Celsius

13. What Should You Consider When Designing Mold For 2K Injection Molding Process?

Designing guidelines for a 2K injection mold are as follows:

  • Internal bonding surface

Bonding of the materials used is not only dependent on material compatibility but also the internal bonding surface.

Therefore, the internal bonding surface should be maximized as possible by increasing the area mechanically.

  • Cosmetic mating surface

Cosmetic mating surface also contribute to the bonding strength of the product formed.

As a result, the cosmetic mating surface of the first and the second injection must provide sufficient bonding surface.

  • Uniformity of wall thickness and sharp corners

Uniformity in wall thickness is required for the two-shot mold sets; male and male mold and female and female mold.

Also, sharp corners should be avoided when designing 2K mold.

  • Rotation angles

The two mold sets should have similar rotation angle and at a radius of 180 degrees.

  • Weight difference

The weight difference between the base and covering material should not be so big.

This will prevent the weight from affecting molding cycle and injection pressure.

14. What Is The Clamping Sequence In 2K Injection Molding?

When the first injection mold is female mold, then it is matched with a first injection male mold. The same applies when the first injection male mold is used.

Likewise, the second injection female mold shot should be matched with a second injection male mold.

A first injection female mold is also matched with a second injection male mold.

This is to ensure that the molds fit perfectly well to achieve tight sealing between them. where a mismatch occurs, modification can be done to rectify as necessary.

15. What Are The Guiding Principle In 2K Injection Molding?

During 2K injection molding, the following principles can be followed:

  • Hard glue is applied once and the soft glue twice.
  • Transparent glue is applied once and the opaque glue applied twice.
  • High molding temperature plastic materials are applied once whereas, low molding temperature plastics are applied twice.

16. What Is The Cause Of Rough Edged Products In 2K Injection Molding?

The resulting plastic product from 2K injection mold process can have rough edges and here is why:

a) High mold temperatures

b) Unfilled first color plastic filling

c) Overfilled second color adhesive

d) Fast shooting glue

e) Large mating mold clearance

17. How Do You Care For A 2K Injection Mold Machine?

Buying a 2K injection machine is an expensive affair, therefore, maximum care must be taken for the machine to serve longer.

 2K injection molding machine

2K Injection molding machine

The following steps can be followed when taking care of a 2K injection mold machine:

  1. Gently clean the machine after use by using a cotton yard to scrub off adhesives from plastic parts.
  2. Ensure clamping pressure is accurately set to reduce power consumption and avoid damage to transmission parts.
  3. All transmission parts should be lubricated at all times.
  4. Avoid heavy impacts to the mold that can cause mold damage or deformation.

You can also learn more about:

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