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Two shot injection molding

Go4 Mold has years of experience with two shot injection molding. Supports you with mould design, in-house mold making, material selection, and more.
Low-cost High-quality Two Shot Molding Production 2

Low-cost high-quality two shot molding production

The designers at Go4 mold are able to make the most of a wide range of materials. The good structural properties of hard plastics are combined with the soft and attractive properties of different materials to achieve exactly the desired result.

We also minimise costs by saving time. You can get your product on the shelf or complete your entire project much faster.

Professional design of two shot molding

Go4 mold has a professional design team. Go4 designers will check the machine injection unit before designing the tool. The injection unit sometimes limits the tool type. Consider the material shrinkage for each material.

In 2K molding, the draft angle is one of the most important factors that determines whether the molded part will jam or rotate.

Contact us for more design guidelines for two shot injection molding.

Two Shot Injection Molding design 2
Two Shot Injection Molding Services and Capabilities

Two shot injection molding services

Go4 mold can assist with all aspects of production, including material selection, prototyping, tooling, production and testing. Because we have in-house tooling capabilities and a team of experts.

With our two shot injection molding capabilities, we offer a range of sizes, materials, and tolerances for a variety of applications.

We can manufacture 1.6 to 46 oz shot sizes ranging from 55 to 400 tons, and we can meet precise tolerances of +/- 0.002 inches.

Custom two shot injection molding

GO4 mold’s 2 Shot Injection Molding is used in a wide variety of industries, including handles, multi-color knobs, hinges, safety color warnings, caps, plastic lenses with gradient or bicolor tinting, dental hygiene products, and more. No matter what the size of the job, we specialize in high volume production. Whether it is tight tolerances or complex design, or additional, value-added finishing.

One Color & One Clear Plastic

One color & one clear plastic

The material is ABS plastic of one color and transparent plastic of one color (ABS, PC, acrylic), which are used for electronic parts. The purpose of using double shot molding is to integrate the light pipe into the button, saving cost and space.
Soft resin with another hard plastic

Soft resin with another hard plastic

This is a product made by combining a soft resin (TPE) with another hard plastic (ABS) through secondary injection moulding. A wide range of colours and textures can be moulded into the item to produce toothbrushes, toys, folding buckets etc. These products using secondary injection moulding are complete without any signs of openings or seams and are extremely durable.
two color injection molding

Two colors plastic injection molding

It is common to use two colors of ABS plastic for 2-colour plastic lenses, computer components, etc. . By using secondary injection moulding of 2-colour plastics, labour and time costs can be reduced, fading problems can be avoided. A greater range of design options are available for added value decoration than by printing or painting.

Two shot injection molding expert

The go4 mould factory is located in the beautiful city of Taizhou in China's Zhejiang Province. It is a modern mould factory, equipped with highly advanced production equipment and mould professionals.

go4 mould Factory view (2) (1)

Mould BaseSD,LKM Standard, HASCO Standard Self-made, etc.
Mould MaterialM238/718S/M238H/718H/M202/MUP/M310/S136/M300/S136H/2738H/NAK80/K460,etc
Moud Precision±0.01mm
Mould Life50-500K shots
Mould CavitySingle cavity, multi-cavity
Runner SystemHot runne system and the temperature control system
GateTypePinpoint Gate, Edge Gate, Sub Gate, Film Gate, Valve Gate, Open Gate, etc.
Metal MaterialAluminum (6061,6063,7075…),Brass, Copper, Brass,Satinless Steel(301,302,303,304…)
Surface TreatmentPolishing,Painting,Chroming,Anodizing, Brushing, Silk Screening,Water Transfering, Laser Cutting,Leather Covering,Texture,Sanblasting,Gilding, UV Painting…
Pls Provide2D, 3D, samples, or the size of the multi-angle pictures

More plastic injection moulds

At go4mold, we have many years of experience and know-how in the plastic injection moulding industry. We can offer you a wider choice of moulds and you can also customise your moulds.

Frequently Asked Questions

Go4 mold has been involved in two shot injection molding for many years. We have extensive experience in designing and building high quality 2 shot injection moulds for a wide range of applications. The following are questions about two shot molding that are of interest to our customers.
1:What is two shot injection molding?

Two shot injection molding, also known as two-colour injection moulding, multi-colour injection moulding or 2K injection moulding. It is a sub-category of injection moulding. Allows engineers to create multi-material or multi-coloured parts without adding additional assembly steps. Two shot injection molding is an innovative manufacturing process. It allows complex designs with lower tolerances, higher repeatability and stronger bonding than other moulding processes.

2:The two shot injection molding process.

two shot injection molding process

Two shot injection molding is the process of ‘over-moulding’ two materials in one moulding cycle and requires a special injection moulding machine. The term “injection” refers to the volume of material injected into the mould cavity. Two shot injection molding is performed on a machine that is programmed to perform two injections in one cycle.

In the first cycle, a nozzle injects the plastic into the mould. The mold then rotates automatically and different types of plastic are injected into the mold from a second nozzle. Double shot injection molding can be used to bond one part of a rigid material to another part of a soft material. The process combines the moulding of two components in a single two-cavity mould.

It can greatly enhance the attractiveness of the product in terms of feel, colour, etc.

3:What is insert moulding?

Insert moulding, sometimes referred to as pseudo-secondary injection moulding. The moulding of two plastic materials into two parts on different injection moulding machines. The product is removed from one set of moulds and placed in another. The second injection moulding (hence why we call the first injection an insert).

Typically, this two-colour injection moulding process usually uses 2 sets of moulds. It does not require a special two-colour injection moulding machine.

4:What are the areas of application for two shot injection molding?

Two shot molded components are used in almost every industry. From consumer goods to construction, but are most often found in applications that require:

  • Removable segments or components
  • Rigid base material with soft grip
  • Vibration or anechoic
  • Surface description or marking
  • Multi-coloured or multi-material components
5:How to choose materials for two shot injection molding?

The key elements that must be met in the material selection process are primarily the application properties and the bonding between the moulded materials. Not all materials will bond perfectly, but some may form very strong molecular bonds. It is recommended that the following principles are followed during the selection phase:

1:Choose the same material as CTE whenever possible.

2:Try to choose a material with the same shrinkage rate.

3:Selection of resins with similar chemical properties.

4:Avoid amorphous and crystalline bonded materials.

A chart of bonding compatibility is given below:

chart of bonding compatibility

6:What to consider before starting two shot injection molding?

GO4 mold performs a flow simulation analysis before starting the manufacture of the mould. Identifies all possible defects in the process and eliminates them before the mould is manufactured. Ensures that the structural part of the design is created in the first shot, maximising savings in manufacturing costs.

1:Consider the shrinkage of both materials. In general, the shrinkage depends on the first (or innermost) injection of material.

2:The sub-gates must be able to close the corresponding runners during part of the process.

3:Consider the position of any moulded logo to prevent damage to it during any part of the process.

4:The design may allow oversizing of the component for the first injection. This ensures higher pressure and stronger adhesion during the second injection.

5:Ensure that the parameters of the injection unit provide the required pressure, flow and cooling capacity.

6:Verify that the structural strength of the first injection can withstand the injection pressure of the second injection.

7:Why choose two shot injection moulding?

1) Product function requirements. For example, power switches, mobile phone buttons, keyboard indicators, car switches, etc. Some LED requirements are transparent. For example power switch buttons, LED lights.

2) Improved feel. Some handheld products require the use of rubber in the handheld section for a more comfortable feel. Examples include walkie-talkie housings, power tool handles, spanners, screwdriver handles, toothbrush handles, thermos cups, etc.

3) Adding aesthetic appeal. Products manufactured in the two shot process look great while retaining their desired structural characteristics. In this process, load-bearing structural components can be shaped in the first step. Final touches can be added in the second step using more attractive materials.

4) Some areas of the product need to be plated. In the plastics range, only ABS and polysulfone (PSU) surfaces can be plated.If the product is to be plated partially or on one side, the plated area should be filled with ABS . Areas that do not require plating should be filled with other materials such as PC.

5) Increased efficiency. Two shot injection molding allows multiple components to be formed using a single tool. This reduces the labour required to run the part and eliminates the need to weld or join components after the forming process.

6) Reduced costs

The process does not require more complex tooling and, as the parts are manufactured in one piece, there is no need to weld or join components together. This saves time and minimises labour, resulting in savings in overall manufacturing costs.

8:What is overmoulding?

There are 3 types of overmoulding: insert moulding, two-colour moulding and co-injection moulding. Like secondary moulding, overmoulding is a multiple injection moulding process that uses two or more different thermoplastics to produce a single end product. This process is ideal for engineers who want to build strong, functional, aesthetically pleasing parts that will not separate over time.

On the downside, the tolerances of parts made by overmoulding are usually not as good as those that can be achieved by two shot moulding. It is also important to remember that plastic compatibility requirements can limit the designer.

It's our honor to be their best partner

GO4mold has been dedicated to two shot injection molding for many years and has accumulated many partners. Customer satisfaction is our team's greatest motivation.
  • star star star star star
    The GO4mold team is very professional and the communication is very good. We are very happy with the moulds that their designers have designed for our company. The quality and accuracy of each part produced by their moulds is very consistent.
    Bert J.
  • star star star star star
    For more than a year GO4mold has been our mass production partner for our company's plastic container production needs. They are ready to execute orders immediately and have all the parts technology we need.
    Magee T.
  • star star star star star
    GO4mold has a strong team. They went from development to testing in 15 days, which saved me a lot of time and cost. The moulds they produced met an exact tolerance of +/-0.002 inches and I was very pleased.
    Daniel J.

Are You Looking For More Information Or Would You Like To Get An Accurate Quote?

If you need a professional mould maker partner to provide you with a high quality, cost-effective, timely and risk-free manufacturing service. Go4mold is your first step towards success.

Go4 Mould: two shot injection molding guide

For over 10 years we have been mastering the art and science of two shot injection molding. Go4 mould has the design, engineering and in-house tooling capabilities you need to streamline your project from concept to production. As a financially stable company, we are ready to expand capacity and scale up operations as your company and the demand for 2 shot injection molding grows.

At Go4 mould, we offer you a comprehensive plastic moulding service. You can customise your own moulds.

1:Injection moulding

  • Single Injection Moulding
  • Two shot injection molding
  • Insert moulding
  • Overmoulding
  • Insert moulding

2:Secondary processing

  • Welding (infrared, hot plate, ultrasonic)
  • Riveting and riveting
  • Hot stamping
  • Foam and acoustic pad assemblies
  • Part identification markings
  • Parts matching


3:Mould design and construction

  • Injection moulds
  • Trimming/manufacturing tools
  • Assembly jigs
  • Quality gauges

4:Rapid Prototyping

  • Professional engineers and designers
  • Dedicated prototyping machines
  • Advanced software and technology
  • Prototype moulds made from wood, epoxy resin, aluminium or steel

5:Advanced Testing Laboratory

  • PPAP
  • Material Performance Analysis
  • Mechanical Testing


  • Resource or transfer operations
  • Project Evaluation
  • Value Added/Value Engineering (VA/VE)
  • Supply Chain Management
  • Project Management/APQP


At GO4 mould, we also use a wide range of plastic materials.


· Thermoplastics

· Polyvinyl chloride

· Peeps

· Polystyrene

· Polypropylene

· Nylon

· Polycarbonate

· High density polyethylene / low density polyethylene

· Co-polymer polypropylene

· Acrylic fibres

· Acetal


What are you waiting for? Our technical sales team is on standby to provide you with the information you need to help you make an informed decision.

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