What are the types of injection mold?

Table of Contents

​​There are many classification methods for injection molds. According to different classification bases, injection molds can be divided into different types.

This article will classify injection molds in detail according to different classification bases. I hope to provide some help for you to further understand injection molds.

What is an injection mold?

Plastic injection molding is a manufacturing process used to mass-produce items of various shapes, sizes, and materials. It involves injecting molten material, usually molten plastic material or metal, into expensive precision molds that are specially designed to create the desired product shape.

With injection molding, many copies of the same product can be produced very quickly and efficiently, with precise results every time. In injection molding, precisely machined tools manufactured to tight tolerances are filled with heated material under tremendous pressure and in a rapid injection molding process.

Raw materials are forced into cavities of the part that match their exact shape due to their delicate machining before being formed into a single solidified product.

The purpose of injection molding is to utilize the production methods mentioned above to reduce the costs associated with manufacturing.

According to the type of plastic material, it is divided into a thermoplastic injection mold and a thermosetting injection mold.

Thermoplastic and thermoset injection molds are the two main types of injection molds used in manufacturing today. Thermoplastic injection molds use heat, pressure, or a combination of these factors to soften the plastic material they work with and shape it into the desired part characteristics.

Thermoset injection molds also use heat or pressure, but chemically crosslink to cure the thermoset resin, making it strong and durable. Both types of injection molds have advantages and disadvantages, depending on their intended use.

According to the number of mold cavities, single-cavity injection mold, and multi-cavity injection mold.

Single-cavity injection molds have one cavity and are used in various industries to manufacture products with complex shapes, such as automotive parts.

On the other hand, multi-cavity injection molds optimize production capacity and are therefore more suitable for high-volume production because each part of the mold is divided into multiple cavities, which can speed up the production cycle.

According to the specific size and type of products produced, enterprises can choose single-cavity or multi-cavity injection molds according to their own needs.

For the production of lower-cost products, enterprises can choose single-cavity injection molds with smaller production volumes; conversely, when higher production volumes are required, multi-cavity injection molds are ideal.

According to the mold installation method, it is divided into a mobile injection mold and a fixed injection mold.

According to the way the mold is installed, there are mainly two types of injection molds, mobile and fixed.

The mobile injection mold can be moved in the injection molding machine according to the parts that need to be produced, while the fixed injection mold is always fixed on the injection molding machine to produce parts with a set of cavities.

Both have their pros and cons; due to their increased flexibility, mobile injection molds can accommodate multiple models or batches in a relatively short cycle time, but they require more space and cost less than stationary The injection mold is high.

Stationary injection molds are simpler in design and very reliable, but they may not offer the flexibility of a mobile solution.

According to the type of injection molding machine, it is divided into horizontal injection mold, vertical injection mold, and right angle injection mold.

Depending on the type of injection molding machine, there are several different types of molds available.

These include horizontal injection molds, vertical injection molds, and right-angle injection molds.

Horizontal injection molds are suitable for high-volume production because the platen can accommodate up to three or four sets of cavities, with a variety of tooling configurations.

Vertical injection molds excel at producing parts with complex shapes or tight tolerances.

Right-angle injection molds are suitable for situations where a part needs to have a specific orientation but still needs to manufacture a large number of product pieces.

No matter what your manufacturing process requires, you can be sure to get the best results with the proper type of injection molding machine.

General injection molds are divided into precision injection molds according to the dimensional accuracy of plastic parts.

Ordinary injection molds are industrial tools used to shape plastic parts. Generally, these molds can be classified as precision injection molds; those created to meet predetermined dimensional accuracy.

Quality considerations such as these ensure that parts remain in the correct shape, size, and position relative to each other.

Therefore, these components exhibit good performance and reliability when used in assemblies or products. Precision injection molds also help in reducing production costs due to their efficient manufacturing process and improved product quality.

Therefore, when manufacturing plastic parts, a properly designed precision injection mold is very important to achieve the desired effect.

According to the mold pouring system, it is divided into cold runner mold, thermal insulation runner mold, hot runner mold, and warm runner mold.

Cold runners consist of two sections and utilize the basic chilled water system; they also feature insulated runner crossovers to help improve efficiency by reducing cycle times.

Hot runner molds no longer require a hot system, but instead, use heated nozzle strips inside the core box. Finally, hot runners are similar to hot runners but use more high temperature-resistant materials in their setup.

This method is mainly used for thermoplastics such as ABS, PMMA, and PBT. All four methods have distinct advantages in the injection molding process, enabling users to find the method that best suits their requirements and project scope.

According to the overall structural characteristics of the injection mold, it can be divided into the following plastic injection mold types.

1. Single-parting surface injection mold

When the mold is opened, the movable mold and the fixed mold are separated to take out the plastic part, which is called a single-parting surface mold, also known as a double-plate mold.

It is the simplest and most basic form of injection mold. It can be designed as a single-cavity injection mold or a multi-cavity injection mold according to needs. It is the most widely used injection mold.

Single-part surface injection molding offers a unique method for rapidly producing parts that do not require post-processing.

By using 3D printing technology, complex plastic parts can be produced in just a few minutes using only one side of the mold.

Single-part surface injection molding has been a boon for manufacturing operations because it enables rapid prototyping and low-volume production runs with little to no waste.

This type of manufacturing process can also be used to produce metal objects faster than traditional machining, making it an attractive option for new projects or extensions to existing product lines.

The single-faceted injection is a modern solution that enables high-quality production to be achieved with a minimum of resources and short lead times.

2. Double-parting surface injection molding

The double-parting surface injection mold has two parting surfaces. Compared with the single-parting surface injection mold, the double-parting surface injection mold adds a partially movable middle plate (also called a movable gate plate, There are gates, runners, and other parts and components required for the fixed mold), so it is also called a three-plate mold (moving template, middle plate, fixed template) injection mold.

It is often used in single-cavity or multi-cavity injection molds with point gate feeding. When the mold is opened, the middle plate is separated from the fixed template by a fixed distance on the guide post of the fixed mold, so that it can be taken out between the two templates. Gating system aggregate.

Double-parting surface injection mold has a complex structure, high manufacturing cost, and difficult parts processing, so it is generally not used for molding large or extra-large plastic products.

Two-component injection molding is a powerful tool used in manufacturing to create complex and complex parts by using two molds that open in opposite directions. Two-part molds are often used to manufacture parts with internal features, deep cavities, sharp edges, decorative surfaces, and grooves, ribs, and threads.

The two halves close together quickly and cushion before closing, allowing the plastic to be evenly distributed even in difficult shapes. Double parting has revolutionized product design as it makes products more unique and complex than before.

It also adds longevity to consumer pieces, as parts manufactured using bipartite molding are stronger due to their faster processing times, allowing them to last longer compared to other types of injection molding.

3. Injection mold with side parting and core pulling mechanism

When the plastic part has side holes or undercuts, it needs to be molded with a laterally movable core or slider.

After injection molding, the movable mold first moves downward for a certain distance, and then the inclined section of the bent pin fixed on the fixed template forces the slider to move outward, and at the same time, the push rod of the demoulding mechanism pushes the push plate to make the plastic part self-forming Take off the core.

Injection molds are an important tool in many industries for quickly creating precise, consistent parts. Injection molds with lateral parting and core-pulling mechanisms are particularly advantageous because they can produce multiple independent parts simultaneously while drastically reducing cycle times.

This type of mold is typically used where large volumes of complex products must be created in the shortest possible time, as side parting and core pulling mechanisms allow for more efficient cooling, faster movement between cavities, and uninterrupted continue to produce.

Additionally, this injection molding system offers greater flexibility for more complex patterns than more traditional systems.

In addition to improving efficiency and accuracy in the production process, injection molds with side parting and core pulling mechanisms help reduce waste and improve product quality while increasing productivity.

4. Injection mold with movable molded parts

Due to some special structures of plastic parts, the injection mold is required to be equipped with movable molding parts, such as movable punches, movable dies, movable inserts, movable threaded cores or rings, etc., which can be combined with the plastic parts during demoulding. Move out of the mold together, and then separate from the plastic part.

Injection molding with moving injection molded parts can be a complex, intricate process consisting of complex mechanics. Invented in the 20th century, the injection mold is a tool for the mass production of plastic products, and now injection molds enable more complex molding.

In particular, injection molding with lateral parting and core-pulling mechanisms allows the formation of hollow objects and those with undercuts or openings that require internal movement during the injection.

Once primarily used for simple components such as bottle caps and plugs, these advanced tools are now being used to form components ranging from housings to door locks.

Injection molding with moving molded parts is creating huge advances in manufacturing technology, enabling designers to achieve greater precision and functionality in their products than ever before.

5. Automatic unthreading injection mold

For plastic parts with thread, when automatic molding is required, a rotatable thread core or ring can be set on the mold, and the mold opening action or the rotation mechanism of the injection molding machine, or a special transmission device, can be used to drive the thread The core or threaded ring turns, thereby releasing the part.

Automated off-line injection molds are a very valuable development for manufacturers, providing them with an automated means to perfect their injection molding processes.

Automatic off-line injection molds quickly and accurately remove threads from plastic parts, saving time and effort for production facilities in industries such as automotive, electronics, and medical device manufacturing.

Not only are automated offline molds a more efficient way to break down existing plastic parts, but they also have the added advantage of allowing businesses to monitor their progress on-site without having to wait or hire outside personnel.

Additionally, they are less expensive to maintain than other types of injection molds because they require less setup. Automatic offline tooling technology has revolutionized the industry, making it easier and faster for companies to produce high-quality plastic parts without sacrificing precision or accuracy.

6. No runner injection mold

The non-runner injection mold refers to the method of adiabatically heating the runner to keep the plastic between the nozzle and the cavity plate of the injection molding machine in a molten state so that there is no pouring system condensate when the mold is opened and the plastic part is taken out.

The former is called an adiabatic runner injection mold, and the latter is called a hot runner injection mold.

Runners injection molds are revolutionizing the way plastic parts are produced. Their innovative design eliminates the need for a runner system, greatly simplifying production and reducing material costs.

Because runners molds can maintain a uniform temperature throughout the injection molding cycle, they can produce intricate designs with perfect detail.

Additionally, they offer greater cost savings and energy efficiency because they allow processors to utilize more products and less recycled plastic material, which typically has a shorter lifecycle than runner-formed parts.

This not only maximizes productivity but also ensures faster turnaround times as well as consistent quality.

Runners injection molds are undoubtedly changing the way everyday goods such as toys and kitchenware are produced, and look poised to have an even greater impact on manufacturing across industries across the globe in the coming years.

7. Right angle injection mold

Right-angle injection molds are only suitable for angle injection molding machines. The difference from other injection molds is that the feeding direction of this type of mold is perpendicular to the direction of mold opening and closing during molding.

Its main channel is opened on both sides of the moving and fixed mold parting surfaces, and its cross-sectional area is usually constant, which is different from other injection molding machine molds.

The end of the main channel is designed to prevent the injection molding machine from In case of wear and deformation of the nozzle and the inlet end of the main flow channel, a replaceable flow channel insert can be provided.

Right-angle injection molds are an innovative breakthrough in manufacturing. While injection molds have traditionally been limited to a single straight line of material flow due to gravity, right-angle injection molds allow manufacturers to produce more complex shapes and intricate designs.

Right-angle injection molds allow for faster cooling times, which translates into greater efficiency and a higher quality end product.

Best of all, they produce parts faster and at significant cost savings while utilizing existing equipment, making them an excellent choice for many operations requiring complex shapes and textures.

Right-angle injection molds have revolutionized the way companies manufacture products, proving that innovation always pays off.

8. Injection mold with demoulding mechanism on the fixed mold

In most injection molds, the demoulding device is installed on the side of the moving mold, which is beneficial to the work of the ejector device in the mold opening and closing system of the injection molding machine.

In actual production, because some plastic parts are limited by their shape, it is better to leave the plastic part on the side of the fixed mold for molding.

In order to make the plastic part out of the mold, it is necessary to set the molding on the side of the fixed mold. mechanism.

Injection molding can be difficult to handle, and even harder to manage if the ejection mechanism is not in the correct position.

By placing the ejection mechanism on a fixed mold, the complexity is greatly reduced, the accuracy is improved, and the production time is not affected too much.

Injection molds require powerful machines that need to be tuned to optimize performance, adding an ejection mechanism that can be easily activated from a stationary mold makes it easier for workers to create high-quality products.

In addition, some parts of the injection product may need to be reworked, while the ejection mechanism on the fixed mold allows workers to make modifications efficiently without affecting the quality.

In conclusion, a knockout device on a fixed mold is an important step in creating a more precise and higher-quality final product.


Injection molds are classified according to their intended use, each suitable for a particular use. Knowing the classification of injection molds can help you choose the right type for your needs.

If you’re not sure which type of injection mold is best for your project, our team can help you decide.

We have years of experience in manufacturing injection molded parts and can recommend the perfect solution according to your needs, we are always happy to help our customers!

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