Normally, the main cost driver in injection molding is the cost of the mold, also known as the tooling cost. The cost of designing and building a mold depends on the required production volume, the complexity of the part design, mold material, and the process used to create the mold.

The three scenarios in the table show the methods and the mold types that result in the lowest cost per part depending on the production volume.

In general, all thermoplastic polymers, from the simplest to the most technical, are compatible with the bi-injection process. In the case of flexible materials, the over-molded material is generally SEBS/TPE (Styrene-ethylene-butylene-styrene) or TPU (thermoplastic polyurethane) with different Shore hardnesses and possible textures. Most often, the two assembled components are different but similar and show good chemical compatibility.

For enterprises with the equipment and tools for injection molding, choosing to create molds in-house could be the least expensive option if the technical know-how is also available. If the tools needed for injection molding are not readily available, then outsourcing reduces the cost associated with developing a mold.

Mid-volume production is the most efficient with machined aluminum molds that have a lower cost than traditional steel mold, but are durable enough to last a few thousand shots, depending on factors like the material and the design. In most cases, low-volume injection molding is only reasonable with 3D printed molds—in our example, if we were to use an aluminum mold to produce 100 parts, its cost would account for $30 for each part, while a traditional steel mold would mean $200 for each part.

Material cost is defined by a model’s design, the material chosen, and the amount of material used to execute the injection molding process.

Special-purpose machines are used for injection molding that can range from smaller desktop injection molding machines that businesses can use in-house to large industrial injection molding machines that are mostly operated by service providers, contract manufacturers, and large manufacturers.

While injection molding is traditionally considered a manufacturing process only for mass production due to its high tooling costs, leveraging 3D printing to fabricate injection molds empower you to use this process to produce high-quality and repeatable parts for prototyping and low-volume production.

It is a fast, intensive process where high heat and pressure are involved to inject molten material inside a mold. The molten material depends on the scope of the manufacturing project. The most popular materials are various thermoplastics, such as ABS, PS, PE, PC, PP, or TPU, but metals and ceramics can be injection molded as well. The mold consists of a cavity that accommodates the injected molten material and is designed to closely mirror the final features of a part.

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Applications of bi-injection molding are quite numerous in a variety of industries such as household, cosmetic and electrical products and increasingly in the automotive sector.

The cost of the mold is largely defined by the complexity and the amount of time it takes to produce it. We advise adhering to design for manufacturing principles to drive down part costs with injection molding.

Setup/configuration cost: The setup labor focuses on the time taken to configure the utilized equipment to produce the mold and the finished product.

Repair cost: Repair and maintenance tasks involve the replacement of defective parts and the use of tools to execute the maintenance process.

Online injection molding cost estimators or quotes from injection molding service providers can provide benchmarks and help you estimate the cost of injection molding specific parts.

Our injection workshop is equipped with automated presses and is suitable for this type of process (up to 480 tones). Molds used for bi-injection are also manufactured in our in-house mechanical workshop.

CNC machining: CNC machines are the most commonly used tools for manufacturing aluminum and stainless steel molds with high precision levels. CNC machining removes material by a spinning tool and fixed part. Machining can produce molds where the cavity design is highly complex, but they might require multiple tool changes that can slow down the process, which means that costs increase in line with complexity. CNC machines are industrial tools that require a skilled workforce and a dedicated space, which means that many companies outsource mold production to service providers.

Bi-injection molding, or 2k injection molding, is a plastic injection process allowing the production of a part made of two materials with different characteristics using a single press and a single tool. Examples of its use include parts requiring two colors or two different hardness levels. As a specialist in plastic injection molding, we’ve developed advanced know-how in dual injection molding of plastic materials.

Embrace the use of self-mating parts to reduce the need to create multiple molds when one universal mold can be used to achieve similar results.

Apply a core cavity approach that simplifies the design of Side B of a mold. The core cavity approach involves sinking the wall cavities into the mold base, thereby reducing the need to mold steep draft angles while improving surface finish.

In single-material injection, resin is injected into a cavity and then, after an appropriate cooling time, the two mold halves are opened, and the part is ejected. In biomaterial molding, the two resins are injected into the mold. For this purpose, a space must be created in the mold to accommodate the additional resin. To do this, several bi-injection methods for tooling are available: transfer molds, molds with rotatory plate, molding with a rotating base, molding with core-back process.

Use 3D printed injection molds with both benchtop and industrial machines to efficiently and affordably produce hundreds to thousands of functional prototypes, parts to accelerate product development, reduce costs and lead times, and bring better products to market.

Producing low volumes of parts with injection molding is the most cost-effective with smaller desktop injection molding machines and 3D printed molds. If you are new to injection molding and are looking into testing it with limited investment, using a benchtop manual injection molding machine such as the Holipress or the Galomb Model-B100 could be a good option. Automated small-scale injection molding equipment such as the desktop machine Micromolder or the hydraulic machine Babyplast 10/12 are good alternatives for medium-series production of small parts.

Production volume: The number of items to be produced using injection molding determines the production technology and the quality of material to use when creating the mold. Low volume projects might require 3D printed or lower-grade machined aluminum molds, while large production volumes will require high-grade steel molds or even multiple molds to manage the process without wear and tear affecting the quality of produced items. This affects the cost of the mold, but of course, the increased cost of high volume molds is distributed among more parts, which normally leads to a lower per part cost.

The table below highlights the cost associated with injection molding a hypothetical plastic item, such as a small enclosure of an electronic device, which makes the cost dynamics of injection molding easier to understand:

Evaluate the model’s design to eliminate unnecessary features. This reduces the mold’s size and the material used to develop the model.

Understanding the different types of costs associated with injection molding requires an in-depth analysis of the process.

3D printing: 3D printing is a powerful solution to fabricate injection molds rapidly and at a low cost. It requires very limited equipment, saving CNC time and skilled operators for other high-value tasks in the meantime. Manufacturers can benefit from the speed and flexibility of in-house 3D printing to create molds that can be used on both desktop and industrial molding machines. Furthermore, product development benefits from the ability to iterate on the design and test the end-use material before investing in hard tooling for mass production. Stereolithography (SLA) 3D printing technology is a great choice for injection molding. It is characterized by a smooth surface finish and high precision that the mold will transfer to the final part and that also facilitates demolding. 3D prints produced by stereolithography are chemically bonded such that they are fully dense and isotropic. Desktop SLA printers, like those offered by Formlabs, start below $5,000 and can seamlessly be integrated into any injection molding workflow as they are easy to implement, operate, and maintain.

Whether or not to use bi-material injection depends on various inherent constraints of your project and a preliminary study to validate your selection is generally required. Bi-injection is often used for large-volume production, complex geometries or in cases where over-molding is not suitable. Below we present some of the advantages and disadvantages of this process compared to mono-injection or over-molding:

Tooling costs for injection molding are very high and depend on a number of parameters and design complexity. Molds for injection molding are normally CNC machined out of aluminum or tool steel, EDM machined to shape a workpiece, or 3D printed. The machined or printed part is then finished to achieve the desired standard. The finished mold consists of features such as the surface geometries needed for a part, a runner system to guide the flow of injected materials, and cooling channels to ensure the mold cools down quickly.

In this video, we've partnered with injection molding service provider Multiplus to walk you through the steps of the injection molding process using 3D printed molds.

Other applications are also possible, depending on the type of part and the specifications of your product. Bi-injection molding also allows the production of transparent parts comprising an opaque zone (colored or not) to create colorful graphics and elegant finishes that enhance product functionality and added value. It’s possible to create rigid zones with flexible zones: hinge effect, shock-absorbing zones, push buttons, etc.

Download our white paper for guidelines for using 3D printed molds in the injection molding process to lower costs and lead time and see real-life case studies with Braskem, Holimaker, and Novus Applications.

This solution can be advantageous (in time and cost terms) while also satisfying very precise constraints. Bi-material injection molding involves a certain technicality and requires good mastery of tool design, materials selection and the injection phase itself. For this reason, we can support you upstream of your project to guarantee that it remains feasible and viable.

A molding cost comparison table also serves a similar purpose. Injection molding service providers use cost comparison tables to provide prospective customers with a rough estimate of the process.

* Equipment costs are not calculated into the production costs in this example as the cost of these tools can be distributed among multiple projects. Purchasing a desktop injection molding machine and an SLA 3D printer allows businesses to get started with injection molding for less than $10,000.

Specialist in plastic injection in China for more than 15 years. From the study to  industrialization of parts and sub-assemblies, we can guarantee you secure, easy, qualitative and competitive cooperation.

It is important to note that a majority of the injection molding process is dedicated to cooling. The quicker a mold cools down the faster the injected material solidifies and the faster the production cycle can be repeated. Thus, cooling channels play an important role, especially for high-volume production, and should be included in the design of the mold. For low-volume production with 3D printed molds, manual cooling using compressed air is an option.

This white paper showcases the cost-dynamics for real-life use cases, and presents guidelines for using SLS 3D printing, injection molding, or both.

In general, the process is fairly similar to conventional (single material) injection molding. The materials are brought to their melting point and then fill the mold cavities.

In this guide, we provide an extensive breakdown of the different factors that make up the total injection molding cost.

The equipment associated with injection molding is generally self-regulating and relies on automation to get the job done. CNC machines, EDM machines, and 3D printers rely on the specifications of the CAD design to produce a mold. The injection molding machine also relies on automation to inject materials into the mold, and industrial IM machines often cool and eject the finished item autonomously.

Part design: Complex part designs with intricate geometries require complex molds to execute the project. Mold designs usually have 2 sides: sides A and B. Side A, also known as the cosmetic side, is usually the side seen by the user. Side A is expected to be smooth and aesthetically pleasing. Side B contains the hidden structures that support the usage of the part. Side B structure may include ribs, bosses, etc., and its finish is usually much rougher than that of Side A. Molds with complex Side A and Side B designs are generally more expensive to fabricate compared to simpler molds. Complex designs that feature undercuts might also require sliding side-actions and cores, increasing the cost of the mold.

The cost of purchasing materials for molds differs according to the material chosen. Thermoplastic pellets cost approximately $1 to $5 per kg.

A third application of bi-material injection is to develop sealing functions with molding of joints directly on the part without the need for an assembly step after injection.

A wide variety of plastics can be used for injection molding depending on the requirements of the final parts, including ABS, PS, PE, PC, PP, or TPU.

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Bi-injection uses a press equipped with a second screw and hopper to inject the complementary material at the same time. The definition of the parting line is generally validated during the part analysis phase.

Part size: The larger the item or part to be molded, the larger its mold will be to accommodate the part. Larger parts tend to require more injected materials to complete production cycles. Larger mold designs usually come at an increased cost compared to fabricating the same design but with smaller dimensions.

– Reduced unit cost per part – Elimination of assembly step – Single production phase (reduced lead times) – Complex geometries possible – Improved integrity and durability

Injection molding is one of the leading processes for manufacturing plastics. It is widely used for mass-producing identical parts with tight tolerances. It is a cost-effective and extremely repeatable technology that yields high-quality parts for large series production.

Simple low-volume 3D printed molds can cost as little as $100, while the cost of designing and manufacturing complex molds for high-volume production may hit the $100,000 mark. Despite the considerable fixed start-up costs, the injection molding process has low variable costs due to the inexpensive thermoplastics materials, short cycle times, and the labor needs decrease progressively due to automation and economies of scale. This means that the variable costs of production are low and the process becomes more efficient and the cost per part decreases at higher volumes as the costs get distributed among hundreds or thousands of parts.

When producing in-house, these costs are calculated into the labor costs. When a business outsources injection molding, the labor and the markup of the service provider are added to the service cost.

Monitoring costs: Despite the reliance on automation, equipment operators are expected to monitor the progress of the injection molding process. Operator wages accrued during the process are added to the total cost of injection molding.

Another application of bi-injection is injecting a material with another material to create a soft or grip effect in a functional gripping area (flexible or rigid material) – tactile grip effect on matte red.

We regularly produce all types of bi-material parts according to our customers’ needs. Below are 3 examples of parts we have produced, illustrating the 3 primary applications of bi-material thermoplastic injection:

Before including a bi-injection solution in your specifications, please contact us to determine that it is feasible and cost-effective. Our internal organization allows us to support you in your analysis since we benefit from having a design office and mechanical workshop in house.

In general, injection molding is the most efficient at higher volumes, as the costs then get distributed among thousands of parts. But even though the cost per part for low-volume injection molding is slightly higher, it is still substantially more affordable for low-volume production than other manufacturing methods.

Evaluate the CAD model to determine its feasibility before undertaking an injection molding project. Eliminate potential bottlenecks such as steep angles, undercuts, and other complex geometries.

In this white paper, learn how to combine rapid tooling with traditional manufacturing processes like injection molding, thermoforming, or casting.

Large industrial injection molding machines can cost anywhere from $50,000 to $200,000+. These machines also come with more stringent facility requirements and require skilled labor for operation, maintenance, and monitoring. As a result, unless injection molding is a core competence, most enterprises outsource mass production to service providers and contract manufacturers, in which case the equipment costs are included in the service costs.

Depending on the properties of the part and the project constraints, our team of designers and engineers is responsible for determining the most suitable solution for you from among these different tools.

Simple low-volume 3D printed molds can be produced on an SLA 3D printer for as little as $100. An aluminum mold for a mid-volume production run of approximately 1,000-5,000 units falls within the range of $2,000 to $5,000. For molds with more complex geometries and primed for larger production runs of approximately 10,000+ units, the cost of mold can range from $5,000 to $100,000.

Electrical discharge machining (EDM): The EDM method is generally used to create highly complex mold designs that cannot be easily reproduced using standard machining methods. EDM involves the use of a workpiece and a tool electrode to create the desired mold shape. The tool electrode and workpiece electrode are separated by a dielectric fluid and subjected to voltages that cause recurring current discharges. The discharges are responsible for shaping the workpiece electrode into the final mold. EDM is highly accurate and does not generally require any additional post-processing. Similar to CNC machining, EDM is also an industrial process that many companies outsource to machine shops.

The short answer: plastic injection molds cost anywhere between $100 for a 3D printed low-volume injection mold to $100,000+ for a complex multi-cavity steel mold for high-volume production, which generally represents the most significant fixed start-up cost in injection molding. However, as these costs get distributed among hundreds or thousands of parts, injection molding is an ideal process to mass-produce plastic parts affordably.

A very common application of the bi-injection process is to produce parts made of two similar materials but with different masstinted colours – in this case, creamy white with red.

Part volume and cavities: Part volume refers to the cavity size of a mold. The more cavities or cavity volume a mold requires the longer the press time. Increased press time slows down the production process which leads to increased cost.

– Feasibility study – Part analysis – In-house tooling design and development – Mold flow analysis – Machining of tools – Testing and validation – Series production

Developing more complex molds requires technical expertise. As a result, enterprises often outsource specific aspects of the injection molding process such as the design and fabrication of the mold.