The short answer is: Plastic injection molds range from about $100 for low-volume injection molds printed with a 3D printer to over $100,000 for complex multi-cavity steel molds for mass production, which is generally considered the highest fixed initial cost in the injection molding process. However, as these costs are averaged over hundreds or thousands of pieces, injection molding becomes an extremely suitable process for producing large quantities of plastic parts at a cost-effective price.
In this guide, we have provided a comprehensive breakdown of the various factors that make up the total cost of injection molding.
Introduction: How much does injection molding cost?
Injection molding is one of the leading processes for plastic production. This process is widely used to manufacture large quantities of identical parts with low tolerances. It is a cost-effective technology that can be consistently reproduced at a high rate, providing high-quality parts for large-scale production.
It is a fast and intensive process that involves high heat and pressure to inject molten material into the mold. The molten material will depend on the scope of the production project. The most popular materials are various types of thermoplastics, such as ABS, PS, PE, PC, PP, or TPU, but metals and ceramics can also be injection molded. The mold consists of a cavity that holds the injected molten material and is designed to reflect the final details of the part as closely as possible.
Typically, the main factor driving costs in injection molding is the cost of the mold, also known as tooling cost. The expenses for designing and creating the mold depend on the desired production volume, the complexity of the part design, the material of the mold, and the processes used to create the mold.
Simple molds printed with a 3D printer for low-volume production can cost as little as $100, while the costs of designing and producing complex molds for high-volume production can reach up to $100,000. Although there is a relatively high fixed initial cost, the injection molding process has low variable costs, as it uses inexpensive thermoplastic materials, has short production cycles, and decreasing labor demands due to automation and the benefits of larger production scales. This means that variable costs in production are low, and the process becomes more efficient. Additionally, the cost per piece decreases when produced in higher quantities, as costs are averaged over hundreds or thousands of pieces.
Types of costs in injection molding
Understanding the different types of costs associated with injection molding requires a detailed analysis of the process.
Equipment costs
Specialized machinery is used for injection molding, ranging from small tabletop 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.
Producing parts in low volumes with injection molding is most cost-effective when using small tabletop injection molding machines and molds printed with 3D printers. If you are just starting with injection molding and looking to test with a limited investment, using manual tabletop injection molding machines, such as Holipress or Galomb Model-B100, may be a good option. Small automatic injection molding equipment, such as the Micromolder tabletop machine or the Babyplast 10/12 hydraulic machine, is a good choice for producing small parts at a moderate volume.
Large industrial injection molding machines can range in price from $50,000 to over $200,000. These machines also come with much stricter site requirements and require skilled labor for operation, maintenance, and inspection. Therefore, unless injection molding is a core expertise of the organization, most companies will hire service providers and contract manufacturers for mass production, in which case the equipment costs will be included in the service fees.
Mold costs (tooling costs)
As mentioned in the introduction, mold costs, or tooling costs, are often the primary factor driving injection molding costs.
Molds for injection molding are generally produced using three methods:
CNC Machining: CNC machines are the most widely used tools for producing aluminum and stainless steel molds with high precision. CNC machining removes material using rotating cutting tools and a workpiece that is held stationary. Machining can produce molds with highly complex cavity designs, but the process may require multiple tool changes, which can slow down the process and mean that costs increase with complexity. CNC machines are industrial tools that require skilled labor and specific space, so many companies outsource mold production to external providers.
Electrical Discharge Machining (EDM): The EDM method is generally used to create highly complex mold designs that cannot be easily replicated using standard machining methods. EDM involves using a workpiece and a tool electrode to create the desired mold shape. The tool electrode and the workpiece electrode are separated by a dielectric fluid and are supplied with voltage to create repeated electrical discharges. These electrical discharges are responsible for shaping the workpiece electrode into the final mold. EDM is highly precise and typically does not require additional finishing processes afterward. Like CNC machining, EDM is an industrial process that many companies choose to outsource to external machine shops.
3D printing: 3D printing is a powerful solution for rapidly and cost-effectively producing injection molds. It requires limited equipment, saving CNC machine time and skilled labor 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 with both desktop and industrial injection molding machines. Additionally, product development benefits from the ability to iterate designs and test real-world materials before investing in hard molds for mass production. Stereolithography (SLA) 3D printing technology is an excellent option for injection molding, characterized by smooth surfaces and high precision, which the molds will transfer to the final parts, and it also facilitates easy removal of parts from the molds. 3D printed parts produced with stereolithography technology are chemically bonded, resulting in full density and isotropic properties. Desktop SLA printers, such as those offered by Formlabs, start at under $5,000 and can seamlessly integrate into the injection molding workflow due to their ease of use, operation, and maintenance.
The development of more complex molds requires technical expertise; therefore, organizations often outsource parts of the injection molding process, such as mold design and production.
For organizations that already have equipment and tools for injection molding, choosing to create molds in-house may be the most cost-effective option, provided they have the necessary technical expertise. If the necessary tools for injection molding are not readily available, outsourcing can help reduce the costs associated with mold development.
Simple molds for low-volume production printed with a resin 3D printer (SLA) can be produced for about 100 US dollars. Aluminum molds for medium-volume production of about 1,000-5,000 pieces will cost around 2,000 to 5,000 US dollars. For molds with more complex geometries, prepared for high-volume production of about 10,000 pieces or more, the cost of the molds may range from 5,000 to 100,000 US dollars.
Injected material cost
Various types of plastics can be used for injection molding, depending on the requirements of the final part, including ABS, PS, PE, PC, PP, or TPU.
The cost of purchasing materials for injection molding varies depending on the type of material selected. Thermoplastic pellets cost about 1 to 5 US dollars per kilogram.
Material costs are determined by the design of the model, the type of material chosen, and the amount of material used in the injection molding process.
Labor costs or service fees
Equipment related to injection molding is generally self-controlled systems that rely on automation to operate. CNC machines, EDM machines, and industrial 3D printers rely on specifications from CAD designs to produce molds. Injection molding machines also depend on automation to inject materials into molds, and industrial injection molding machines often automatically cool and eject the finished parts.
Labor costs consist of:
Setup/configuration cost: Labor in the installation phase focuses on the time spent configuring the equipment used to produce molds and finished products.
Repair cost: Repair and maintenance work involves replacing defective parts and using tools to carry out maintenance processes.
Monitoring costs: Although relying on automation, machine operators are still expected to monitor the progress of the injection molding process. The wages of operators incurred during the process will be included in the total injection molding costs.
When produced in-house, these costs are included in labor costs. When a business outsources injection molding, labor costs and the profit margin of the service provider are included in the service fee.
Overview of injection molding costs
The table below highlights the costs associated with the injection molding of a hypothetical plastic part, such as a small cover for electronic equipment, making the dynamics of injection molding costs easier to understand.
|
Low-volume production |
Medium-volume production |
High-volume production |
|
|
Production volume |
100 |
5,000 |
100,000 |
|
Method |
In-house mold manufacturing and in-house injection molding |
Outsource mold manufacturing and injection molding |
Outsource mold manufacturing and injection molding |
|
Mold |
3D printed polymer |
Machined aluminum |
Machined steel |
|
Time until the finished part is obtained |
1-3 days |
3-4 weeks |
4-8 weeks |
|
Required equipment |
3D printer, desktop injection molding machine* |
- |
- |
|
Mold cost |
100 US dollars |
3,000 US dollars |
20,000 US dollars |
|
Material cost |
0.5 US dollars / piece |
0.5 US dollars / piece |
0.5 US dollars / piece |
|
Labor cost or external wages |
$2.50 / piece |
$1.50 / piece |
$1.00 / piece |
|
Total production cost |
$400 |
$13,000 |
$170,000 |
|
Cost per piece |
$4.00 |
$2.60 |
$1.70 |
* In this example, equipment costs are not included in the production cost calculation, as the costs of these tools can be averaged across multiple projects. Purchasing a desktop injection molding machine and an SLA 3D printer allows businesses to start injection molding with a budget of less than $10,000.
The three scenarios in the table illustrate the methods and types of molds that result in the lowest cost per piece, depending on production volume.
Generally, injection molding is most efficient when produced in large quantities, as costs are averaged across thousands of pieces. However, even though the cost per piece for low-volume injection molding is slightly higher, it remains significantly more cost-effective than other manufacturing methods for low-volume production.
Medium-volume production is most efficient when using machined aluminum molds, which are less expensive than traditional steel molds but durable enough to be used for thousands of injection cycles, depending on various factors such as material and design. In most cases, low-volume injection molding is only reasonable when using molds printed with a 3D printer — in our example, if we use aluminum molds to produce 100 pieces, the cost of the mold would be $30 per piece, whereas using traditional steel molds would mean a cost of $200 per piece.
Variables affecting injection mold costs
The tooling costs for injection molding are very high and depend on several parameters including design complexity. Injection molds are typically machined with CNC from aluminum or tool steel, shaped with EDM to create the part's geometry, or printed with a 3D printer. The machined or printed parts are then finished to the required standards. Completed molds will include various features such as the necessary surface shapes for the parts, runner systems to control the flow direction of the injected material, and cooling channels to ensure the mold cools quickly.
An important thing to note is that the injection molding process is largely used for cooling. The faster the mold cools, the quicker the injected material solidifies, and the production cycle can be repeated more quickly. Therefore, cooling channels play a crucial role, especially for high-volume production, and should be incorporated into the mold design. For low-volume production using 3D printed molds, manual cooling using compressed air is also an option.
Injection mold cores printed with 3D printers, which are assembled with the metal mold shell.
Other variables that affect the injection molding process and are directly related to the cost of injection molds include:
Part size: The larger the part or component to be molded, the larger the mold must be to accommodate that part. Larger parts typically require more injection material to complete the production process. The design of large molds often has higher costs compared to producing the same design but at a smaller size.
Part design: Complex part designs with intricate geometries require complex molds to execute the project. Mold design generally has two sides: Side A and Side B. Side A, also known as the cosmetic side, is typically the side visible to the user. Side A is expected to have a smooth surface and be aesthetically pleasing. Side B consists of hidden structures that support the functionality of the part. The structures on Side B may include ribs, bosses, etc., and the surface of this side is often rougher than Side A. Molds with complex designs on both Side A and Side B generally have higher production costs than simpler molds. Complex designs with undercuts may require additional sliding side-actions and cores, which increase mold costs.
Production volume: The number of parts to be produced through injection molding determines the manufacturing technology and the quality of the materials used to create the mold. Low-volume projects may require molds printed with 3D printers or lower-grade machined aluminum molds, while high-volume production will require high-grade steel molds or even multiple molds to manage the process without wear affecting the quality of the produced parts. This impacts the cost of the molds, but of course, the increased mold costs for high volumes will be spread over a larger number of parts, which typically reduces the cost per part.
Part volume and cavities: Part volume refers to the size of the cavity in the mold. The more cavities the mold needs to have or the larger the cavity volume, the longer the press time will be. Increased press time will slow down the production process, leading to higher costs.
Injection molding cost calculator
Online injection molding cost estimation tools or quotes from injection molding service providers can provide standard reference values and help you estimate costs for specific parts.
Options for injection molding cost estimation tools to assist in the calculation process include:
CustomPart
ICOMold
3D Hubs
Protolabs
Cost comparison tables for injection molding serve a similar purpose. Injection molding service providers use cost comparison tables to give interested customers a rough estimate of the process.
Reducing injection molding costs
The cost of molds is primarily determined by complexity and the time taken to produce them. We recommend adhering to design for manufacturing principles to reduce the cost of injection molded parts.
The cost of producing molds can be reduced by using the following design approaches:
Evaluate the CAD model to assess feasibility before starting the injection molding project, eliminating potential bottlenecks such as overly steep angles, undercuts, and other complex geometries.
Evaluate the design of the model to eliminate unnecessary features, which will help reduce the size of the mold and the amount of material used in developing the model.
Use a core cavity approach that simplifies the design of the B side of the mold. The core cavity approach involves making the cavity walls sink deep into the mold base, which reduces the need for steep draft angles while improving surface quality.
Accept the use of self-mating parts to reduce the need for creating multiple sets of molds when a single universal mold can achieve similar results.
Getting started with rapid injection molding
Although traditional injection molding is viewed as a manufacturing process suitable only for mass production due to high tooling costs, using 3D printing to produce injection molds allows you to utilize this process for producing high-quality, repeatable parts for prototyping and low-volume production.
Use injection molds printed with 3D printers in both desktop and industrial machines to produce functional prototypes and parts in quantities ranging from hundreds to thousands efficiently and cost-effectively. This helps accelerate product development, reduce costs and lead times, and bring better products to market.
