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How do you create custom tooling for injection molding?

Manufacturing injection molded parts often begins with custom tooling. This article explains everything you need to get started, including material selection, design considerations, and tips for reducing the cost and lead time of producing tools.

Injection molding is a highly efficient and widely used manufacturing process for producing large quantities of high-quality, highly accurate plastic parts. The success of the injection molding process, however, heavily depends on the right tooling.

“Tooling” is a term used to describe the molds, dies, and other tools that are used to create final, plastic parts. Often, tooling can be used for various production processes or part types. But sometimes, custom tooling is a better choice – or a requirement – to create parts that are best suited for specific purposes.

What is custom tooling?

In manufacturing, “custom tooling” refers to the creation of specialized tools and equipment that are designed and built specifically for a particular manufacturing process or product. They are typically made from metal, and include custom jigs, fixtures, cutting tools, molds, dies, and gauges.

Custom tooling is often necessary when a particular product or manufacturing process requires an approach or design that cannot be achieved with off-the-shelf tools or equipment. For example, a manufacturer may need to create custom molds to produce a new product with a unique shape or design – or they may need to design a custom fixture to hold a part in place during a machining operation.


Why is custom tooling used for injection molding?

Custom tooling is used for injection molding because it allows for more precise and consistent final parts. By creating custom tooling, designers and engineers can ensure that each part is made to exact specifications, reducing the risk of defects and increasing overall production efficiency. Additionally, custom tooling can help reduce lead times and costs by allowing for faster production and better quality control. 

What are the advantages and disadvantages of using custom tooling for injection molding?

Producing custom tooling for injection molding can optimize manufacturing processes for specific products or applications. 

On the other hand, designing and building custom tooling can involve a significant investment of money and time. It is important, then, for manufacturers to carefully evaluate the advantages and disadvantages of creating custom tooling before starting a project.

Advantages of injection molding with custom tooling include:

  • Precision. Custom tooling allows for precise control over the shape, size, and of the final product, which can lead to a higher level of accuracy and consistency.

  • Cost savings. While creating custom tooling brings with it relatively high startup costs, it can ultimately result in cost savings over time, as molds can be reused for multiple production runs.

  • Flexibility. Custom tooling can be designed to accommodate a wide range of product specifications, enabling manufacturers to produce a diverse array of products.

  • Quality control. Custom tooling can help ensure that final products meet specific quality standards, such as consistent wall thickness, uniformity in color and texture, and dimensional accuracy.

Disadvantages of creating custom tooling for injection molding include:

  • High initial costs. The creation of custom tooling can be expensive, requiring significant investment in design, materials, and production.

  • Time-consuming. It takes time to produce tooling, as it involves design, prototyping, and testing before the final mold is ready for production.

  • Limited flexibility. Custom tooling is specific to the product being produced. This means changes to a product’s final design may require the creation of a new mold.

  • Maintenance. Custom tooling requires regular maintenance to ensure its continued effectiveness, which can add to the overall cost of production.


What materials are used to create custom tooling for injection molding?

Custom tooling is typically made from metal, with the most common materials being aluminum and steel. These materials are chosen for their strength and durability, as well as their ability to withstand high temperatures and pressure. Other materials, such as copper and brass, can also be used in certain situations.

How do you choose a material to create custom tooling for injection molding?

When choosing a material for custom tooling, you should consider several factors, including the desired life of the tool, the volume of production, the material being molded, and the temperature and pressure requirements of the molding process. 

For example, if a high volume of production is expected, a more durable material like steel may be preferred, while if the mold will only be used for a small number of parts, aluminum may be a more cost-effective option.


Design considerations for creating custom tooling with injection molding

Several design considerations should be taken into account when creating custom tooling for injection molding.

  • Part geometry. The mold must be designed to create the desired part shape, with consideration given to any undercuts or other features that may require additional tooling.

  • Ejection system. The mold must include a mechanism for ejecting the part from the mold after it has been formed.

  • Cooling system. The mold must be designed with a cooling system to regulate the temperature of the mold and prevent warping or other defects.

  • Venting system. The mold must include vents to allow any gasses to escape during the molding process.


How to reduce cost and lead time when creating custom tooling for injection molding

You can reduce cost and lead time when creating custom tooling for injection molding by adopting several key strategies.

Design optimization. By ensuring the mold will work effectively at the design stage, engineers can reduce material and machining costs, as well as lead times.

Collaboration. Working closely with the tooling manufacturer via Protolabs Network's injection molding project managers can help identify areas where costs and lead times can be reduced

Material selection. Choosing the right material for the mold can help reduce costs and lead times by minimizing the need for repairs and replacements.

Process optimization. By optimizing the injection molding process, manufacturers can reduce the amount of time required to produce each part, ultimately reducing lead times and costs.

Find out more about injection molding with Protolabs Network and request a free quote. You can also find a breakdown of the costs involved in injection molding, how to design parts for molds, and tips for avoiding common manufacturing defects.

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Frequently asked questions

How long does it take to create custom tooling for injection molding?

Generally, it can take anywhere from several weeks to several months to design and create custom tooling. Along with your quote, Protolabs Network can provide a Gantt chart to help visualize the timeframe of your project.

How much does it cost to create custom tooling for injection molding?

The cost of custom tooling will vary depending on the size and complexity of the mold, the material used, and the manufacturer's rates. Generally, custom tooling can cost several thousand dollars or more. The Protolabs Network team can provide you with a quote within 48 hours.

Can the same custom mold be used for different parts?

In some cases, custom tooling can be used for multiple parts with similar shapes and sizes. Typically, however, molds are designed for a specific part or product.

What are the advantages of creating custom tooling for injection molding?

The advantages of custom tooling include improved product consistency, increased efficiency, and faster turnaround times.

What are the disadvantages of creating custom tooling for injection molding?

The disadvantages of custom tooling include high upfront costs, longer lead times for initial production, and limited flexibility for design changes.

What materials are used to create custom tooling for injection molding?

Custom molds are typically created with steel or aluminum, with additional coatings or treatments for durability and performance.


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