Custom Plastic Injection Molding

3D print molds for prototyping in the final material

PolyJet 3D Printing has made it feasible to quickly create custom injection molds that produce low volumes of parts in the final production plastic.

This is especially useful for prototypes, which can now be created onsite in just hours, from mold design to final test product, using the normal plastic injection molding process and production materials for accurate functional testing.

Custom Injection Molding With 3D Printed Tooling

Digital rendering of injection mold in Objet Studio software

Prototypes are most useful when they’re made of the same plastic as the final production part. And during product development, quick feedback is essential. But it’s hard to justify the cost to create injection molded prototypes when they require the same expensive, time-consuming tooling as production parts — even though you only need a small quantity of parts for testing.

3D printing your prototype molds in-house with PolyJet technology offers a fast, affordable way to produce injection molded prototypes. Designers and engineers can test their work more frequently and more accurately, and go to production with confidence. Product managers can shrink time to market and products can turn out better.

PolyJet Injection Molds

Core side of a PolyJet 3D printed injection mold

PolyJet technology creates smooth, detailed, accurate molds. Digital ABS 3D printing material is strong enough to hold up to short injection molding runs of about 10 to 100 parts. You can install the 3D printed mold directly onto your injection molding machine. If testing reveals that you need to make a design improvement, you can alter the mold in directly in CAD and 3D print the next iteration. Depending on size, the new mold can be printed and ready to inject in just a few hours.

PolyJet 3D printed molds are not production tools. But during the design and testing phase, they offer a clear advantage over conventional injection molding. Product designers and manufacturers can use these molds to perform thorough functional testing without worrying about cost-prohibitive tooling. Flaws based on the final production process, geometry or choice of plastic can be discovered early, when they are easiest to fix. This can reduce costly, time-consuming mold corrections, increase product innovation and speed product development.

When to Use PolyJet Tooling

Complex injection molded plastic prototype component

PolyJet 3D Printing is a good method for creating prototype injection molds when:

  • Complex geometry would make traditional tooling difficult
  • Low quantities are needed
  • Design changes are likely
  • Rapid prototyping from the final production plastic is important

Injection Molding Prototyping With PolyJet

This is an overview of the process to create a 3D printed injection mold. For detailed steps, material information and cost comparisons with traditional methods, see the white paper “Precision Prototyping: The role of 3D printed molds in the injection molding industry.”

1. Design the mold

Designing a 3D printed injection mold is much the same as designing the final mold. A few considerations, such as increasing draft angles and gate size, and using sprue or edge gates rather than tunnel or point gates, will increase part quality and mold life.

2. Print the mold

PolyJet 3D Printing offers a glossy mode, which you should use to achieve the smoothest possible tooling. Print your mold so that layer lines are oriented in the same direction in which polymer will eventually flow into the mold.

3. Optional finishing

Many molds require no post-processing and are ready to use right away. Refer to this white paper for best practices on when and how to post-process your mold.

4. Mount the mold

5. Produce your prototype

When working with a 3D printed injection mold, manufacturing time is slightly longer per part than with conventional tooling. This white paper offers guidelines for a successful process.

White Paper: 3D Printed Injection Molds

This 3D printed mold created prototype threaded caps

Get up to speed on creating fast, affordable prototype injection molds. Find guidance on design, expected part quantities, material selection and process considerations.

Read the white paper