Among today’s manufacturers, both 3D printing and injection molding are viable options for producing complex plastic parts and components. While these two techniques were originally considered competing technologies — and in some instances still are — for the most part, both have been recognized for having their own unique advantages, and can even be used together to help optimize production efficiency.
For OEMs wondering whether plastic injection molding or 3D printing is the right process for their next project, we’ll explain when to use each technique and how they can be used in conjunction to support one another.
When to Use Each Process
3D printing and injection molding are both helpful processes in their own right. 3D printing has given engineers the power to create plastic designs at their desks and bring them to life in a matter of hours. Injection molding, on the other hand, can quickly and reliably produce high-volume runs of complex plastic designs, with enhanced durability.
3D Printing is Best-Suited For:
- Quick turnaround times (1-2 weeks)
- Low volume production runs (100 parts or fewer)
- Designs with frequent changes
- Relatively small plastic parts or components
Injection Molding is Best-Suited For:
- Longer turnaround times (5-7 weeks for simple parts)
- High volume production runs (1,000+ parts per run)
- Final part design (no more prototyping)
- Parts of any size or complexity
Though 3D printing has recently been grabbing more headlines, as it’s used in innovative and experimental scenarios, the majority of today’s plastic products are manufactured via the injection molding process.
Tooling design is one of the most expensive and time-consuming parts of the injection molding process, and today, some molders have started using 3D printed molds in the prototype phase to help reduce development time and lower tooling costs. Not all prototype molds need to be fabricated with metal, and there are now certain instances where they can be 3D printed. Stereolithography (SLA) 3D printing, for example, can be a cost-effective alternative, as SLA parts are fully solid and isotropic, and can withstand the pressure of low-volume molding.
For larger volume production runs and more precise molds, however, traditional tooling remains the best option. Likewise, if a part requires the use of thermoplastics, metal tools are the best option to handle those resins with melting temperatures of 500°F or higher.
Custom Part Design
If there’s one area where 3D printing really excels, it’s in its ability to create custom plastic part designs and prototypes in a matter of hours or days. In the medical industry especially, 3D printing technology has exploded in popularity, and is now being used to create custom items like prosthetics, dental products, orthopedics, exoskeletons, bones, implants, artificial heart valves, and more, with researchers even working on 3D organ printing technologies.
3D printing’s quick turnaround time and the ability for OEMs using the process to quickly make design changes allows medical providers to create custom designs for their patients, saving critical time in the process. However, there’s still a large demand for injection molding in the medical industry, as it’s the best process for producing large quantities of plastic medical device and equipment components.
By combining both processes, injection molders can use 3D printing technology to build a cost-effective prototype mold and use it for testing before creating a final metal tool. Using these two techniques in conjunction can ultimately help shorten pre-production iteration cycles and allows for better testing moving forward. Rather than treating the two as competing processes, it’s important to look at the advantages and disadvantages of each, and see how they can be used to their fullest potential.
Want to learn more about how you can optimize the tooling process? Download our whitepaper, Tooling Design for Injection Molding.