In the world of plastics manufacturing, there has been a definitive line between 3D printed parts and plastic injection molded parts. However, in recent years, that line has blurred as more injection molders not only see the value in 3D printing for prototyping parts or low-volume runs but also to help create efficiencies in their own manufacturing processes. While using 3D printing to improve injection molding outcomes is not always common practice, PCI’s forward-thinking engineers have identified areas where additive molding plays a significant role in enhancing machine functionality.

Before we dive into the details of these innovative practices, I’ll outline the main differences between 3D printing and injection molding.

3D printing is an additive process where parts are created as plastic is often built up layer by layer by a number of different methods. This process can be viewed in real-time, which is often useful during the progression of prototype development and part qualification.

3D printing is used most often for:

• Quick turnaround of hours for a part or days/weeks for a small number of parts
• Low volume production runs (from <100 up to 1000’s of parts)
• Designs which may still be fluid and incur frequent changes or alterations
• Small parts or components that are otherwise difficult to manufacture

Injection molding uses steel or aluminum molds where molten plastic material is flowed into the mold and cooled until the finished part is complete.

Injection molding is best used for:

• Longer turnaround times (5 weeks or more)
• High volume production (1,000+ parts)
• Parts that have already been qualified and tested in the prototyping process
• Any size part
• Any level of complexity

Learn the comprehensive steps in the injection molding process from design to production in our Injection Molding 101 Guide. 

While injection molding is the predominant process run in PCI’s facilities, the team works with prototype molding partners to create components that are capable of being tested, marketed, or used for short term or low-production needs. In addition to this service, PCI’s engineering team has identified a number of areas where the use of in-house 3D printing, specifically, can improve the efficiency of processes and machine functionality for the company.

I had the opportunity to sit down with Engineering Manager, Kurt Behrendt, to discuss how PCI uses innovative 3D printing practices.

Q. When did PCI begin using 3-D printing to support business processes?

A. PCI has had 3D printing capability since 2009. In 2019, PCI expanded these capabilities with the purchase of a MarkForged Mark Two 3D printer.

Q. What are some of the main benefits and capabilities of 3-D printing?

A. -The opportunity to quickly and cost-effectively create proof of concept samples

-The ability to test ideation / design for manufacturing

-The ability to create fixtures, brackets, coupling mechanisms, and even insulator blocks to support various measurement and manufacturing needs

Q. What are some of the main limitations?

A. The MarkForged Mark Two printer suits many of our needs; however, it is limited as a viable solution for additive manufacturing. PCI has established relationships with trusted service providers to satisfy low volume production needs through additive manufacturing.

Q. What are the material capabilities and limitations when using 3-D printing?

A. The MarkForged Mark Two prints in Onyx (Nylon) resin. In addition, it is capable of weaving fibers (carbon, Kevlar, glass) with a variety of meshing techniques into the Onyx material for enhanced functional properties. This enables our engineers to develop creative solutions where strength, wear, or temperature might constrain other 3D printing techniques.

Q. What are some of the specific ways / projects PCI has put 3-D printing into practice?

Since purchasing the Mark Two, 3D printing, with its structural meshing techniques, is now used to build a number of our nests for holding parts for metrology in our CMM and other measurement devices where constraining the part yields increased accuracy and improved GR&R results. 

3D printing is also used for end-of-arm tooling for robotic applications. We can quickly and cost-effectively print custom part holders, insulation blocks, and even couplings.  One recent example is a 3D printed block that provided sufficient insulation from a 300F mold surface to enable our engineers to spec out lower temperature and more robust sensors.  

Q. Are you using 3-D printing at all to create part production efficiencies for customers?

A. Yes, but this is most beneficial when it is done upfront in the DFM process. In the design for manufacturing process, PCI often prints samples with alternate geometry for customers to consider in their applications. These samples lead to production efficiencies (simpler, more robust tooling, cycle time reduction, and/or enhanced quality attributes) for the life of the program. In my experience, iterative and collaborative design often leads to the greatest production efficiencies, well before a production part is even made.

Q. How might 3-D printing be incorporated into your processes further in the future?

A. 3D printing has evolved tremendously over the past five years, and now has the capability of cost-effectively supporting a variety of material and applications through additive manufacturing. PCI is able to satisfy these needs through a solutions provider, but the potential is there to invest in additive manufacturing if substantial need is identified in the marketplace.

A. PCI’s experience is that 3D printing promotes ideation by helping to break the pricing and lead-time constraints of other manufacturing processes. As an example, our team now prints quality fixtures at one-tenth the price of machined aluminum fixtures, and the fixtures are available within one day. If the fixture requires additional engineering, we can simply modify the design and print another one, again, within one day. This speed and flexibility enables our engineers to rapidly iterate concepts without worrying about cost. While this example relates specifically to measurement fixtures, this unbridled concept vetting process helps engineers to solve part design, tooling, and robotic challenges for our customers.

Would you like to learn more about PCI’s use of 3D printing to improve manufacturing processes? Or how this resource can support your need for complex, quality plastic parts? Contact our experienced team of plastics engineers today.