Freeform Injection Molding Case Study: PepsiCo Bottle Cap

The challenge

Conventional tools lack design freedom and speed.

Solution

3D-printed tools enable unprecedented speed and design freedom in the desired customer-specific materials.

A classic bottle cap for your beloved Pepsi. The material used for this project is PepsiCo blue HDPE.

Construction

The design of bottle closures is often unique and brand-specific and presents an additional challenge as the inner part of the closure has critical features.

60 minutes

Mold making

Once the design is complete, the digital design (STEP file) is converted into a mold design by turning the part into a cavity in a block of material and then adding the inlet(s) and the first vent.

The two-part first draft enables quick visual quality assurance.

24 minutes

Print tools

The moulds were printed with a resolution of 100 μm to ensure good mould quality and at the same time optimize the setup for fast production.

5 minutes

Freeform Injection Molding (FIM)

The parts were molded on a 7-ton babyplast. However, the molds work hand in hand with each installed basic molding unit.

The cycle time per part was about 5 minutes, and one minute of cooling time was required after each shot.

1 day

Demolding

Nexa3D’s alkaline solution was used to demold these parts in just one day.

This time can be optimized by redesigning the mould, by removing part of the mould before demoulding or by removing the part directly, if possible.

Total time to the injection-molded part:

89 minutes + 1 day demolding

Observations

  • Designing the mold is a simple process, similar to building a mold box around the design, and then it becomes a cavity.
  • The blue HDPE material from PepsiCo filled the molds well. We have also tested other materials such as PEEK and carbon-filled nylon.
  • Optimization of the demoulding process is recommended for further iterations. The more material that can be removed or reused, the faster the process will run.
  • Standard material data for shaping, settings, pressure, temperatures and more.
  • For most team members, early hands-on testing to verify assembly and performance using parts that come out of the mold first is valuable. This includes materials, design, processes and compliance with regulations. If required, the free-form injection molding process enables further iterations on the same day.