Freeform Injection Molding
in packaging

Flip Caps

The part is a classic flip cap in different designs.
The materials used are both recycled polypropylene and food grade polypropylene.

Part Design(s)
Part Design(s)
Different iterations of part design for flip caps.
The flip cap often come in unique designs. The challenging aspect is often around the ‘living hinge’. We preferably work with STEP files as input from our clients.
90 minutes
Mold Design(s)
3D Render of molding tools for flip caps.
Next step is converting the STEP file into a mold design which is done by inverting the part into a cavity, in a block of material, and then adding the inlet gate(s) and initial venting.

The 2-part initial design allows for quick visual Quality Assurance.
60 minutes
Printed Tooling
3D Printed injection mold tool for flip caps.
The first molds were printed in a 100µm resolution. However, 50µm was also tried and as there was no difference in part performance, speed was prioritized over visuals.
5 minutes
Freeform Injection Molding (FIM)
Photo of flip caps being injection molded.
The parts were molded on a 50-ton Krauss Maffei. However, the molds work hand-in-hand with any installed base molding unit.

An aluminum mold frame was used to hold the assembled mold, cycle time per part was around 5 minutes, and 1 minute cooling time after each shot.
1-2 days
Close up photo of the living hinge on a flip cap made with 3d printed tooling.
The Addifab alkaline solution was used for demolding these parts, over a 2 day period.

This can be time-optimized by mold re-design or by removing a part of the mold before demolding.
Total time to 1st injection molded part:
155 minutes + 1-2 days of demolding

- The mold design is an easy process; similar to building a mold box around the design, and then make it a cavity.

- The polypropylene materials filled the molds nicely in the first test rounds and 4 other polypropylene materials were tried successfully as well.

- Optimization of the demolding is recommended when running next iterations. The more material that can be removed or reused, the faster the process will be.

- Datasheet materials were used for molding data, settings, pressure, temperatures, and more.

- Early hands-on testing for i.e. assembly and performance using first-out-of-tool parts is valuable for most team members: materials, design, process, regulatory, and if you need to make another round of iterations, you can do these the same day.


One of the Injection Molding machines at Addifab.
Accelerated development with unseen injection molding tools


Employee at Addifab, assembling the 3D Printer.
An enabling foundation for unseen opportunities

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