NumBlox: Open Source Numberpress

PROJECT IDEA

During our studies, we had the opportunity to meet with Kokono, a company dedicated to the design and local production of cradles for babies in Africa. During this meeting, we explored an innovative and promising idea for a new project: creating a multifunctional toy. This toy, initially designed as an accessory to be added to the cradle, can later transform into an educational abacus. Our goal is to combine Kokono’s cradles with an educational tool that stimulates children’s cognitive development, providing significant added value both in terms of play and education.

COMPRESSION MOLDING

Compression molding is a manufacturing process used to create plastic components by applying heat and pressure. This method involves the use of a press and a mold, which consists of two halves: an upper part and a lower part. Here’s how it works in detail:

Material Preparation: The raw plastic, often in the form of powder or pellets, is weighed and measured to ensure the correct amount of material.

1. Placement in the Mold: The measured plastic material is placed into the heated mold. The mold is designed with the specific shape of the final product.
2. Mold Closing: The press closes the two halves of the mold, applying pressure. The combined heat and pressure cause the plastic to melt and completely fill the mold cavity.
3. Cooling and Solidification: Once the plastic has filled the mold, it is kept under pressure for a certain period, allowing the material to cool and solidify.
4. Mold Opening and Part Removal: After cooling, the press opens, and the molded part is removed. The mold can be cooled with water or air to speed up this process.

In our research journey to develop an innovative project with Kokono, we explored various forms and ideas for toys that could transform into an educational game once the cradle was no longer needed. After evaluating several options, we decided on a design that allows the toy to be stacked in a manner similar to an abacus. This approach provides children with an educational tool to learn counting, combining the initial function as a cradle accessory with an interactive and fun learning experience.

TOOLS/MATERIALS YOU NEED

• Steeltube with an external diameter of 90mm, 2mm thickness, and 100mm height
• Steelpress with interchangeable inserts
• Shredded plastic flakes (recycled plastic material, polypropylene)
• Heat-resistant gloves
• Camping Stove or Other Heat Sources
• M8 steel screw for extracting the printed object

LOW COST MOLDING

Or if you want to make it low cost: 3D printer and papermold

COMPONENTS

• MOLD 1
• MOLD 2
• TUBE
• NUMBERED INSERT

Processings for the realization

• Mold 1 and Mold 2 were made of steel using metal 3D printing, but they can also be produced through CNC machining processes such as milling and turning

• The tube was purchased to size, but it can also be manufactured through turning.

• The numbered inserts were made using metal 3D printing, but they can also be manufactured through milling.

We began by researching existing designs, materials and processes for compression molds related to different materials: salt dought, papermold and plastic flakes. In this way, best practices were identified. For the final pressing with plastic it was interesting to choose the right plastic. In plastics processing, there are two main groups of materials that are used for the die casting process: Thermoplastics and Duroplastics. We choosed the Thermoplastic Polypropylene.

Thermoplastics:

Become soft and flexible when heated.

Hardens on cooling but retains the ability to be formed.

Can be heated and cooled several times without permanently changing their shape.

Duroplastics:

Undergo irreversible chemical changes during polymerization when exposed to heat.

After molding, they retain their shape permanently and cannot be reshaped.

The requirements for the compression mold were clarified during the research and testing. This included the desired shapes, sizes, tolerances and the planned application of the molded plastic parts.

The research phase was characterized by practical tests as well as sketches and concept drafts for the press. 

Phases:

Phase 1: Position a camping stove as the heat source

Phase 2: Place spacers in the pot (nuts to separate the mold from the pot)

Phase 3: Insert part of the mold into the pot (optionally use a mold release agent)

Phase 4: Add 85g of plastic flakes into the mold

Phase 5: Turn on the stove to melt the plastic

Phase 6: Once the plastic has melted, place the upper counter-mold into the mold

Phase 7: Using a metal piece, apply pressure to the upper counter-mold

Phase 8: Remove the mold from the heat source and allow it to cool

Phase 9: Remove the molded piece from the mold

Phase 10: Remove any surface imperfections with sandpaper

Phase 11: Repeat the previous phases, changing the numbered insert to obtain other numbers

WHAT IS NUMBLOX?

Numblox is an affordable game made from recycled plastic, designed to be integrated with the Kokono cradle. As the child grows, this game transforms into an abacus, helping them learn to count.

TEST 1



In the first test, we created various types of molds using 3D printing. This step was useful for identifying the best solution for the final mold production. We evaluated the pros and cons of each mold and, through the "paper mold" technique, gained a clearer idea of how the shapes would turn out.

TEST 2

In the second test, we focused on plastic, studying its melting temperatures and shrinkage. We also observed how the plastic interacted with steel, checking whether it adhered or detached easily.

3D FILES for creating compression mold parts with 3D printing, milling or turning

The tube component can be purchased or made by turning

3D FILES for the creation of numbered inserts with 3D printing and milling