Prototyping with Mamilla: Bringing Our Ideas to Life

Welcome back to another article with Mamilla!

In this feature, we will cover our prototyping methods and detail how we have so far iterated our design and continue to do so with the support of RS.

To those new to our articles, we are a group of six master's students from Imperial College London who are working on an educational device designed to empower, encourage, and enable individuals to achieve an optimised breastfeeding latch.

While we aim to share insights into our journey, some details might seem intentionally vague to protect the intellectual property of Mamilla. We appreciate your understanding as we work to bring this vision to life!

Having decided to produce a physical product that ensures mothers are equipped with the knowledge and understanding of the latching process, we now enter the second part of the second diamond of the double-diamond design process: "Deliver". This is an ongoing process involving substantial iterations and tuning of the design to meet both form and functional requirements.

Physical Prototyping

Throughout our process, we have prioritised translating our digital designs into physical prototypes! This has allowed us to iteratively refine our design, explore electronics configurations and troubleshoot potential issues early on. Physical prototypes have been especially valuable during user interviews to allow us to observe “honest behaviour” revealing less obvious insights. The following section details our casing prototyping process to date.

Guided by anthropometric data from neonatal medical papers, we began by modelling the internal cavity which aims to be representative of an infant’s mouth. We then scaled this cavity and added partitions to accommodate electronic components. To insert the electronics, we then divided the casing in half. After printing the first model, however, it was clear that space was too restricted. To address this, we used non-uniform scaling to bring the device from its original oval shape to a much more circular to be more representative of an infant’s head. In addition to providing extra space for the electronics, this increase in size also improved the ergonomics, making the device easier to grip.

Next, we refined methods for installing electronics. Splitting the casing in half caused alignment issues and disrupted the minimalist design. To resolve this, we redesigned it with a larger front section, and a smaller rear lid. We added a front-facing lid for easy removal of the silicone insert, enhancing both aesthetics and functionality.

Core Prototyping Learning:

1. Time Efficiency: With some prints lasting up to 18 hours we learnt to schedule models to be printed overnight and when possible, we lowered the infill percentage to reduce the printing time at the sacrifice of quality when this was not a priority.
2. Impact of Print Orientation: Altering the print orientation significantly changes the supports required when printing. Removing these supports was a mechanical process that led to minor visual defects. We took this into consideration to aim for the majority of defects to occur on hidden surfaces.

Alongside the development of the casing, a similarly iterative approach was adopted to create a detachable silicon insert.

Initial ideation was developed on paper via simple sketches and further explored using CAD modelling.

3D visualisations helped to conceptualise ideas and put into context the product requirements identified earlier, such as needing to account for milk production during use and how this would affect the complexity of the component’s geometry. A key consideration at this stage was deciding the production method. While resin 3D printing could achieve anatomically accurate forms, casting was more suitable due to the need for a cavity to store expressed milk.

We adopted a two-part casting process using a wax mould to create cavities in the silicone insert. Iterations focused on geometry, pour directions, basin positioning, and seam placement for optimal wax extraction and accuracy. While hands-on learning was invaluable, earlier research could have highlighted the benefits of a flexible female mould for easier extraction. Limited machinery made production intricate and time-consuming, with risks due to the single-use wax mould. Despite these challenges, the process improved our understanding of casting design and considerations for scaling.

Prototyping Materials

To select our prototyping materials we began by defining our desired and required parameters.

For the casing, key considerations included:

1. Recyclability - Given that we continuously iterate on the original design, it is essential to sustainably dispose of old or unneeded prints.
2. High Fracture Toughness to Density Ratio - ensures that the casing is able to withstand accidental drops and knocks.
3. Electrical Insulator: With frequent adjustments to electrical components, there is a risk of loose wires. The casing's insulating properties help protect users from potential electrical hazards.
4. Compatible and Affordable to 3D Print - With the intricate details of our casing and the constraints of our budget, 3D printing was chosen as the prototyping method. Therefore, the material needed to be compatible with this process and affordable.

Based on this analysis, we selected Acrylonitrile Butadiene Styrene (ABS) as the most suitable material for prototyping the casing.

Our additional key considerations included:

1. Non-toxic: Since some extensive testing of our device requires direct body contact, the material must be safe for use on the skin.
2. Translucent: This offers reassurance that the insert is entirely clean.
3. Service Temperature (>120°C): this allows the insert prototypes to be sterilised through boiling, a process that is commonly used for infant products.

Based on these criteria, silicone elastomer was selected as our ideal prototyping material. In addition to meeting the above requirements, it is also known for its high quality, wear resistance and moisture sealant properties. Moisture sealant is important to prevent any breast milk that may collect in the insert from reaching the casing.

Electronics Prototyping

The electronics prototyping was also crucial in developing functionalities by allowing mothers to learn the features of an optimal latch. The development process can be divided into two main parts: the development of the sensing and feedback features and the integration of the electronics into the casing.

Features Development

Key Considerations

• The device should be battery-powered, rechargeable via a standard cable, with controlled charging to prevent overcharging.
• A feedback interface on the top of the device should indicate whether or not the device is on and the quality of the latch based on information from the sensors within the product.

To meet the objectives mentioned earlier in the article, different sensing mechanisms were brainstormed and tested using different electronic components to find the best fit.

The process involved wiring multiple circuits and programming, testing the logic using the Arduino console. An iterative approach was then applied, testing each feature by experimenting with various sensors and interactions between components until the desired outcome was achieved. However since this is just a prototype, there is still room for improvement.

During this process, we underwent a steep learning curve as we examined various sensing mechanisms used in different applications and then tried to apply them to develop the features of our product. Programming and understanding different sensing modules while combining them into a single code with all functionalities working in unison was challenging. However, by iterating and initially focusing on individual functions separately, we were able to make this process easier.

Electronics Integration

Due to the constraints of the form and size of our product, several iterations were performed for the integration of the electronics into the final casing.

• The first step was to measure all the components used in our device after testing the final circuit on a breadboard. This was useful in order to think about the positioning of components and allow for iterations of the CAD.
• The next step was sketching out how the electronic components could be housed safely in the main body casing. Several modifications were made to the casing and soldering of wires to have the most efficient assembly.
• Finally, the soldered wires and components were installed into the device and powered by a switch at the bottom of the device.

The electronics integration process required constant communication with team members working on developing the physical form of the product. Even a slight variation in the height of a chosen LED could necessitate changes in the CAD design. Therefore, precise measurements of components, wire lengths were crucial for correctly housing the electronics within the device.

What is Mamilla?

Mamilla offers more than just a product, it’s a mission. With Mamilla, we aim to support mothers in their breastfeeding journeys by addressing one of the most significant challenges they face: achieving an optimal latch. We realised that, while there are many resources for breastfeeding support, there is a lack of practical, hands-on tools that teach mothers how to latch optimally. Mamilla wants to help mothers with a tool that gives them feedback and practical support, things that a support group or an app does not always fully replicate.

We recognise that developing a product like this requires the support and collaboration of many. If you are a mother, healthcare provider or breastfeeding expert, we would love to hear your input in order to refine our product and make sure we offer a real solution. Mamilla is still in its early stages, but with the right support, we believe it can make a real difference in the lives of mothers and their babies.

Please reach out to us at: mamilla.breastfeeding@gmail.com

LinkedIn: https://www.linkedin.com/company/mamilla-breastfeeding