Seeing is Believing: Showcasing a Year's Growth in Seconds

?Authored By- Parth Dhomkar, Product Design and Innovation Lead, Aretto

The Expanding Last

Three sizes - one shoe!

This is the simplest possible culmination of what Aretto is all about.

Aretto shoes grow with the child’s feet, offering a flexible, adaptable, and sustainable footwear solution for growing children. But, feet grow organically and this growth is millimetric, making it hard to observe in a single moment. One would need to wear the shoes for a few months to see the gradual growth of the Aretto shoes in action!?

So basically, the dilemma was, we had designed the world’s first truly growing shoes, BUT, people couldn’t believe us!

So, we felt the need to bridge imagination and reality, to find a way to showcase our patented Supergrooves technology, and the Aretto design team quickly sprung into action to make this happen, finding a creative way to display their proof of concept. The result? We found a way to show up to 3 sizes of growth (which would typically take a year or so), in a matter of 3 seconds!??

Introducing: The Last.

Traditionally, shoes are manufactured over a shaping mould called a ‘last’, which stays inside the shoe during most of the manufacturing process. We thought - “why not use the last to illustrate how Aretto shoes work?”?

We decided to put our Aretto proprietary last inside the shoe to trigger the expansion. Since growth of 3 shoe sizes is mostly concentrated in the front and back, i.e the toes and heel, our last had to grow in the front and back as well to accurately depict the growth of the foot.?

Once the idea for an expanding last took root in our minds, it was time to get to work! Since we like being organized, here at the Aretto office, the rollout for the mechanical last was a structured process that included -?

1. Define - Various linear motion mechanisms were studied extensively by our team. Feasibility was our top priority, as everything was dependent on time, cost, and resource efficiency.?

2. Ideate - We decided to utilize the crankshaft mechanism which turns a circular motion into a linear motion. A central vertical crankshaft was ideated, the purpose of which would be to simultaneously push out the toe and the heel to mimic natural growth. The same crankshaft would pull in the toes and the heel to return to its original state when it completed 360 degrees of rotation. Rough sketches were compiled and we started working on the Computer Aided Design (CAD) within 7 days of getting the initial brief.?

3. Build & Prototype - The next step was to test the mechanism. Using the CAD model we created a hand-operated version of this ‘expanding last’. The last was broken down into individual elements, and these elements were 3D printed through our in-house 3D printer in batches. It took us about 48 hours to get the first batch printed and we moved on to the final steps.

4. Analyze - We assembled the last and manually turned the crankshaft. Much to everyone’s delight - it worked as expected! Now it was time to put it in the shoe and try again.?

At this point, we heard a cracking sound from inside the shoe, halfway through the growth process and knew that the pressure exerted on the plastic last by the shoe had caused something inside to break. This little setback turned out to be an important learning for us - we realised that we needed to strengthen the joints of the last for it to be able to sustain the pressure exerted on it by the shoe. Back to the drawing board!

Equipped with the proof-of-concept for our proof-of-concept - we decided to make some adjustments to the last. It became clear that to resist the pressure and yet push the toe and heel out, the last needed a higher torque along with strengthed moving parts and joineries. We shortlisted a high torque low RPM motor from a hobby shop and designed a housing around it with its battery. This housing sat above the last right where the ankle of a foot would be. When switched on, the motor kept cycling the crankshaft for expansion and contraction of our shoe.

And there we had it - the perfect mechanical last to show a year’s growth in a few seconds! Euphoria!

We printed half a dozen expanding lasts to display our technology. This expanding last, coupled with our growing Aretto shoe helped us successfully demonstrate our concept at our pop-up stores and stalls. But, it also turned out to be a useful tool to pitch Aretto as well (so we got some brownie points from our founders! ??)!?

Conceptualizing and developing the mechanical last instilled a lot of confidence in our problem-solving abilities as well as rejuvenated our ‘maker’ spirits!

The best part of this experience was that it was executed entirely in-house, facilitated solely by our capabilities and creativity. It gave us ‘nerdy’ designers the golden opportunity to jump with joy and celebrate our efforts - the non-designer colleagues were quite startled by this rare sight - but we soldiered on and were thrilled to bask in the glory of a simple, necessary, and innovative accomplishment!?