[ Design Physiology ]

[jaredreason252]

The skin I produced is composed of 5 layers just like normal skin, but is designed to function better when put under weight. The porous outer layer and supporting inner layers all help to disperse pressure across the whole area of the foot, instead of concentrated pressure on particular points. This product would be ideal for athletes, ballet dancers, or any person who spends extended periods of time on their feet.

[jaredreason252]

I then looked at podiatry and treating pressure which occurs in the sole of the foot. A skin which could function similarly to an orthotic sole. Dispersion of pressure across the whole area of the foot instead of concentrated pressure on certain points.

[jaredreason252]

Structure of human skin consisting of 5 different layers which all serve different function. New cells are produced in the Stratum Basale and pushed upwards to replenish the dead skin cells. The entire Stratum corneum is made up of layers of dead cells.

[jaredreason252]

Initial Research

To start with, I did some research about the skin to understand how it works and how it is structured:

Epidermis The epidermis is the outer layer of skin. The thickness of the epidermis varies in different types of skin. It is the thinnest on the eyelids at .05 mm and the thickest on the palms and soles at 1.5 mm.

The epidermis contains 5 layers. From bottom to top the layers are named:

stratum basale

stratum spinosum

stratum granulosum

stratum licidum

stratum corneum

The bottom layer, the stratum basale, has cells that are shaped like columns. In this layer the cells divide and push already formed cells into higher layers. As the cells move into the higher layers, they flatten and eventually die.

The top layer of the epidermis, the stratum corneum, is made of dead, flat skin cells that shed about every 2 weeks.

[jaredreason252]

Final renders of my ideal fit ring design. I wanted to make it look like a piece of coral with an intricate and colourful appearance. For the Shapeways ring I have chosen Full Colour Sandstone for my material as it has a interesting matte clay texture and means that I'll be able to print in full colour.

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The small fit ring. I took the dimensions from my ideal fit ring and made them into a circle instead of an irregular shape. This meant that the ring became slightly tighter so that it struggled to get past my second knuckle. I printed this in shore-50 hardness which provided a lot more flexibility and the perforations around the ring allowed for the movement necessary to get past my second knuckle. I wanted this ring to look like a clammy and slimy tentacle, again giving a weird sensation as the ring is put on the finger.

[jaredreason252]

The loose fit ring. I defined the dimensions by slightly enlarging the ideal fit profile to make a bigger area inside the ring and then added small teeth right around the inside edge to ensure that the ring wouldn't slip off my finger. My design was inspired a variety of underwater creatures namely the sea urchin and various types of deep sea fish. This ring gives a strange sensation as the fine teeth run along my finger, almost becoming a creature of its own.

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Final dimensions of my perfect fit ring.

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Various sketches for the design of my three rings. I mainly focused on marine organisms such as the sea anemone and the sea urchin to inform my designs.

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After about 10 prints of trial and error with tolerancing I finally had the perfect fit!

[jaredreason252]

I printed many trial models to get a ring which fitted MY finger perfectly down to 0.1mm. I did this because although the plaster cast was relatively accurate, the materiality of the cast was completely different to my actual finger. This was a process of printing off the ring, putting the ring on my finger to see what needed to be changed and then slightly altering the profile on solidworks to progressively reach the perfect fit. Doing this allowed me to know when I had the exact dimensions because I could physically feel when the ring fitted perfectly.

[jaredreason252]

Here I used the blend tool in Illustrator to combine the slice closest to the knuckle and the slice furthest away. This created a variety of profiles which would act as a good starting point to begin tolerancing the ideal fit ring physically.

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I then scanned the four slices and determined the measurements both digitally and with a vernier caliper.

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After casting my finger I cut it into 4 slices each 2mm apart past the second knuckle where the ring will fit. This is so I can collect accurate measurements of my finger to inform my design.

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My final presentation slides. I tried to present the information I had found in a really simple and comprehensive way with nice graphics and photos showing various details, parts and an overlap onto a real leg showing the full arc of movement in a real context. I took care to highlight the exact measurements I took as shown in my orthographic projection.

[jaredreason252]

Views of my final Solidworks model. It consists of 2 major parts 1 with a subassembly of three different parts which I joined together to form the Patella and tibia/fibia bone structure. A small piece of wire slots into the holes of each part which are nicely aligned in the middle to create a hinging motion. I made sure the hinge only flexed for 155 degrees by making the two parts meet to form a nice curved contact point between the two bottom faces.

[jaredreason252]

My functioning UP printer prototype test looking at the simple rotational movement between two parts. This model gave me a great idea of how my final model would move.