NU RING DESIGN

A JOURNEY THROUGH DESIGN & MANUFACTURING

— ROLE

(DfM Intern Summer '23)

@ Jewelex India Pvt. Ltd

— DATE

June '23 – August '23

The Gist:

Creating the NU Ring meant paying homage to Northwestern University. Embodying the experiences of students and the essence of the institution.

I was fortunate to see this idea through, from initial ideation to fabricating a final wearable product.

Relevant Skills:

- 3D Design

- Prototyping

- Manufacturing – Lost Wax Casting, 3D printing

- Surface Finishing & Metalworking

IDEATION

I wanted to create this ring as an homage to Northwestern University, to symbolize experiences and the legacy of the institution. I wanted the nature of this design to be elegant, versatile and defined.

Challenge

- Adapting the 2D facade on the Northwestern logo into a 3D form without compromising on the recognition factor and visual brand language.

- Creating a solution that could be manufactured at scale for the graduating class.

Constraints

- The line-of-sight limitations of CNC Milling made me reconsider the nature of my design.

- The shrinkage, porosity and short filling possibilities resulting from lost wax casting were also a challenge.

I put my thoughts down on some paper and was drawn to the idea of adding some sharp chamfers to accentuate the design.

The NU Ring was ready to be designed.

Engineering drawings of the NU Ring with initial dimensions

Casting Shrink

Dimensioning the ring meant making sure to account for the 2.5% shrink that the part would undergo.

This meant that both the inner and outer diameter would shrink by roughly 2.5% as per empirical testing. Which meant I had to oversize the ring.

To meet the desired inner diameter of 18.4mm, I had to oversize the diameters by 0.47mm.

Casting Deformation

The fact that the ring did not have a uniform cross section throughout meant that the first prototype shrunk into an oval shape. To account for this, I added thin wax supports.

Here's my rationale…

Balancing the 2D facade of the ring with the 3D shape during modelling required changing the dimensions on a curve to make it a correctly proportioned flat ‘N’ on viewing.

Accounting for Shrinkage and porosity

- Through cuts are dangerous

- Uncertainties in CNC are smaller

ATTEMPT 1

CNC MILL

I attempted CNC Milling to take advantage of the dimensional accuracy and attempt to optimize the sharpness of the chamfers all around the ring.

Tradeoffs I had to account for were the minimum radius of the tool, which would alter the nature of the design, as well as the thickness of the print.

VERDICT: NOT IDEAL. RETHINK AND REPEAT!

ATTEMPT 2

LOST WAX CASTING

Unsatisfied with the CNC part, I decided to try again.

Lost wax casting seemed to be a natural choice for this operation. But it came with its caveats that I had to design for. I had to account for a shrinkage factor for 925 Silver, in my dimensioning and tolerancing.

Other factors I had to account for were surface finishing the DLP 3D print to avoid the layers being visible in the casted result. I also had to account for shrinkage and porosity in the final part. Which meant asking the casting professionals about ideal burnout temperatures and cycle lengths.