Laura Ngan


Koin Pond

A sand cast coin catch all, inspired by waves

Problem Statement:
Create a “quick-start” project with a simple piece on a single-sided pattern board.

Project Details:
Individual project in a graduate-level sandcasting class (2018)

I initially chose to create a modern vase, with the outer form inspired by a flowing wave, juxtaposed against the still water within. When creating the mold, I came across some manufacturing constraints, and modified my goal to be a coin catch-all with the same visual form.

CAD/CAM: SolidWorks, HSMWorks
ShopBot CNC router

After concepting and modelling the vase in SolidWorks and generating a CAM program in HSMWorks, an initial pass at creating the pattern on the ShopBot made it evident that the modulan block I used--and the vase I envisioned--was too tall. I fastened the modulan to a piece of sacrificial duron using plastic brad nails, and the length of the nail was not long enough to prevent the top of the modulan from vibrating. In addition, the height of the modulan necessitated a longer tool, which added an unavoidable element of vibration from the tool itself.

I went back to the drawing board and decided that my top priority in the design was to maintain the undulating form. Therefore, I redesigned my piece to be significantly shorter: a coin catch-all with walls of even wall thickness that were very similar in shape to those of the original vase.

Straight off the machine bed, the pattern contained very rough tool paths which needed to be sanded off. The tool paths on the interior of the catch-all, however, were visually mesmerizing, and also added texture to the surface which would help the coins stay in place. I chose to keep these tool paths, and if I were to create another round of designs, I would model this swirling path into my CAD. Ultimately, this pattern, with its association to zen gardens and peaceful koi ponds, was the inspiration for the pun in the project name.