Computer Controlled Machining

Design Concept

I wanted to design a Charukasera-style furniture piece where kids( not just kids, you can too) can lie down, lean back, and relax comfortably. Since it is meant for resting, I wanted the furniture to feel warm, safe, and full of affection.

I really like how elephants show love. They gently lean their heads on each other and twist their trunks together in a caring way. That moment feels calm, protective, and soft — exactly the feeling I wanted children to experience while using this furniture.

Form development

The legs of the chair are inspired by the curved shape of an elephant's trunk.
These trunk-like forms extend and connect to the other leg and the footrest, visually representing two elephants standing close with their trunks twisted together.

I believe this connection provides structural support and also conveys a sense of bonding, calmness, and emotional comfort through the design.

Designing the Model in Fusion 360

I created the furniture model in Fusion 360 and worked on making it parametric so it could adapt to different machines and materials. This was the most challenging part of the process.

Before machining on the ShopBot, we produced a test model using cardboard on the Trotec laser cutter, which is why the material thickness should be in parametic. To manage this, I made the material thickness parametric in Fusion. This allows me to change the thickness anytime without disturbing the overall design.

To make the slots on the curved part, I drew an arc between the legs and created a 45 mm curved slot. The slot width was set to material thickness minus 0.1 mm clearance. Using a circular pattern, I made 9 slots along the curve, and added 35 mm slots at the bottom of the legs.

Laser cutting - joinery test

Before cutting the final plywood model on the ShopBot, tested the design using cardboard on the Trotec laser cutter. To check the fit of joints, dimensions, and overall assembly. This helped identify design errors early, saved material, reduced machining time, and prevented costly mistakes on the final plywood.

After measuring the cardboard at multiple points, I calculated an average thickness of 2.94 mm. I used this value to find the scale ratio for reducing the model from 12 mm to 2.94 mm. The calculated scale factor was entered into the Scale tool in Fusion 360, and the thickness parameter was then adjusted to 3 mm.

CAM: V- Curve

We used VCarve software to perform the CAM process and generate the toolpaths for CNC machining.

In VCarve, all vector sketches need to be joined and closed because toolpaths follow the vector boundaries.
For that click on each shapes, and check if it has closed pink dotted boundaries. If not, has to join the vector using "join vector tool"

used to join separate lines, arcs, or curves into one continuous closed shape. Combines broken or separate vector segments and closes gaps between lines.

Fixing the material to the sacrificial layer(bed) is very important before machining. If it is not secured properly, the material can move due to machine vibrations, which affects cutting accuracy and can even break the tool. It may also cause rough edges or the piece lifting during cutting. The sacrificial layer also protects the machine bed when the tool goes slightly deeper than the material.

To fix the material properly, we plan the drill holes in the CAM software itself. This is safer than drilling manually because we may not know where the internal cut pieces are located, and wrong drilling can damage endmill.