📻 Opus Build: Carving the enlosure
Mar 27, 2018
2 minute read

The Plan

The main body of the enclosure consists of 11 equal parts. We’ve been calling these pieces the vertebrae, due to their similar shape. These vertebrae are to be glued together to form the backside of the enclosure.

During the design phase, I’ve made sure the backside’s width is a multiple of 18mm, in order to use a common size of MDF board thickness in its construction.

The fact that we’ll be veneering everything brings an added difficulty to the project: veneering around curved surfaces is tricky. To have good cohesion between the veneer and the backside, we require an equal pressure over the whole surface area. For this we’ve designed an inverse of the vertebrae which can form a pressure mould.

The Preparation

The parts of our sketchup design are exploded into individual objects and exported as SVG. We’ve imported them in Inventable’s Easel web application. This simple GUI allows us to physically place the cut lines on the work area. Sincd the router bit being used has a diameter, we don’t want to cut on the lines, but besides them. After all, the lines indicate the outer edge of our object pieces, not the cutline itself. For a 18 inch bit, the cut lines are shifted 1/16th inch outwards.

The final design in Easel can be found here: http://easel.inventables.com/projects/f2RSPNxVxRgMM206p77NzA

The Carve

I asked around at various locations on price estimates for doing the carving and it quickly costs more than €150 euro, excluding materials.

Luckily, my buddy has a Inventable’s X-Carve CNC router and offered to do the cutting for me.

Using a 18 inch bit, the vertebrae are carved out of a single 80x60cm sheet of 18mm thick MDF. Another similar sheet is used to cut out the vertebrae for the mould.

In the video below you’ll see the X-Carve working away on one of the mould vertebrae. As the MDF is 18mm thick, it uses multiple passes of 1.3mm depth to cut all the way through. The two boards take about 4 hours to be cut.

Small tabs at the bottom are left uncut to ensure the vertebrae won’t jiggle around while being cut. Once finished the board can be flipped and the tabs cut with an x-acto knife. You can see them well in the photos below.

Rough cut - front

Rough cut - back