I have made a chair using only flat pieces of wood.

Supplies

CNC machine
4x4ft 3/4 inch plywood
Fusion 360
Cardboard and cardboard cutters

Step 1:

Brainstorming

For any good project you need to brainstorm. I searched for flatpack chair and looked at all the images but the only ones that did catch my attention weren't possible with the materials we had. I had tried modeling multiple chairs but some didn't obey laws of gravity, some were to simple, and others just didn't make me excited about building a chair. I thought of chairs I've sat in before and I remembered a small beach chair that I brought camping. I put the chair in a shallow creek and the water level was above the seat of the chair. This chair was my inspiration. It has 2 arc shaped arm rests and a seat that supports the chair. However, I knew my materials were different so I have to tweak the design.

Step 2: Card Board Design

I decided to start with the cardboard design because I thought why take the time to design in fusion if it didn't work well and receive praise as a cardboard model. I used card board and hot glue but on the actual chair I plan to have the chair connect to itself using slots and hooks. I changed the way the seat looks because the cardboard model, having planks on the arc would be uncomfortable and inefficient. The arc also changed during designing. I think that my cardboard model strayed too far from my inspiration so I made sure to stay true to the beach chair when 3d modeling.

Step 3: Fusion Modeling

This is probably the hardest part of the design process. I started by making the arcs. I made the measurements for the width and the length but for the exact shape of the arc I just messed around with the sketch until I found a shape I liked. After this I added slots where the seat and seat back would connect to the arcs. I would have to change these later based on the placement of the seat and seat back.

The next thing I designed was the seat. I wanted the seat to be the other support for the chair. As you can see in the picture the seat is very long but where you sit is about half the length of the seat. I made the end of the chair 2 legs to reduce the amount of wood used. I also designed the front of the chair to slot into the arcs by making it wider than the arcs and then cutting a slot where the arcs would go. Another thing I did for the seat but also most of the components was filleting the edges. Where it was unnecessary to have an edge I made the edge rounded. This is so people wouldn't hurt themselves on the chair adding to the comfort of the chair. Finally, I made a slot in the seat for the seat back to slot into the seat.

The last component was the seat back. I made a general shape first, filleted the edges, and made an insert for the seat. I added slots for the arcs too. This was difficult because it was hard to find the distance from the end of the arc to where the seat would be. I found about where it was but I struggled to fix the slots of the arcs so I just messed around and tested until it worked. Worst case scenario I have to use a saw.

I connecting all the parts using joints and made them all different components. And to make sure it was ready for the CNC machine I made it into an arrangement.

Step 4: Miniature Model Chair

Before possibly wasting a 48' by 48' of wood I made a smaller, to scale model first.

Step 5: CNC Machine Cutting

I made a sketch from the arranging and make a projection by selecting all the components. To turn into a dxf file I went to the sketches folder and right clicked on my last sketch and saved as a dfx file. Then, I opened carbide create and went to file and open. I selected my chair file. I moved around the components to fit into the cutting area. I used this same process for the full sized chair.

Step 6: Assembly and Testing

Once the chair has finished cutting, it's time to put it together. I started with the seat and the arcs. I put one arc into the slot on the seat and then the other. I made sure it was stable by putting some weight on the seat. Next, I put the seat back on the chair. I lined up the outlets of the seat back with the arcs and the insert on the bottom of the seat back with the seat's slot. To test, I started by pushing down on the seat and the seat back to make sure it can handle at least a little force. Then, I slowly sat on the chair.