Designing Folded Cardboard Furniture Using Fusion 360

Cardboard furniture are great as they are easy to make, lightweight, flat foldable, and environmentally responsible. There are lots of designs on the web for many furniture ideas. This will be a brief intro in using CAD to design some folded furniture.

We will be using Fusion 360 for this demo. It is a full-fledged CAD tool with many different workspaces, one of them is a sheet metal workspace which, with some modification can be used for simple cardboard folding structures.

A primer to different types of cardboard

1. Types of corrugated board

2. Cardboard types Adafruit

Motivational Ideas

1. Hex table

2.Corvase Arm Chair

3.Chairigami

4. The Papton chair

Supplies

1. 5 ply / 3ply Cardboard (Shipping cardboard would do nicely)

2. Some way to cut the Cardboard.

3. Some way to measure the Cardboard.

Step 1: Using the Sheet Metal Workspace

Take a look at this introduction to Sheet metal in Fusion 360. Sheet metal workspace is designed to be used with metal. But for cardboard, we have to modify some settings to account for the way cardboard bends. This can be done by editing the Sheet metal rules section.

The Thickness you set based on the cardboard you are using, it goes from 3mm in 3ply to 7mm in 5ply cardboard. Measure your cardboard and give an average value.

The K Factor is how much a material expands when it is bent. When you bend cardboard it dosen't expand at all, it just folds at that place, so we can give the value as zero.

The default bend radius is the material thickness, but for cardboard, we need to bring it to an arbitrarily low value like 0.25 mm.

These values let us approximate the behaviour of bending cardboard. This lets us do simple folded designs using the Flange tool.

Step 2: Making a Portable Laptop Stand

I wanted a way to keep my laptop off the floor/grass/bed and provide an ergonomic height for working. Cardboards are great for this as they are lightweight and flat foldable, easy to travel with.

Things to keep in mind when building with Cardboard.

1. Know that cardboard has a thickness and this will affect the clearance and spacing of holes and features.
2. Know the orientation of the Cardboard, it is strong when bending is perpendicular to the flutes and weak in the other direction.
3. Bending thicker cardboard is difficult and the exact dimension after folding will vary a little bit, make sure to accommodate for the way it bends and provide spacing.
4. Remember that most cardboards have a good/finished side and a not-so-good side, always face the good side to the floor when cutting out the design.

The design started with a sketch of how big I wanted it to be and the relative sizes of all the sides. I'm drawing from the top view first, as it's the least effort and covers the most dimensions in one sketch. I then use the Flange command to make an extruded version to the height I liked.

I used two planes to cut the extruded figure at two angles to give a tapered shape to the profile. One thing to note is that the fusion will not let you create a flange from the side the plane was cut, So I had to omit drawing one side and later used an extrude command to extrude it to the proper length (4th image).

The folded parts were made using the Flange command, where you can also specify the angle and the length of each side, use it to draw the folding locks on the top and the bottom. Two horizontal slits are cut on the other side to lock the flanges in place and complete the loop.

Use the Make flat pattern command to open up the sheet metal profile into a 2D drawing. This is where the magic happens, all the folds we designed will be unfolded into a 2D drawing which you can modify and export as DXF file, to be later used for cutting.

Step 3: Designing a Foldable Stool With Your Imagination + CAD

In the first example, we used the sheet metal workspace for designing our furniture. Now we are going to use something more powerful, the power of friendship, Ahm I mean the power of imagination + some CAD to help get the dimensions.

When designing a folding structure, it's good practice to take some paper and try folding them into your pattern.

Let's get started designing a foldable stool.

This design consists of two parts, which mesh together to form the structure. It starts with determining the dimensions of the stool you want to build, luckily for us, we can leverage the parametric properties of the sketch in fusion 360. That means, we can assign variables to each dimension and also specify relations between them like the width is 0.7* height, etc.

Certain things like where the two parts will join are difficult to determine, so we separate out the different views and draw relations to get the meeting points, like in the second figure.

With all the proportions determined and the dimensions, laid out, we can just extrude the geometry to clean up the lines and do some filleting. Finally, project the face and export the document.

Step 4: Cutting Out the Design and Assembly

This is the time when you get your hands dirty, with measuring cutting, and folding the design. Cardboard has a good side lined with kraft paper and the other side with a recycled liner. Take care to face the good side of the cardboard towards the ground, so that when you fold up the design, it will be on the outside.

Luckily, I'm fortunate to have access to a digital cutting machine like the ZUND at the Super fablab facility in Kochi. I'll be using these to make the design, the process is similar but the machine makes it very easy to do quickly. It has multiple tool heads that can cut and crease the cardboard according to the DXF design.

Step 5: Enjoy Your Furniture

The last step is fundamental, after building the furniture and take a seat and you realize how incredibly lightweight and awesome the strength of folded structures made of cardboard are.

Lastly, I would like to leave you with Paul Jackson's Folding Techniques for Designers It's a great book for design inspiration and learning how the different folding patterns work.

Cheers,

Stay safe