Kirigami Honeycombs

Honeycombs can be found in a vast variety of structures, especially as core infill for composite sandwiches used in aerospace structures as well as your everyday kitchen door. For certain applications it is useful to have section-varying honeycombs to perfectly match your profile. Here we introduce a simple and efficient method to produce variable cross-section honeycomb structures from a simple sheet of paper. This is achieved using kirigami, which is a close variation of origami. The main difference is that kirigami also includes cutting of the paper rather than just folding it like in the case of origami. This powerful technique can be used for many purposes, and is not only limited to paper sculptures or pop-up booklets as you will see in this Instructable.

Step 1: Print the Pattern

There are many ways to cut and etch paper. A laser cutter would propably be the fastest and most precise way to do it. I went for the straightforward ruler and cutter, so that everyone can replicate the process as long as a printer is available. First of all print the pattern in attachment. This is the pattern for the cheesegrater honeycomb to be seen at the beginning. I will explain at the end how to create your own honeycomb. You will notice a specific color code:

1. blue = mountains
2. red = valleys
3. black = slits

Step 2: Cut and Etch

Following the provided color code, with a ruler and a cutter (or by hand if you are skilled enough) slit the black lines (slits), and etch the blue ones (mountains). The red lines (valleys) have to be etched on the the other side of the sheet of paper. You will notice that the slits already provide the guidelines you will need to follow, although the pattern has not been printed. I normally avoid printing the pattern on both sides as they always tend to be mismatched.

Step 3: Fold and Glue

At this point you are completely set up to start folding your honeycomb:

1. Fold along the mountains and valleys as in the first picture
2. Once you have folded the paper in one direction you can do the same in the opposite one. You will notice that the structure will fold pretty naturally
3. Glue the matching faces together and repeat until the last row is glued

And there you go with your ready-to-use folded kirigami honeycomb.

Step 4: Custom Cross Sections

To build your own honeycombs with variable cross sections, download the Dynamo or Grasshopper definition attached. All you need to do is define the cross section curves taking care that the end points lie on the same vertical line. The integer slider defines the number of cells in the horizontal direction. Once you've defined the unrolled strip, you will have to mirror and copy the pattern depending on the width of your final honeycomb, print, fold, glue and enjoy!

For those of you interested in the implementation details give a look at this paper.