In a recently published study, researchers from SIT, Japan, developed a cost-effective method of making paper sheets that fold themselves without any human intervention into honeycomb structures with superb structural and mechanical properties. (Image: Hiroki Shigemune from SIT, Japan)

A research team at Shibaura Institute of Technology (SIT), Japan, demonstrated a method to easily manufacture self-folding origami honeycomb structures, which make for great protective packaging materials due to their low weight, high porosity, heat insulation, and mechanical-shock absorption.

The team developed a low-cost process to produce SHSs using only a paper cutter and a standard inkjet printer.

The key to the production process is taking advantage of the physicochemical interactions between the paper and the printed solution. The team first cut out a grid of rectangles on a flat paper sheet and then used the inkjet printer to apply the printing solution in a carefully devised pattern; this resulted in the honeycomb structures folding themselves in minutes.

The team’s focus was on analyzing how various parameters of the cutting and printing patterns affected the structural and mechanical properties of the final product. After they found a set of optimal parameters, they tested two additional ways to improve the mechanical performance.

The first was stacking multiple honeycomb layers on top of each other — this greatly increased the cushioning performance of the final structure with negligible height changes. The second was pre-straining the honeycomb structure — essentially applying a single strong compressive force before the material is used. The latter method eliminates a compressive force peak that occurs the first time a brand new SHSs is compressed, which could damage the protected object.

“Our technique could be used to create tailor-made cushioning materials at farm sites based on the type and harvesting period of fruits and vegetables,” said SIT Associate Professor Hiroki Shigemune. “Alternatively, it could be used to produce evacuation equipment, such as helmets and beds, using SHSs as a core material.”

Another advantage of these structures is that they’re made of paper, which is low cost and takes up less storage space. In addition, SHSs can be considered green technology, as they are made from nontoxic materials and use very little energy.

“Our technology contributes to sustainable development goals because it allows us to protect fragile components and vegetables, which translates to fewer losses,” said Shigemune.

Here is a Tech Briefs interview with Shigemune.

Tech Briefs: What inspired your research?

Shigemune: Various interesting origami structures have been proposed. Our study was designed to simplify and reduce the cost of the production process, and to make the origami structure more widely available in the market.

Tech Briefs: What were the biggest technical challenges you faced?

Shigemune: The construction of the experimental system and selection of materials to induce self-folding took a great deal of time and money.

Tech Briefs: Can you explain in simple terms how the origami method works?

Shigemune: The reaction between the paper and the printing ink helps the origami structure to automatically form.

Tech Briefs: What’s the next step with regards to your research/testing?

Shigemune: The next step is to optimize the structure and impart further property for specific applications.

Tech Briefs: In what other applications could this approach to creating SHSs be used?

Shigemune: The self-folding method can be applied for all origami structures. Effective origami structures differ depending on the application, so we want to create highly functional self-folded origami structures that are suitable for each application.

Tech Briefs: Do you have any advice for engineers aiming to bring their ideas to market?

Shigemune: There are many interesting phenomena in the world that are not fully understood. Using wisdom to deepen understanding and create new value will have a significant impact on society.