Origami-Inspired, Self-locking Structures With 3D Printing

Researchers recently shared details on creating foldable, self-locking structures by using multi-material 3D printing. These origami-inspired designs can transition between flat and three-dimensional forms, locking into place without needing external support or fasteners.

The 3D structure of origami-inspired designs comes from mountain and valley fold lines in a flat material. Origami designs classically assume a material of zero thickness. Paper is fine, but as the material gets thicker things get less cooperative. This technique helps avoid such problems.

An example of a load-bearing thick-film structure.

The research focuses on creating so-called “thick-panel origami” that wraps rigid panels in a softer, flexible material like TPU. This creates a soft hinge point between panels that has some compliance and elasticity, shifting the mechanics of the folds away from the panels themselves. These hinge areas can also be biased in different ways, depending on how they are made. For example, putting the material further to one side or the other will mechanically bias that hinge to fold into either a mountain, or a valley.

Thick-panel origami made in this way paves the way towards self-locking structures. The research paper describes several different load-bearing designs made by folding sheets and adding small rigid pieces (which are themselves 3D printed) to act as latches or stoppers. There are plenty of examples, so give them a peek and see if you get any ideas.

We recently saw a breakdown of what does (and doesn’t) stick to what when it comes to 3D printing, which seems worth keeping in mind if one wishes to do some of their own thick-panel experiments. Being able to produce a multi-material object as a single piece highlights the potential for 3D printing to create complex and functional structures that don’t need separate assembly. Especially since printing a flat structure that can transform into a 3D shape is significantly more efficient than printing the finished 3D shape.

Saving The Planet With Carefully Cut Paper

You may not think much of origami or its cousin-with-cutouts kirigami, but the latter could (and already is) helping to save the planet. But let’s back up a bit.

Most readers will be familiar with origami, the Japanese art of folding paper. But there is also kirigami, which uses a series of cuts to produce 3D shapes from 2D stock. Turns out that if you cut paper just right, you can turn it into highly-recyclable packaging that even interlocks with itself, negating the need for folding or even tape.

The video after the break takes a look at 3M’s Scotch Cushion Lockā„¢ protective wrap through the eyes of its inventor, Tom Corrigan. It all started when 3M wanted to create a self-assembling box from a flat piece of cardboard.

So far, that particular invention hasn’t come to fruition, but after many long nights with paper and X-Acto knives, Tom came up with a honeycomb design with strong vertical walls that absorb energy much like bubble wrap or packing peanuts. The toothiness of each honeycomb wall adds height which adds strength, and allows the packaging to interlock with itself.

Not only is this packaging easier to recycle, it takes up way less space than other packaging alternatives. Once expanded, a 1,000 square foot roll of this stuff is equal to 2,500 square feet of bubble wrap, which constitutes about a dozen rolls.

Now, what to do about all that expanded polystyrene packaging still out there? With the right tool, you can turn it into insulation.

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Ply Your Craft With Tubular Origami

Researchers at the University of Pennsylvania have just published a paper on creating modular tubular origami machines which they call “Kinegami”, a portmanteau of “kinematic” and “origami”.

Diagrams of "kinegami" folds for various modules and joint mechanism

The idea behind their work is to create individual modules and joint mechanisms that can then be chained together to create a larger “serial” robot. Some example joints they propose are “prismatic” joints, allowing for linear motion, and “revolute” joints, which allow for rotational motion. One of the more exciting aspects of this process is that the joint mechanisms are origami-like structures which can be constructed from a single piece of flat material which is folded and glued together to make the module. Of particular interest is that the crease pattern for the origami-like folds can be laser cut into a material, cardboard or thin acrylic for example, which can be used as a guide to create the resulting structure. The crease patterns for the supporting structures, such as tubes or joints, can be taken from pre-formatted patterns or customized, so this method is very accessible to the hobbyist and could allow for a rich new method of rapid project prototyping.

The researchers go on to discuss how to create the composition of modules from a specification of joints and links (from a “Denavit-Hartenberg” specification) to attaching the junctures together while respecting curvature constraints (via the “Dubins path”). Their paper offers the gritty details along with the available accompanying source files. Origami hacking is a favorite subject of ours and we’ve featured articles on the use of origami in medical technology to creating inflatable actuators.

Video after the break!

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Cranes made by Origami (Orizuru). The height is 35mm.

Bringing The Art Of Origami And Kirigami To Robotics And Medical Technology

Traditionally, when it comes to high-tech self-assembling microscopic structures for use in medicine delivery, and refined, delicate grippers for robotics, there’s been a dearth of effective, economical options. While some options exist, they are rarely as effective as desired, with microscopic medicine delivery mechanisms, for example, not having the optimal porosity. Similarly, in so-called soft robotics, many compromises had to be made.

A promising technology here involves the manipulation of flat structures in a way that enables them to either auto-assemble into 3D structures, or to non-destructively transform into 3D structures with specific features such as grippers that might be useful in both micro- and macroscopic applications, including robotics.

Perhaps the most interesting part is how much of these technologies borrow from the Japanese art of origami, and the related kirigami.

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