Hello, my name is Juri Fujii. I’m a graduate student at the University of Tokyo. Today I’ll be presenting our project Layerpump: Rapid Prototyping of Functional 3D Objects with Built-in Electrohydrodynamics Pumps Based on Layered Plates.
We propose LayerPump, a novel design method that embeds pumps and liquid paths in 3D objects. The pump is driven by electrohydrodynamics (EHD) which can control the flow of fluid by applying an electric field. To arrange the EHD pumps and fluid paths in appropriate positions inside 3D objects, we stacked acrylic plates and inserted electrodes.By using these embedded pumps, we can control the flow of fluid to change the objects’ color, shape, and motion.
The development and widespread use of digital fabrication tools such as 3D printers and laser cutters has facilitated the fabrication of customizable 3D objects and accelerated the speed of prototyping. More recently, the advanced design of materials and internal structure as well as the external shape has enabled the fabrication of functional objects.
Among them, 3D object design that embeds fluid flow channels is attracting attention as a method for providing sensing, displaying, and actuating capabilities on the object. Also, the fluid can be used to change multiple functions such as color change as well as deformation by transporting different materials like gas, liquid, and light. However, these approaches still have some drawbacks. External control devices such as pumps and valves that are used to control fluids tend to make the system large, complicated or noisy. It is still difficult to embed both interactions and control devices within the objects.
To solve these drawbacks , we have focused on electrohydrodynamics (EHD) and aimed at applying it to fabrication of functional 3D objects. EHD can move certain dielectric liquids by applying an electric field and work as a hydraulic pump. One of the features of this pump is that it can be electrically driven, so it is very quiet. The EHD pump has a simple structure consisting of positive and negative electrodes and an outer shell that surrounds and seals them. By simply placing the electrodes in the flow path, the flow path and the pump can be integrated.
The basic structure of LayerPump consists of 5 plates. Each plate has holes in appropriate positions and the outer shape can be designed into any flat shape. These plates are stacked and glued together to create the pump, tank, and flow path inside the object. The pump plate contains the electrodes that are cut out with a cutting plotter.
The electrodes are made of PET sheets and conductive material, which is soft and can bend. Various shapes of electrode arrangements have been proposed in previous research of EHD pumps. In this project, we used a comb-shaped electrode that can be made into a flat surface.
The EHD pump can increase the flow of the liquid by raising the applied voltage and the number of electrodes. Therefore, the output of the pump can be increased by expanding the space for the electrodes. For example, the pump can be enlarged in various ways, such as by making the pump part wider in the form of a flat surface, or by making use of the electrode’s soft material and bending one long electrode in half. In addition, multiple pumps can also be inserted.
To simplify the electrode layout, we designed a brush pattern using Adobe Illustrator. According to the shape of the drawn line, the electrode pattern will be generated automatically.
Fabrication process is simple. First, copper tape is glued to a PET sheet using a roller. Second, a cutting plotter is used to cut the tape into the designed shape. After cutting, unnecessary copper tape is removed using tweezers. The cut out electrodes are then inserted into the pump part of the object.
Using this system, we have prototyped 3 types of objects. The first prototype uses the EHD pump to move colored liquids. To move Colored liquids by pump, we can display information and create animation on the objects
We have also applied our method for prototyping butterfly shaped biomimetic actuators. We propose a biomimetic structure that moves according to liquid flow. For this object, a soft membrane made of elastomer is placed on the butterfly’s body.
Finally, the tactile presentation object. Just like the butterfly, we attached a sheet of elastomer to the pump. We created a device that presents haptic sensations by sending liquid and pushing the elastomer up and down.
We propose LayerPump, a novel design method that embeds pumps and liquid paths in 3D objects. For future studies, we plan to develop a simulation software that makes it easier to design the flow path and electrodes. Furthermore, we would like to realize tangible interactions based on user inputs such as touch and gestures. Thank you.