We just printed out the microphone on a 3D printer in the laboratory - and then there will be complete science fiction

The idea of ​​creating a physical object from a digital file seems exciting. She recalls Star Trek replicators that can do everything from clothes to spacecraft parts and food. Today's 3D printing takes impressive steps in this direction, which causes great interest among many manufacturers. For example, it became possible to print the components of complex electronic devices on relatively simple equipment - as my research team had just demonstrated , creating, we believe, the first microphone printed on a 3D printer.

There are already quite a lot of different materials available for 3D printing, including wood and silver-like materials . However, most machines are limited to working with synthetic materials - plastic, rubber polymers and nylon. Usually, machines print only one material at a time, or switch over a palette of two or three materials. But it still leaves a lot of potential, especially to give different properties to materials. This can be achieved by mixing the nanoparticles of another material that has the properties you need.


If you, for example, want your material to conduct current, you can add silver, gold or carbon nanotubes to it. This makes it possible to print electronic circuits. If you need piezoelectricity - electricity generation during compression - you can add barium titanate to the material. The resulting object can be turned into a sound or heat sensor, or into a power drive, a device that forces other components to move.
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By switching between circuits, sensors and drives during one print, you can create a working electronic component as a whole. In recent years, people have used this technique to manufacture things such as, for example, optical components for lenses or panels, or accelerometers — devices that measure the movement of various objects, from a running person to earthquakes. She allowed us to create our microphone, transfer it from a digital file to reality in just six hours.

Feed your plastic

Ideally, we would like to use one of the popular MakerBot 3D printers, which cost starts at £ 1000, but they don’t like to add tiny particles to the material. They work by squeezing out a plastic thread, which then cools and hardens, and the nanoparticles clog up this system - especially if you add enough of them to enhance the properties of the material.

Instead, we used the Asiga Pico 27 ​​plus for a price of £ 6,000. It uses digital light processing and cures the plastic by illuminating it with ultraviolet light. Light is built using 4000 micromirrors, similar to those used in home projectors. To make a model, the printer projects a set of two-dimensional images onto liquid plastic, and slightly shifts the model up each time the layer is cured. Nanoparticles change the duration of the illumination required for curing, and slightly absorb and scatter the incident light, but with this in mind, printing can be done quite successfully.


One of the drawbacks of this technology is that it has a bad attitude towards changing the types of material. Since the source material is liquid plastic, it must be kept in a container: the model is immersed in liquid when printing each subsequent layer. To change the material, you have to stop everything and change the capacity manually, before printing the next layer.

This can be circumvented by leaving a hole in the model in place of another material. Then you can change materials and print inside this hole, resulting in a three-dimensional object with interconnected internal properties.

What will happen next

The technical problems of a 3D printout of a working microphone are mainly related to the control of the process, the choice of the time of exposure to ultraviolet light with an accuracy of millisecond and careful combination and mixing of different materials. The result is a device that behaves almost like a normal microphone, with the exception of a rather poor signal-to-noise ratio and a rather large resistance of conductive layers. He, for example, can not be compared with a silicon microphone, standing in your smartphone.


Our microphone

Other teams that have tried printing using nanocomposite materials have encountered similar problems. In the manufacture of the optical components or accelerometers mentioned by me, they usually tried either to build in prefabricated microchips and sensors into the printed objects, or to tinker with the plastic after printing. We have not yet reached the level where it will be possible, for example, to print a smartphone of decent quality from scratch: Samsung and Apple can relax for now.



However, our current abilities still open up amazing possibilities for us, in particular, because good drives are easier to print than good sensors. Welcome to the nascent area of soft robotics , where the potential exists for printing hands gripping as softly and precisely as human hands; or nanorobots, unpacked as origami, upon reaching the desired organ in the human body; or even whole robots, like fish by reference , capable of imitating complex animal movements.

Prototypes of such devices already exist, although they combine printed and conventional components. After 10 years they will most likely be printed entirely. So, just like the characters in Star Trek from the 24th century, we, too, will soon be able to choose a file with some interesting device and print it to order. What do you say - a soft robotic tentacle? Well, while for such things there are no mobile applications yet, but it is only a matter of time .