Ultrasonically enabled supportless 3D printing (Sonobeamer)

Lead Research Organisation: University of Glasgow
Department Name: School of Engineering

Abstract

In this proposal we outline how we will develop a system capable of 3D printing without physical support structures by ultrasonically supporting the desired print whilst it is being printed. This will facilitate the creation of complex geometries that previously were not possible whilst at the same time, for the majority of prints, by removing the need for infill as well as removing physical supports, it will increase the speed and reduce the energy and amount of material needed for each print. Removing the need for physical support could also reduce the solid waste created by this printing method to as low as zero plastic waste. To achieve this, we will develop a novel ultrasound transducer array, the SonoBeamer, which we will then integrate into demonstration 3D printing setups. The SonoBeamer array will consist of tiles (circa 50x50mm) with each tile comprising up to 208x208 transducer elements. Each tile will itself consist of lines of transducers, or staves, which will then be assembled into the 2D tile. We will design custom Application Specific Integrated Circuit (ASIC) chips which will be bonded onto a flexible circuit board attached to each stave. The AISC chips will give precise electrical pulse trains, both in amplitude and phase allowing optimised control over the phased array of ultrasound transducers whilst minimising the power used and the heat generated. Before developing the SonoBeamer arrays we will test the design parameters by using a smaller array (12 elements) of available off the shelf ultrasound transducers and use this to establish the optimum geometry, size of array and size of each pixel, for the Sonobeamer. We are targeting applying the SonoBeamer tiles to stereolithography (SLA) 3D printing and so the first small array will be used to demonstrate the method of holding a 3D printed object in resin whist it is being printed. Once we have then developed the SonoBeamer tiles we will then create two test systems which we will use to demonstrate their capabilities and learn their abilities and limitations so that we can further develop them with a second generation of SonoBeamer devices. The first test system will be based on a bespoke optical system and will have SonoBeamer tiles on four sides of the printer's resin tank. This will allow optimal control over the pressure distributions in the resin tank providing fine control over the structure as it is being printed. We will use this system to develop algorithms and software to drive the Sonobeamer tiles to achieve the control we want in the complex environment created by the printed structures being created. Using this system, we will demonstrate orientational control over the print as it is formed allowing us to go beyond printing layer by layer as in traditional additive manufacture. We will also demonstrate the novel control the system offers by printing of one freely moving object completely within another printed object e.g. a set of nested hollow spheres. In our second test system we will integrate a set of SonoBeamer tiles into a commercial SLA printer's resin tank. As we will not be able to place SonoBeamer tiles around four sides of this tank this will produce a reduced functionality, with less orientational control, however it will allow the ultrasonic support of the print so that the need for infill and physical supports will be reduced. This will give us a quick pathway to increasing the speed and reducing the energy and waste of commercial systems. We will install one of these prototype systems into the manufacturing facility of our industrial partners Step3D who will test it for us in a commercial setting and feedback to us the advantages and disadvantages they, and their customers, find with the system.

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