Ultrasonically enabled supportless 3D printing (Sonobeamer)

在本提案中，我们概述了我们将如何开发一个能够在没有物理支撑结构的情况下进行3D打印的系统，在打印时通过超声波支持所需的打印。这将有助于创建复杂的几何形状，而这在以前是不可能的，同时，对于大多数打印，通过消除填充物和去除物理支撑，它将提高速度，减少每次打印所需的能量和材料量。消除对物理支撑的需求还可以将这种印刷方法产生的固体废物减少到零塑料废物。为了实现这一目标，我们将开发一种新型超声换能器阵列，即SonoBeamer，然后我们将其集成到演示3D打印设置中。SonoBeamer阵列将由瓷砖（大约50x50mm）组成，每个瓷砖包含多达208x208个传感器元件。每个瓦片本身将由换能器或线材组成，然后将其组装成二维瓦片。我们将设计定制的专用集成电路（ASIC）芯片，该芯片将被粘接到附着在每个木板上的柔性电路板上。AISC芯片将提供精确的电脉冲序列，包括幅度和相位，允许对超声换能器相控阵进行优化控制，同时最大限度地减少使用的功率和产生的热量。在开发SonoBeamer阵列之前，我们将使用可用的现成超声换能器的较小阵列（12个元件）来测试设计参数，并使用它来确定SonoBeamer的最佳几何形状、阵列大小和每个像素的大小。我们的目标是将SonoBeamer瓷砖应用于立体光刻（SLA） 3D打印，因此第一个小阵列将用于演示在打印时将3D打印对象放在树脂中的方法。一旦我们开发出SonoBeamer瓷砖，我们就会创建两个测试系统，我们将使用它们来展示它们的能力，并了解它们的能力和局限性，以便我们可以用第二代SonoBeamer设备进一步开发它们。第一个测试系统将基于定制的光学系统，并将在打印机树脂罐的四面安装SonoBeamer贴片。这将允许对树脂槽中的压力分布进行最佳控制，从而在打印过程中对结构进行精细控制。我们将使用该系统开发算法和软件来驱动Sonobeamer瓷砖，以实现我们在打印结构创建的复杂环境中想要的控制。使用这个系统，我们将演示方向控制，因为它是形成的，使我们能够超越传统的增材制造一层一层的打印。我们还将演示该系统通过在另一个打印对象（例如一组嵌套的空心球体）中完全打印一个自由移动的物体来提供的新型控制。在我们的第二个测试系统中，我们将把一组SonoBeamer瓷砖集成到商用SLA打印机的树脂槽中。由于我们无法将SonoBeamer瓷砖放置在该容器的四面，这将减少功能，减少方向控制，但它将允许超声波支撑打印，从而减少对填充物和物理支撑的需求。这将为我们提供一个快速的途径来提高速度，减少商业系统的能源和浪费。我们将把这些原型系统中的一个安装到我们的工业合作伙伴Step3D的制造设施中，他们将在商业环境中为我们测试它，并向我们反馈他们及其客户使用该系统的优点和缺点。

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.