Insiders and analysts predict the 3D printing trends to watch in our latest series of articles focused on the3D打印的未来。
阿德里安·鲍耶（Adrian Bowyer）博士RepRap, has made a blog post outlining a new method of multi-material resin 3D printing.
Following a recent推文说“ SLA不能在单片上做多种材料”，鲍耶（Bowyer）得到了许多回应，指出他的错。与任何终身学习者一样，他将其视为拓宽视野并分享自己关于如何使用两个或更多树脂实现多物质3D打印的想法的机会。
Bowyer describes his method as simple but wasteful, so those that prioritize material savings should take a seat before proceeding.
How does resin 3D printing work?
To appreciate Bowyer’s method, it’s essential to understand how conventional single-material resin 3D printing works. Vat photopolymerization, which encompasses the SLA, DLP, and LCD 3D printing technologies, involves curing photopolymer resins into solid parts.
将对紫外线敏感的液体聚合物倒入储罐中，该水箱位于透明膜窗口的顶部。窗户下方是由LCD面膜过滤的紫外线发动机，该发动机将树脂的某些区域暴露于紫外线。这将树脂的裸露区域固化成构建板上的固体层。构建板由一毫米的一小部分抬起，并且该过程重复自我，将层固化，直到制造最终的3D对象为止。
This process works but you can’t have more than one resin in the tank, not without cross-contamination, so multi-material prints aren’t an option.
Bowyer’s multi-material approach
Bowyer’s multi-material proposal is a simple one. You could print the first layer in resin A and pour it away. Then add resin B and print the first layer again in resin B. Moving onto the second layer, you could print in resin B, pour it away, and print it again in resin A. By cycling through two resins like this, you could print every layer in a part with two different materials. To automate the resin removal process, you could angle the 3D printer towards one of its corners and drain the resins out using a solenoid valve.
Of course, this sounds too good to be true. It wouldn’t work because resin is sticky and simply pouring it out wouldn’t eliminate the problem of cross-contamination. Pouring and draining resin also results in bubbles, so those would have to be removed before any layers are cured.
为了解决交叉污染问题，鲍耶提出了一种蛮力的方法（这就是使它浪费的原因）。用树脂B代替树脂A时，您可以使用树脂B冲走树脂A的遗迹，从而丢弃受污染的树脂A-B混合物。然后，您可以将纯树脂B倒入，当需要用树脂A替换树脂B时也可以做同样的事情。
这留下了泡沫问题。树脂具有非常低的蒸气压，这就是使它们适合常规真空树脂铸造的原因。如果提出的3D打印过程是在真空室内进行的，则将完全消除增值税中的气泡。
If this is simply too wasteful, Bowyer could also see a third solvent being used to flush the resins between material changeovers. Isopropyl alcohol, the go-to resin cleaner, wouldn’t work because it has a vapor pressure of 33 hPa at 20°C, meaning it would just boil in the vacuum. However, an organic solvent with a lower vapor pressure such as aniline (0.4 hPa at 20°C) just might work.
鲍耶总结说：“我看不出为什么此处描述的过程不起作用的技术原因。显然可以扩展使用任何数量的树脂，而不仅仅是两个树脂，从而允许绝缘子和导体，不同的填充物和不同的颜色。”
作为开源的拥护者，多年来，鲍耶（Bowyer）和重演社区一直是几种新颖3D印刷思想的来源。英国工程师以前已经详细介绍了螺线管（一种类型的电磁体）床加热器，可与FDM 3D打印机一起使用雷电竞app下载。Unlike a conventional heating element, a solenoid heater would also allow for the print bed to be removed once the heating was turned off.
More recently, RepRap created a novel Python script that enables users to3D打印低成本PLA梁that are as stiff as steel counterparts. The open-source FreeCAD program is designed to be as accessible as possible, as it only requires users to specify some very basic parameters. The script then automatically generates the entire beam in the form of a 3D printable model.
Interested in resin 3D printing? So are we! Take ourresin 3D printing survey现在。
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特色图片显示阿德里安·鲍耶（Adrian Bowyer）博士。通过Phaidon的照片。
