There can be little doubt that 3D printing offers the possibility to change manufacturing radically. It can produce shapes that are too complex to build any other way. They can often produce an object as a single piece whereas other processes can only produce parts that must be assembled. And it’s possible to go straight from computer file to printed object.
But, with the current state of the technology, there are some serious flaws to overcome before it can be adopted widely.
The reason for the problem lays in the underlying method used by current 3D printers. Although we call them 3D printers, the truth is that they actually print in 2 dimensions over and over. These layers are stacked on top of each other gradually to create a final shape. This layer-stacking approach is the source of the method’s weakness. 3D printing suffers from 3 serious flaws:
– It takes a long time to print something. There may be thousands of thin layers to a single object, and printing them one-by-one can take several hours or even days depending on the size. While it beats making a model by hand, 3D printing is very slow compared to other manufacturing processes.
– The layered structure of the printed material introduces serious mechanical flaws that can lead to fracturing. The boundaries between the layers are weak against shear forces, which makes the manufactured parts unsafe for many applications. This also requires a measure of planning when determining the orientation of the object being printed.
– There are few material choices. As a result, the types of objects that can be printed with the deposition technique are limited.
These are all serious problems, and, as a result, 3D printing has been relegated to a rapid prototyping tool. But thanks to new technology developed by Carbon3D, this is set to change.
Carbon3D is a new Californian company that has been working in secret on a new approach to 3D printing. Their new method is called CLIP, which stands for Continuous Liquid Interface Production.
Speaking at a TED presentation, CEO Dr. Joseph DeSimone showcased his technology with a live demonstration. During his 6 minute talk, a printer on stage produced a complex object composed of geodesic shapes. The shape was chosen because it’s impossible to make with traditional manufacturing processes. Printing the shape using existing 3D printers would take several hours to complete, so it was a truly impressive accomplishment. In fact, this method of printing is between 25 and 100 times as fast as regular 3D printing.
He explained that the technology uses a combination of UV light and oxygen to harden liquid resin selectively. Bizarrely, he claimed that his process was inspired by the film “Terminator 2,” and the famous liquid terminator, the T1000.
In the printer, light is shone into the vat from below. It enters through a special window, which is permeable to oxygen. The light hardens the resin through a process called photopolymerization. Oxygen, which inhibits this reaction, is allowed to diffuse into the resin above the window to create a dead zone. In other words, the photopolymerization is contained on the plane of the image at the window.
During the process, the object is slowly lifted from the liquid as it is being “grown” from beneath. The image projected onto the window is coordinated with the platform lifting the object using sophisticated software. Because it occurs in a single fluid motion, the object doesn’t contain layers, and so it’s free of the flaws that usually make printed parts weak.
There are many different materials that are suitable for the photopolymerization process, so it’s possible to select a material with the right characteristics. Hard, strong materials and soft, elastic ones are both suitable for this type of printing.
The technology is still in its infancy, and currently there are no models available for sale. Dr. DeSimone says they are working on ways to make it faster, and believes that they can speed it up to be 1000 times faster than current 3D printing methods. These are strong words, but on the weight of the evidence presented at the talk, it seems very plausible.
But he’ll have to move fast. Already, a competitor has popped up, in the form of Gizmo 3D. This new Australian company has been working on a method that shares some similarities but promises to offer a simpler solution. Instead of using a thin layer of oxygen as a mask, Gizmo 3D’s machine uses a laser projection to form a continuous shape. Instead of pulling the object out of the pool, working against gravity, the device lowers the forming object into the tank. Gizmo 3D claim that this top-down approach makes the process simpler and, therefore, cheaper.
They are planning to bring their product to the market soon, with a Kickstarter launch in September. It will be exciting to see which of these technologies win in the end. Either way, they are both a big step towards making 3D printing a viable manufacturing choice.
