CLIP 3D Printing Technology: Objects Created in Liquid Resin
A New Method of 3D Printing
An impressive method of 3D printing was introduced at the TED 2015 conference in Vancouver and is now available commercially. The technology uses ultraviolet light and oxygen to create an object from a pool of liquid resin. As shown in the videos below, the object appears to "grow" from the liquid, reminiscent of the creation of the T1000 from the Terminator 2 movie. In fact, the CEO of the company that created the technology says that he was inspired by this movie.
The new printing method is known as CLIP, which stands for Continuous Liquid Interface Production. CLIP enables strong, functional, and attractive objects to be printed rapidly in an all-in-one process. In other 3D printing methods, a medium is deposited in layers in order to gradually build an object. The process is known as additive manufacturing.
Printing an object by additive manufacturing can be a time consuming process, taking hours or even days to complete. In addition, because the object is made of layers that are fused together, the final product sometimes lacks strength. The layers may also be visible in the final product, giving the object a banded appearance. CLIP can overcome these problems.
TED stands for Technology, Education, and Design. It's a nonprofit organization whose goal is to spread new ideas, primarily through speeches given by people who have something thought provoking to share.
Printing a Lattice Shape With CLIP Technology (7X Speed)
The Carbon Company
The CLIP technology belongs to a company known as Carbon, which is based in Redwood City in California. The company was formerly called Carbon3D and still has the official name of Carbon3D, Inc. Based on the staff descriptions on the company's website, Carbon is run by some highly qualified and experienced people. The company has been in operation since 2013 but kept its endeavours secret—or at least unpublicized—until 2015.
The CEO of the company is Joseph DeSimone. He's on leave from his position as Chancellor's Eminent Professor of Chemistry at the University of North Carolina at Chapel Hill and from his other academic positions. He's said to be very knowledgeable about polymers. His team consists of chemists, engineers, computer scientists, and business people.
Chemistry, engineering, and computer science are involved in a CLIP printer's action. The object is created by starting and stopping chemical reactions. The equipment that allows this to happen in an engineering feat. The instructions that "tell" the equipment what to do are provided by a computer program.
We think that popular 3D printing is actually misnamed - it's really just 2D printing over and over again.— Joseph DeSimone, CEO of Carbon3D, Inc.
Printing a Mini Eiffel Tower in Six Minutes
Printer Structure and Basic Function
In CLIP technology, a build platform moves upwards, pulling a gradually-forming shape out of a container of liquid. The liquid is a resin that is curable by UV light. The term "curing" refers to the hardening of a liquid by the formation of polymers, or long chains of molecules, and the creation of cross-links (bonds) between the polymers. Curing is triggered by the addition of energy, such as ultraviolet light or heat, or by the addition of certain chemicals.
At the bottom of the container of liquid resin in the new printers is a transparent window that is permeable to oxygen. Underneath the window is a projector that emits ultraviolet light. The Carbon company likens the window to a contact lens, since it allows both light and oxygen to pass through it and enter the resin.
The combination of ultraviolet light and oxygen allows a 3D object to be created. The UV light triggers polymerization and the creation of cross-links in the resin, which causes solidification. Oxygen has the opposite effect. It stops the formation of polymers and prevents solidification.
A printer needs instructions that control its actions, "telling" it how to translate a 3D graphics model into a real object. These instructions are supplied by sophisticated computer software that controls the variables involved in the printing process.
How Does CLIP 3D Printing Work?
In a CLIP printer, a continuous sequence of cross sectional images from a 3D graphics model is projected into the resin. The images are sent in the form of UV light patterns.
A very thin layer of resin just above the window in the resin container is rich in oxygen. The oxygen-rich layer doesn't polymerize as UV light passes through it and is referred to as the dead zone. The resin just above the dead zone lacks oxygen and does polymerize when the light strikes it, forming a solid according to the shape of the projected UV image.
The solid is slowly pulled out of the liquid as it forms. The suction forces that are created by this movement cause more liquid to move into position below the object. This means that the object that is being printed can be much taller than the depth of the liquid.
There is always liquid below the developing object, so the object doesn't stick to the bottom of the container. In addition, the object is both created and pulled upwards continually and smoothly without any pauses. These factors help to prevent the formation of layers and bands in the finished product.
Once an object has been printed, it's baked in a forced-circulation oven. This triggers a new chemical reaction that strengthens the object. The process is known as thermal curing. The double curing process involved in CLIP printing technology is said to produce an engineering-grade material.
Potential Benefits of the New Technology
CLIP printing is 25X to 100X faster than previous techniques. (The process may eventually reach 1000X times faster than conventional 3D printing.) This is a highly significant increase. It should end a lot of the frustration created by the time needed to produce a three dimensional object. It should also greatly increase the number of applications for 3D printing, allowing custom built items to be printed whenever we need them.
In addition, the all-in-one printing method should create a stronger object, depending on the printing medium that's used. Printed parts have consistent properties and look much more like injection-molded parts than the usual 3D printed items. The new technology can also make flexible and rubbery objects.
Joseph DeSimone and a New Printer
Some Possible Problems With the Technology
So far, the new printers can only use a resin as a printing medium. The currently available resins are useful, however. They include an elastomer. Elastomers are elastic polymers, as their name implies. New resins continued to be announced, including three in January, 2017. Some people wonder about the scope of the printers, however, because they are limited to media that can be polymerized by light.
Another potential limitation is that the current printers produce relatively small objects. Questions have been raised about the ability of the new technology to produce larger objects and about how long this will take.
Although the price of a CLIP printer is out of range for many people, there is a cheaper option. The Sculpteo website prints 3D objects from the designs that people upload. One option offered by the website is CLIP printing.
The Present and Future for CLIP
Carbon says that its beta printers are being used by select companies and institutions. On April 1st, 2016, the first commercial version of the printer—known as the M1—became available. The printer is a professional model and isn't aimed at consumers. It's available on a subscription plan rather than a purchase one. Even so, the subscription costs thousands of dollars per month and is only affordable by certain businesses. The current minimum subscription length is three years.
Joseph DeSimone predicts many possible benefits of the printer. In the future, doctors may be able to create stents of the correct size for a patient during an operation. (Stents are used to keep blood vessels open.) Dentists may be able to print tooth implants while a patient is sitting in a dentist's chair. Car parts and other manufactured goods may be produced rapidly whenever they're needed.
There are many ideas in technology that don't live up to their expectations and fizzle out. There are also ideas that are successful and allow technology to take a leap forward, sometimes improving our lives significantly. The CLIP 3D printing technology may be one of the latter ideas. It will be very interesting to see if this is true.
© 2015 Linda Crampton
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