Thursday, March 19, 2015

3-D Printing has a New Competitor

I won't be so bold as to say that 3-D printing as we know it died on Monday [1], but it certainly took a good body blow (open access article after registration). Take a look at this video and you decide:
Pretty neat, huh?

That this is a UV-cured acrylate may not be overly surprising. By judicious choices in the monomers and photoinitiators, acrylates can cure pretty quickly. But the big question is how is the curing controlled to create such detailed topologies? 2-Photon absorption is one option, but it is a very slow process. So what is the key here?

Like any magic trick, once you know the secret, it seems pretty simple [2] and this is no different.
CLIP Process
The picture on the right shows what is happening in the liquid pool. The real secret is the yellow piece at the bottom which is Teflon AF 2400. Not only is it highly permeable to oxygen, but it is also UV transparent. With photopolymerization of acrylates, UV and O2 will take you in two different directions. The UV will cure the acrylates, while the O2 will inhibit the polymerization.

Knowing all this, it's pretty easy to connect the dots. The oxygen creates a "deadzone" just above the Teflon, while the UV creates a "livezone" just above the deadzone. By having an array of UV light sources under the Teflon with the ability to control which elements of the array are on and off, you can then control the formation of your object.

Being that this is acrylate chemistry, there are an endless number of monomers and comonomers available to make materials with a wide range of mechanical properties. You are not locked into a limited range of mechanicals, but you do need to have a system that is O2 inhibited. Throwing in some thiol-based monomers for instance, will ruin everything. Also, unlike standard 3-D printing, the use of monomers may limit the use of this technique to industrial users, at least initially. But regardless, this is some exciting new technology and I can't wait to see where it goes.

The researchers have named this process "CLIP" (Continuous Liquid Interface Processing) and have started their own company with a flashy website if you want more details or want to see more cool videos.

Since this post transitioned to the business side, I was curious at to what this announcement did to the stock price of existing 3-D printing companies, such as Stratasys or 3-D Systems. Apparently nothing. On Monday, Stratasys opened at $57.77 and is now at $58.34 having been as high as $60.49 late yesterday. 3-D Systems is behaving the same way. That is not what I would have expected, but picking stocks has never been my strength [3].

Update: I forgot entirely to mention that @Chemjobber pointed this article out to me. Mea culpa

[1] After all, Gutenberg's movable letterpress printing method is still being used 576 years later.

[2] For some people, knowing the secret to a magic trick ruins it. Not for me.

[3] Don't ask me to pick NCAA Basketball brackets either.

Previous Years

March 19, 2014 - "Openness in Science"

March 19, 2012 - Plastics Recycling Conference

March 19, 2010 - Another Use for FTIR in the Medical Lab

March 19, 2009 - Nitrogen Enriched Gasoline???

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