Printing Production

There is clearly a growing interest in how the additive process can be further moved from limited production to, well, production.

According to Dr. Joseph DeSimone, CEO and co-founder of Carbon (carbon3d.com), a company that produces additive manufacturing equipment, the economics of additive, in terms of going to volume, aren’t what they could be, primarily because for the most part, they aren’t going to volume.

That is, as DeSimone noted in a letter on the Carbon website, “In the world of injection molding, it’s long been understood that as volumes go up, the cost per part comes down, through the amortization of tooling costs over an increasing number of parts. But for 3D printing this has not been the case–it’s long been assumed that the price per part is invariant with volume. The small number of 3D printed parts kept resin demand so low that 3D printing resins have been held at very high price points for decades.” And the high cost of 3D printing means that the volumes have stayed comparatively low.

Carbon has developed a process called “CLIP,” or “Continuous Liquid Interface Production,” which is a photo polymerization approach, that facilitates “Digital Light Synthesis” (DLS). To greatly simplify the whole thing, there is an oxygen permeable lens through which UV light is shined and oxygen moved into a reservoir that contains liquid resins. The light is controlled such that it creates the part that in effect “grows.” Additionally, there is another heat-activated chemistry in the resin that comes into play in a force-circulation oven: the Young’s Modulus of a part that comes out of the reservoir is on the order of 250 to 290 MPa; when it is cured in the oven those numbers go to 3,800 to 4,000 MPa.

Another thing to know about this process is that it is faster than many additive processes; during a TED talk, DeSimone joked that some mushrooms grow faster than some additive parts are created. They estimate that the speed of CLIP is on the order 25 to 100 times faster than some of the competitors and that the parts have high-quality mechanical properties and a good surface finish.

Still, there is the aforementioned issue of cost.

Carbon has established a “bulk discount” program for three of its resins, one of which, RPU 70, a rigid polyurethane which the company says is “comparable to ABS,” had already been on bulk offer. It has added EPX 82, “a rigid, high-strength, temperature-resistant material comparable to glass-filled PBT,” and EPU 41, “a highly elastic, tear-resistant, and resilient material comparable to traditional TPU elastomers.”

For those who place an order for 50 or more liters of these resins will get pricing of $50 per liter, which is in line with a promise that the company had made last year that it would achieve a sub-$100-per-liter price.

As DeSimone put it, “This dynamic will enable parts made by DLS to be increasingly cost competitive with injection molding pricing, which in turn will dramatically grow the total available market, rapidly grow resin volumes, and enable yet more high-value applications in a virtuous cycle, as designers and manufacturers transition from traditional manufacturing to the digital age.”

Obviously, it is in Carbon’s best interest to get companies using its equipment and to source its resin.

But it does point to something bigger, which is that there is the potential for additive manufacturing to expand far beyond where it is today, which is still, with few exceptions, fairly limited in volume. (Carbon is proud to point out that in this calendar year it will be producing more than 100,000 midsoles for use by adidas in its shoes, and that it expects that it could scale that to the millions.)

Additive processes have been invented and improved for nearly 40 years. Yes, the process is, on the one hand, becoming more mature, but on the other there is clearly a growing interest in how it can be further moved from limited production (in some cases, really limited, which goes back to that other moniker, “rapid prototyping,” which is rapid only in comparison to operations where tooling must be produced to create the prototype) to, well, production.

Let’s face it: there aren’t TED talks about milling.

So maybe we are on the cusp of a plethora of processes and materials that will be economically viable to produce parts that otherwise couldn’t be made as well as those that are individually tailored.

Every day there are new announcements from companies including Stratasys (stratasys.com), HP (www8.hp.com/us/en/printers/3d-printers.html), Materialise (materialise.com), Evolve (evolveadditive.com). . . .

At something of a production tipping point for additive? It begins to seem like it.