Three Things We Can’t Do… Yet.

by Aaron H. Pratt

The proliferation of printers in the 3D space has been remarkable. Among the most exciting things in the news in the past few weeks have been a 3D pen for manually drawing with plastic at a sub-$100 price point(1), and of course President Obama’s acknowledgement of the industry in his State of the Union Address(2). President Obama correctly acknowledged the laboratory where “new workers are mastering 3D Printing” as the appropriate domain of the 3D Printer today. He also keyed in on the technology as having the “potential to revolutionize the way we make everything”, which is simultaneously visionary and (in the short run) unrealistic. But progress is being made.

Shortly before the State of the Union Address, in The Promise of 3D Printers(3), I also acknowledged that 3D printing was in the “learning” stage. We identified the education market as one of the signs of hope for the industry. As desktop 3D Printers at the low-end become more solidly commercialized, one of the first hurdles to overcome is a shortage of users that are acquainted with 3D design.

Today, my children are all getting at least the fundamentals of CAD courses in their junior-high level industrial tech classes. But the economy today is largely staffed by people who couldn’t name a 3D Design program, much less operate one. Even amongst the earliest adopters of the kit-style 3D printers out there, relatively few seemed to be designing their own models at first. It may be hard to believe, but many of the initial purchasers of 3D printer kits were more interested in putting together the printer than in producing a printed part. Even as the profile of purchasers matures into actual designers, the manufacturers of the printers themselves (and I am guilty as charged) still show off the printers mostly using downloaded trinkets from Thingiverse. But that is changing rapidly. More and more frequently, people approach me with a design file of their own that they would like to see printed.

To quote the immortal Dr. Seuss, “You have brains in your head. You have feet in your shoes. You can steer yourself any direction you choose.” Now we are seeing a rising generation of people that have “things in their head and plastic to ooze, and soon they’ll make any contraption they choose.”(4)

While today we can’t make everything that is in our heads, the technology will catch up with demand. Here are three benchmarks that symbolize the necessary and future evolution of 3D printing. Once you see desktop printers that can do these, you’ll know we’ve arrived.


The trouble with 3D printing jewelry is twofold. First, jewelry features are often tiny. While small details are becoming more and more feasible every day, small features are not. For example, a small trace outline of a window on the Taj Mahal is very easy to do (especially if the object is oriented so that the detail is printed in the right dimension.) But the same size arm extending outside of a figurine might turn out distorted, detached, or not at all. The reason is that the microstepper motors that control an extruder can be programmed to move in very small dimensions, but starting and stopping the flow of filament is more problematic. The result is that a 1mm surface detail can work well, while even a 5mm feature like an appendage might completely fail.

The second struggle is that jewelry is meant to be cast in metal. Casting from a sculpture is an art unto itself. I had the privilege a couple of years ago of meeting and touring the studio of the talented Minnesota Sculptor Kimber Fiebiger(5). I was struck by the process; after building a wire armature and sculpting the clay around it, the process had only begun. Liquid rubber and plastic are applied to the sculpture to create a mold, the mold is removed and then wax is poured into the mold. The wax piece is then dipped in a shell, and the wax is burned out, creating a new mold in to which molten metal can be poured. If casting a sculpture were analogous to the photographic process, it would be as if the photo were converted to a negative, then a positive, then a negative, then a positive again before you had a final print. Of course the troubling part for a 3D printer is the wax stage; if we want to provide a time savings and cost savings to the sculptor, we need to be able to take the 3D print and create a mold right away. Unfortunately, ABS plastic (and even PLA) doesn’t burn away like wax, so casting is inconvenient at best.

The appeal of 3D printing in jewelry lies in customization. Because of what a piece of jewelry symbolizes (especially a wedding band or even a Mothers’ Day gift), the idea of a custom piece is very attractive to the consumer – and therefore potentially very profitable to the jeweler. I’ve met with several talented jewelry designers who are excited by the prospects of 3D printing. They have visions of endless design flexibility in their minds – once we can print features such as the prongs in a setting reliably and accurately, and once we can print using a material that would burn away like lost wax in the cire perdue process.


Another application that begs for customization is dentistry. The relative difference between the mouths of different adults is uncomfortably noticeable when we subject ourselves to the tools used in every day procedures, like bitewings for x-rays. When it comes to more significant oral surgeries, customization and precision are not merely convenient, they are required. Clear Choice Dentistry, which has built a nationally recognized business around providing dental implants, starts every patient with a 3D cat scan of the mouth(6). That is the first step before placing an implant, a titanium screw that is permanently inserted into the jawbone as the root for the abutment and crown that will be placed on top of them. Clear Choice and other dental providers have established a new expectation for what was once a long and painful process. Analagous to Lasik optical surgery, they have positioned themselves as a “one-stop shop”, endeavoring to provide the service of dental implants with a minimal level of pain, a minimal number of appointments, and minimal surgery. 3D modeling is an important part of that process.

We’ve been approached by a number of dentists who are trying to use 3D printing to extend that innovation in new ways. For example, a drill guide that has been customized to the patient’s mouth can minimize errors, pain, time, and cost. Unfortunately, the additive process in desktop printers does not always hold the tolerances required for precision dental or medical work. Low end machines do not yet calibrate and adjust to compensate for variances that occur when extruded filament cools at different speeds. The finished piece can vary slightly in each axis, resulting in a mis-sized or skewed part. And none of us wants to allow for even a small degree of error when it comes to dental drills in the tender parts of our mouths.

The prototyping technologies that are used today in dentistry are not yet a desktop technology. Stereolithography or SLA, is an additive manufacturing process that uses light to cure photopolymers in to a hardened shape. Unfortunately, the cost of stereolithography machines is still prohibitive. Since most (perhaps all) dentists cannot justify the economics of owning such a machine, it remains an outside process; Stereolithographic prints take only a few hours to complete, but the scan has to be sent out, printed, and shipped back to the dentist before the operation can take place.

Manufacturing Extrusion Dies

There are many different processes used in manufacturing. I’m not an expert in any of them. When I tour a factory, I know to keep my fingers and toes away from the equipment. And that’s about it. But the possibilities excite me.

Of course, 3D printers can already do at least a prototype part that closely resembles its progeny on the punch press or CNC. One thing that stands out to me as I look at the manufacturing process is the creation of dies. The die symbolizes investment. Creating the die is a key step in measuring the economies of scale. It’s where manufacturers and designers make crucial decisions. It’s where the tradeoff between aesthetics, durability, and price meet. The day that dies are quick and easy to manufacture is the day that the face of manufacturing changes entirely. Extruding, which requires a die, is a particular process that enables the creation of very complex cross sections of parts with a fine finish.

And extrusions are used for at least a part of nearly every type of durable good.

The problem with printing an extrusion die is that material must be pushed or drawn through it – so it must stand up to significant pressures(7). Similarly to the multi-step casting process in jewelry, you manufacture a die in order to manufacture another part. And then the final product that comes out of the die needs to fit with other things. An extrusion is hardly ever a standalone product; it marries up with other components to provide structure or finish. Whether it is the molding that puts the final touch on a room or a cabinet, or the structure itself in a display or device, extrusions touch, join, and hug other surfaces. Knowing how close of a fit your extrusion will be is very important to manufacturing a successful product.

Today we can (and do) prototype the extrusion itself. We can generate a suitably long test section for at least an initial fit. 3D printers allow us to touch and feel what really started as a 2d design, if only for a few inches of length and in a uniformly semi-rigid material. It would be great if we could also use a 3D printer with very rigid or very flexible materials for different requirements. But prototyping the die itself – that would really be something! If we didn’t like the first extrusion we could start over quickly, make a small adjustment, and extrude again.

These market niches represent three very important potentials for 3D Printing. The potential for consumer markets is best exemplified by the high-priced and emotionally charged transactions in jewelry. The potential for medical markets is symbolized in the very-customized and rapidly growing needs for dentistry. And the potential for the industrial manufacturing markets is represented by the versatility and strength of extrusion (a not-unrelated process to 3D printing itself!)

When we see desktop models of 3D printers begin to meet the needs of these three niches, we will truly have begun to realize the potential that President Obama described. We will see the rising generation of designers enabled by technology. These are the technological water marks by which we will be able to measure the rising tide of 3D printing in the present and future economy.

Author’s note: Just as this article was being prepared for publication, Stratsys announced a new dental-specific printer, the Objet30 OrthoDesk 3D Printer, that is a significant step towards resolving some of the issues cited in the article.

  4. I apologize, I feel poetic today.