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May 3, 2023

One of the hardest parts of telling any history, is which innovations are significant enough to warrant mention. Too much, and the history is so vast that it can't be told. Too few, and it's incomplete. Arguably, no history is ever complete. Yet there's a critical path of innovation to get where we are today, and hundreds of smaller innovations that get missed along the way, or are out of scope for this exact story.

Children have probably been placing sand into buckets to make sandcastles since the beginning of time. Bricks have survived from round 7500BC in modern-day Turkey where humans made molds to allow clay to dry and bake in the sun until it formed bricks. Bricks that could be stacked. And it wasn’t long before molds were used for more. Now we can just print a mold on a 3d printer.
A mold is simply a block with a hollow cavity that allows putting some material in there. People then allow it to set and pull out a shape. Humanity has known how to do this for more than 6,000 years, initially with lost wax casting with statues surviving from the Indus Valley Civilization, stretching between parts of modern day Pakistan and India. That evolved to allow casting in gold and silver and copper and then flourished in the Bronze Age when stone molds were used to cast axes around 3,000 BCE. The Egyptians used plaster to cast molds of the heads of rulers. So molds and then casting were known throughout the time of the earliest written works and so the beginning of civilization.

The next few thousand years saw humanity learn to pack more into those molds, to replace objects from nature with those we made synthetically, and ultimately molding and casting did its part on the path to industrialization. As we came out of the industrial revolution, the impact of all these technologies gave us more and more options both in terms of free time as humans to think as well as new modes of thinking. And so in 1868 John Wesley Hyatt invented injection molding, patenting the machine in 1872. And we were able to mass produce not just with metal and glass and clay but with synthetics. And more options came but that whole idea of a mold to avoid manual carving and be able to produce replicas stretched back far into the history of humanity.

So here we are on the precipice of yet another world-changing technology becoming ubiquitous. And yet not. 3d printing still feels like a hobbyists journey rather than a mature technology like we see in science fiction shows like Star Trek with their replicators or printing a gun in the Netflix show Lost In Space. In fact the initial idea of 3d printing came from a story called Things Pass By written all the way back in 1945!

I have a love-hate relationship with 3D printing. Some jobs just work out great. Others feel very much like personal computers in the hobbyist era - just hacking away until things work. It’s usually my fault when things go awry. Just as it was when I wanted to print things out on the dot matrix printer on the Apple II. Maybe I fed the paper crooked or didn’t check that there was ink first or sent the print job using the wrong driver. One of the many things that could go wrong. 

But those fast prints don’t match with the reality of leveling and cleaning nozzles and waiting for them to heat up and pulling filament out of weird places (how did it get there, exactly)! Or printing 10 add-ons for a printer to make it work the way it probably should have out of the box. 

Another area where 3d printing is similar to the early days of the personal computer revolution is that there are a few different types of technology in use today. These include color-jet printing (CJP), direct metal printing (DMP), fused deposition modeling (FDM), Laser Additive Manufacturing (LAM, multi-jet printing (MJP), stereolithography (SLA), selective laser melting (SLM), and selective laser sintering (SLS). Each could be better for a given type of print job to be done. Some forms have flourished while others are either their infancy or have been abandoned like extinct languages.

Language isolates are languages that don’t fit into other families. Many are the last in a branch of a larger language family tree. Others come out of geographically isolated groups. Technology also has isolates. Konrad Zuse built computers in pre-World War II Germany and after that aren’t considered to influence other computers. In other words, every technology seems to have a couple of false starts. Hideo Kodama filed the first patent to 3d print in 1980 - but his method of using UV lights to harden material doesn’t get commercialized. 

Another type of 3d printing includes printers that were inkjets that shot metal alloys onto surfaces. Inkjet printing was invented by Ichiro Endo at Canon in the 1950s, supposedly when he left a hot iron on a pen and ink bubbled out. Thus the “Bubble jet” printer. And Jon Vaught at HP was working on the same idea at about the same time. These were patented and used to print images from computers over the coming decades.

Johannes Gottwald patented a printer like this in 1971. Experiments continued through the 1970s when companies like Exxon were trying to improve various prototyping processes. Some of their engineers joined an inventor Robert Howard in the early 1980s to found a company called Howtek and they produced the Pixelmaster, using hot-melt inks to increment the ink jet with solid inks, which then went on to be used by Sanders Prototype, which evolved into a company called Solidscape to market the Modelmaker. And some have been used to print solar cells, living cells, tissue, and even edible birthday cakes.

That same technique is available with a number of different solutions but isn’t the most widely marketable amongst the types of 3D printers available.

There’s often a root from which most technology of the day is derived. Charles, or Chuck, Hull coined the term stereolithography, where he could lay down small layers of an object and then cure the object with UV light, much as the dentists do with fillings today. This is made possibly by photopolymers, or plastics that are easily cured by an ultraviolet light. He then invented the stereolithography apparatus, or SLA for short, a machine that printed from the bottom to the top by focusing a laser on photopolymer while in a liquid form to cure the plastic into place. He worked on it in 1983, filed the patent in 1984, and was granted the patent in 1986. 

Hull also developed a file format for 3D printing called STL. STL files describe the surface of a three-dimensional object, geometrically using Cartesian coordinates. Describing coordinates and vectors means we can make objects bigger or smaller when we’re ready to print them. 3D printers print using layers, or slices. Those can change based on the filament on the head of a modern printer, the size of the liquid being cured, and even the heat of a nozzle. So the STL file gets put into a slicer that then converts the coordinates on the outside to the polygons that are cured. These are polygons in layers, so they may appear striated rather than perfectly curved according to the size of the layers. However, more layers take more time and energy. Such is the evolution of 3D printing.

Hull then founded a company called 3D Systems in Valencia California to take his innovation to market. They sold their first printer, the SLA-1 in 1988. New technologies start out big and expensive. And that was the case with 3D Systems. They initially sold to large engineering companies but when solid-state lasers came along in 1996 they were able to provide better systems for cheaper. 

Languages also have other branches. Another branch in 3d printing came in 1987, just before the first SLA-1 was sold. 

Carl Deckard  and his academic adviser Joe Beaman at the University of Texas worked on a DARPA grant to experiment with creating physical objects with lasers. They formed a company to take their solution to market called DTM and filed a patent for what they called selective laser sintering. This compacts and hardens a material with a heat source without having to liquify it. So a laser, guided by a computer, can move around a material and harden areas to produce a 3D model. Now in addition to SLA we had a second option, with the release of the Sinterstation 2500plus. Then 3D Systems then acquired DTM for $45 million in 2001.

After Hull published his findings for SLA and created the STL format, other standards we use today emerged. FDM is short for Fused Deposition Modeling and was created by Scott Crump in 1989. He then started a company with his wife Lisa to take the product to market, taking the company public in 1994. Crump’s first patent expired in 2009. 

In addition to FDM, there are other formats and techniques. AeroMat made the first 3D printer that could produce metal in 1997. These use a laser additive manufacturing process, where lasers fuse powdered titanium alloys. Some go the opposite direction and create out of bacteria or tissue. That began in 1999, when Wake Forest Institute of Regenerative medicine grew a 3D printed urinary bladder in a lab to be used as a transplant. We now call this bioprinting and can take tissue and lasers to rebuild damaged organs or even create a new organ. Organs are still in their infancy with success trials on smaller animals like rabbits. Another aspect is printing dinner using cell fibers from cows or other animals.

There are a number of types of materials used in 3D printing. Most printers today use a continuous feed of one of these filaments, or small coiled fibers of thermoplastics that melt instead of burn when they’re heated up. The most common in use today is PLA, or polylactic acid, is a plastic initially created by Wall Carothers of DuPont, the same person that brought us nylon, neoprene, and other plastic derivatives. It typically melts between 200 and 260 degrees Celsius. Printers can also take ABS filament, which is short for acrylonitrile-butadien-styerene. Other filament types include HIPS, PET, CPE, PVA, and their derivative forms. 

Filament is fed into a heated extruder assembly that melts the plastic. Once melted, filament extrudes into place through a nozzle as a motor sends the nozzle on a x and y axis per layer. 

Once a layer of plastic is finished being delivered to the areas required to make up the desired slice, the motor moves the extruder assembly up or down on a z axis between layers. Filament is just between 1.75 millimeters and 3 millimeters and comes in spools between half a kilogram and two kilograms.

These thermoplastics cool very quickly. Once all of the slices are squirted into place, the print is removed from the bed and the nozzle cools off. Filament comes in a number of colors and styles. For example, wood fibers can be added to filament to get a wood-grained finish. Metal can be added to make prints appear metallic and be part metal. 

Printing isn’t foolproof, though. Filament often gets jammed or the spool gets stuck, usually when something goes wrong. Filament also needs to be stored in a temperature and moisture controlled location or it can cause jobs to fail. Sometimes the software used to slice the .stl file has an incorrect setting, like the wrong size of filament. But in general, 3D printing using the FDM format is pretty straight forward these days. Yet this is technology that should have moved faster in terms of adoption. The past 10 years have seen more progress than the previous ten though. Primarily due to the maker community.

Enter the Makers
The FDM patent expired in 2009. In 2005, a few years before the FDM patent expired, Dr. Adrian Bowyer started a project to bring inexpensive 3D printers to labs and homes around the world. That project evolved into what we now call the Replicating Rapid Prototyper, or RepRap for short. 

RepRap evolved into an open source concept to create self-replicating 3D printers and by 2008, the Darwin printer was the first printer to use RepRap. As a community started to form, more collaborators designed more parts. Some were custom parts to improve the performance of the printer, or replicate the printer to become other printers. Others held the computing mechanisms in place. Some even wrote code to make the printer able to boot off a MicroSD card and then added a network interface so files could be uploaded to the printer wirelessly.

There was a rising tide of printers. People were reading about what 3D printers were doing and wanted to get involved. There was also a movement in the maker space, so people wanted to make things themselves. There was a craft to it. Part of that was wanting to share. Whether that was at a maker space or share ideas and plans and code online. Like the RepRap team had done. 

One of those maker spaces was NYC Resistor, founded in 2007. Bre Pettis, Adam Mayer, and Zach Smith from there took some of the work from the RepRap project and had ideas for a few new projects they’d like to start. The first was a site that Zach Smith created called Thingiverse. Bre Pettis joined in and they allowed users to upload .stl files and trade them. It’s now the largest site for trading hundreds of thousands of designs to print about anything imaginable. Well, everything except guns.

Then comes 2009. The patent for FDM expires and a number of companies respond by launching printers and services. Almost overnight the price for a 3D printer fell from $10,000 to $1,000 and continued to drop. Shapeways had created a company the year before to take files and print them for people. Pettis, Mayer, and Smith from NYC Resistor also founded a company called MakerBot Industries.

They’d already made a little bit of a name for themselves with the Thingiverse site. They knew the mind of a maker. And so they decided to make a kit to sell to people that wanted to build their own printers. They sold 3,500 kits in the first couple of years. They had a good brand and knew the people who bought these kinds of devices. So they took venture funding to grow the company. So they raised $10M in funding in 2011 in a round led by the Foundry Group, along with Bezos, RRE, 500 Startups and a few others.

They hired and grew fast. Smith left in 2012 and they were getting closer and closer with Stratasys, who if we remember were the original creators of FDM. So Stratasys ended up buying out the company in 2013 for $403M. Sales were disappointing so there was a changeup in leadership, with Pettis leaving and they’ve become much more about additive manufacturing than a company built to appeal to makers. And yet the opportunity to own that market is still there.

This was also an era of Kickstarter campaigns. Plenty of 3D printing companies launched through kickstarter including some to take PLA (a biodegradable filament) and ABS materials to the next level. The ExtrusionBot, the MagicBox, the ProtoPlant, the Protopasta, Mixture, Plybot, Robo3D, Mantis, and so many more. 

Meanwhile, 3D printing was in the news. 2011 saw the University of Southhampton design a 3d printed aircraft. Ecologic printing cars, and practically every other car company following suit that they were fabricating prototypes with 3d printers, even full cars that ran. Some on their own, some accidentally when parts are published in .stl files online violating various patents. 

Ultimaker was another RepRap company that came out of the early Darwin reviews. Martijn Elserman, Erik de Bruin, and Siert Wijnia who couldn’t get the Darwin to work so they designed a new printer and took it to market. After a few iterations, they came up with the Ultimaker 2 and have since been growing and releasing new printers 

A few years later, a team of Chinese makers, Jack Chen, Huilin Liu, Jingke Tang, Danjun Ao, and Dr. Shengui Chen took the RepRap designs and started a company to manufacturing (Do It Yourself) kits called Creality. They have maintained the open source manifesto of 3D printing that they inherited from RepRap and developed version after version, even raising over $33M to develop the Ender6 on Kickstarter in 2018, then building a new factory and now have the capacity to ship well over half a million printers a year.

The future of 3D Printing
We can now buy 3D printing pens, over 170 3D Printer manufacturers including 3D systems, Stratasys, and Ceality but also down-market solutions like Fusion3, Formlabs, Desktop Metal, Prusa, and Voxel8. There’s also a RecycleBot concept and additional patents expiring every year. 

There is little doubt that at some point, instead of driving to Home Depot to get screws or basic parts, we’ll print them. Need a new auger for the snow blower? Just print it. Cover on the weed eater break?  Print it. Need a dracolich mini for the next Dungeons and Dragons game? Print it. Need a new pinky toe. OK, maybe that’s a bit far. Or is it? In 2015, Swedish Cellink releases bio-ink made from seaweed and algae, which could be used to print cartilage and later released the INKREDIBLE 3D printer for bio printing.

The market in 2020 was valued at $13.78 billion with 2.1 million printers shipped. That’s expected to grow at a compound annual growth rate of 21% for the next few years. But a lot of that is healthcare, automotive, aerospace, and prototyping still. Apple made the personal computer simple and elegant. But no Apple has emerged for 3D printing. Instead it still feels like the Apple II era, where there are 3D printers in a lot of schools and many offer classes on generating files and printing. 

3D printers are certainly great for prototypers and additive manufacturing. They’re great for hobbyists, which we call makers these days. But there will be a time when there is a printer in most homes, the way we have electricity, televisions, phones, and other critical technologies. But there are a few things that have to happen first, to make the printers easier to use. These include:

  • Every printer needs to automatically level. This is one of the biggest reasons jobs fail and new users become frustrated.
  • More consistent filament. Spools are still all just a little bit different.
  • Printers need sensors in the extruder that detect if a job should be paused because the filament is jammed, humid, or caught. This adds the ability to potentially resume print jobs and waste less filament and time.
  • Automated slicing in the printer microcode that senses the filament and slices.
  • Better system boards (e.g. there’s a tool called Klipper that moves the math from the system board on a Creality Ender 3 to a Raspberry Pi).
  • Cameras on the printer should watch jobs and use TinyML to determine if they are going to fail as early as possible to halt printing so it can start over.
  • Most of the consumer solutions don’t have great support. Maybe users are limited to calling a place in a foreign country where support hours don’t make sense for them or maybe the products are just too much of a hacker/maker/hobbyist solution.
  • There needs to be an option for color printing. This could be a really expensive sprayer or ink like inkjet printers use at first We love to paint minis we make for Dungeons and Dragons but could get amazingly accurate resolutions to create amazing things with automated coloring. 

For a real game changer, the RecycleBot concept needs to be merged with the printer. Imagine if we dropped our plastics into a recycling bin that 3D printers of the world used to create filament. This would help reduce the amount of plastics used in the world in general. And when combined with less moving around of cheap plastic goods that could be printed at home, this also means less energy consumed by transporting goods.

The 3D printing technology is still a generation or two away from getting truly mass-marketed. Most hobbyists don’t necessarily think of building an elegant, easy-to-use solution because they are so experienced it’s hard to understand what the barriers of entry are for any old person. But the company who finally manages to crack that nut might just be the next Apple, Microsoft, or Google of the world.