|Chapter 5: The Personal Fabricator
Originally published by Henry Holt and Company 1999. Published on KurzweilAI.net May 15, 2003.
Thomas Watson, the chairman of IBM, observed in 1943 that "I think
there is a world market for maybe five computers." In 1997 there
were 80 million personal computers sold. To understand his impressive
lack of vision, remember that early computers were
- large machines
- housed in specialized rooms
- used by skilled operators
- for fixed industrial operations
- with a limited market
From there it was too hard to conceive of a computer that could
fit on a desk without crushing it, much less on a lap. Unseen beyond
that horizon in packaging lay the revolutionary implications of
Once computers became small enough and cheap enough for individuals
to own them, their application became a matter of personal preference
rather than corporate policy. Big companies have an unerring knack
for doing dumb things because so many people are involved in specifying
and evaluating what someone else does that it's all too easy to
forget to think. Once it became possible for individuals to write
programs or configure packages to reflect their individual needs,
then instead of marveling at someone else's stupidity they could
do something about it. This represented a loss of control for the
computer companies that were accustomed to prescribing what hardware
and software their customers would use; in return, the market for
computers grew to something more than five machines.
Now consider machine tools. These are the large mills and lathes
and drills that are used in factories for fabrication. For the ordinary
person, they are about as exciting as mainframe computers. In fact,
they really are quite similar. Machine tools are
- large machines
- housed in specialized rooms
- used by skilled operators
- for fixed industrial operations
- with a limited market
Sound familiar? Big companies use big machines to make things we
may not really want. Personal computing has not gone far enough:
it lets us shape our digital environment, but not our physical environment.
By giving computers the means to manipulate atoms as easily as they
manipulate bits, we can bring the same kind of personalization to
the rest of our lives. With the benefit of hindsight, plus a peek
into the laboratory to see what's coming, this time around we can
do better than Thomas Watson and recognize the impending arrival
of the Personal Fabricator.
One of the eeriest experiences in my life came when I first opened
the door of a 3D printer and took out a part that I had just seen
on the screen of a computer. It violated the neat boundary between
what is inside the computer and what is outside. In a strange way,
holding the part felt almost like touching the soul of the machine.
A 3D printer is a computer peripheral like any other, but instead
of putting ink on paper, or data on a disk, it puts materials together
to make objects. Working with a 3D printer engages our visceral
connection to the physical world, which has been off-limits for
so long whenever a computer is involved. When I set up a 3D printer
in my lab, people would come by just to touch the machine and the
parts that it produced. Watching them, I could almost hear the mental
gears grinding as they began to think about how they could make
what they wanted, instead of purchasing what someone else thought
they wanted. If a static shape can have that kind of impact, then
I'm not sure how people will react when the output from the printer
is able to walk out of it. Because we're also learning how to print
sensors, motors, and logic.
To appreciate just how inevitable and important personal fabrication
is, I had to retrace the history of computing in this new domain.
When I arrived at MIT in the early '90s, you couldn't tell that
it had been a pioneer in manufacturing technology. The few remaining
machine shops on campus were in a sorry state, holdovers from the
Iron Age in the midst of the Information Age. The campus had long
since gone digital. Forlorn machine tools were left neglected by
the throngs of students clustering around the latest computers.
As I set out to create a lab that could free computing from its
confining boxes, I knew that we would need to be equally adept at
shaping things as well as ideas. This meant that we would need to
start with a good machine shop. A traditional machine shop is a
wonderful place in which a skilled machinist can make almost anything.
Since this one would be in the Media Lab, where neither the people
nor the computers are traditional, this shop would need to be much
more easily accessible.
The most versatile tool to be added was a milling machine. These
come in two flavors. Manual ones are designed to be used by hand;
a part to be machined is fixed to a bed that is moved under the
rotating cutting tool by long lead screws turned by hand. Numerically
controlled (NC) mills are designed to be run by a computer; the
bed and sometimes the head are moved by motors under software control.
The operator of an NC mill stands at a control panel that can be
some distance from the workpiece, usually with a cryptic interface
that makes it difficult to do much more than start and stop the
I wanted both less and more than a conventional NC mill. Whatever
we bought had to have a direct mechanical linkage that could be
used manually. The feeling of the torque and vibration through the
handles provides essential insight into how well a tool is cutting,
which is invaluable for beginners and important also for experts
working with unfamiliar materials. This is lost when the mill is
controlled from a remote console.
Next, the mill needed to have a graphical interface that made it
simple to specify shapes right on the machine, because the only
things more unfriendly than typical NC controllers are the programs
that engineers use to design parts. Finally, the mill had to be
on speaking terms with the building's network, to make it easy to
transfer designs from the many types of computers in use.
Machine tool distributors laughed when I described what I was looking
for. I knew I had a problem when I got the same reaction from machine
tool manufacturers. Over and over, I was told that I had to choose
between the immediacy of a manual interface and the power of a numerical
As I traveled around the world, I started to make detours to visit
manufacturers. The turning point in my quest came on a trip to see
one of the largest European makers of machine tools. The day started
with them proudly showing me their products—huge mills that
cost $100,000, required skilled technicians to operate and maintain
them, and were difficult to use for anything but repetitive operations.
I then sat down with their eminent director of development to discuss
my requirements. As I spoke, he became increasingly agitated. Soon
he was pounding on the table and shouting that I must not ask for
such a machine.
At first I wasn't sure whether to laugh or cry. As he continued
to hold forth, I felt like I was being transported back a few decades
to reenact a familiar scene. I wanted to buy a PC; he wanted to
sell me a mainframe. He was making all of the same arguments for
why small computers could never replace big computers: machining/computing
requires expert skills, NC mills/mainframes have narrow markets,
personal systems are toys that can't do serious work. We parted
agreeing that we lived on different planets.
Fortunately, I came back and found what I was looking for in my
backyard. A company on Boston's Route 128, Compumachine, started
with a nice manual milling machine, added motors so that a computer
as well as a person could control it, then put on a keyboard and
screen to run it. Instead of the usual impenetrable industrial controller,
the computer was a familiar PC.
In the machine tool industry this was viewed as dangerous lunacy,
because the inevitable system crashes could cause real crashes of
the mill, destroying it if not its operator. What makes the mill
safe is an illusion: the computer only appears to be in charge.
There's a layer of circuitry between it and the mill that actually
issues the commands, monitoring everything the computer requests
in order to prevent anything unsafe from happening.
An NC mill is such a specialized piece of equipment that it usually
has to earn its keep with manufacturing operations. Putting one
in the hands of graphic designers, and programmers, and musicians,
led to all sorts of clever things getting made in a way that would
never occur to a traditional engineer. The mill was used to build
a parallel computer with processors embedded in triangular tiles
that could be snapped together in 2'D or 3'D sculptures, exchanging
data and power through the connections. Miniature architectural
models were created to serve as tangible icons for a computer interface.
The success of these kinds of projects led me to wonder if physical
fabrication could be made still simpler to reach still more people.
An alternative to making something by machining away parts that
you don't want is to assemble it by adding parts that you do. Lego
blocks are a familiar example of additive fabrication that make
it possible to quickly and easily build impressive structures. There's
a surprising amount of wisdom in this apparently simple system;
Lego has spent decades getting the bricks just right, experimenting
with the size of the posts, the angle of the faces, the hardness
and finish of the plastic. The earliest bricks look almost like
the current bricks, but these ongoing incremental improvements are
what make them so satisfying to play with.
Anyone who has been around kids building with Legos understands
the power of a child's drive to create. This is on display at the
Legoland near Lego's headquarters in Denmark, an amusement park
filled with spectacular Lego creations. There are Lego cities with
buildings bigger than the kids admiring them, giant Lego animals,
Lego mountain ranges. What's so amazing about this place is the
kids' reaction. There are none of the things we've come to expect
that children need to be entertained, no whizzy rides or flashy
graphics or omnipresent soundtracks. Just great structures. And
the kids are more engaged than any group I've ever seen, spending
awed hours professionally appraising the marvels on display. The
people who work for Lego, and who play with Lego, share a deep aesthetic
sense of the pleasure of a nicely crafted structure.
In the Media Lab, Professor Mitch Resnick has one of the world's
most extensive Lego collections. For years his group has been working
to extend the domain of Lego from form to function, embedding sensors
and actuators as well as devices for computing and communications,
so that the bricks can act and react. At first, conventional computers
were externally interfaced to the Lego set; now they've been shrunken
down to fit into a brick. These let children become mechanical engineers,
and programmers, with the same comfortable interface they've known
for years. Kids have used the system to make creatures that can
dance and interact, to animate their fantasy worlds, and to automate
their homes. This system has been so successful that it has now
left the lab and become a new line of products for Lego. The only
surprise, which isn't really a surprise, is that grown-ups are buying
the sets for themselves as well as for their kids.
At the opposite end of the spectrum is Festo. Festo is to industrial
engineers as Lego is to kids; they make the actuators and controllers
that are used to build factories. In fact, Lego's factories are
full of Festo parts making the Lego parts. Festo also has a system
for prototyping new factories and teaching people to design and
run them. This is Lego for grown-ups. When I first brought its components
into my lab there was a rush of ooh's and aah's, because it could
do what Lego couldn't: make large precise structures. The hefty,
shiny metal parts spoke to their serious purpose.
Following detailed instructions, with some effort, we used this
system to put together an assembly line to make pencil sharpeners.
And that's all we did. People left as quickly as they appeared,
because it soon became clear that it was too hard to play with something
this exact. Too many specialized parts are needed to do any one
thing, assembling them is too much work, and interactively programming
the industrial controllers is all but hopeless.
Between Lego and Festo the needs of children and industrial engineers
are covered. Mitch and I began to wonder about everyone else. Most
people don't make most of the things that they use, instead choosing
products from a menu selected for them by other people. Might it
be possible to create a system that would let ordinary people build
things they cared about? We called this "Any Thing" and set up a
project to develop it. Drawing on the lessons from Lego and Festo,
this kit would build electrical connections for data and power into
every mechanical joint, so that these capabilities did not need
to be added on later. The parts would snap together in precise configurations,
without requiring tools. And it would be made out of new composite
materials, to be light, strong, and cheap. Armed with these guiding
principles, we first tried out computer models of the parts, then
prepared to start building it. At this point we called a design
review meeting. We filled a room with as many alternative construction
kits as we could find for comparison, and then added as many people
and as much pizza as we could fit in. The night took many surprising
Unfortunately, Any Thing had been developed entirely by a bunch
of geeky guys (like me). This was the first time any women had seen
it. One of the first questions that one of my female colleagues
asked was what it was going to feel like; our jaws dropped when
we realized that we had designed bones without thinking about skin.
As the night proceeded and people played with the various commercial
construction systems, they were uniformly frustrated by the nuisance
of chasing around to find all of the fiddly little bits they needed
to complete whatever they were working on. The Any Thing vision
of personal fabrication necessarily entailed a personal warehouse
to store an inventory of all the required components.
The more we talked, the more we realized that the most interesting
part of Any Thing was not our proposed design, it was the 3D printer
we were using to prototype it. Three-dimensional printing takes
additive fabrication to its logical conclusion. Machine tools make
parts by milling, drilling, cutting, turning, grinding, sanding
away unwanted material, requiring many separate operations and a
lot of waste. Just as a Lego set is used to construct something
by adding bricks, a 3D printer also builds parts by adding material
where it is needed instead of subtracting it where it is not. But
where Lego molds the raw materials to mass-produce bricks in the
factory, in a 3D printer the raw materials are formed on demand
right in the machine.
There are many ways to do this. One technology aims a laser into
a vat of epoxy to cure it just where it is needed, another spreads
layers of powder and squirts a binder where it should stick together,
and our Stratasys 3D printer extrudes out a bead of material like
a computer-controlled glue gun that leaves a three'dimensional trail.
These techniques can all go from a computer model to something that
you can hold, without requiring any special operator training or
setup. This convenience is significantly decreasing the time it
takes companies to make product prototypes. The machines are currently
expensive and slow, but like any promising machinist they are steadily
becoming more efficient.
As interesting as 3D printing is, it's still like using a PC to
execute a mainframe program. The end result is not very different
from what can be made with conventional machine tools, it's just
the path to get there that is simpler. The real question posed by
our Any Thing design review was whether 3D printing could be extended
as Lego had been to incorporate sensors and actuators, computing
and communications. If we could do this, then instead of forcing
people to use their infinitely flexible and personal computers to
browse through catalogs reflecting someone else's guesses at what
they want, they could directly output it. Appliances with left-handed
controls, or ones with easy-to-read large type, would become matters
of personal expression rather than idle wishes.
This is the dream of the personal fabricator, the PF, the missing
mate to the PC. It would be the one machine that could make all
your others, a practical embodiment of the perennial science-fiction
staple of a universal matter output device. As we began to dare
to dream of developing such a thing, we realized that we had been
working on it all along.
Joe Jacobson's printer for the electronic book project was already
laying down the conductors, insulators, and semiconductors needed
to make circuits on paper. Just as an ink-jet printer has cartridges
with different-colored inks, it is possible to provide a printer
with more types of input materials so that it can also deposit structural
shapes and active elements. One of the first successes was a printed
motor that used carefully timed electric fields to move a piece
of paper. If your desk was covered by such a structure then it could
file your work away for you at the end of the day.
The semiconductor industry is trying to reach this goal of integrating
sensors, circuits, and actuators, by cutting out tiny little silicon
machines with the fabrication processes that are currently used
to make integrated circuits. This idea is called MEMS, Micro-Electro-Mechanical
Systems. Although the industry sees this as an area with great growth
prospects, MEMS fabrication has the same problem as mainframes and
machine tools. MEMS devices are designed by specialists and then
mass-produced using expensive equipment. The desktop version could
be called PEMS, Printed Electro-Mechanical Systems. Unlike MEMS,
it can make people-size objects rather than microscopic machines,
and the things are made where and when they are needed rather than
being distributed from a factory.
A PEMS printer requires two kinds of inputs, atoms and bits. Along
with the raw materials must come the instructions for how they are
to be placed. One possibility is for these to be distributed over
the Net. Instead of downloading an applet to run in a Web browser,
a "fabblet" could be downloaded to the printer to specify an object.
This would significantly lower the threshold for a company or an
individual to sell a new product, since all that gets sent is the
information about how to make it. But it stills leaves people selecting
rather than designing what they want.
To bring engineering design into the home, the CAD software that
engineers currently use is a valuable guide for what not to do.
These packages generally betray their mainframe legacy with opaque
user interfaces and awkward installation procedures, and isolate
the design of mechanical structures, electrical circuits, and computer
programs into modules that are barely on speaking terms.
A design environment to be used in the home should be so simple
that even a child could understand it. Because then there's some
hope that their parents might be able to also. There's already a
pretty good precedent that's routinely used by children without
any formal training: Lego. It provides simple standard parts that
can be used to assemble complex systems.
That was the original inspiration for the Any Thing project, which
in retrospect was the right idea for the wrong medium. It was a
mistake to assume that the physical fabrication process had to mirror
the logical design process. By moving the system from a bin of parts
to a software version that exists only inside a computer program,
the intuitive attraction of building with reusable components can
be retained without needing to worry about ever running out of anything.
Computer programmers use "object-oriented programming" to write
software this way; with a PEMS printer the objects can become tangible.
It's important that the reusability be extended to the physical
as well as the virtual objects. The arrival of fast high-resolution
printers has created the paperfull office of the future because
printing is now so convenient. This is a cautionary tale for PEMS,
which threatens to do the same for physical things. Two-dimensional
sheets of paper get thrown away in three-dimensional recycling bins;
three-dimensional objects would need a four-dimensional recycling
A slightly more practical alternative is to let the PEMS printer
separate discarded objects back into raw materials. This is what
a state-of-the-art waste facility does on a large scale; it's a
bit easier on the desktop because the task is restricted to a much
smaller group of materials that can be selected in advance to simplify
their separation. Just as coins get sorted by weight, differences
in the materials' density, melting temperature, electrical conductivity,
and so forth can be used to separate them back into the printer's
Complementing a PEMS printer with intuitive design tools and the
means to recycle parts provides all of the ingredients needed to
personalize fabrication. This just might eliminate some of the many
bad ideas that should never have been turned into products. I have
a theory for why so many companies full of smart people persist
in doing so many dumb things. Each person has some external bandwidth
for communicating with other people, and some internal processing
power for thinking. Since these are finite resources, doing more
of one ultimately has to come at the expense of the other. As an
organization expands, the volume of people inside the company grows
faster than the surface area exposed to the outside world. This
means that more and more of people's time gets tied up in internal
message passing, eventually crossing a threshold beyond which no
one is able to think, or look around, because they have to answer
their e-mail, or write a progress report, or attend a meeting, or
review a proposal. Just like a black hole that traps light inside,
the company traps ideas inside organizational boundaries. Stephen
Hawking showed that some light can sneak out of a black hole by
being created right at the boundary with the rest of the world;
common sense is left to do something similar in big companies.
So many people are needed in a company because making a product
increasingly requires a strategy group to decide what to do, electrical
engineers to design circuits that get programmed by computer scientists,
mechanical engineers to package the thing, industrial engineers
to figure out how to produce it, marketers to sell it, and finally
a legal team to protect everyone else from what they've just done.
It's exceedingly difficult for one person's vision to carry through
all that. Focus groups help companies figure out when they've done
something dumb, but they can't substitute for a personal vision
since people can't ask for things they can't conceive of.
Companies are trying to flatten their organizational hierarchies
and move more decision making out from the center by deploying personal
computing to help connect and enable employees. But the impact of
information technology will always be bounded if the means of production
are still locked away like the mainframes used to be. For companies
looking to foster innovation, for people looking to create rather
than just consume the things around them, it's not enough to stop
with a Web browser and an on-line catalog. Fabrication as well as
computing must come to the desktop.
The parallels between the promise and the problems of mainframes
and machine tools are too great to ignore. The personal fabricator
now looks to be as inevitable as the personal computer was a few
decades ago. Adding an extra dimension to a computer's output, from
2'D to 3'D, will open up a new dimension in how we live.
This revolutionary idea is really just the ultimate expression
of the initial impetus behind multimedia. Multimedia has come to
mean adding audio and video to a computer's output, but that's an
awfully narrow notion of what constitutes "media." The images and
motion don't have to be confined to a computer screen; they can
come out here where we are.
WHEN THINGS START TO THINK by Neil Gershenfeld. ©1998 by
Neil A. Gershenfeld. Reprinted by arrangement with Henry Holt and