The RepRap project started as a British initiative to develop a 3D printer that
can print most of its own components and be a low-cost 3D printer, but it is now
made up of hundreds of collaborators world wide. RepRap uses an additive
manufacturing technique called fused filament fabrication to lay down
material in layers; a plastic filament or metal wire is unwound from a coil and
supplies material to produce a part. The project calls it Fused Filament
Fabrication to avoid trademark issues with the "fused deposition modeling"
term. As an open design, all of the designs
produced by the project are released under a free software license, the GNU
General Public License. Due to the self-replicating ability of
the machine, authors envision the possibility to cheaply distribute RepRap
units to people and communities, enabling them to create complex products
without the need for expensive industrial infrastructure including
scientific equipment. They intend for the RepRap to demonstrate evolution in
this process as well as for it to increase in number exponentially. A
preliminary study has already shown that using RepRaps to print common products
results in economic savings, which justifies the investment in a RepRap.
History RepRap was founded in 2005 by Dr Adrian
Bowyer, a Senior Lecturer in mechanical engineering at the University of Bath in
the United Kingdom. The first four official 3D printing
machines RepRap project were: "Darwin", released in March 2007, "Mendel",
released in October 2009, "Prusa Mendel" and "Huxley" released in 2010, although
hundreds of variations exist. The core developers have named each after famous
evolutionary biologists, as "the point of RepRap is replication and evolution",
however, other variants are often named after individual designers or names they
prefer. 23 March 2005
The RepRap blog is started. Summer 2005
Funding for initial development at the University of Bath is obtained from the
UK's Engineering and Physical Sciences Research Council
13 September 2006 The RepRap 0.2 prototype successfully
prints the first part of itself, which is subsequently used to replace an
identical part originally created by a commercial 3D printer.
9 February 2008 RepRap 1.0 "Darwin" successfully makes
at least one instance of over half its total rapid-prototyped parts.
14 April 2008 Possibly the first end-user item is made
by a RepRap: a clamp to hold an iPod securely to the dashboard of a Ford
Fiesta. 29 May 2008
Within a few minutes of being assembled, the first completed "child" machine
makes the first part for a "grandchild" at the University of Bath, UK.
23 September 2008 It is reported that at least 100 copies
have been produced in various countries. The exact number of RepRaps in
circulation at that time is unknown. 30 November 2008
First documented "in the wild" replication occurs. Replication is
completed by Wade Bortz, the first user outside of the developers' team to
produce a complete set for another person.
20 April 2009 Announcement of first electronic circuit
boards produced automatically with a RepRap, using an automated control
system and a swappable head system capable of printing both plastic and
conductive solder. Part is later integrated into the RepRap that made it.
2 October 2009 The second generation design, called
"Mendel", prints its first part. The Mendel's shape resembles a triangular
prism rather than a cube. 13 October 2009
RepRap 2.0 "Mendel" is completed. 27 January 2010
The Foresight Institute announces the "Kartik M. Gada Humanitarian Innovation
Prize" for the design and construction of an improved RepRap. There are two
prizes, one of US$20,000, and another of $80,000. The administration of the prize
is later transferred to Humanity+. 31 August 2010
The third generation design, "Huxley", is officially named. Development is
based on a miniaturized version of the Mendel hardware with 30% of the original
print volume. First half 2012
RepRap and RepStrap building and usage are widespread within the tech, gadget,
and engineering communities. RepRaps or commercial derivatives have been
featured in many mainstream media sources, and are on the permanent watch
lists of such tech media as Wired and some influential
engineering-professionals' news media. Late summer/fall 2012
There has been much focus on smaller startup companies selling derivatives,
kits, and assembled systems, and R & D results into new related processes for
3D Printing at orders-of-magnitude-lower prices than current industrial offers.
In terms of RepRap research, the most notable result is perhaps the first
successful Delta design, Rostock, which is maturing slowly and has an initial
working solution for experimentation by self-sourcing builders of some
experience. While the Rostock is still in an experimental stage with major
revisions almost monthly, it is also near the state of the art, and a
radically different design. The latest iterations use OpenBeams, wires instead
of belts, and so forth, which also represents some of the latest trends in
RepRaps. 2013
Hobby friendly machines have been made to allow hobbyists and small companies
to produce their own filament for 3D printing, thus bringing down
manufacturing costs and allowing for small-scale recycling and experimenting
with different plastics and materials. Hardware
As the project was designed by Adrian Bowyer to encourage evolution, many
variations have been created. As an open source project designers are free to
make modifications and substitutions, but they must reshare their
improvements. However, RepRap 3D printers generally consist of a
thermoplastic extruder mounted on a computer-controlled Cartesian XYZ
platform. The platform is built from steel rods and studding connected by
printed plastic parts. All three axes are driven by stepper motors, in X and Y
via a timing belt and in Z by a leadscrew.
At the heart of the RepRap is the thermoplastic extruder. Early extruders
for the RepRap used a geared DC motor driving a screw pressed tightly against
plastic filament feedstock, forcing it past a heated melting chamber and
through a narrow extrusion nozzle. However, due to their large inertia, DC
motors cannot quickly start or stop, and are therefore difficult to control with
precision. Therefore, more recent extruders use stepper motors to drive
the filament, pinching the filament between a splined or knurled shaft and a
ball bearing. RepRap's electronics are based on the
popular open-source Arduino platform, with additional boards for controlling
stepper motors. The current version electronics use an Arduino-derived
Sanguino motherboard, and an additional, customized Arduino board for the
extruder controller. This architecture allows expansion to additional
extruders, each with their own extruder controller.
= Major revisions= The first publicly released RepRap,
Darwin, has an XY gantry mounted above a moving Z-axis print bed. Darwin's Z axis
is constrained by a leadscrew at each corner, all linked together by timing
belts to turn in unison. Electronics are mounted on the steel supports of its
cuboid exterior, and on a second platform at the base. In an effort to
minimize the number of non-printed components, Darwin uses printed sliding
contact bearings on all of its axes. Mendel replaced Darwin's sliding
bearings with ball bearings, using an exactly constrained design that
minimizes friction and tolerates misalignment. It also rearranged the
axes, so that the bed slides in the horizontal Y direction, while the
extruder moves up and down and in the X direction. This makes Mendel less
top-heavy and more compact than Darwin, while also removing the overconstraint
of Darwin's four Z axis leadscrews. The build envelope for Mendel is 200 mm ×
200 mm × 140 mm or 8" × 8" × 5.5". One of the more popular RepRap variants
from 2013 and beyond is the Rostock delta-style RepRap.
Software RepRap has been conceived as a complete
replication system rather than simply a piece of hardware. To this end the
system includes computer-aided design in the form of a 3D modeling system and
computer-aided manufacturing software and drivers that convert RepRap users'
designs into a set of instructions to the RepRap hardware that turns them into
physical objects. Initially two different CAM toolchains
had been developed for the RepRap. The first, simply titled "RepRap Host", was
written in Java by lead RepRap developer Adrian Bowyer. The second, "Skeinforge",
was written independently by Enrique Perez. Both are complete systems for
translating 3D computer models into G-code, the machine language that
commands the printer. Later, other programs like slic3r,
pronterface, Cura, repetier host were created. The closed source KISSlicer
also seems popular. Virtually any CAD or 3D modeling program
can be used with the RepRap, as long as it is capable of producing STL
files.(slic3r also supports .obj and .amf files) Content creators make use of
any tools they are familiar with, whether they are commercial CAD
programs, such as SolidWorks and Autodesk AutoCAD, Autodesk Inventor,
Autodesk 123D Design, Tinkercad, or open-source 3D modeling programs like
Blender, OpenSCAD, and FreeCAD. Replication materials
RepRaps print objects from ABS, Polylactic acid, Nylon, HDPE, TPE and
similar thermoplastics. Polylactic acid has the engineering
advantages of high stiffness, minimal warping, and an attractive translucent
colour. It is also biodegradable and plant-derived.
The mechanical properties of RepRap printed PLA and ABS have been tested and
have been shown to be equivalent to the tensile strengths of proprietary
printers. Unlike in most commercial machines,
RepRap users are encouraged to experiment with printing new materials
and methods, and to publish their results. Methods for printing novel
materials have been developed this way. In addition, several RecycleBots have
been designed and fabricated to convert waste plastic, such as shampoo
containers and milk jugs, into inexpensive RepRap filament. There is
some evidence that using this approach of distributed recycling is better for
the environment and be useful for creating "fair trade filament".
In addition, 3D printing products themselves at the point of consumption
by the consumer has also been shown to be better for the environment.
The RepRap project has identified polyvinyl alcohol as a potentially
suitable support material to complement its printing process, although massive
overhangs can be made with using thin layers of the primary printing media as
support, which are mechanically removed afterwards.
Printing electronics is a major goal of the RepRap project so that it can print
its own circuit boards. Several methods have been proposed:
Wood's metal or Field's metal: low-melting point metal alloys to
incorporate electrical circuits into the part as it is being formed.
Silver/carbon-filled polymers: commonly used for repairs to circuit boards and
are being contemplated for use for electrically conductive traces.
Direct extrusion of solder Conductive wires: can be laid into a
part from a spool during the printing process
Using a MIG welder as a print head a RepRap deltabot stage can be used to
print metals like steel. The RepRap concept can also be applied
to a milling machine. Construction
Other 3D printer designs and parts constructed by other means may be used
to "bootstrap" the RepRap process by building RepRap parts. Many such
machines are based on RepRap designs and use RepRap electronics. These are
generally known by the name RepStrap by the RepRap community. A RepStrap is any
open-hardware rapid-prototyping machine that makes RepRap parts and is itself
made by fabrication processes which aren't under the RepRap umbrella yet.
Some RepStrap designs are similar to Darwin or Mendel, but they have been
modified to be made from laser cut sheets or milled parts. Others, such as
the Makerbot, share some design elements with the RepRap, but with a completely
reconfigured mechanical structure. Although the aim of the project is for
RepRap to be able to autonomously construct many of its own mechanical
components in the near future using fairly low-level resources, several
components such as sensors, stepper motors, or microcontrollers are
currently non-replicable using the RepRap's 3D printing technology and
therefore have to be produced independently of the RepRap
self-replicating process. The goal is to asymptotically approach 100% replication
over a series of evolutionary generations. As one example, from the
onset of the project, the RepRap team has explored a variety of approaches to
integrating electrically-conductive media into the product. The future
success of this initiative should open the door to the inclusion of connective
wiring, printed circuit boards, and possibly even motors in RepRapped
products. Variations in the nature of the extruded, electrically-conductive
media could produce electrical components with different functions from
pure conductive traces, not unlike what was done in the sprayed-circuit process
of the 1940s named Electronic Circuit Making Equipment, described in the
article on its designer, John Sargrove. Printed electronics is a related
approach. Another non-replicable component is the threaded rods for the
linear motions. A current research area is in using replicated Sarrus linkages
to replace them. Project members
The "Core team" of the project has included:
Dr. Adrian Bowyer, Former Senior Lecturer, Mechanical Engineering
Department, University of Bath Michael S. Hart, creator of Project
Gutenberg, Illinois Dr. Forrest Higgs, Brosis Innovations,
Inc., California Rhys Jones, postgraduate, Mechanical
Engineering Department, University of Bath
James Low, undergraduate, Mechanical Engineering Department, University of
Bath Sebastien Bailard, Ontario
Simon McAuliffe, New Zealand Vik Olliver, Diamond Age Solutions,
Ltd., New Zealand Ed Sells, postgraduate, Mechanical
Engineering Department, University of Bath
Zach Smith, United States Erik de Bruijn, The Netherlands
Josef Průša, Czech Republic Project sponsors include:
Reece Arnott The Bath University Innovative
Manufacturing Research Centre The Engineering and Physical Sciences
Research Council The Fluorocarbon Co. Ltd
Michael Ingram Lukasz Kaiser
The Nuffield Foundation Carl Witty
Goals The stated goal of the RepRap project is
to produce a pure self-replicating device not for its own sake, but rather
to put in the hands of individuals anywhere on the planet, for a minimal
outlay of capital, a desktop manufacturing system that would enable
the individual to manufacture many of the artifacts used in everyday life.
From a theoretical viewpoint, the project is attempting to prove the
hypothesis that "Rapid prototyping and direct writing technologies are
sufficiently versatile to allow them to be used to make a von Neumann Universal
Constructor". The self-replicating nature of RepRap
could also facilitate its viral dissemination and may well facilitate a
major paradigm shift in the design and manufacture of consumer products from
one of factory production of patented products to one of personal production
of un-patented products with open specifications. Opening up product
design and manufacturing capabilities to the individual should greatly reduce the
cycle time for improvements to products and support a far larger diversity of
niche products than the factory production run size can support.
Education applications RepRap technology has great potential in
educational applications. RepRaps have already been used for an educational
mobile robotics platform. Some authors have claimed that RepRaps offer an
unprecedented "revolution" in STEM education. The evidence for such claims
comes from both the low cost ability for rapid prototyping in the classroom by
students, but also the fabrication of low-cost high-quality scientific
equipment from open hardware designs forming open-source labs.
See also Notes
References External links
Official website Video of a talk by Adrian Bowyer on
RepRap