astronomy

RepRap

RepRap is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand RepRap rather than just read about it. In short: RepRap (a contraction of replicating rapid prototyper) is a project to develop low-cost 3D printers that can print most of their own components. As open designs, all of the designs produced by the project are released under a free software license, the GNU General Public License.

Key takeaways

RepRap belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect RepRap to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of RepRap from memory before moving on to harder problems.

Reference excerpt

RepRap (a contraction of replicating rapid prototyper) is a project to develop low-cost 3D printers that can print most of their own components. As open designs, all of the designs produced by the project are released under a free software license, the GNU General Public License. Due to the ability of these machines to make some of their own parts, authors envisioned the possibility of cheap RepRap units, enabling the manufacture of complex products without the need for extensive industrial infrastructure. They intended for the RepRap to demonstrate evolution in this process as well as for it to increase in number exponentially. A preliminary study claimed that using RepRaps to print common products results in economic savings. The RepRap project started in England in 2005 as a University of Bath initiative, but it is now made up of hundreds of collaborators worldwide.

History

RepRap was founded in 2005 by Adrian Bowyer, a Senior Lecturer in mechanical engineering at the University of Bath in England. Funding was obtained from the Engineering and Physical Sciences Research Council. On 13 September 2006, the RepRap 0.2 prototype printed the first part identical to its own, which was then substituted for the original part created by a commercial 3D printer. On 9 February 2008, RepRap 1.0 "Darwin" made at least one instance of over half its rapid-prototyped parts. On 14 April 2008, RepRap made an end-user item: a clamp to hold an iPod to the dashboard of a Ford Fiesta car. By September that year, at least 100 copies had been produced in various countries. On 29 May 2008, Darwin achieved self replication by making a complete copy of all its rapid-prototyped parts (which represent 48% of all the parts, excluding fasteners). A couple hours later the "child" machine had made its first part: a timing-belt tensioner. In April 2009, electronic circuit boards were produced automatically with a RepRap, using an automated control system and a swappable head system capable of printing both plastic and conductive solder. On 2 October 2009, the second generation design, called Mendel, printed its first part. Mendel's shape resembles a triangular prism rather than a cube. Mendel was completed in October 2009. On 27 January 2010, the Foresight Institute announced the "Kartik M. Gada Humanitarian Innovation Prize" for the design and construction of an improved RepRap. On 31 August 2010, the third generation design was named Huxley. It was a miniature of Mendel, with 30% of the original print volume. Within two years, RepRap and RepStrap building and use were widespread in the technology, gadget and engineering communities. In 2012, the first successful Delta design, Rostock, had a radically different design. The latest iterations used OpenBeams, wires (typically Dyneema or Spectra fishing lines) instead of belts, and so forth, which also represented some of the latest trends in RepRaps. In early January 2016, RepRapPro (short for "RepRap Professional", and one commercial arm of the RepRap project in the UK) announced that it would cease trading on 15 January 2016. The reason given was congestion of the market for low-cost 3D printers and the inability to expand in that market. RepRapPro China continues to operate.

Hardware As the project was designed by 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 allow any of their potential improvements to be reused by others. There are many RepRap printer designs including:

Prusa i3 Hangprinter RepRap Fisher RepRap Snappy RepRap Morgan RepRap Ormerod RepRap Darwin RepRap Mendel

Software

RepRap was conceived as a complete replication system rather than simply a piece of hardware. To this end the system includes computer-aided design (CAD) in the form of a 3D modeling system and computer-aided manufacturing (CAM) software and drivers that convert RepRap users' designs into a set of instructions to the RepRap to create physical objects. Initially, two CAM tool chains were developed for RepRap. The first, called "RepRap Host", was written in Java by lead RepRap developer Adrian Bowyer. The second, "Skeinforge", was written 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 and Cura were created. Recently, the Franklin firmware was created to allow RepRap printers to be used for other purposes such as milling and fluid handling. Free and open-source 3-D modeling programs like Blender, OpenSCAD, and FreeCAD are preferred in the RepRap community, but almost any CAD or 3D modeling program can be used with the RepRap, as long as it can produce STL files (Slic3r also supports .obj and .amf files). Thus, 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, Tinkercad, or SketchUp along with the libre software.

Replication materials

RepRaps print objects from ABS, Polylactic acid (PLA), Nylon (possibly not all extruders can), HDPE, TPE and similar thermoplastics. The mechanical properties of RepRap-printed PLA and ABS have been tested and are equivalent to the tensile strengths of parts made by proprietary printers. Unlike with most commercial machines, RepRap users are encouraged to experiment with materials and methods, and to publish their results. Methods for printing novel materials (such as ceramics) 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 can be useful for creating "fair trade filament". In addition, 3D printing products at the point of consumption has also been shown to be better for the environment. The RepRap project has identified polyvinyl alcohol (PVA) as a potentially suitable support material to complement its printing process, although massive overhangs can be made by extruding thin layers of the primary printing media as support (these 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:

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with RepRap

Start with the simplest possible case. Write down what RepRap claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to RepRap before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about RepRap ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of RepRap

In research: RepRap appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses RepRap in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: RepRap is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2005 establishments in England, Open-source hardware, RepRap project, so understanding it makes those chapters shorter.
In everyday life: Look for RepRap outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study RepRap in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what RepRap means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain RepRap out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is RepRap in simple terms?

Why does RepRap matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study RepRap?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on RepRap.