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Rapman V 3.1. assembled at TECFA (picture taken just after assembly in January 2010)
RapMan was one of the first commercial kits of the RepRap 3D printer sold from 2009. RepRap is short for Replicating Rapid-prototyper since it was developed in a research project on self-replicating machines. TECFA bought its kit in november 2009 and we assembled it in the end of January 2010 (File:Invoice490DanielSchneider.pdf) As of 2019, it is displayed as museum piece in our location at Uni Pignon, Geneva.
See also:
The fab lab article for a wider perspective with respect to this kind of technology.
This 3D printer builds the parts up in layers of plastic with the help of a custom-made Thermoplast Extruder. The machine takes a 3mm diameter filament of a polymer, forces it down a heated barrel, and then extrudes it as a melt out of a fine nozzle. The resulting thin stream is laid down in layers to form the parts that RepRap makes. The extruder should work up to a temperature of 260 degrees Celsius. It works with various polymers like ABS (Lego-like plastic) and polylactic acid. The extruder can move left/right (X axis) and forward/backward (Y axis) The printed object sits on a platform that will move down (Z axis)
Printing instructions are written in a language called G-code. A user will copy a g-code file to an SD card. This card is then inserted into a slot of the RapMan board for printing.
Assembly of V3.1 RapMan takes at least three full days. It can be done by any person who has good reading skills, patience and some "gift" for assembly. Bits from Bytes did produce a mostly very good set of documentation.
It is very important to understand what you are going to build. E.g. it's a good idea to look at a video like thisfilm made for BECTA.
You also should understand more or less the following picture:
Meshes (different objects) may be combined / merged. You can do this with the free Netfabb Studio and Meshlab programs. Creation of simple mashups with Netfabb and Meshlab is explained in the Meshlab for RapMan tutorial article.
An easier solution is to acquire the Netfabb Professional. It can export several objects (originally from *.STL files and other sources) as a single .STL file.
(3) Create and fix the .STL
In most cases, your 3D general purpose modeling or CAD program can't directly produce g-code. You first must export the
model to .STL (or another format like *.PlY).
You then may need to fix your .STL model, i.e. first make sure it has the right size and the right position. But there may be more tricky issues, like repairing "holes" (use Netfabb for this)
The coordinate system of the RapMan puts the origin in the middle. To manipulate size and coordinates, there are some options:
Use skeinforge: turn on multiply plugin in skeinforge, setting the matrix to 1x1 or another value
Use Netfabb for more simple resizing and moving operations (that's what I use)
Get a model from Thingyverse (or another repository for 3D printable objects. Make sure to select one that has a "rapman" or "reprap" tag on it. A fun thing to do would be printing all the Beco blocks. Since they are all similar, you can vary printing parameters and learn about calibration of small simple object printing without having to look at the same object...
You likely will find almost directly usable .STL files, but you may have to align them to x/y/z = 0. You also may find various source formats produced with various 3D modelers.
Import to skeinforge or netfabb and generate g-code. In both cases, make sure that it sits in the right position.
Then verify the g-code manually
Build an easy model with an easy 3D modeler
Build a model with Google sketchup
Export to Collada .DAE
Import to Meshlab and save as .STL
Import to NetFabb and repair, then save as .STL again
At some point you really must understand the interaction of relationship between Head speed (how fast the extruder moves on the X/Y axis) and extrusion Rate (RPM, how much plastic comes out) and how they impact Layer thickness.
Always extrude 1/2 m of filament before printing. Also play with temperatures. E.g. 247 for ABS may be too much.
Make sure that your .STL files have the x/y/z values set right. Minimal z value = 0. The middle of the object should roughly sit on x=0 and y=0. Get the free Netfabb Studio to achieve this. Also use this software to clean up bad .STL files.
Then move on and try to figure out how to calibrate for different parts of objects and different kinds of objects. As we mentioned before, Skeinforge documentation is not easy to understand (in the absence of better you can wade through the forums or read this or buy the for RapMan Basic software.
Home print head with the menu in the board and switch it off/on after each printing (in particular if you print high objects or if you manually moved the extruder).
Do not leave your printer unattended ! Make sure that filament wheel turns smoothly and that the pressure wheels are tight: Tighten quite a lot (without forcing), then untighten when the motor stops, i.e. you hear a loud clicking.
Print some spare parts once you figured out how to correctly print ABS (have to check it they correspond to V3.1, I thing that having a second extruder gear would quite smart.
Moving on:
Explore other RapMan-related articles in the category RapMan. You may follow the order suggested in the wiki book.
RepRap, a British project, is short for Replicating Rapid-prototyper. This 3D printer builds the parts up in layers of plastics. It can be assembled from parts bought in various places. There exist many commercial designs derived from various RepRap versions, see 3D printing.
See Meshlab for RapMan tutorial. Meshlab is the open source, portable, and extensible system for the processing and editing of unstructured 3D triangular meshes.
This article is also available under the following copyright: Contents of this page (including pictures) are also available under GNU General Public licence and Creative commons Attribution-Share Alike 3.0. E.g. companies that sells RepRap kits can take the contents ...