RepRapOneDarwin

RepRap 1.0 "Darwin"

This page, and those to which it links, are a complete set of instructions for building the first release of the RepRap machine. These instructions are currently being built themselves; we will make a (big) announcement when they are complete, which should be quite soon.

Overview

RepRap 1.0 "Darwin" is a Fused Deposition Modelling (FDM) rapid prototyping machine that is capable of making the majority of its own component parts. It is available free under the GNU General Public Licence from this website to everyone.

As Darwin can copy itself, once you have one you can make others for your friends; or if they have one you can ask them to make one for you. Of course, you can also make as many as you want for yourself; the more you have, the faster you will be able to make other items.

RepRap etiquette asks that you use your machine to make the parts for at least two more Darwins for other people, as well as using it to make other items and more Darwins for yourself.

Above is a picture of the prototype. This will be updated to the released version shortly.

Darwin consists of a rectangular frame made from ground-steel rods and rapid-prototyped parts. A flat build platform (A) moves vertically in that frame, driven on screw threads (B) by a stepper motor (C). At the top of the frame there are two write heads (at D - not fitted in the picture) that move horizontally (driven by toothed belts and two more steppers - E) extruding a thin stream of molten plastic onto the build base. These build up the bottom layer of the objects to be made. The build base then moves one increment down, the second layer is extruded, and so on. There are two heads to allow a filler material to be laid down as well as the plastic. This filler is used to support overhanging parts of the objects being built, and is removed when the process is finished.

Specification

The RepRap 1.0 "Darwin" machine has the following characteristics:

• Working volume: adjustable, but nominally a 300 mm cube
• Working materials: Polycaprolactone and a filler/support
• Configuration: 3-axis cartesian drive using stepper motors
• Computer interface: RS232 (or USB -> RS232) at 19200 baud
• Two fixed material deposition heads, user exchangable
• Power supply needed: 8A at 12V
• Driving computer and operating system needed: Microsoft Windows, Linux, Unix, or Mac.

In what order do I do things?

The first thing to do is to get the software you will need working. It will run without a RepRap machine attached, and, as you start to build hardware, you can connect it up in a partly-finished state to your computer for testing.

After comissioning the software, you should start to build the six circuit boards for the electronics of the RepRap machine. The first (and simplest) controlls the communications, the next three control the X, Y, and Z axes of the machine, and the final two control the machine's write heads. Note that it says "start to build". With the exception of the communications board, the boards are all based on the PIC 16F628 microcontroller, and each board will work with just that chip and its power supply. So. You build the boards with just those components on plus an indicator LED each. Then you connect them all up (first individually, then together) via the communications board to your computer and check that everything is talking to everything else.

Then you put the driver electronics on each of the last five boards to connect to the motors, heaters, and sensors of the RepRap machine. Once more you can test without the rest of the machine - just plug in the stepper motors, for example, and the software will cause them to rotate on your workbench.

Finally, you build the hardware of the write heads and the cartesian robot that carries them. The order here is not so important, but probably a good way to progress is to make one write head, then make the robot, then get those working together. Finally you add the last head, and your RepRap machine is complete.

Software

These instructions assume that you will be working with the source code of the RepRap software. A little after the first release we will also be putting out binaries for people who do not wish to get into the details of the code.

Note that all the electronic information needed to buid a RepRap machine (that is, the circuit diagrams and mechanical designs, as well as the software for your main computer and the firmware for the RepRap machine's microcontrollers) is available from the RepRap Subversion repository at Sourceforge. In the sections below you will be instructed on how to download all this; not just the software for your main computer.

Follow the link that is appropriate to your computer platform:

• Downloading and installing the RepRap software under Microsoft Windows
• Downloading and installing the RepRap software under Linux or Unix
• Downloading and installing the RepRap software on a Mac

Commissioning and Testing

-- Main.AdrianBowyer - 30 Oct 2006