For some time I have wanted to design my own printer. Partly so that it will be able to do what I want and secondly for the challenge. Obviously it is much easier these days given the number of designs out there. For my design I had several things that it must be capable of:

1) More than one extruder
2) Use as many of the same vitamins as possible
3) Be simple to construct with the minimum of tools
4) Use as many printable parts as possible
5) No Bowden tube

Now I am not above thinking that some of those ideals may have to be altered but so far, in the planning stage, I think I have hit all of them.

So taking each point in turn:

It currently has space for two extruders – I wanted at least two so that I can leverage Slic3r’s ability to have one extruder for the shell and another for infill. That way I can use Faberdashery’s great colours for the shell and a cheap bulk black or white for the infill. The current extruder/hotend design means that only around 50mm of Y axis is lost when using both extruders.

Each axis uses the same linear bearings, all the printed framework attaches using M4 bolts, bearings used in the belt idlers as used in the extruders and so on. I want to not have a BoM as long as your arm and be able to order from only a few places. Personally I think this is the ideal that will change as the build progresses.

The tools that I think will be needed are screwdrivers, allen (hex) key, wire cutters and a wrench. Again this will probably change as the build progresses.

All structural support parts are printed, only the obvious items aren’t (frame, smooth rods, threaded rod etc).

No Bowden tube for the extruders are used. The current design is for a direct drive extruder – the hobbed bolt is directly attached to the stepper – which reduces the size of the extruder and the need for large printed gears. The actual reason for no Bowden tubes is purely down to I want to print flex-polyester and I haven’t been able to get it to work through my current Huxley’s Bowden. I am considering having one direct drive extruder and maybe replace the second with a Bowden system to reduce carriage weight. This would also allow for another hotend to be potentially added.

Mechanical test video is available: http://youtu.be/PYqmosbdoSI

Build log on my blog: http://fabing3d.wordpress.com/category/dsf/