I’ve been fascinated for a few years now with cheap 3D printers like the RepRap and MakerBot Replicator. One of the issues with these printers is that they can only create relatively small items. I believe that a relatively small change to how they are constructed could help with that.

The models listed above are constructed in the shape of cubes. The side of the items they can make is constrained by the size of the cube, as well as the degree of motion of the extruder head.

The following crude illustration shows what I mean. The maximum proportions of the item are going to be less than the X/Y/Z lengths of the printer cube:

If we were to remove one of the vertices, one of the constraints goes away:

The X-axis can now extend indefinitely:

What would be required is some way to grip and move the item as it is being printed, so that the already printed parts can be extended outside of the printing “area”. There are several ways to do this, including putting wheels under the printer itself, so it can move, and then clamping the item to a table. In addition, the remaining structure of the printer would need to be reinforced as a result of the missing column.

In this way items of fairly large size can be printed – possibly up to several feet squared. That could allow people to print body panels for a DIY automobile, for instance.

Unfortunately this doesn’t solve the issue of the high cost of plastic for the extruder!