Recent prints

After switching to a J-head nozzle, and making a few other adjustments, the machine is extruding more consistently. Most of the parts shown in the photographs below were printed at a layer height of approximately 250 micron - some slightly lower. The prints of Sapphos head were an experiment in high-resolution printing, with layer heights of 85 micron in one case and 55 micron in another. When I tried to go below this there were artifacts in the prints.

Notice that the resolution in the Z direction is largely independent of that in the X-Y plane. The resolution in the latter is determined mainly by the diameter of the orifice in the hot-end you are using, while the latter can be set almost arbitrarily.

Dimensional accuracy

The dimensional accuracy is acceptable for many purposes, but could probably be better. Consider the following object, and compare the dimensions in the CAD model with those on the printed part.

The value indicated on the digital calipers is slightly misleading, as there is actually a slight variation in width from one layer to another. I'm not quite sure what the reason for this is yet.