But, when printing at .125mm, it is apparent that one more issue may need to be tackled. And, that is probably some issue with some relatively minor Z-Axis wobble.
This video isn't all that great. The lighting is poor and the image is 640x480 because it was shot at 240fps so we could analyze the image in slow motion. I'll try to get better images of all four threaded rods this evening.
However, it is still useful enough to use right now.
What this video shows is that if there is any wobble at all, it is very. very minor. Yet, because we are working with such tiny tolerances, it is still noticeable in the printed output. As the following samples show.
Here is the test object. It's a tower having 3 equal sides. This shape was chosen because it results in 3 sharp edges. It was printed at .125mm resolution. And, as you can see, there are some visible ridges that probably indicate Z-Axis wobble.
|Test Tower - Crop showing ridges more clearly|
|Lighting to accentuate the ridges|
|Ridge pattern through a 20x microscope|
In subsequent posts, we'll explore some of the solutions that other 3D printer users have come up with to deal with this issue. But, before we leave this subject, it might be interesting to see what we are up against in dealing with the threads of the threaded rods.
|Threaded Rob Up Close and Personal|
While looking at the screw, it dawned on me that I should be able to place the test tower next to the threaded rob and take some macro images to see if the threads match the pattern of ridges. I'm guessing they do. :)