Wednesday, March 28, 2012

The Cube's Astonishing Accuracy

As a former science teacher, I have an abiding interest in microscopy.  So, I have many of them around my workspace.  Among my favorites are low power stereo microscopes because few things are as useful when trying to analyze the performance of mechanical things.

I pulled out a 10x-40x zoom stereo microscope to try to analyze a phenomenon called Z-Axis wobble common the RepRap style 3D printers.  The wobble is not bad in my particular RapMan.  But, it is something that I want to try to eliminate entirely if I can.

Here is what Z-Axis wobble looks like in a printed piece.

Z-Axis Wobble Evidence

Notice that the edge is scalloped.  This is because the bed that held the piece wobbled slightly as the screws that raise and lower the bed turned.  One or more of the threaded rods has a slight bend in it.

Now, compare the edge on the above image with this edge under the same microscope at 40x.  Notice that it is perfectly straight with no scalloped pattern.  This piece was printed on a Cube.  At 40x the depth of field is poor.  So, just focus on the edge.

No Evidence of Z-Axis Wobble

It is evidence that the Cube's platform is very, very stable and that the alignment is virtually perfect.  My impression, when I compare the two Cube pieces that I have with the pieces I print with the RapMan is that the Cube is noticeably finer right out of the box.  The RapMan can print this fine; but, only after I solve the threaded rod wobble issues.

This next image, with the microscope set to 10x, demonstrates even more starkly just how accurately and uniformly the Cube prints.

Very Smooth edges from the Cube

To me, the above image is remarkable.  Just look at the walls and the uniform slope that was delivered by the Cube's print control system.  The layers are even and the edges straight.  I doubt that any extrusion printer gets much better than this.  (The indentations are the brick design patterns.)

You can be sure that once I get my hands on one, I will be this particular about analyzing the output that I am able to achieve.  And, I have the perfect STL for testing.  In the meantime, I will be working with the RapMan printer in an attempt to bring it to this level of print accuracy and smoothness.  I am sure it can be achieved.  But, it will mean some serious thinking and work.

The Cube, however, should come right out of the box printing just as we see here.  And, I am REALLY looking forward to having that experience.

I'm truly looking forward to the arrival of the Cube.

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