Wednesday, March 11, 2015

Calibrate, Calibrate, Calibrate...and then Calibrate!

Is There Such a Thing as an "Out of the Box Printer"?

I am assuming that when you buy a 3D printer that advertises an out of the box experience that you don't need to calibrate said printer?  I wonder.   I know of someone who got a demo high end printer, one of the resin based units capable of super high precision, and they never got it to work.  If a printer in the 10-20K pounds can not work then I would be interested to know if paying a couple thousand quid really does get you a true out of the box experience with all the details and bridging and dimensional accuracy working at one?


Expect some Calibration to be Needed

In any case, I did not expect this with the Wanhao and so have not been surprised to be spending quite a bit of time perfecting its output.  I am also looking for a pretty high standard and have some challenging requirements that entail a lot of bridges.  Bridges being what really challenges a printer like either of mine.

In fairness to the printer most of the time that I have spent frustrated has been with Simplify 3D which continues to battle me for supremacy.   Once I got the software talking to the hardware I was able to make some pretty much right out of the box prints that were of pretty darn good quality.  In fact I have a little test print that I have been doing that came out of the box looking about as good as the one from my Prusa I3 and was printed in almost half the time.


Calibration for General Quality and Bridging

At the moment I think that the printer is pretty well calibrated for general quality (as opposed to dimensional accuracy which is next).    The major changes that I made to the defaults given by Simplify 3D were:
  1. Set ABS to 210C and PLA to 185C as the lowest temperatures where filament would still be extruded reliably (I can probably go a little lower on my both temperatures but I am concerned that Sailfish undershoots so badly on downward changes....and....I have been having trouble getting Simplify 3D to handle multiple changes).   If I were able to go lower the need for the fan is postponed.
  2. Adjusted bridge parameters to 
    1. Extrude less plastic (50%) 
    2. Move much more slowly (10%) than default.
    3. Increased perimeters rather than gap fill for thin walls (better bridges on those thin walls).
  3. Increased the minimum time on a layer to 20 seconds.
  4. Added a fan highly directed at the print area (more on this in a later post).
I am pretty happy with my output quality.   Particularily with the ABS side.   This is somewhat ironic as on my Prusa I3 the reverse was true though a lot of that had to do with the Prusa I3 being an open printer and just not (IMHO) setup for ABS temperatures.

My next calibration challenge will tackle dimensional accuracy.   The printer currently fails even the easiest dimensional accuracy test so some work lies ahead.

Images of Selected Calibration Prints

This was printed right after I unpacked the printer.   The only adjustments that were needed were some slightly lowered print temperatures given this is PLA and the temps suggested by Simplify 3D seemed way to high.

Bridge testing.   The two on the left are while calibration was in process and the one on the right is where things have been left for the moment.


This is a bridging torture test and from the top and side it looks ok but is still a bit of a stringy mess from below.   I am thinking my next generation fan may help here.   More about fans in a later post.

This is a post calibration version of my test print.   I tossed the first one that I did for some reason.  I am pretty happy with the quality though the tiny little droop on the bridge is really not needed and the top of the circle cutout is also a little messy.   Again, fan improvements are calling out.

These prints illustrate the difference that a fan can make as well as the difference between 0.2 and 0.1 layer heights.   Marvin on the left is 0.2 layer height without a fan.  His neighbor in the center is the same layer height and has the fan running.  Marvin on the left is 0.1 layer height and also had the fan running.

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