Sunday, September 9, 2012

Printing A Lathe - First Part

The first print of the lathe parts during the night was successful.  The image below is a screenshot of SketchUp showing the imported geometry from the complete lathe .stl file from  http://www.thingiverse.com/thing:12472


The part that I decided to print first is highlighted in blue above, and shown in its own file below.


I exported the .stl from this single file and sliced it using Slic3r, using 0.7 as an infill factor, 3 perimeters and 3 solid layers, and it took my printer right at 4 hours to make the piece shown below.


My MendelMax 1.5 is performing well, but I am starting to see an issue in the last few prints that I had not seen before.  There appears to be a slight gap between traces of plastic on the same layer, and the infill even on the outer "solid" layers appears to be thin.  See the next two images of the print shown above.


These top layers should be solid and there should be no open holes, especially not as large as the ones that appeared here on the inside of the print:


Except for the hole in the middle with the nut capture geometry and the two holes spaced out at 90 degrees from the center, the surfaces shown above should be completely solid.  I even saw some delamination of some of the bottom layer traces:


Zoomed in here:


I definitely have seen signs that my PLA has absorbed too much moisture--blobbing, small puffs of smoke from the water buildup, even what looks like some water oozing out of the nozzle when the machine is warming up and I feed filament through to make sure it's primed.  It has been open sitting on a spool holder on top of my machine for right at three weeks now.  I think moisture absorption is causing the traces to be undersized or varying in size.  

For now I have fudged the filament diameter setting lower to force a little more material out, and will wait until I get my next batch of PLA in before I do any more investigation.  At the rate I'm burning through filament on this lathe project, the next spool of PLA will need to be here about another day from now anyway . . . :)

D  


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