Plate 5 From The Lathe Print
Unfortunately, the part in the lower left corner with 6 spokes and knobs on the ends did not slice correctly. I didn't have enough time yesterday morning to figure out why, but when I was able to start working again yesterday afternoon I installed NetFabb Studio http://www.netfabb.com/ and loaded the .stl file that SketchUp exported to identify the problem.
NetFabb looks like a very powerful piece of software, with capabilities for 3D part design, tool path creation, even 3D printer machine operation. At this time, I'm only using it to analyze .stl files for errors or holes.
NetFabb clearly identified the issues with the .stl file by highlighting them in burgundy. The screenshot below is of the part after I had made some changes to try and simplify it.
NetFabb Screenshot With Error Faces Highlighted
After more redesign is SketchUp, export, check in NetFabb, redesign in SketchUp, export, repeat, repeat, I finally got to a part that had no holes and would slice properly so that I could run the print. I learned a lot about design elements and SketchUp behaviors to avoid so that the .stl comes out solid and will slice properly, but it did take up a large chunk of my available 3D printing time yesterday.
Last night I finally was able to restart printing plate 5. I went upstairs while the bottom layer printed (since this can take 30 - 45 minutes with my settings and the size of these prints) and then came back down to turn on the fans around the machine for the remainder of the print. I reached over to turn on a small portable fan I have sitting near the printer on my work bench, and the instant that I flipped the switch, the printer froze!
The hot end was still heating (the LED connected to the hot end output was flashing on and off), and the bed was turning on and off, but none of the motors were moving at all. I tried to pause and resume the print in Pronterface, and after clicking on a few more movement commands with no response from the printer the software hung up. I was out of time anyway, so I killed the software and the power to the printer and went back upstairs to sleep.
This morning I was very, very happy to see that I was able to connect to the printer again, so I new the board wasn't totally fried. When I tried moving the motors, though, there was no response, and the software seemed to hang again. I was able to turn the hot end and HBP on and off, so I decided that there was something wrong in the code dealing with motor movement, and Pronterface was looking for a response from the board and not getting it and thus becoming unresponsive itself. I fired up the Arduino software, re-flashed Marlin onto the board, restarted Pronterface and bingo--all is again right with the world.
So now I'm printing plate 5 again, and have made it past the first layer and turning the fan on. I was very scared when I flipped the switch, I have to admit. I have no idea why turning on the fan messed with the board--it could have been a dirty spike in the power line, some strange EMI issue, or I could have bumped against the Arduino or RAMPS boards or cables and shorted something out.
I know enough about controls and electronics to go ahead and file this problem into the "avoid" rather than "solve" category. I hope to get a fan duct printed and installed at some point, and can then start using a much more focused, less powerful cooling fan that is turned on automatically by the software after the first layer. That would mean a much more predictable and less severe change in power requirements, and I hopefully will not see this type of failure again.
D
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