Sunday, December 13, 2009

Better Luck

I spent the day trying to figure out what might be causing my hangs during printing. I started by trying to print a simple object - a leg for the Makerbot. Like the maker of these legs, my power supply had a fan pointing down, so I needed to raise the Makerbot up a bit to get air to the power supply. My legs are shorter than pattywac's; I didn't want the Makerbot raised up so high.

I ended up trying to print 13 legs, and 8 were usable. My first four prints went great, then things went downhill from there. The two conditions I tested were (1) turning off the fluorescent lights above the workbench, and (2) using a real Ethernet cable for the motherboard-to-extruder cable, rather then the home-crimped cable I had been using. I also routed the extruder cable away from the USB line and the Z stepper motor wires.

Results: with the lights off and the cable replaced, I had three of four prints go fine, with the fourth hanging at the 13 minute mark just as the piece finished printing. When I switched back to the old extruder cable, I got an immediate failure, then two successes. Turning on the fluorescent lights caused a couple of immediate failures, but things didn't improve after the cable and light were replaced. I wondered if something was overheating after several prints, but couldn't find any unusually hot pieces.

Still, I had pretty good luck today. Here's pictures of my Makerbot legs, sitting on their own. I modeled these in SketchUp Pro, then used Blender and skeinforge to convert them to a printable form.

I also tried printing building fronts as a model railroad project. The Makerbot did a great job with the curved lines of a Spanish Revival building, but the piece warped pretty quickly and eventually jammed the extruder nozzle. I even tried printing on a piece of 0.060 inch sheet styrene, but the extruded plastic only stuck a bit better than on the acrylic.

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