After tons of wrangling, I’m slowly getting closer to my goal of producing prints of an acceptable quality (and doing so consistently). I had printed Zaggo’s whistle, but due to extruder issues (as explained below), it was missing a few layers, causing the finished product to be fragile, but if you pressed the layers together hard enough, you can use it.
First there was the firmware issue. Going up to the 2.1 motherboard & 2.3 extruder combo did seem to stabilise my temperatures, but I did get heaps of empty payload errors. The biggest issue with that was that the extruder occassionally miss the command to start extruding and entire layers can go missing.
Initially I tried to reroute my cables to reduce the amount of electromagnetic interference that the extruder is subjected to. That didn’t help much.
Then I relocated the extruder controller to the side of the Cupcake. This didn’t seem to help at all. However, I now have a great view of the idler wheel as it turns.
On the Makerbot Operators group, some have suggested using a shielded ethernet cable to connect the extruder to the motherboard. Not having any handy, I wrapped the cable with aluminium tape and hooked the makeshift shielding to ground.
That seemed to help things, but usually after 10 or so minutes later, the bot starts to suffer from payload errors again.
So, in the end I bit the bullet and downgraded my firmware back to the 1.6⁄1.8 MB/EC combo. So far that’s given me decent quality prints.
The second issue that I’m currently facing is the fact that 3 of my Z-rods are slightly bent, causing the Z-stage to wobble and occasionally bind due to the heat from the heated build platform. I want to implement twotimes’ wobble arrester, but I don’t have a ready source for the rods and brushings. So for the moment, I’ve just added one to my most bent rod (adding it to all bent rods without the support rods caused the platform to wobble even worse it seems).
I’ve also disconnected all my endstops. They don’t seem to help me much. However saying that, I might just keep the minus endstops, so I can easily home the platform to -xyz and then have an my gcode startup move the platform 50mm +x and +y. This should reduce the need for me to manually position the platform before every build.
Also, I’ve decided to further test the boards that initially came with the kit. Yes, the ones that I believed were toast. Turns out, the stepper controllers were all in working order. Awesome! Not sure what I’d use them for yet… Maybe I might build a Mendel.
Looking forward, I have lots more to do next… Tuning Skeinforge (that’s a whole different bag of issues there), getting capacitors to add a suppression circuit to the extruder motor, getting a real shielded ethernet cable, and purchase some upgrades for the extruder from MakerGear.