Dollo 3D Printable 3D Printer

[spegelius]

Finally got the damn thing printing. Took some effort, electronics was really the thing that caused some problems:
- as mentioned previously, fet was blown due to bed drawing too much juice. The bed resistance is 1.1 ohms, so @14V that is ~180W, with is bit too much for the fets that are rated for 10amps I think? Replaced the fet and tuned the bed max power from full power to ~115W (duty cycle from 255 to 160). I think there's bit room to go higer, but I'll see how this works. Bed seems to heats up reasonably fast.
- the electronics cover I printed was too small. The display connector cables were too high, so had to redesign the model 10cm taller and reprint it. Dollo3D.2 to the rescue again, new cover done and works fine
- while assembling the RAMPS to the new cover, some of the pins didn't go the the Arduino connectors and obviously caused problems with endstops and display. Common problem with RAMPS, you need to align the boards correctly and check that the pins aren't bent.
- while debugging this problem, I accidentally nudged stepper driver heatsink off and it caused a short on top of the driver. Result: z-axis is dead. Depression ensued. But resolved this problem by switching the E1 and Z driver pins in Marlin and now Z is driven by E1 socket driver. No big loss since won't be using E1 on this printer.

After I got all things sorted out, ran the selftests, XYZ, Z and first layer calibrations. Everything checks out, my frame is 100% correct if Prusa's algorithms are to bebelieved. Awesome.

Still, couple of things to sort out:
- Trinamics and the 0.9 degree motors doen't seem to like each other. Ugly coil whining, even though everything moves properly. Probably switch A4988 drivers in for now. Sad, was really hoping to have the Trinamics interpolation.
- X-endstop mounting screw head hits the left z-coupler at minimum z-height just enough to cause skipped steps. Need to file some stuff off of the screw head or the coupler.
- top frame isn't stable. Not a surprise since it's printed. Need to design clamps to tighten it. Wont affect print quality with small z-heights, but taller prints will suffer.

Classy Marvin scaled to 50%. Some PLA I purchased from Amazon. Seems to need bit more retraction and maybe cooling. Also first layer is a mess due to the z-skipping, lucky that print even stuck to the bed. I'll try Benchy tomorrow.