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A project log for Arcus-3D-C1 - Cable 3D printer

3D printable, Open Source Hardware, tripod kinematics, cable driven 3D printer

daren-schwenkeDaren Schwenke 10/21/2017 at 09:070 Comments

Wiring is done and working.  Cape is done and working.  

Well nothing caught on fire, it powers the machine up and shuts down, Machinekit starts and I can access the remote interface over wifi, but nothing will move.  I think I missed some estop logic as the normal pop of the steppers that accompanies starting up is missing.  I'm also pretty sure I didn't configure the tripod kinematics settings correctly as my starting Z position is 10,000 meters.  Now that is a big printer...

I hollowed out the bottom of the MDF enough that the BBGW, the wiring, and my cape all fit within the 3/4in thickness of the MDF.   Invisible controller.  :)

I could get away with totally enclosing the controller because my stepper drivers are out on my actual steppers, and the power mosfets I'm using are ridiculously over-rated.   I could run 10x as much power through them and they still wouldn't even get warm.  They are true logic level mosfets and are fully 'on' at 1.2v, so driving them to saturation at my PWM frequency directly from the 3.3v@4mA outputs of the Beaglebone easily works.

I took the extruder back off the push-rod.  Well technically I dropped the machine on it's side and it took itself off.  I think that was a bad idea (putting it there to begin with, dropping it worked out well).

It is super light without it, which should translate to fast/more accurate.  The end effector assembly without the hot-end was like 6 grams.  Adding the stepper just felt wrong.  It was kinda like buying a new Italian sports car with a carbon fibre composite body, and driving it around with the trunk full of lead.  

If I allow it to pivot hanging from a rail I can get virtually the same travel with a slightly longer tube and no added end effector mass.  

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