Darwin Upgrades

As mentioned in the last post, I have been making some mechanical changes to the Darwin in the hope of making it into a useful printer once again (I had previously butchered it to get the first child working as the extruder stepper on the Darwin had been previously borrowed from the Prusa parts for the Darwin so that I could print the plastic parts for the Prusa (1^st Child)).

1)     Removed X carriage completely drilled out  X ends (motor & idler) to 10mm from 8mm so that I could fit the induction hardened rails I had bought in error for the Prusa to the Darwin, I really need to print better X ends later as they were designed for 8mm rods so this is a fairly major bodge.

2)     Fitted 10mm linier bearings and new custom quick-fit X carriage to X rails (this is when I realized that the belt clamp positions were also different on the Darwin so I drilled 4 extra holes in the carriage to bodge another temporary solution.)

3)     Fitted 608 bearing to idler to replace the “creaking” (yes it was audibly creaking in use) resin cast idler wheel, this required a selection of different sized washers to effect a belt guide 2 of which I had to cut to fit the idler housing, hacksaw job.

4)     Fitted 8mm linier bearings to Y carriage rails and modeled out the holes in both the idler and motor carriage ends to fit using a sharp knife, I will need to come up with some way of securing the bearings to the carriage ends until I can print replacements.

5)     Fitted 608 bearing holder to the Y axis motor end rod (far end from the motor) this replaces a cast resin bush hopefully further reducing friction in the system, I could also print 2 more of these for the idler end of the Y carriage (will do these later)

6)     Reassembled the whole shebang and ran up to Darwin Pronterface setup I had last used several months ago to see if it would move, and yey it lives.

Now I just need to purchase another stepper motor and make a better hexnut nozzle and th darwin should be capable of printing once again.

I still have a whole host of mechanical issues with the Darwin (mentioned in previous posts) and I am planning to upgrade the electronics using  the Gen 3 plus solution (don't want to dump the Gen3 electronics just yet)

I should be able to rewire the extruder stepper so that it is directly connected to the gen 3 mobo, remove the RS-485 extruder controller completely (may try and repurpose this as a filabot extruder controller) and connect the hot end heater and temp probe directly to the gen3 mobo, this should allow me to load the sprinter/marlin (sailfish?) firmware and that will be a major upgrade to the Darwin’s capabilities.

I am also planning to remove two of  the Z axis corners and run the print bed similar to the Prusa (just with 1 motor and a timing belt, rather than 2 motors) this should significantly decrease the friction in the Z axis and I am hoping improving reliability.

I may also add 608 bearings to these two remaining Z corners to improve the mechanical stability and accuracy of the Z axis.