Upgrade/Repair Ender 3

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My 3D printer's power supply failed and made the mainboard unstable, started blowing breaker (I think false arc faults from EMI) so both needed to be replaced. Since I was taking the machine apart and making changes I decided to overhaul a few things.

>>View Model<<

Project Punch List:

Essential:

  1. Replaced mainboard and power supply
  2. Modelled a bigger chassis for new components and power supply
  3. Grounded main frame, X axis & gantry, and heatbed
  4. Replaced poorly designed dual extruder - the steel teeth dug into the aluminum frame(looked like it could fail soon)

Upgrades:

  1. Installed Dual Z axis and switched to 2mm pitch threaded rods
  2. Installed power metering module - measures voltage/frequency/current/wattage and total kWh
  3. Installed new all metal hotend that allows >300C rated thermocouple so eventually printing carbon fiber nylon and other high temp filaments
  4. Installed higher wattage hotend heating cartridge
  5. Installed 24 volt cable to supply power to filament dryer

Bottlenecks:

Some problems came up with dual Z axis and thread pitch change.

  1. Adjusting for the new thread pitch was easy - just increased the steps to 1600steps/mm and print and measure calibration cube then adjusted based on findings
  2. Had issues with binding/grinding/squealing from the threaded rods binding up in their mounts which was resolved with the following (order of importance)
    1. Increased the Z motor amperage from the default to ~1 amp - this was the first thing I figured which restored my hope in the project. This increased binding but fixed the issue with only one Z stepper turning and the other partially
    2. Loosened the bolts holding threaded nut to the X axis which allowed the threaded rod some up/down play on the y axis. Largely eliminated binding
    3. Lots of dry lube. Decreased squealing
    4. Installed flexible shaft couplings to the rods. Decreased the chance of binding
When replacing the heating cartridge with a higher wattage I ran PID tuning then reconfigured with those results.

The modeling took about 6 hours to do but I procrastinated. Once I moved from having a 2D sketch to having a 3D outline of the bottom I knocked out the rest of the project of the next couple of weeks - modeling and test printing.

Both the Dual Z and the slower pitch threaded rod greatly improved my tall prints. I think this is mostly because of the increased Z precision from the 1600 steps per mm from the 400 I had previously.