Lulzbot AO-100 problems and solutions

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The Lulzbot is currently inoperative.

There are currently two main problems (edit date 12/5/2016):

1. The new hot end has been installed. The E3Dv6 is wired in, but the wiring harness still needs to be cleaned up and tied back after the hot end has been tested and is working correctly. The firmware on the Arduino Mega has been updated for the new hot end, but there are still overtemp faults when the hot end reaches nominal temperature.

note: The current hot-end is the E3Dv6, configured for 3mm ABS, which has an "all-metal" design to allow printing at hotter temperatures. This provides access to newer types of filament, including PLA, Nylon, and flexible filament. As yet, these new filaments have not been tested in the LulzBot. It's worth noting that the LulzBot and the Series 1 now both share the same model hotend, but the LulzBot is configured for 3mm filament, while the Series 1 hotend is set up for 1.75mm filament. Connectors and wiring should* be the same on both machines. This "semi-redundant" design allows us to swap the hotends between the two printers if that's ever needed.

2. The software tool chain needs to be updated and simplified. The Lulzbot "runs" with the version of Repetier Host that exists on the linux computer it is connected to, in that the machine heats up, can extrude plastic, and will move in X, Y, and Z axes. The zero limit switches work, and we were able to print a small uncomplicated ABS print. The problem occurs when the hotend reaches a specific temperature, but the software throws an overtemp error, shutting down extrusion and causing the print to fail.

Steps for fixing the Lulzbot:

A) Solve the overtemp issue: determine whether it's being caused in firmware (thermistor settings?) or printer control software (printer settings/preferences/configuration?) and make the appropriate correction.

B) clean up and tie down all wiring, with special attention to two problem areas: the wires that are close to the hot end (they'll burn if they're allowed to get too close) and the cable harness where it connects to the frame near the arduino. Another wiring trouble spot has traditionally been the Y axis rear limit switch-- sometimes that cable gets in the way of the limit switch itself.

C) load and configure new versions of all printer control software in a clean OS environment: Repetier Host, Cura engine, Slic3er (and possibly consider KISSslicer as a legacy alternative.

D) load and configure a Raspberry Pi with OctoPrint for headless printer control. This will require users to slice their own prints on their laptops or other computer that has been configured with the LulzBot profile. The resulting LulzBot-ready gcode file is sent wirelessly to the printer, which operates in a "headless" mode.

E) Test, print, tweak, rinse, repeat. This reprap printer needs TLC to print properly. Users should understand that this is not a point-and-print machine, and it requires careful setup, alignment and monitoring to print reliably. Blue-green PET tape should be available to coat the two glass plates that are used for printing.

The Lulzbot is still a viable printer, capable of sturdy, quality prints, and is arguably worth upgrading. Additional retrofits that are planned include:

- full software toolchain renewal. The current linux machine (Tesla) is badly in need of a system wipe and full reload. When the machine is renewed, we will reload the latest versions of printer control software and provide how-to instructions.

- a new filament spooling arrangement. The Lulzbot is configured for 3mm filament. The current filament dispenser system is kludgy, and needs rework. Care should be taken to protect expensive filament from dust and moisture.

-we have many of the original parts and some new pieces for the old-style budaschnozzle hot end. Since this hot end will bolt easily to the existing extruder frame, we should consider repairing/refurbishing the original hot end, in the even that we ever need to swap out the E3Dv6. -

  • "should be the same" means trust, but verify.