LulzBot TAZ 6 Research and Development

The LulzBot TAZ 6 was officially released May 17, 2016. There have been many improvements to the quality, reliability, and performance. The electrical system experienced a massive overhaul compared to the TAZ 5.

The requirements for the electrical system in the TAZ 6 were the following:

  • Repeatably pass FCC and CE Class B radiated emissions as well as compliance with all other EMC standards; Introduce proper grounding, masking, shielding, filtering, and low impedance return path schemes (test report)
  • Significantly reduce the complexity of installation and assembly for the electronics and wiring; increase rate of production (manufacturing’s assembly documentation)
  • Introduce ESD protection and significant immunity to ESD events
  • Endstops are normally-closed to reduce EMI and to account for open-circuit failure modes

The EMC improvements made could only be done at the machine/wiring level due to the electronics having been designed in proprietary software. Several TAZ 6 machines were tested and passed Class B, significantly increasing our sample size. On the TAZ 5 which lacks proper grounding, shielding, and filtering the PCB transmits quasi-peaks which are ~7dB above the Class B limit.

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Figure 1: TAZ 6 Electrical Enclosure

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Figure 2: TAZ 5’s Crammed, Messy Electrical Enclosure

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Figure 3: LulzBot TAZ 6 (3 Meter) Test Setup for Radiated Emissions

Here is a video of a customer describing the EMC mitigation efforts:

The requirements for the firmware in the TAZ 6 were the following:

  • Base the release off of upstream Marlin 1.0.2
  • Add proper thermal runaway protection (commits: 94308924490ed460d8461a9f,  18f22da21171073934caae06,  106d928ad9bb)
  • New feature to allow the user to adjust the Z-Offset from the GLCD in real-time during the print and store the value to the MCU’s EEPROM when done (see Figure 4)
  • Eliminate several bugs present in upstream
  • Create pull requests and have them merged upstream for all significant bug fixes and improvements to the firmware (commits merged upstream)
  • Create a makefile which can be used to build the firmware
  • Create a manufacturing firmware checksum script and procedure
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Figure 4: Adjusting the Z-Offset From the GLCD with Animations

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